WET 110 Combined

_______________ is the process of changing the organic matter contained within sludge into gasses and liquids and a more stable solid form. These changes take place as microorganisms feed on sludges in either anaerobic (more common) or aerobic digesters.

Sludge digestion Correct

Raw Sewage Characteristics: Component Concentration Range Typical Concentration

Total Suspended Solids, TSS 155 - 330 mg/L 250 mg/L

In general, preliminary treatment begins with screening. Screens remove large solids such as rags, sticks, plastics and similar materials from the wastewater.

True

____________ is a condition produced by the activity of anaerobic bacteria. If severe, the wastewater produces hydrogen sulfide, turns black, gives off foul odors, contains little or no dissolved oxygen, and leaves the wastewater with a high oxygen demand.

septic

Settled activated sludge is generally ______ than raw sludge.

thinner

What percentage of BOD after about 2 hours in a clarifier?

30%

"Fixed Film Systems

Fixed film systems grow microorganisms on substrates such as rocks, sand or plastic. The wastewater is spread over the substrate, allowing the wastewater to flow past the film of microorganisms fixed to the substrate. As organic matter and nutrients are absorbed from the wastewater, the film of microorganisms grows and thickens. Trickling filters, rotating biological contactors, and sand filters are examples of fixed film systems.

Wastewater or other liquid - raw (untreated) or partially treated - flowing INTO a reservoir, basin, treatment process, or treatment plant.

Influent

Lagoon Systems

Lagoon systems are shallow basins which hold the waste-water for several months to allow for the natural degradation of sewage. These systems take advantage of natural aeration and microorganisms in the wastewater to renovate sewage."

________ treatment is the removal of metal, rocks, rags, sand, eggshells, and similar materials, which may hinder the operation of a treatment plant. _________ treatment is accomplished by using equipment such as racks, bar screens, comminutors, and grit removal systems. _____________ treatment occurs in the "headworks".

Preliminary

The seepage (leaking) of groundwater into a sewer system to include seepage through service connections is infiltration (its infiltrating the system). Infiltration and Inflow are often used in conjunction as I and I.

T

____________ is the heavy, coarse mixture of grit and organic material carried by wastewater. _______________ is also called GRIT.

The correct answer is: Detritus.

A major characteristic of a metal-plating waste is high

d. Toxicity

What are the (4) most popular forms of secondary treatment?

*trickling filters' *rotating biological contractors *variations of the conventional activated sludge process *Lagoons

Clarifier sludge percentage:

--<6%, and specific gravity 1.03.

Which of the following would be acceptable primary clarifier concentrations for dissolved oxygen (mg/L) after collecting a sample in the effleunt launder?

0-2

Fine screens spacing?

0.06-.25 inches

Experiments show that 0.2mm sand partciels will settle downward at about _______fps

0.075 fps

Which of the following would be acceptable primary clarifier effluent concentrations for settleable solids ?

0.2-3

Most grit chaccels are designed to remove_____mm size sand particles and all others that are larger.

0.2mm

Which of the following would be acceptable primary clarifier effluent concentrations for settleable solids ?

02.-3

The specific gravity of water is _____________?

1

The specific gravity of water is _____________?

1 Clarifiers allow gravity to settle solid particles that are heavier than water (SG >1.0), while providing a mechanism to capture those solid particles that are lighter than water (SG <1.0).

Grit chambers- rectangular 30 to 60 feet long. A proportional weir at the effluent end of the channel would create a water depth that reduced the velocity to___fps

1 fps

Aerated grit chambers provide a period of wastewater detention to trap grit through air-induced rotation of the wastewater at approximately what speed?

1 fps (0.3 m/s)

Coarse or Large Screens spacing?

1"-2"

General maintenance? part 1

1. Maintain excellent operational records. File them using computer software in a manner that all operators can retrieve them for analysis. Keep all O&M manuals and manufacturers' instructions. Maintain a list of manufacturers' representatives in the local area. 2. ALWAYS lubricate using PROPER oils/greases per manufacturer's instructions. DO NOT void a guarantee or warrantee by not following instructions. 3. Clean equipment and structures regularly. Baffles, weirs, launders and walls all need cleaning. An old saying "Cleanliness is next to Godliness" is so true in a treatment facility. Minimize odors and unsightliness.

SEDIMENTATION-DIGESTION UNITS COMMONLY FOUND:

1. PACKAGE TREATMENT PLANTS 2. MOBILE HOME PARKS 3. SCHOOLS 4. CAMPGROUNDS (FEDERAL & STATE) 5. MOUNTAIN/SEA CABIN DEVELOPMENTS 6. NEAR OCEAN COMMUNITIES 7. INDUSTRY (FOOD PROCESSING)

Describe (5) places where SEDIMENTATION/FLOTATION UNITS ARE COMMONLY FOUND:

1. PRIMARY CLARIFIERS 2. SECONDARY CLARIFIERS 3. COMBINED SEDIMENTATION-DIGESTION UNITS 4. FLOTATION UNITS 5. IMHOFF TANKS

(TDS) Total Dissolve Solids Test: Part 3

1. Performing the Total Dissolved Solids Test. Take the Desiccator with Muffled Dishes to the Weighing Room. 2. Returning from the Balance Room, we are going to Pour an UNKNOWN amount of Wastewater through the UNWEIGHED GFF. ***This is the TDS (Filtrate) We now analyze this Dissolved material*** 3. Disassemble the Filtering Apparatus, Pour the Filtrate from the Erlenmeyer, Side Arm Flask into a Graduate Cylinder, Mark the Volume as C, in mL. 4. Pour the Filtrate (Volume C, in ml) into the clean dry "Muffled" Coors Evaporation Dish. Place in Drying Oven. 5. Remove the Coors Dish from the Drying Oven and Place into the Desiccator. 6. NOW: In the Balance Room weigh the Total Dissolved Solids (TDS) that are contained in the Coors Dish.

What are the 3 shapes of clarifiers?

1. ROUND (Shaped like a "tuna can") 2. RECTANGULAR (Shaped like a "shoe box") 3. SQUARE (Shaped like an "ice cube")

WHAT YOU NEED TO DO WITH PRIMARY CLARIFIERS:

1. Remove as many settleable solids as possible. o Inorganic solids (that will not bio-degrade later). o Organic solids (the settleable organics that do contain a large concentration of bio-degradable BOD materials). 2. Remove as much floatable matter as possible. o Non- to Very Slow- bio-degradable floatable like hair and chips of wood. o Rapidly bio-degradable floatable that are aesthetically unpleasant like oils and grease and other congealed substances that form "float" balls upon aeration in later processes.

Where does wastewater come from?

1. Source: domestic, industrial and extraneous flows (infiltration, inflow, unknown entry) 2. Waste Constituents: Physical and chemical

With primary clarifiers, WHAT ARE THE FORCES YOU MUST CONSIDER? Part 1

1. Specific Gravity (SG) o The SG of water is 1.000 at 4 °C (39.2 °F). Water weighs 8.34#/gallon at this SG. When the SG of water is increased to 1.050, water will weigh 8.76 #/gallon. o Oils and Greases have SGs from 0.75 to 0.95 and will therefore float. o Organic and Inorganic matter will have SGs from 1.001 to over 2.50. The organic settleables will normally have a SG of only 1 to 5% heavier than water, therefore they settle VERY SLOWLY.

Total Solids Test Procedure 2nd Procedure? (Dissolve Solids Part 2)

1. clean and wash coors evaportaing dished, then towel dry them 2. place dishes in drying over, temp set at 103-105 C, leave until they are dry 3. place dishes in Muffle Furnance at 550 C leave at least for 15 minutes 4. open muffle furnace, remove evaporating dishes, and transfer the dishes to a desiccator 5. cool and store the dishes, get ready to go to the balance room for weighing 6. weigh each dish, record all weights in grams, this will be for calculating ***MARK as A*** 7. return dishes to lab, remove dishes from the disiccator 8. pour the freshly collected sample (or refridgerated sample) in a gradulated cyclinder ***Mark as C in mL*** 9. place dishes into the drying over, ensure temperature is 103-105 C, evaporate liquid until dryness (overnight) 10. After all the Water has Evaporated from the Dishes, Remove them from the Drying Oven to the Desiccator. weigh each dish containing the dried solids, ***mark this weight as B in grams*** 11. Take the Dishes to the Balance Room for Weighing on the Analytical Balance.

The flow to a rectangular sedimentation basin is 3 mgd. The basin is 60 ft by 30 ft x 10 ft deep. What is the detention time?

1.08hrs

The flow to a rectangular sedimentation tank is 12,000 cubic meters per day. The tanks dimensions are 20 meters long X 10 meters wide by 3 meters deep. What is the detention time?

1.2 hrs

Clarifier average detention time

1.5 - 2.5 hours based on average flow, QA,d.

(TDS) Total Dissolve Solids Test: Part 2

1.Prepare the Evaporation Dishes for the TDS Test 2. Prepare (rinsing) the Glass Fiber Filters for the TDS Test 3.Place the Clean Rinsed Filters with the Aluminum Dishes directly into the Drying Oven at 103 ºC. 4.Remove Al Dishes and Dried Filters from the Oven. Put Everything into the Muffle Furnace at 550 ºC. 5. Remove Al Dishes and Dried Filters from the Muffle Furnace Cool, and Store in the Desiccator.

the septic tank does the following three things. step 1

1.Removes solids from liquid. As sewage enters the tank, the rate of flow is reduced and heavy solids settle, forming sludge. Grease and other light solids rise to the surface, forming a scum. The sludge and scum are retained and break down while the clarified effluent (liquid) is discharged to the drainfield for soil absorption.

How can you offer the best possible treatment?

1.Removing wastes from wastewater to protect the receiving waters 2.Meet the NPDES Permit requirements 3.Minimize odors and avoid nuisance complaints 4.Offer the best treatment at the least cost 5.Minimize consumption of energy 6.Maintain an effective Preventive Maintenance (PM) program

Fecal Coliform Bacteria

10

Total Coliform Bacteria

10

Aerated grit chambers are much larger and deeper than non-aerated units. The 1 fps velocity is maintained by using aerators to create a rolling flow in the tank. The detention times are increased to _____ minutes

10-45 minutes

Total Solids TS Temp?

103 C

Total Suspended Solids temp?

103 C

According to our textbook (Chapter 2) and Standard Methods For Water and Wastewater Analysis ,suspended solids, also referred to as filterable residue, represent the weight of solids remaining on a glass fiber filter following filtration and drying at ___ degrees C. (ABC)

103-105

According to our textbook (Chapter 2) and Standard Methods For Water and Wastewater Analysis ,suspended solids, also referred to as filterable residue, represent the weight of solids remaining on a glass fiber filter following filtration and drying at ___ degrees C. (ABC)

103-105 The solid components of domestic wastewater can be classified in a number of ways. For example, wastewater solids can be categorized on the basis of several operational procedures used in the wastewater treatment laboratory. Total solids may be determined by driving off the water fraction, and suspended solids may be determined by filtering out the solid fraction on a porous pad and drying. Settleable solids may be determined by permitting a sample to settle in a special Imhoff Cone apparatus. The categories used most often in the wastewater treatment field are suspended solids and total solids. The colloidal fraction of domestic wastewaters comprises about 20 percent of the solid component of an "average" wastewater. As stated, this component is characterized by being non-settleable, that is, usually long periods of time would be required for them to settle by gravity alone. Colloidal components of wastewater do not fit neatly into a component that can be determined in the laboratory and colloids are found in both the suspended and dissolved solid fractions. Any estimate of wastewater composition can give only an average composition. The amounts of solids indicated cannot be applied equally to all wastewaters at all times.

HDT (the time household wastewater remains in the tank) is usually____-____hrs

12-24 hours

Which of the following would be acceptable weakly minimum primary clarifier influent concentrations for BOD5 (mg/L) ?

150-400

5-Day Biochemical Oxygen Demand, BOD

155 - 286 mg/L 250 mg/L

Total Dissolved Solids temp?

180 C

According to the EPA Total Dissolved Solids are dried at this temperature (ABC)-note EPA follows Standard Methods Analysis.

180 C The TS and TSS fractions are dried at 104º C while the TDS fraction is dried at 180º C. Total solids are important to measure in areas where there are discharges from sewage treatment plants, industrial plants, or extensive crop irrigation. Total solids are dissolved solids plus suspended and settleable solids in water. Higher concentrations of suspended solids can serve as carriers of toxics, which readily cling to suspended particles.

According to the EPA Total Dissolved Solids are dried at this temperature (ABC)-note EPA follows Standard Methods Analysis.

180c

What is the "scour" velocity in a collection system, in feet per second? a. 1½ b. 2 c. 2½ d. 5 e. 10

2 fps

Common settling times in primary clarifiers range from (about 120-180 minutes; ABC)?

2 to 3 hours "Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. "

The normal range of detention times used in sedimentation basins in conventional water treatment plants is about:

2-6 hrs

Trash/Bar racks spacing?

2-6 inches

With primary clarifiers, WHAT ARE THE FORCES YOU MUST CONSIDER? Part 2

2. Velocity of water (V) o Scouring Water Velocity of 2.0 fps occurs in the collection system. o Grit Channel Water Velocity of 0.7 to 1.4 fps allows for the heavier inorganic materials to settle. o Primary Clarifier Water Velocity of 0.017 to 0.033 fps (1 - 2 feet per minute) will allow for particles with a SG greater than 1.05 to settle out.

The minimum scouring velocity normally used for sanitary collection lines is (ABC; hint: what is typical sewer flow rates)?

2.0 ft/sec.

A circular primary clarifier has a diameter of 80 ft and an average depth of 10 ft. The flow of wastewater is 4.0 MGD and the suspended solids concentration is 190 mg/L. What is the detention time in hours?

2.3 hrs

The heavy material present in wastewater, such as sand, coffee grounds, eggshells, gravel and cinders are called grit. What is the typical specific gravity of grit?

2.5 greater

the septic tank does the following three things. step 2

2.Provides biological treatment. Natural processes break down the solids and liquids by bacterial action. The breakdown occurs in the absence of oxygen (anaerobic conditions). The anaerobic conditions are referred to as "septic," giving the tank its name.

The flow to a rectangular clarifier is 4.0 MGD in a tank 75.2 feet by 22.4 feet wide. What is the surface loading rate in gpd per square foot of surface area?

2374 gpd/ sq ft 75.2 ft X 22.4 ft = 1684 sq ft 4,000,000 gpd / 1684 sq ft = 2374.6 gpd/sq ft

1.0 yd^3 =

27ft^3

the septic tank does the following three things. step 3

3.Stores scum and sludge. The solids accumulate in the bottom of the tank to form sludge. The scum is a partially submerged mat of floating solids and grease. Scum and sludge are digested over time and compacted into a small volume. Areas with warm climates, such as the southern United States, allow more complete breakdown of solids and scum than in the cooler climates of the North. For this reason, tanks in warm climates do not usually need to be pumped or cleaned out nearly as often as those in cold climates. Regardless of climate, a nonvolatile residue of material remains in the tank. Sufficient volume for the solids must be provided in the tank between pumpings or cleanings.

What's the average concentration of FOG in domestic wastewater?

30 - 50 mg/L

The influent BOD to aprimary clarifier is 200 mg/L, and the effluent BOD is 140 mg/L. What is the effeciency of the primary calrifier at removing BOD?

30% BOD Removal

Ammonium-Nitrogen, NH

4 - 13 mg/L 10 mg/L

General maintenance? part 2

4. Attend to all alarms, noises, leaks, gauge inconsistencies, belts electrical systems, and safety issues. 5. In rectangular clarifiers fitted with wooden flights, when taken "offline" you need to keep the flights moistened to eliminate warping and cracking. 6. Ensure that all influent/effluent weirs are level. This task will reduce the chance of short-circuiting and increase clarifier performance/efficiency.

(BOD) Biochemical oxygen demand analytical time?

5 days

What is the lower threshold for acceptable dissolved oxygen content in a surface water body?

5 mg/l A concentration of 5 mg/L DO is recommended for optimum fish health.

(TOC) Total Organic Carbon Analytical Time?

5 mins

Which of the following would be acceptable primary clarifier effluent concentrations for total suspended solids (mg/L) ?

50-150

The "clarified" liquid then flows from the primary clarifier to further treatment called secondary or biological treatment. Approximately ________% of the solids contained in the raw wastewater are removed in the primary clarifiers.

50-60%

When infiltration occurs it should be limited to how much?

500 gal/d*mi*in

(COD) Chemical Oxygen Demand analytical time?

5hrs

pH

6 -9 s.u. 6.5 s.u.

What percentage of solids settle after about 2 hours in a clarifier?

60%

What is the suspended solids removal efficiency of a primary clarifier if the influent concentration is 300 mg/l and the effluent concetration is 120 mg/l?

60% suspended solids removal

Each Clarifier/tank will be sized, as a maximum, for _________ percent of the plant design flow (facilitydesigns will normally include two tanks)?

67%

The vortex-type grit chamber removes a high percentage of fine grit, up to _____%

73%

A circular primary clarifier has a diameter of 80 ft and an average depth of 10 ft. The flow of wastewater is 4.0 MGD and the suspended solids concentration is 190 mg/L. What is the surface loading rate in gpd/sq ft?

800 gpd/sq ft

Waste Water % Breakdown?

99.9% Water 0.1% Solids

What is the Typical Wastewater breakdown %?

99.9% Water and 0.1% Total solids ======= *.08% TDS + *.02% TSS

Collection of wastewater

: a collection system is simply a network of pipes and pumps whose prime work is to convey (move) water/wastewater from the generated source to the point of treatment/disposal. ***Wastewater collection is NOT wastewater treatment!**** ***The facilities to collect and move wastewater are not the facilities to treat the wastewater****

PACKAGE TREATMENT PLANT

A "package treatment plant" refers to a small wastewater treatment plant often fabricated at the manufacturer's factory, hauled to the erection site in components, and installed as one facility. The package plant is usually either a small primary or a secondary wastewater treatment facility. These facilities can be found at truck stops, mobile home parks, recreation areas, and public campgrounds.

How do you Calculate the mg/L TOTAL SOLIDS

A + B + C A: Weighed dish in grams B: weighted dish + dried solids in grams C: Sample Volume in mL TS, mg/L =(B, in gms - A, in gms)(1,000,000) C, in mL

How do you calculate the mg/L TOTAL DISSOLVED SOLIDS (TDS)

A + B + C A: weighed coors dish, in grams B: weighed coors dish containing TDS, in greams C: sample Volume, in ML TDS, mg/L: (B, in grams - A, in grams (1,000,000) ___________________________________ C, in mL

How do you Calculate the mg/L TOTAL SUSPENDED SOLIDS

A + B + C A: weighted Al Dish with GFF, in grams B: Weighted Al Dish with GFF and TSS, in grams C: Sample Volume in mL TSS, mg/L = (B, in grams - A, in grams (1,000,000) ____________________________________ C, in mL

ACTIVATED SLUDGE PROCESS

A biological wastewater treatment process which speeds up the decomposition of wastes in the wastewater being treated. Activated sludge (a whole bunch of microorganisms) is added to wastewater and resulting in a thick mixture (mixed liquor, ML) which is constantly aerated and agitated (mixed). After some time in the aeration tank (a condominium for microorganisms), the activated sludge is pushed out and allowed to settle (due to gravity) by sedimentation. Finally, these microorganisms are either disposed of (wasted or "killed off") or reused (returned/recycled to the aeration tank) as needed. The remaining wastewater then undergoes more treatment like filtration and disinfection or perhaps more sophisticated tertiary treatment so that the eventual water can be beneficially used.

IMHOFF CONE

A clear, cone-shaped container marked with graduations. The cone is used to measure the volume of settleable solids in a specific volume. This laboratory settleability test is usually performed on primary clarifier influent (and sometimes primary clarifier effluent). Usual Sample Volume is: One liter (1-L) of wastewater.

WET WELL

A compartment or tank in which wastewater is collected. The suction pipe of a pump may be connected to the wet well or a submersible pump may be located in the wet well.

COMPOSITE (PROPORTIONAL) SAMPLE

A composite sample is a collection of individual samples obtained at regular intervals, usually every hour or two during a 24-hour (1-day) time span. Each individual sample is combined with the others in proportion to the rate of flow, when the sample was collected. The resulting mixture (composite proportional sample) forms a representative sample and is analyzed to determine the average conditions that occurred during the sampling period.

SEPTIC

A condition produced by anaerobic bacteria. If a severe septic condition exists in wastewater, the wastewater will produce hydrogen sulfide, turn black, give off foul odors, contain little or no dissolved oxygen, and the wastewater will exhibit a high oxygen demand (BOD).

Grit Chambers/ Grit Channels

A grit chamber/channel slows the velocity to 1.0 fps so the sand, eggshells, small rock, and cinders will fall out A velocity of 0.7-1.4 fps in the grit channel seems to be ideal to settle out the larger inorganic material, while keeping the putrefuiable organics in suspension, this is desirable.

EMULSION

A liquid mixture of two or more liquid substances not normally dissolved in one another; one liquid is held in suspension in the other.

DENSITY

A measure of how heavy a substance (solid, liquid or gas) is for its physical size. Density is expressed in terms of weight (or mass, M) per unit volume (V). An example of density would be milligrams per Liter (mg/L) or pounds per cubic foot (lbs/ft3) and is one way to express concentration of a substance. The density of water (at 4EC or 39EF) is 1.000 kilogram per Liter (kg/L) or about 62.4 pounds per cubic foot (lbs/ft3).

MILLIGRAMS PER LITER, mg/L

A measure of the concentration by weight (mass) of a substance per unit volume. For practical purposes, one mg/L of a substance in water is equal to one part per million parts (ppm). Thus, one liter of water with a specific gravity of 1.0 weighs one million milligrams, 1L = 10+6 mg. This is because the specific gravity of pure water is 1.0 at standard pressure (1.0 atmosphere) and standard temperature (20EC). If the water contains 10 milligrams of dissolved oxygen, the concentration would be 10 milligrams of DO per million milligrams of water, or 10 milligrams per liter (10 mg/L), or 10 parts per million (10 ppm). Imagine a credit card lying on a football field; = 1 part per million parts.

WET OXIDATION

A method of treating or conditioning sludge before the water is removed. Compressed air is blown into the liquid sludge. The air and sludge mixture is fed into a pressure vessel where the organic material is stabilized. The stabilized organic material and inert (inorganic) solids are then separated from the pressure vessel effluent by dewatering in lagoons or by mechanical means.

MICRON (μ)

A micron is an old term. One micron 1: = one millionth of a meter (10-6m) in length.

MOLECULE

A molecule is the smallest division of a compound that still retains or exhibits all the properties of the substance.

SANITARY SEWER

A pipe or conduit (sewer) intended to carry wastewater or waterborne wastes from homes, businesses, and industries to the POTW (Publicly Owned Treatment Works). Storm water runoff or unpolluted water should be collected and transported in a separate system of pipes or conduits (storm sewers) to natural watercourses.

Monster Muffin?

A popular comminutor

BIOCHEMICAL OXYGEN DEMAND (BOD) TEST

A procedure that measures the rate of dissolved oxygen use under controlled conditions of time and temperature. Standard test conditions include dark incubation at 20°C for a specified amount of time (usually five days); therefore, you may see this as BOD5. Standard BOD bottle has a volume of 300 mL, glass stoppered and contains a water/wastewater sample.

PHOTOSYNTHESIS

A process in which organisms with the aid of chlorophyll (green plant enzyme), convert carbon dioxide (CO2) and inorganic substances into oxygen (O2) and additional plant material, using sunlight for energy. All green plants grow by this process.

Disinfection

A process to "rid" or "Kill or inactivate" the water of organisms

REPRESENTATIVE SAMPLE

A sample portion of material or waste stream that is as nearly identical in content and consistency as possible to that in the larger body of material or waste stream from which the material is being sampled.

DESCRIBE PRINCIPLE OF THIS UNIT !!

A sedimentation-digestion tank is gradually replacing Imhoff Tanks and "clustered" Septic Tank systems. In general the wastewater is treated the same as a "Primary" clarifier would treat the waste (65% TSS and 35% BOD removal). The digestion chamber is an "unheated" anaerobic digester very similar to a septic tank. Solids become stabilized, but need further treatment before land disposal would be granted.

STORM SEWER, STORM WATER

A separate pipe, conduit or open channel (sewer) that carries runoff from storms, surface drainage, and street wash, but does not include domestic and industrial wastes. Storm sewers are often the recipients of hazardous or toxic substances due to the illegal dumping of hazardous wastes or spills created by accidents involving vehicles and trains transporting these substances. Also see SANITARY SEWER.

COMBINED SEWER

A sewer designed to carry both sanitary wastewaters and storm or surface water runoff.

Combined Sewers

A single network of piping that is intended to carry both sanitary wastewater and storm runoff. This network intercepts all waters and attempts to convey them to the treatment facility. This works quite well when there is NO RAIN. However, when the rain comes, the networks is overloaded and the combination of sanitary wastewater and storm runoff is by-passed to the nearest natural waterway

RECEIVING WATER

A stream, river, lake, ocean, or other surface or groundwaters into which treated or untreated wastewater is discharged.

MILLIMICRON (mμ)

A unit of length that is equal to 10-3 microns (or oneone thousandth of a micron) and equals either 10-6 millimeters, or 10-9 meters; more correctly called a nanometer (nm). The prefix nano- means one billionth).

Pressure Sanitary sewer

A wastewater collection system that is fed by localized personal pumping stations after the waste has been preliminary treated by a septic tank. Sometimes this system is synonymous with Septic Tank effluent pumping or STEP. The septic tank effluent is then treated in a wastewater facility rather than absorbed into the soil on individual land parcels.

Vacuum sanitary sewer

A wastewater system that is fed by localized personal generated waste Vacuum sewers can be installed more afford ably and cost less to maintain and operate, than gravity systems: 1. traditional gravity line carries wastewater from the customer to a valve pit package. 2. Then 10 gallons of wastewater collects in the sump, the valve opens and differential pressure propels the contents to the vacuum main 3. wastewater travels at 15-18 fps in the vacuum main 4. wastewater enters the collection tank: when it fills to a predetermined level, sewage pumps transfer the contents to the treatment plant via a force main. 5. vacuum pumps cycle ON/OFF as needed to maintain a constant level of vacuum on the entire collection system

PRIMARY TREATMENT

A wastewater treatment process that takes place in a rectangular or circular tank and allows those substances in wastewater that readily settle or float to be separated from the water being treated.

PRIMARY TREATMENT

A wastewater treatment process that takes place in a rectangular or circular tank and allows those substances in wastewater, which readily settle or float, to be separated from the water being treated.

SECONDARY TREATMENT

A wastewater treatment process used to convert dissolved or suspended materials into a form more readily separated from the water being treated. Usually the process follows primary treatment by sedimentation. The process commonly is a type of biological treatment process followed by secondary clarifiers that allow the solids to settle out from the water being treated.

SECONDARY TREATMENT

A wastewater treatment process used to convert dissolved or suspended materials into a form more readily separated from the water being treated. Usually the secondary process follows the primary treatment process. The secondary treatment commonly is a type of biological process followed by secondary clarifiers that allow the solids to settle out from the water being treated.

AEROBIC BACTERIA

AEROBIC BACTERIA These are bacteria which will live and reproduce only in an environment containing oxygen (specifically Dissolved Oxygen or DO). DO is available for their respiration (breathing). The source for this DO is the atmosphere (about 20% Oxygen). The air is compressed and the DO is dissolved in water (due to decompression). Oxygen combined chemically, such as in water molecules (H20) is referred to as "combined" oxygen and cannot be used for respiration by aerobic bacteria. Staphlococcus: (Aerobic Bacteria) Nitrogen-fixing: (Gloeothecea) (Aerobic Bacteria)

Waste Treatment Ponds

AKA Lagoons have been used to stabilize wastewater for centuries. Ponds are simple, cheap, easy operate and very flexible. Ponds can be: shallow (less than 3ft, aerobic) medium (3-5 feet, facultative) deep (more than 6ft, anaerobic) Most lagoons found in the USA are the facultative type that treat waste both aerobically (surface) and anaerobically (Down deeper). They can be designed to "treat" wastes, to "polish" wastes, as an "oxidation" process, or to do the entire "Waste stabilization" process

What are the (2) major groups of the Anaerobic Organisms?

Acid Formers: They begin eating the organic fraction of the sludge and produce organic acids Methane Formers: They convert the organic acids produced by the Acid Formers into stable organic forms and volatize gas into both methane 70% and carbon Dioxide 30%

Describe the way a facultative pond works when compared to a clarifier, a digester and an aeration tank:

Acts like a clarifier by allowing solids to settle to the bottom, like a digester because solids on the bottom are decomposed by anaerobic bacteria and like an aeration tank because of the action of aerobic bacteria in the upper layer of the pond.

Cl2 is added to _________ effluent for disinfection purposes

Aeration tank.

Bacteria which will live and reproduce only in an environment containing oxygen (specifically Dissolved Oxygen or DO). DO is available for their respiration (breathing). The source for this DO is the atmosphere (about 20% Oxygen). The air is compressed and the DO is dissolved in water (due to decompression). Oxygen combined chemically, such as in water molecules (H 20) is referred to as "combined" oxygen and cannot be used for respiration by _________ bacteria.

Aerobic

Bacteria that will live and reproduce only in an environment containing atmospheric oxygen or DO in water:

Aerobic bacteria group

Bacteria that will live and reproduce only in an environment containing atmospheric oxygen or DO in water:

Aerobic bacteria group

Which of the following are considered compatible inorganic constituents of wastewater? Fe Ca Mg All the above

All of the below: Fe Ca Mg

Where do we get the samples for the fixed and volatile solids test?

All our samples are in the desiccator

Secondary Clarifiers

All secondary processes (except lagoons) must include a secondary clarifier. The clarifier follows the TF, RBS, AS tank. The purpose of the secondary clarifier is to provide a quiet basin in which the created bio-solids can be separated from the treated wastewater. Removed bio-solids (secondary sludge) from the clarifier is either returned to the process for further treatment or wasted (thrown away to solids handling/treatment. Secondary processes grow bugs. If these excess bugs are not wasted, operators would soon be awash in biomass. The excess bugs are wasted over to the "solids Side" for solids handling and eventual disposal.

Which of the following are considered organic constituents of wastewater?

All the Below: FOG (fats oils greases) herbicides pesticides

What types of physical activities do wastewater operators do?

All the Below: a. turns valves b. pushes switches c. collects samples d. lubricate and maintain equipment e. paint and maintain landscape f. repair machinery g. keep maintainance records "Employment of water and liquid waste treatment plant and system operators is expected to grow by 20 percent between 2008 and 2018, which is much faster than the average for all occupations."

What functions are performed at the headworks of a WWTP? a. sampling b. flow measurement c. chemical addition d. screening e. grit removal

All the above

What are the objectives for chapter 2?

All the below: a. Identify types of waste discharges b. Recognize the effects of waste discharge on recieving waters c. describe the different types of solids in wastewater d. explain what happens in the natural cycle

Waters flowing into a treatment plant may include?

All the below: a. Storm water b. Wastewater c. Groundwater infiltration d. Surface water inflow

Which of the following is true about aerobic bacteria?

All the below: a. An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. b. The genera vary morphologically, being spheric (cocci), rod-shaped (bacilli), spiral (spirochetes), or comma-shaped (vibrios). c. bacteria that can survive and grow in the presence of free oxygen in their immediate environment obligate aerobic bacteria require oxygen as a source of energy and therefore for growth.

Which of the following are objectives for chapter 3 in your text?

All the below: a. Describe Collection Systems b. Describe Types of wastewater treatment plants c. identify methods of effluent discharge reclamation and re-use d. identify types of solids removal

Receiving water uses protected by the wastewater operator include:

All the below: a. Fishing b. Drinking water supply c. Stock and wildlife watering d. Boating/Recreation

Who does a wastewater treatment plant operator work for?

All the below: a. Municipalities b. Sanitation district c. Private corporation

Which of the following problems could develop, when wastewater remains trapped in the collection system too long? a. Odors b. Algal growth c. Corrosion of pipe and structure d. Infiltration/Exfiltration e. Production of H 2S

All the below: a. Odors b. Algal growth c. Corrosion of pipe and structure d. Infiltration/Exfiltration e. Production of H 2S

Waters flowing into a treatment plant may include ________.

All the below: a. Storm water b. Wastewater c. Groundwater infiltration d. Surface water inflow

Effluent limitations that may be specified in an NPDES permit include: a. Toxic substances b. Acceptable range of pH values c. The MPN of coliform bacteria d. Total Suspended Solids e. Biochemical Oxygen Demand

All the below: a. Toxic substances b. Acceptable range of pH values c. The MPN of coliform bacteria d. Total Suspended Solids e. Biochemical Oxygen Demand

CONTAMINATION

All water is contaminated with something. Fortunately, in the Pacific Northwest we have very little drinking water contamination. One teaspoon of salt in one gallon of water is considered contaminating the water. As contamination grows such that the water is changed to hinder any beneficial use of that water, then the water is said to be polluted.

Scum Pipe

Allows the collected scum to flow from the skimmer box to a scum tank or a pump.

What kind of bacteria causes hydrogen sulfide gas to be released?

Anaerobic Bacteria

Bacteria that obtain their oxygen by breaking down chemical compounds which contain oxygen, such as SO4 -2 are:

Anaerobic bacteria group

Bacteria that obtain their oxygen by breaking down chemical compounds that contain oxygen, such as SO 4 -2 are:

Anaerobic bacteria group

ANAEROBIC BACTERIA

Anaerobic bacteria live and reproduce in an environment containing no "free" or dissolved oxygen. Anaerobic bacteria obtain their oxygen supply by breaking down chemical compounds, which do contain a "combined" oxygen source, such as sulfate (SO4 =) or nitrate (NO3 -).

Clarifier average hourly flow

At average flow: SORA < 700 ~ 1000 gpd/sf.

How do you Calculate the mg/L VOLATILE SOLIDS Test?

B-D/C B: weighed dish or filter with ashed solid D: weighed dish or filter with total solid C: sample volume, in mL TVS/TVSS/TVDS, mg/L= (B, in grams - D, in grams)(1,000,000) _____________________________________ C, in mL

ANAEROBIC BACTERIA

Bacteria that live and reproduce in an environment containing no "free" or dissolved oxygen. Anaerobic bacteria obtain their oxygen supply by breaking down chemical compounds, which contain oxygen, such as sulfate (SO4-2).

AEROBIC BACTERIA

Bacteria that will live and reproduce only in an environment containing dissolved oxygen (DO). This DO or Oxygen dissolved in water is available for the respiration (breathing) required by the bacteria. Oxygen combined chemically, such as in water molecules (H20), the nitrate ion (NO3-1), the phosphate ion (PO4-3), etc. cannot be used for respiration by aerobic bacteria.

PATHOGENIC ORGANISMS

Bacteria, viruses, or cysts which can cause disease (typhoid, cholera, dysentery) in a host (such as a person). There are many types of organisms which do NOT cause disease and which are NOT called pathogenic. Many beneficial bacteria are found in wastewater treatment processes actively cleaning up organic wastes.

Barminutor

Barminutors - A barminutor is a combination of a bar screen and a comminutor. Vertical operating comminutors. Shred solid matter The advantage of the barminutor is that as the cutting action cycles (up and down), the cutting blades come out of the wastewater (easier to fix and maintain)

How does the operator become involved with public relations?

"By explaining the operation, purpose, and reasons for operation of the facility to visitors, civic organizations, reporters, city or district representatives. Become involved in PR early in your career".

Describe "Chaining the Slot"

"Chaining the Slot" refers to taking a logging chain, dropping it partially into the sedimentation chamber, then "unplugging" the slot by slowly working the chain up and down (vertically) as you move across the slot (horizontally).

This work was done by Metcalf and Eddy in 1915.

"It is the organic constituents, amking up on the average perhaps ⅔ of the matter in suspension and ½ of the matter in solution, which constitute the chief problem

SLOUGHINGS

"Sloughings" is a term given to Trickling filter (TF) & RBC slimes that have been washed off the filter media. These "sloughings" are generally quite high in BOD and will lower the overall effluent quality unless removed by a clarifier.

Why is it important that the operator be present during the construction of new facilities; plant, pump station, etc?

"To become familiar with the specific facility, its wiring, mechanical requirements, etc. before the facility comes 'on-line'".

Calculate the approximate monthly screenings-disposal cost for a 10-mgd wastewater treatment plant. Assume that on a typical day, 1.2 yd3, 2.3 yd3, and 0.7 yd3 of compacted screenings were removed during the first, second, and third 8-hour shifts, respectively. The plant pays $45 to dump each 12-ft-long, 4-ft-wide, 5-ft-high container at the landfill.

$662 per month Correct Calculate the amount of screenings collected each month: (1.2 yd³ + 2.3 yd³ + 0.7 yd³) × 30 d = 126 yd³ per month. Calculate the volume of the screenings container in yards: (12 ft × 0.33 yd/ft) × (4 ft × 0.33 yd/ft) × (5 ft × 0.33 yd/ft) = 8.6 yd³. Calculate how many containers are needed each month: 126 yd³ per month ÷ 8.6 yd³ per container = 14.7 containers per month. Calculate the cost: 14.7 containers per month × $45 per container = $661.50 ≈ $662 per month.

A rectangular wet well is 8 ft long, 10 ft wide. With no influent to the well, a pump lowers the water level 0.5 inches during a two minute pumping test. What is the gpm flow rate? Handy Dandy #52

(0.5")(1 ft/12") = 0.42 ft Pumping Rate = (length ft) (width ft) (Well level ft) (7.48 gal) Duration of test PR= (8 ft)(10 ft)(0.42 ft) = 33.6 cu ft 33.6 cu ft (7.48 gal / 1 cu ft) = 251 gal 251 gal = 2 minutes 126 gpm

WEIR

(1) A wall or plate placed in an open channel and used to measure the flow of water. The depth of the flow over the weir can be used to calculate the flowrate, or a chart or conversion table may be used to convert depth to flow. (2) A wall or obstruction used to control flow (from settling tanks and clarifiers) to ensure a uniform flow rate and avoid short-circuiting.

Name (7) steps of an Operation and Maintenance Manual for a circular clarifier?

(1) Check Collector Drive mechanism for oil/alignment/completeness (2) Inspect sumps/hoppers and piping for debris/obstructions (3) Look at all "below water" mechanisms for proper installation/operation (4) Look for sand/debris & obstructions. (5) Squeegee blades on collector plows for distance from floor of the tank. (6) Look at gaskets/gears/sprockets/drive motor for installation & proper rotation. (7) Control Gates operating properly

What are the 8 steps in operation and maintenance of circular clarifiers?

(1) Control Gates operating properly. (2) Look for sand/debris & obstructions. (3) Check Collector Drive mechanism for oil/alignment/completeness. (4) Look at gaskets/gears/sprockets/drive motor for installation & proper rotation. (5) Squeegee blades on collector plows for distance from floor of the tank. (6) Look at all "below water" mechanisms for proper installation/operation. (7) Inspect sumps/hoppers and piping for debris/obstructions. (8) Inspect tankage (structure) for cracks/corrosion and structural failure; this could be earthquake damage.

Name (7) suggestions that may help workers in this field to stay healthy on the job?

(1) Open cuts or wounds should be protected, be sure to replace contaminated dressings. (2) Chemical hazards are also present at wastewater treatment facilities. In some cases (such as chlorine), the chemical hazard may be deadly. Be sure to read and understand the MSDS for the chemical product you are working with (3) DO NOT stick your fingers or hands in your mouth, nose, eyes or ears. (4) Be careful of the many dangers associated with confined spaces with one of the primary hazards being atmospheric. (5) Avoid direct contact with wastewater, always wear rubber gloves and protective clothing when working with wastewater. (6) Keep your fingernails short and DO NOT bite your nails! (7) Workers at wastewater facilities should wash their hands frequently with anti-bacterial soap.

SLUDGE

(1) The settleable solids separated from liquids during processing. (2) The deposits of foreign materials on the bottoms of streams or other bodies of water.

Dewatering

(1) To remove or separate a portion of the water present in a sludge or slurry. To dry sludge so it can be handled and disposed of. (2) To remove or drain the water from a tank or a trench.

DEWATER or DEWATERING

(1) To remove or separate a portion of the water present in a sludge or slurry. To dry sludge so it can be handled and disposed of. (2) To remove or drain the water from a tank or a trench.

Give (5) characteristics of a Vortex Type Grit Chamber

(1) Vortex grit removal systems have a consistent removal efficiency over a wide flow range. (2) There are no submerged bearings or parts that require maintenance. (3) The "footprint" (horizontal dimension) of a vortex grit removal system is small relative to other grit removal systems, making it advantageous when space is an issue. (4) Minimal Headloss 6 mm (0.25 in). (5)These systems are also energy efficient.

SPECIFIC GRAVITY

(1) Weight of a particle, substance or chemical solution in relation to the weight of an equal volume of water. Water has a specific gravity of 1.000 at (4EC or 39EF). Wastewater particles or substances usually have a specific gravity (SG) between 0.5 and 2.5. (2) Weight of a particular gas in relation to the weight of an equal volume of air at the same temperature and pressure (air has a specific gravity of 1.0). Chlorine has a specific gravity of 2.5, when in its gas form.

Name (4) characteristics of a Cyclone Degritter

(1) rapid spinning motion to separate the heavy inorganic solids or grit from the light organic solids and discharge them directly to a storage container. (2) slurry hits the cone section of the cyclone at the edge causing a swirling or spinning action of grit material. (3) Heavy material is forced outward and drops to the bottom due to gravity. (4) The lighter organic material is bled off the top

Grit Channel Length, ft =

(13.33)(Channel Depth, ft)

If the residue remaining on a filter paper is the suspended solids, these are the solids that pass through the filter.

(TDS) Dissolved All solids analyses require a minimum residue of at least 10 mg material on the filter or in the crucible to count as a detect

Flotsam

(floatables like scum)

Jetsam

(settleables like sludge)

Settleable Solids Testing

*Collect the Wastewater and Return to the Lab *Pour Wastewater into Imhoff Cone (1L mark) *Wait for Solids to Settle (45 - minutes) *Stir gently (Use a glass stirring rod) *Wait for Stirred Solids to Settle (15 - minutes) *Read Volumetric Settled Solids (in mL) *Report Answer as Settleable Solids (mL/1L)

List (4) characteristics for Clarifier SludgeCollection and Removal

*Direction of sludge removal is from outlet to hopper;  *Conveyor chain and flights or travelling bridge;  *Collector linear speed = 2 fpm - 3 fpm;  *Cross screw collector rotates at 10 rpm.

Operational strategies: Visual observations, describe them

*Equipment Failures. (Mechanical/Electrical) * Excessive Hydraulic/Solids Loading. * Surface gasified sludge, or Rising sludge. * Bulking sludge condition in Secondary clarifiers. * Surface is skimmed adequately. (Oils/Greases) * Pumped solids are of a consistent thickness.

Describe "crystalline solids"

*In crystalline solids the atoms or molecules are stacked in a regular manner, forming a threedimensional pattern which may be obtained by a threedimensional repetition of a certain pattern unit called a unit cell.

List (3) characteristics of a Clarifier SludgeHopper

*Minimum side wall slope, 1.7:1 (vertical:horizontal);  *Hopper bottom width, 2 ft;  *Extra depth are not acceptable to avoid septic

List (3) characteristics of Clarifier SludgeWithdrawal

*Non-clog Centrifugal pumping can be used; Sludge line > 6";  *Shortest and straight suction pipes;  *Continuous or interval withdrawal; Flushing water connected to suction & discharge lines.

SAFETY CONSIDERATIONS part 1

*OSHA will normally dictate "safe design", but you need to ensure that all designed safety mechanisms are properly installed, operational, functional, and every operator is trained in safe operations. o Non-skid surfaces should be installed and equipped with toe boards, and cover grating as appropriate.

name (4) Disadvantages of rectangular clarifiers over circular clarifiers

*Possible dead corners *Sensitive to flow surges *Restricted in width by collecting equipment *Higher maintenance costs of sprocket, chains & flights

Operational strategies: determine clarifier operational variables. describe

*Settleable Solids Concentration (Set Sol), HD#30. *Raw Sludge Pumping Rate (RSP), HD#31 *Hydraulic Detention Time (HDT), HD#38. *Clarifier Surface Overflow Rate (CSOR), HD#39. *Clarifier Weir Overflow Rate (CWOR), HD#40. *Clarifier Weir Length (CWL), HD#41. *Efficiency in Removals (%E), HD#26. *Solids Loading Rate (SLR), or Mass Flux HD#22. *Surface Area(s) SA, HD#1, or HD# 6. *Mass Flux Loading Rate (MLR), HD#22/HD#1 or #6

What is a Glass Fiber Filter?

*They come from the manufacturer in Packages of 100 and the ones we use are 47 mm in diameter. *Filter pore size *A single filter is handled only with forceps (tweezers)

List (4) actions for Clarifier Scum Collection and Handling

*Tilting scum trough extends the full width, close to outlet and stop the loss of scum into effluent; *Blade scraper manually or mechanically scrap scum.  *Scum transport and handling *Keep mixing and maintain warm temperature in tank during pumping; *Standby pump and cleanout, flushing connections.

list (3) characteristics for Clarifier Outlet Design

*Uniform withdrawal and avoid short circuiting;  *Adjustable weir for leveling;  *V-notch or flat weir under free fall flow; Weir rate 10,000 gpd/ft - 15,000 gpd/ft

Rotating biological contactors

*fixed media treatment *requires primary treatment *microorganisms colonize contactors (disks) *Rotation creates alternate wetting/draining of microorganisms *nitrogen reduction

Conventional Collection system components:

*gravity sewer lines through manholes and into pumps stations *pump stations force the sewage to higher elevations *The force main ends in a "terminal" manhole

Define Clarifier characteristics

*have 3 shapes: round, square, rectangle *slow the horizontal velocity of wastewater to about 0.03 FPS *hold water for about 1.5-2 hours prior to secondary treatment. *remove 60% of TSS and about 30% of BOD *have weirs to allow water to exit, break up the water velocity and smoothly allows the water to exit at a rate of about 10000 gallons per day for each 1 linear foot of weir *are sized such that water can be loaded into the primary clarifiers at about 600 gallons per day for each 1 square foot of surface area. *designed to withdraw sludge and floatable scum

Primary treatment is used as a preliminary step ahead of biological treatment. The purpose of primary treatment is to remove solids which are not removed duringpreliminary treatment. Processes which can be used to provide primary treatment include the following:

*primary sedimentation, also called clarification; *microscreens; *Imhoff tanks.

Name (4) factors that must be taken into considerationwhen selecting a grit removal process?

*quantity and characteristics of grit, potential adverse *effects on downstream processes, head loss *requirements, space requirements, removal *efficiency, organic content, and cost.

BULKING

Bulking refers to the clouds of billowing sludge that occur throughout secondary clarifiers and sludge thickeners, when the sludge does not settle properly. In the activated sludge process, bulking is the usual result of filamentous bacteria or bound water found in younger microorganisms.

Primary treatment

CLARIFICATION clarification allows solids to settle and scum to float. Both of these undesirable products are then removed in the clarifier and treat on the "solids side". Primary treatment can also be defined in terms of "fine screening".

Results of the settleable solids test run using Imhoff cones may be used to ___________.

Calculate the pounds of primary solids pumped to the digester The settleable solids test is the measurement of the volume of solids in one liter of sample that will settle to the bottom of an Imhoff cone during a specific time period. The test indicates the volume of solids removed by settling in sedimentation tanks, clarifiers or ponds. The settleable solids test indicates whether the primary and secondary processes are functioning properly. The settleable solids test on wastewater can tell the operator a lot about what kind of wastewater is coming into the plant and how the solids are settling. Also, the settleable solids test can help the operator estimate the volume of sludge to be expected in the clarifier.

What are typical operational values for the DIGESTION COMPARTMENT?

Capacity about 1.0 - 3.0 ft3/person SRT about 3 to 12 months

Storm Sewer

Carries storm water runoff from streets, land, and building roofs in a separate conveyance system. Most often the "storm runoff" goes from your street directly to the nearest natural waterway and no treatment is accomplished en-route

Drive Unit

Causes the collector to rotate. Power and gears connecting to the vertical drive cage.

Bar Racks

Certainly everything greater than 3" should be removed by a "BAR RACK" *WIDE* "Screening Process": Usually by bar racks/screens consisting of several parallel bars. Rocks, cans and bottles are usually removed by Bar Racks & Screens. Racks are found in the bypass channels while the screens are in parallel to the racks but with narrower openings. Bar Racks Parallel bars are spaced 3" - 4". The racks are used for "bypass" purposes and are usually cleaned by the operator; manually

What is the most frequently used means of disinfecting treated wastewater?

Chlorination

What strong oxidant is typically used for the purpose of disinfection?

Chlorine

"Plows/Scrappers) are used in ______shaped clarifiers? To do what?

Circular tanks They push the settled sludge towards the center and into the sludge hopper.

With primary clarifiers, WHAT ARE THE FORCES YOU MUST CONSIDER? Part 5

Clarifier Surface Loading Rate (CSLR) o Water should be loaded into a primary clarifier at a rate of 600 - 1 000 gpd/ft2. And loaded into a secondary clarifier at a rate between 800 and 1 200 gpd/ft2. If the clarifier is following the activated sludge basins this rate may drop down to 300 gpd/ft2. o Surface Overflow Rate calculations require the operator to know flowrate into the clarifier and clarifier surface dimensions. c. Clarifier Weir Overflow Rate (CWOR) o Water should not be allowed to flow over the effluent weirs of a primary clarifier at a rate in excess of 15 000 gpd/lineal foot of weir. And allowed to flow out of a secondary clarifier at a rate between 5 000 and 10 000 gpd/lineal foot of weir. o Weir Overflow Rate calculations require the operator to know the flowrate into the clarifier and the lineal feet of overflow weir. d. Clarifier Solids Loading Rate (CSLR) o Depending on the "unit process" Solids Loading Rates are different.

What federal law regulates point and nonpoint pollution into our nations water supply (ABC)?

Clean Water Act "The objective of the Federal Water Pollution Control Act, commonly referred to as the Clean Water Act (CWA), is to restore and maintain the chemical, physical, and biological integrity of the nation's waters by preventing point and nonpoint pollution sources, providing assistance to publicly owned treatment works for the improvement of wastewater treatment, and maintaining the integrity of wetlands."

How to avoid falling:

Clean up oil and grease slicks on walkways ASAP. o Walk very carefully around clarifiers. DO NOT Run. o Keep all tools in a safe storage area. Avoid clutter. Pick up hoses, ropes, cables, buckets, etc. o DO NOT sit, climb or hang over guard/hand rails. o Ensure covers, gratings, and safety chains are operable and inplace. Falling into a confined space with limited oxygen available could cause more than just an injury.

COAGULANTS

Coagulants are a group of chemicals that promote the clumping together (flocculation) of very fine particles to form larger particles. This process makes it easier to separate the solids from the water by settling, skimming, draining or filtering.

Sludge Sump

Collects and traps the sludge before it is withdrawn from the clarifier.

Effluent Launder

Collects the settled wastewater flowing over the weirs and conveys it from the sedimentation basin.

According to Chapter 2 and VTech ONLINE Water and Wastewater COURSE, ______________ solids, are extremely fine particles that you can see but will not settle (non setteable) from the liquid portion. They can *usually* be filtered from the liquid to a 0.45-um membrane filter (ABC).

Colloidal A colloid is defined as very small, finely divided solids (particles that do not dissolve) that remain dispersed in a liquid for a long time due to their small size and electrical charge. These particles have negligible settling velocity because their small mass has a low gravitational force compared to surface frictional forces Suspended solids are composed of two parts: settleable and nonsettleable. The difference between them depends on the size, shape and density of the particles. The suspended solids determination is one of the major parameters used to evaluate the strength of waste waters and the efficiency of treatment units. Both the total and the volatile suspended solids tests are used. The measurement of suspended solids begins with separating those solids that can be removed from suspension in the water by filtration. These solids contain organic and inorganic materials. The measurement of the organic materials is referred to as "volatilization". This is accomplished by a combustion procedure in which the organic material is converted into water and carbon dioxide by controlled temperature. The remaining material is considered "fixed" or "inorganic". A suspension of tiny particles in some medium is called a colloidal dispersion, or a colloid. The suspended particles are single large molecules or aggregates of molecules or ions ranging in size from 1 to 1,000 nanometers. Because the colloidal particles all have an outer layer of ions with the same charge, they repel each other and do not easily aggregate to form particles that are large enough to precipitate.

COLLOIDS

Colloids are very small, finely divided solids (particles that do not dissolve) that remain dispersed in a liquid for a long time. This is due to their small size and electrical charge. When most of the particles in water have a negative electrical charge, they tend to repel each other. This repulsion prevents the particles from clumping together, becoming heavier in mass, and then settling out. Note the steel grey colors in Canadian rivers; colloids.

Define Colloids

Colloids are very small, finely divided solids/particulates that DO NOT DISSOLVE in water. They are electrically charged and very small (usually <200 nm). They are a problem because organic based colloids exert a high demand for dissolved oxygen. Colloids are associated with high BOD values. Their removal is desirable.

Define Mixed Liquor (ML)

Combination of microorganisms, air and wastewater

Comminution/Shredding

Comminution devices to cut either vertically (barminutor) or horizontally (comminutor), either in pipelines Comminutors are "cutting" devices with the added benefit of "screening". Comminutors are HORIZONTAL grinders Large Garbage disposal smaller waste volume Rocks and metal can stop it cold turkey

Conventional Sanitary Sewer:

Conventional Sanitary Sewer: Carries wastes from households, commercial establishments, and industrial wastes from origin to treatment facility (~2 ft/sec).

Biological activity in long, sluggish-flow, flat-grade sewer lines will likely (ABC)

Create oxygen deficiency in the air in manholes, sewers, or wet wells.

List some examples of incompatible organics?

DDT Dioxin Pesticides Phenols herbicides PCBs

Chlorine (Cl2) problems:

DEATH by suffocation. Irritant to eyes, skin, and all mucous membranes. This gas is VERY TOXIC, causes CHOKING and DEATH. Have a SCBA available.

What does It Take To Be a Treatment Plant Operator?

DESIRE

Collection system

DOES NOT treat the conveyed water or wastewater, it just contains it and moves it along.

It takes several elements to become a "most" qualified wastewater professional. What is the greatest contributing factor to success:

Desire

____________ is the heavy, coarse mixture of grit and organic material carried by wastewater. _______________ is also called GRIT.

Detritus

Define Clarifier design

Dimensions of tank; Influent structure; Outlet structure; Sludge system; Scum removal system (not required);

The wastewater treatment process designed to kill or inactivate pathogenic (disease-causing) bacteria is called:

Disinfection

Name (3) Clarifier Inlet Design

Dissipate the inlet velocity; Distribute flow equally both horizontally & vertically;  Eliminate corner pockets and dead ends; Maintain velocity of inlet channel > 1.0 fps;  Baffle of full-width, 6" below the water surface and 12" below the inlet orifice bottom.

According to our textbook (Chapter 2) and Standard Methods For Water and Wastewater Analysis , total solids can be divided into suspended solids and ________ solids (ABC).

Dissolved Standard Methods Total solids, as the term implies, includes all of the solid constituents of a wastewater. Total solids are the total of the organic and inorganic solids or the total of the suspended and dissolved solids. In an average domestic wastewater, total solids are about half organic and half inorganic, and about two-thirds in solution (dissolved) and

According to our textbook (Chapter 2) and Standard Methods For Water and Wastewater Analysis , ___________ solids remain in liquid solution and are defined as the solids that will pass through a 0.45um membrane filter (ABC).

Dissolved Total dissolved solids (TDS), also referred to as filterable residue, represents the portion of the sample (water, wastewater, effluent) that passes through a filter of a particular size. Generally, a pore size of 0.45 mm is considered to be adequate to differentiate between microscopic particulate and dissolved material. The final result, after evaporation and drying to constant weight at 180oC, represents the total dissolved solids. (1)

Total Dissolved Solids (TDS, mg/L)

Dissolved Solids include "all solids" that will pass through a "standard" filter, usual pore opening of 5Fm (5 micro-meters, 5 microns, 5 x 10-6 meter). Think of salt or sugar dissolved in water. These are examples of Total Dissolved Solids where salt is a dissolved inorganic solid and sugar is a dissolved organic solid. After filtration the filtrate (material that passed through the filter) is evaporated to dryness at 103 EC.

Total Solids consists of______and _______ solids, both of which contain organic and inorganic matter

Dissolved and Suspended solids

How to avoid electrical shock

Do not use water for cleaning in/around electrical panels and the MCC, or any other electrical equipment. o Use rubber floor mats in front of all electrical panels. o Call a qualified electrician or authorized "limited" electrical licensed person to perform the work on all electrical/electronic equipment.

Main Sludge Collector

Drags settled solids (sludge) to the sump. A continuous chain with crosspieces (flights or scrapers) attached.

Sludge Collector Mech.

Drags settled solids across clarifier bottom to a sludge collection pit or sump.

Cross Collector

Drags sludge to deep end of pump for removal by pumping. Also prevents bridging of sludge in sump.

Incineration

During the 1970s the burning of sludge solids became a very popular way to "sterilize" and reduce the volume of solids. However, increasing air pollution standards and the required air pollution abatement equipment required to meet these emerging standards, made this form of sludge reduction marginally cost effective

Sanitary sewer collection systems collect sewage and other wastewater and transport it to a facility for proper treatment and disposal. Sanitary sewer overflows occur when untreated sewage is discharged from the collection system due to pipe blockages, pipe breaks, infiltration and inflow from leaky pipes, equipment failures, and insufficient system capacity. Which set lists the three types of collection systems (see chapter 3)?

EPA Definitions Combined, sanitary, and stormwater

Methane (CH4)

EXPLOSIVE, ODORLESS, can cause DEATH by asphyxiation. It is a product of anaerobic decomposition.

Dissolved Oxygen

Effluent 0 - 2 mg/L

Coliform Group Bacteria

Effluent 5 000 - 2 000 000/100 mL Removal Efficiency 25%-75%

_____________ ensures equal (even) effleunt flow over all weirs and eliminates short circuiting. Designed for small surface elevation (water level) adjustments in the clarifier provided the plate is designed for vertical movement (up or down). Leads the water to the launder region.

Effluent Weir An Effluent Weir collects the settled wastewater flowing over the weirs and conveys it from the sedimentation basin.

Define Emulsions

Emulsions are liquid mixtures of two or more substances not normally dissolved in one another. Emulsions contain suspended globules (grease, oil, fat) and exhibit a high oxygen demand, therefore a high BOD.

Effluent Weir

Ensures equal flow over all weirs. Designed for small surface elevation (water level) adjustments in the clarifier provided the plate is designed for vertical movement (up or down).

PREVENTION OF POLLUTION

Essentially, the operator's main job is to protect the users of receiving waters. You must also be aware that "prevention of pollution" also covers waste sludges and biosolids. You must not impair the environment with biosolids application that renders the soil "useless". REMOVE THE "UNDESIRABLES" FROM WATER

What single factor (of those listed below) contributes to the "Natural Cycle"?

Evaporation

Scum Baffle

Extends above the water surface and prevents the floating material from reaching the effluent trough.

Fixed and Volatile Solids Test: Part 1

FIRST: GET THE SAMPLES Where do we get the samples for the fixed and volatile solids test? All our samples are in the desiccator

Manholes Hazards

Fall Hazards Cover lifting hazards Atmospheric hazards Traffic Hazard Engulfment Confined Space Entry/Safety

All storm runoff from streets, land, and roof buildings is collected only in a sanitary sewer.

False

Chapter 1 Department of human services is responsible for wastewater operators?

False

Inorganic wastes are chemical substances of organic origin.

False

Once that you (the operator) have passed your certification exam, there is no further study of the subject required.

False

Plant visitors are often impressed by careful record keeping that show efficient operation of the municipal facility. Visitors never are influenced by the appearance of the facility and its grounds.

False

Raw wastewater is plant influent, or wastewater after any treatment.

False

The sole purpose of the operation of a wastewater treatment plant is to protect the downstream water user.

False

The spacing between the bars in bar screens is typically 0.25 to 0.5 in. (6.35 to 12.7 mm).

False

Wastewater may be diverted into receiving waters without treatment provided there is enough water in the receiving stream to quickly "dilute" the wastewater and its impact.

False

When excess quantities of FOG enter the secondary treatment process and merge with biomass, settleability improves ?

False

Activated sludge (a whole bunch of microorganisms) is added to wastewater and resulting in a thick mixture (raw activated sludge, RAS) is constantly de-aerated and agitated (mixed). After some time in the aeration tank (a condominium for microorganisms), the activated sludge is pushed out and allowed to settle (due to gravity) by sedimentation.

False Activated sludge (a whole bunch of microorganisms) is added to wastewater and resulting in a thick mixture (mixed liquor, ML) which is constantly aerated and agitated (mixed). After some time in the aeration tank (a condominium for microorganisms), the activated sludge is pushed out and allowed to settle (due to gravity) by sedimentation.

Some modern wastewater treatment plants use both coarse screens and fine screens. Bar racks are designed to remove large solids, rags, and debris they are sloped at an angle between 50° and 75° from vertical.

False Bars set at 30 to 45 degrees from vertical to facilitate cleaning. Primarily used in older or smaller treatment facilities, or in bypass channels. Bars set at 30 to 45 degrees from vertical to facilitate cleaning. Primarily used in older or smaller treatment facilities, or in bypass channels.

Some modern wastewater treatment plants use both coarse screens and fine screens. Trash racks, are constructed of heavy, parallel rectangular or round steel bars with 0.06- to 0.25-in. (2- to 6-mm) spacing set in a channel.

False Fine screens are typically used to remove material that may create operation and maintenance problems in downstream processes, particularly in systems that lack primary treatment. Typical opening sizes for fine screens are 1.5 to 6 mm (0.06 to 0.25 in). Very fine screens with openings of 0.2 to 1.5 mm (0.01 to 0.06 in) placed after coarse or fine screens can reduce suspended solids to levels near those achieved by primary clarification. Trash Rack Designed to prevent logs, timbers, stumps, and other large debris from entering treatment processes. Opening size: 38 to 150 mm (1.5-6 in). Fine screens are typically used to remove material that may create operation and maintenance problems in downstream processes, particularly in systems that lack primary treatment. Typical opening sizes for fine screens are 1.5 to 6 mm (0.06 to 0.25 in). Very fine screens with openings of 0.2 to 1.5 mm (0.01 to 0.06 in) placed after coarse or fine screens can reduce suspended solids to levels near those achieved by primary clarification.

Clarifiers are equipped with a rotating arm mechanism called a hopper that removes the floating scum from the clarifier

False Hoppers are for sludge blanket removal Rakes are for skimming the top

Sanitary sewers are placed at a slope that is sufficient to produce a water velocity of 300 ft/sec?

False NO WAY. 300 ft/sec is crazy flow rates for wastewater. We are more on the order of flow rates at 2 ft/sec (just fast enough to keep solids moving but not clogging the pipes). Flow velocity greater than 10 ft/s leads to excessive turbulence at junctions and erosion of the line. The maximum velocity of wastewater in a sanitary collection system should be 10 ft/sec, The minumum velocity should be about 2 fps. The typical design velocity for low flow conditions is 0.3 m/s (1 foot/second). During peak dry weather conditions the sewer lines must attain a velocity greater than 0.6 m/s (2 feet/second) to ensure that the lines will be self cleaning (i.e., they will be flushed out once or twice a day by a higher velocity). Velocities higher than 3.0 m/s (10 feet/second) should be avoided because they may cause erosion and damage to sewers and manholes (Qasim 1994).

Proper disinfection kills all organisms (ABC)?

False Sterilization is the term for killing all organisms. Disinfection just reduces the numbers of pahtogenic organisms but not all organisms.

Trash racks, also called bar racks, are constructed of heavy, parallel rectangular or round steel bars with 0.06- to 0.25-in. (2- to 6-mm) spacing set in a channel?

False Trash/Bar racks typically have 2- to 6-in. (50- to 150-mm) spacing. Fine screens have 0.06- to 0.25-in. (2- to 6-mm) spacing.

A screenings (dumpster) has a capacity of 400 cubic feet. If an average of 3.4 cu ft of screening materials are removed daily from the wastewater flow, in how many days will the dumpster be full (handy Dandy #32; Detention Time)?

Fill Time = (Volume Cu ft) Screenings Removed, cu ft /day Fill time= (400 cu ft / 3.4 cu ft/day) = 117.6 days

Belt Filter Press

Filters that press water out of the sludge

FLOCCULATION

Flocculation is the gathering together of fine particles after coagulation to form larger particles by a process of gentle mixing.

What is the likely cause of excessive grit in the bar-screen chamber?

Flow velocity is too low.

Force Mains

Force Mains- At design average flow a velocity of at least 2 fps (0.61 m/s) shall be maintained. Except where grinder pumps or septic tank effluent pumps are used, force mains shall be at least 4 inches in diameter. Automatic air relief valves shall be placed as needed (at high points) in the force main to prevent air locking. The force main and fittings, including reaction blocking, shall be designed to withstand normal pressure and pressure surges (water hammer).

FREEBOARD

Freeboard is defined as the vertical distance from the normal water surface to the top of the confining wall. It can also be the vertical distance from the surface of the water to the top working deck of a ship.

SOLIDS IN WATER

From the first days of wastewater treatment, removing Solids from water has been the primary function. Solids reduction can be obtained in the Primary Treatment process.

GASIFICATION

Gasification is the conversion of both soluble and suspended organic materials into various gasses during either aerobic or anaerobic decomposition. In clarifiers the resulting gas bubbles can become attached to the settled sludge and cause large clumps of sludge to rise and float on the water surface. Further, an example of gasification can be found in an anaerobic sludge digester where these gasses are collected, separated, and burned for fuel or simply disposed of using a waste gas burner.

GBTs

Gravity Filters that allow gravity to separate (thicken) the sludge from the water

Conventional Sewer System

Gravity sewer lines through manholes and into pump stations Pump stations force the sewage to higher elevations The force main ends in a "terminal" manhole

Is Public "perception" is all important.

Great plant records and meticulous management mean nothing unless the visiting public perceives your facility is neat and tidy, and that the PLANT EFFLUENT IS AS CLEAR AS THE RECEIVING STREAM!

Grit Cap. ft3grit/MG wastewater =

Grit volume, ft3/day/Flowrate, MGD

What are typical operational values for the settling compartment?

HDT about 1.0 - 4.0 hours CSOR about 600 - 1 200 gpd/ft2 CWOR about 10 000 - 20 000 gpd/ft TSS removal about 45% - 65% BOD removal about 25% - 35%

Biological hazards in collection system operations include (ABC)

Hepatitis A

Vertical (p) in ft/Particle velocity, in fps =

Horizontal distance (w), in ft/water velocity, in fps

Comminutor

Horizontal shredding

HYDRAULIC LOADING

Hydraulic loading (HL) refers to the flowrate (gpm, MGD or cu m/day) to a treatment plant or treatment process. Process variables such as hydraulic detention times, surface loadings rates, and weir overflow rates are directly influenced by hydraulic loading flowrates.

What is the gas that can form in the pipeline that would cause corrosion and/or damage to the concrete.

Hydrogen Sulfide

The pH is a measure of the concentration of _____ ____ in a solution (ABC).

Hydrogen ions "pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water. http://ga.water.usgs.gov/edu/phdiagram.html"

Which of the following has a rotten egg odor?

Hydrogen sulfide "Anaerobic bacteria release hydrogen sulfide as well as methane gas, both of which can create hazardous conditions. Even as the anaerobic action begins in the collection lines of a sewer system, deadly hydrogen sulfide or explosive methane gas can accumulate and be life threatening."

What are some of the dissolved substances in water?

Hydrogen, oxygen, carbon, manganese, sodium, iron, nitrogen and organic material

HYDROSTATIC SYSTEM

Hydrostatic simply means "water at rest", as in a pool, pond, or basin. We know that a deep pond of water can create large pressures at the pond bottom (23.1 feet of water depth results in an increased gauge pressure of 10 psi). An example of a "hydrostatic system" would be a hydrostatic sludge removal system. If the surface of the water for example in a clarifier is higher than the surface sludge found in a well or hopper, sludge material will be forced from the bottom of the clarifier to flow through a piping system to the sludge well or hopper. This difference in elevation is known as hydrostatic head or pressure head.

Why should an operator have an understanding of natural cycles?

IN order to control wastewater processes and odors, protect the receiving waters

Describe icebergs and ice cubes

Icebergs are comprised of water that has frozen, similar to ice cubes in a drink. The density of the ice is slightly less than water, causing them to float. Roughly 9/10 of the iceberg is below water.

What are Imhoff Tanks?

Imhoff Tanks combine sedimentation and sludge digestion in the same unit, much like the Sedimentation-Digestion Unit already discussed.

Secondary Treatment

Implies that we grow/cultivate/manage a biological culture to convert most of the remaining unstable materials out of the water so it can be safely released. Secondary treatment is an aerobic process, meaning lots of dissolved oxygen (DO) must be supplied for good results.

Wet Well/Pump Stations/Lift Stations

In conveying wastewater from outlying areas to a treatment plant by gravity flow, it is occasionally necessary to install a lift station or pump station. Sewage is fed into and stored in an underground pit, commonly known as a wet well. The well is equipped with electrical instrumentation to detect the level of sewage present. The pump may lift wastewater directly to a higher sewer where it continues to gravity flow or lifts it directly into the treatment plant. Sewer flow minimum of 2 ft/sec!!!!! Pump station may increase the velocity

Grit is removed by a conveyor with scrapers, buckets, or plows.

Indeed

A velocity of 0.7 to 1.4 fps in the grit channel seems to be ideal to settle out the larger?

Indeed! ideal velocity is 1fps

What term is used to describe groundwater that seeps into the collection system through defective or cracked pipes, manhole walls, and joints? ?

Infiltration

Inflow and infiltration or I & I are terms used to describe the ways that groundwater and stormwater enter into dedicated wastewater or sanitary sewer systems. Dedicated wastewater or sanitary sewers are pipes located in the street or on easements that are designed strictly to transport wastewater from sanitary fixtures inside your house or place of business. What term is used to describe groundwater that seeps into the collection system through defective or cracked pipes, manhole walls, and joints (Chapter 3)?

Infiltration Inflow is stormwater that enters into sanitary sewer systems at points of direct connection to the systems. Various sources contribute to the inflow, including footing/foundation drains, roof drains or leaders, downspouts, drains from window wells, outdoor basement stairwells, drains from driveways, groundwater/basement sump pumps, and even streams. Infiltration is groundwater that enters sanitary sewer systems through cracks and/or leaks in the sanitary sewer pipes. Cracks or leaks in sanitary sewer pipes or manholes may be caused by age related deterioration, loose joints, poor design, installation or maintenance errors, damage or root infiltration. Groundwater can enter these cracks or leaks wherever sanitary sewer systems lie beneath water tables or the soil above the sewer systems becomes saturated.

When referring to a wastewater collection system, the term (I & I) refers to which of the following statements?

Infiltration and Inflow

Inflow and infiltration or I & I are terms used to describe the ways that groundwater and stormwater enter into dedicated wastewater or sanitary sewer systems. Dedicated wastewater or sanitary sewers are pipes located in the street or on easements that are designed strictly to transport wastewater from sanitary fixtures inside your house or place of business. What term is used to describe water that enters the collection system from sources such as foundation drains, holes in manhole covers, surface runoff, and cross connections between sanitary and storm sewers (Chapter 3)?

Inflow Inflow is surface water that enters the wastewater system from yard, roof and footing drains, from cross-connections with storm drains, downspouts, and through holes in manhole covers. Inflow occurs as a result of storm events such as rainfall, snowfall, springs or snow melt that contribute to excessive sewer flows. Peak inflow can occur during heavy storm events when storm sewer systems are surcharged, resulting in hydraulic backups and local ponding. See picture above for a graphical view of the sources of inflow.

BOD5

Influent 125-350 mg/l Effluent 50-200 mg/l Removal Efficiency 25%-50%

Total Suspended Solids

Influent 150-400mg/l Effluent 50-150 mg/l Removal Efficiency 40-70%

Temperature

Influent 40-75F

Settleable Solids

Influent 5 - 15 mL/L Effluent 0.2 - 3 mL/L Removal Efficiency 95 - 99 %

pH

Influent 6.5-8 Effluent 6.3-7.8

Imhoff Tanks are rarely constructed today. Last one in the local area that I am aware is Ridgefield, WA. Usually constructed in the US and State forest parks.

Interesting

SHREDDING

Is comminution. This is a mechanical treatment process which cuts large pieces of wastes into smaller pieces so they won't plug pipes or damage equipment. SHREDDING and CO

What Does a Treatment Plant Operator Do

Keep the water reclamation facility (wastewater treatment plant) operating, maintained, and well managed. Key word here is "Do". Do what? Turn valves, operate switches, collect samples for analysis, analyze water samples

Fixed and Volatile Solids Test: Part 3

LAST STEP: Weighing the "ASHED" Solids for Each: TS, TSS, and TDS

How did many receiving waters become polluted?

Lack of public concern and by discharging wastewater into the receiving water beyond its natural purification capacity

LAUNDERS

Launders are found on all clarifiers and sedimentation tanks. They are the effluent troughs that collect and transport the "clarified" wastewater. Launders are easy to spot because they are fitted with hundreds of overflow weir plates, usually in the shape of a V.

LINEAL

Lineal is a direct line. It has units of measurement. For example, a board 12 feet long contains 12 lineal feet in its overall length.

SUBNATANT

Liquid removed from beneath floating sludge. Subnatant commonly refers to the liquid found between the floating sludge on the surface and non-floating (inert) sludge found on the bottom of an anaerobic digester. This liquid is usually returned to the influent wet well or to the primary clarifier for re-treatment. WATER ON BOTTOM

SUPERNATANT

Liquid removed from settled sludge. Supernatant commonly refers to the liquid between the sludge on the bottom and the scum on the surface of an anaerobic digester. This liquid is usually returned to the influent wet well or to the primary clarifier. WATER ON TOP

MPN

MPN is the Most Probable Number of coliformgroup organisms per unit volume of sample water. MPN is an estimate of the number of organisms or population of organisms per 100 mL of sample water volume. You could say that MPN is a density or concentration of organisms; however this is not the proper application of the word density.

Tasks least likely to be performed by collection systems personnel is

Making water connections

MASKING AGENTS

Masking agents are substances used to cover up or disguise unpleasant odors. Liquid masking agents are dripped (fed) into wastewater, sprayed (misted) into the air, or evaporated (using heat) along with the unpleasant fumes or odors subsequently discharged into the air by blowers to make an undesirable odor less noticeable. Bathroom sprays are masking agents.

Gasoline & Other Petroleum Products problems:

May cause FIRES or EXPLOSIONS. As the concentration increases, O2 decreases and it is DEATH by asphyxiation.

Total Solids Test Procedure 1st Procedure?

Method: 2540 B. Total Solids (TS), dried at 103 - 105 ºC 1. get sample and bring it back to lab 2. place sample into a clean glass containter 3. ice the sample doen to 4 C and go to the Lab 4. lab supervisor will decide what will be done next (refrigerate up to 24hrs at 4 C OR analyze immediately)

(TDS) Total Dissolve Solids Test: Part 1

Method: 2540 C. Total Dissolved Solids (TDS) dried at 180 ºC 1. locate the sample point, take sample 2. place sample into a clrean glass container 3. ice the sample down to 4 C and go to the lab 4. lab supervisor will decide what to do (refrigerate up to 24hrs at 4 C OR analyze immediately)

(TSS) Total Suspended Solids Test Procedure, 1st part?

Method: 2540 D. Total Suspended Solids (TSS), dried at 103 - 105 ºC Get the Sample & Bring it back to the Laboratory 1. locate the sample point, take sample 2. place sample into a clrean glass container 3. ice the sample down to 4 C and go to the lab 4. lab supervisor will decide what to do (refrigerate up to 24hrs at 4 C OR analyze immediately)

Fixed and Volatile Solids: Break them down into parts

Method: 2540 TOTAL VOLATILOE SOLIDS (TVS) & FIXED SOLIDS (TNVS) IGNITED AT 550 ºC Let's Break Solids Apart! Total Solids: Total Volatile solids, Total non-volatile solids Total Suspended Solids: Total volatile suspended solids, total non-volatile suspended solids Total Dissolved Solids: Total volatile dissolved solids, total non-volatile dissolved solids

ALGAE

Microscopic plants which contain chlorophyll and live floating or suspended in water. They also may be attached to structures, rocks, or other submerged surfaces. Algae produce dissolved oxygen during sunlight hours and use oxygen during the night hours. Their biological activities appreciably affect the pH, alkalinity, and dissolved oxygen of the water.

Would it be a good idea to use trickling filter media of various sizes so it could pack together better?

NO If the media were packed together, air could not circulate and the organisms on the media would not get enough oxygen

What does NPDES stand for?

National Pollutant Discharge Elimination System

Trickling filters treat waste by the filtration process. Yes or No.

No

Floatable Solids

No test is currently available to quantify floatable solids; that is to determine "how much" concentration of floatables per unit of water. Treatment units are designed to specifically remove floatable material.

Does disinfection usually kill all organisms in the plant effluent?

No, disinfection is designed to kill or inactivate pathogenic organisms sterilization KILLS ALL organisms in wastewater

Carbon Dioxide (CO2) problems:

Odorless & Tasteless. Causes ASPHYXIATION by displacing O2. It is found in poorly ventilated areas. Conc. Of 10% can cause UNCONSCIOUSNESS and DEATH.

Carbon Monoxide (CO) problems:

Odorless, Tasteless, Non-irritating, Flammable, Explosive. Product of incomplete combustion. Causes DEATH by asphyxiation.

Trickling Filters

One of the oldest and well established methods for treating wastewater. Well operated TF's can remove up to 85% of BOD and TSS found in waste 1. Primary clarifier effluent runs into a rotating sprinkler 2. the sprinkled wastewater is allowed to trackle down over a 6 foot depth of 4-5 inch rochs. 3. slime that grow on the rocks "clean" the wastewater by removing the organics and "holding on" to the solids. Dissolved Oxygen (DO) is offered naturally by air movement through the rock bed

COLIFORM

One type of bacteria. The presence of coliform-group bacteria is an indication of possible pathogenic bacterial contamination. The human intestinal tract is one of the main habitats of coliform bacteria. They may also be found in the intestinal tracts of warm-blooded animals, and in plants, soil, air, and the aquatic environment. Fecal coliforms are those coliforms found in the feces of various warm-blooded animals; whereas the term "coliform" also includes other environmental sources. A filtered wastewater sample incubated at 35°C for 24 hours in a growth media, shown here.

Organic and Inorganic Solids

Organic Solids implies Total Volatile Solids (TVS) Inorganic Solids implies Total Non-Volatile Solids (TNVS) The relative amounts of Organic and Inorganic Solids can be determined by the TNVS and TS test then the volatile solid (TVS) component is found by math subtraction: TVS = TS minus TNVS This test is done to estimate the percentage (%) of solids captured/destroyed as the wastewater is cleaned through the treatment process. The usual relative amounts for wastewater solids is 75% TVS and 25% TNVS. This test is done after drying the solids at 103 EC, then "baking" them in a muffle furnace at 550 EC. The solids that remain as ash are TNVS.

TYPES OF WASTE DISCHARGES

Organic Wastes: Domestic, Industrial (Dairy, Slaughter House, etc) Inorganic Wastes: Gravel Washing, Plating, Battery Manufacturing, etc. Thermal Wastes: Nuclear Power Plants (remember Trojan) Radioactive Wastes: -Hospitals -Laboratories -Industry

What are the 3 chemical characteristics?

Organic profile Inorganic profile oxygen consumption

ORGANIC WASTE

Organic waste is waste material that comes mainly from animal or plant sources. Organic wastes generally can be consumed by bacteria and other small organisms. Inorganic wastes are chemical substances of mineral origin.

The main difference between organic and inorganic wastes is

Organic wastes contain carbon

What causes oxygen depletion when organic wastes are discharged to the water?

Organic wastes in water provide food dor the bacteria. These bacteria require oxygen to survive and consequently deplete the oxygen in the water in a way similar to the way oxygen is removed when people breathe.

What is the term given to excess combined wastewater that must be bypassed to avoid hydraulic overload of the sewerage system.

Overloaded

what are the typical ranges in the "digestion compartment" lab testing process?

PH: 6.7-7.3 Alkalinity: 1000-3000 mg/l Volatile Acids: 100-500 mg/l

What is the term that means "Disease causing"

Pathogenic

What are disease producing bacteria called?

Pathogenic Pathogenic bacteria are bacteria that cause bacterial infection

(TSS) Total Suspended Solids Test Procedure, 3rd part?

Performing the Total Suspended Solids Test Take the Desiccator with All Dishes and Washed Glass Fiber Filters (GFF) into the Balance Room for Weighing

What Pay Can a Treatment Plant Operator Expect?

Personal achievement and job satisfaction are high on the list. Money comes, however, if you want to "roll the dice of life". If that's the case you may choose the "corporate option" (i.e. OMI, US Filter, Chip Manufacturers, etc.). Modest and comfortable income, excellent health/dental benefits, and a great retirement annuity are some of the rewards you will come to enjoy.

Human Health

Poor or inadequate treatment of wastes can have a tremendously negative effect on public health. The spread of disease-causing bacteria and viruses are likely to result from negligence of treatment and disinfection. Over the centuries serious outbreaks of communicable diseases coming from drinking water, food supplies, and direct contact with improperly treated wastes have been documented. The wastewater treatment operation kills disease causing bacteria (pathogenic organisms) either through natural die-off or proper disinfection. When disinfection is poorly attempted, the environmental release of disease causing bacteria is likely. No documentation of HIV or AIDS infecting anyone in our industry has ever been reported.

________ treatment is the removal of metal, rocks, rags, sand, eggshells, and similar materials, which may hinder the operation of a treatment plant. _________ treatment is accomplished by using equipment such as racks, bar screens, comminutors, and grit removal systems. _____________ treatment occurs in the "headworks".

Preliminary Treatment

Preliminary Treatment

Prepare sewage for physical solids settling and scum flotation in the primary process. HEADWORKS "first" glance at the waste about to be treated. Big stuff is shredded, or removed; wastewater flowrates are measured and logged in; and grit that will interfere with pumps is removed Screen-shred-grit ***debris to landfill***

(TSS) Total Suspended Solids Test Procedure, 2nd part?

Prepare the Glass Fiber Filters for the TSS Test. Rinse (wash) the Glass Fiber Filters with Distilled Water 1. rinse filter, insert filters then place filters into an aluminum dish 2. place filters with the aluminum dishes directly into the drying over at 103 C NOTE: you have the aluminum dish, and the clean filter, put them both into the drying oven at 103 C 3. remove all dishes and dried filters from the over, cool and store in the desiccator. get ready to go to the blance room for weighing 4.

Wearing Shoe

Prevents wear on the scraper crosspieces. Usually a piece of iron attached close to the outer ends of the scrapers.

Clarifier Solids Loading Rate (CSLR) Usual loading maximum values are:

Primary Clarifiers: not a consideration Secondary Clarifiers: 12-30 ppd/ft^2 AS Secondary Clarifiers: 24-30 ppd/ft^2 DAF Units 05-40 ppd/ft^2 Sludge Thickeners 05-20 ppd/ft^2

Sludge and Scum

Primary Treatment = Clarification of Wastewater. Sludges and scum found in raw wastewater are meant to be removed in the PRIMARY clarifiers. Solids are settled, while scum floats and is scraped into a receptacle. Both sludge and scum enter the solids processing scheme while "clarified" waste is to proceed onto Secondary Treatment. If the treatment plant operator is not doing the job, sludge and scum can end up in the receiving water; river or lake.

Types of Solids

Primary Treatment removes Settleable Solids (tested using the Imhoff Cone). This eliminates most of the Total Suspended Solids (both organic and inorganic). From here wastewater goes through Secondary Treatment where Total Dissolved Solids (usually the organic portion only) is removed. Inorganic Dissolved Solids are very hard to deal with and therefore we try to prohibit them from entering the wastewater collection system (Industrial Permitting System).

Septic waters are, or can

Produce hydrogen sulfide

The MAIN benefit of a successful wastewater treatment program is:

Protect the public health

Angle Track

Provides a track on which the main collector crosspieces ride.

Sludge Collector Drive

Provides power that causes the main and cross collector units to move.

POTW is the short version for _________________________ ?

Publicly Owned Treatment Works This term is used by the US Environmental Protection Agency to designate treatment works which are owned by a state, municipality, city, town, special sewer district or other publicly owned and financed entity. This is opposed to similar treatment facilities which are privately (i.e. industrial) owned. This definition includes any devices and systems used in the storage, treatment, recycling and reclamation of municipal sewage (wastewater) or industrial wastes of a liquid nature. POTW also includes sewers, pipes, pumping stations and other conveyances only if they carry wastewater to a POTW treatment plant.

A rectangular wet well is 12 ft long, 10 ft wide. With no influent to the well, a pump lowers the water level 1.2 ft during a four minute pumping test. What is the gpm flow rate? Handy Dandy #52

Pumping Rate = (length ft) (width ft) (Well level ft) (7.48 gal) Duration of test PR= (12 ft)(10 ft)(1.2 ft) = 144 cu ft 144 cu ft (7.48 gal / 1 cu ft) = 1077 gal 1077 gal = 4 minutes 269 gpm

The depth of wastewater in a wet well is sufficiently low to allow shutting off all pumps. With a rod and a stop watch, you are able to determine that the water level rises 1.5 ft in 2 minutes and 30 seconds. The pumps are re-started. What is the gpm influent rate to the 8 ft long , 8ft wide rectangular wet well? Handy Dandy #52

Pumping Rate = (length ft) (width ft) (Well level ft) (7.48 gal) Duration of test PR= (8 ft)(8 ft)(1.5 ft) =96 cu ft 96 cu ft (7.48 gal / 1 cu ft) = 718 gal 718 gal = 2.5 minutes 287 gpm

ROTATING BIOLOGICAL CONTACTOR (RBC)

RBC is a secondary biological treatment process for domestic and biodegradable industrial wastes. Biological contactors have a rotating "shaft" surrounded by plastic discs called the "media". The shaft and media are called the "drum". A biological slime grows "fixes itself" on the media, when conditions are suitable. These living "fixed" microorganisms within the slime then treat the wastewater being sent through the RBC basins.

Rotating Biological Contactors

RBC's are similar to TF. The difference is that TFs allow water to fall over the media (rock) while RBSs allow the media (plastic) to dip into.out of the water. This plastic media rotates on a long 25ft shaft. Today, RBC's are rarely designed as this technology is dated and allows for almost no operating flexibility. Their design life is only 20 years.

Screenings Removal

Range of 0.5 to 12 cu ft screenings per MG of wastewater flow are typically removed Need to keep records of screenings removed from wastewater flow.

Influent Well

Receives flow from the influent pipe, reduces velocities and distributes flow evenly.

Sump

Receives settled sludge from the floor of the sedimentation basin. Stores sludge in sufficient quantity to avoid frequent (less than once per hour) removal by pumping, but of sufficient volume to maintain sludge thickness and to exclude water in the sedimentation basin from being pumped out during the pumping cycle.

Scum Trough

Receives the floating material from the scum skimmer for removal.

Who do you protect?

Receiving Waters Downstream Users Neighbors Public Health

"Flights" are used in _____shaped clarifiers? To do what?

Rectangular usually wooden beams attached to endless chains. the collector flights travel on the surface in the direction of the flow, conveying grease and floatable solids down to the scum trough to be skimmed off to the solids handling facilities.

Which one of the following is not part of a good public relations program (ABC)?

Referring all complaints to the manager

The main goal of primary treatment is to:

Remove sludge and scum from wastewater

Sludge Withdrawal Pump

Removes the sludge from the sump (pit).

Sludge accumulations in settling basins over a period of time usually (ABC):

Result in odor problems

RETENTION TIME

Retention time is the time that water, sludge or solids are retained or held in a clarifier or sedimentation tank. See DETENTION TIME. Retention Time (or Solids Retention Time, SRT) usually applies to the time that sludge or solids are retained in a treatment system. Detention Time (or Hydraulic Detention Time, HDT) usually applies to the time that water is retained in a treatment system.

Hydrogen Sulfide (H2S) problems:

Rotten Egg Odor. This will quickly dull you sense of smell. Combines with water to form sulfuric acid (dissolves concrete). It is a respiratory irritant that can cause bronchitis, & pulmonary edema. This gas is VERY TOXIC, can be FLAMMABLE and EXPLOSIVE when mixed with air (O2).

Hydrogen sulfide gives off an odor similar to?

Rotten Eggs

Fixed and Volatile Solids Test: Part 2

SECOND: Perform the Volatile Solids Profile Analysis This is called "ASHING" the Samples *Open the Muffle Furnace (550 ºC) *Burn for at least 15 minutes (this Volatilizes the Organic Material) NEXT: Transfer the "ASHED" Samples to the Desiccator

What can be added to remove (dechlorination) residual chlorine?

SO2

Clarifier peak hourly flow

SORp < 1500 gpd/sf;

clarifier removal efficiency: SS BOD 5

SS 50-60% BOD5 25-40%

Which of the following require a "Balance" to complete an analysis? TSS TS TDS SS

SS Suspended Solids

SLUDGE VOLUME INDEX (SVI)

SVI is a math calculation that can indicate the tendency of activated sludge solids (aerated solids) to thicken or to become concentrated during the sedimentation/thickening process. SVI is calculated in the following manner: (1) allow a mixed liquor sample from the aeration basin to settle in a Mallory Settleometer for 30 minutes; (2) determine the total suspended solids (TSS) concentration for a sample of the same mixed liquor (ML); (MLTSS) (3) Calculate SVI by dividing the measured (or observed) wet volume (SSV) at the end of 30 minutes settling by the dry weight concentration of the Mixed Liquor sample (MLTSS) in milligrams/Liter (mg/L). To obtain the correct units (mL/g) associated with conventional SVI you must multiply the results by (1 000 mg/1g)

Name (2) examples of dissolved solids:

Salt Sugar

FLIGHTS

Scraper-boards, made from redwood, other rotresistant woods or plastic composites, used to collect and move settled sludge or floating scum usually in rectangular clarifiers.

Blades Scraper Squeegees

Scrapes the settled sludge from bottom of clarifier to sump.

During one week, a total of 290 gallons of screenings are removed from a wastewater flow. What is the average screenings removal reported as a cu ft/ day?

Screenings Removal = (Cu ft) Day Screenings= (290 gal) (1 cu ft/ 7.48 gal) = 38.77 cu ft 38.77 cu ft = 7 day 5.5 cu ft/day

A total of 55 gallons of screenings are removed from a wastewater flow during a 24 hour period. What is the screenings removal reported as a cu ft/ day?

Screenings Removal = (Cu ft) Day Screenings= (55 gal) (1 cu ft/ 7.48 gal) = 7.4 cu ft 7.4 cu ft = 1 day 7.4 cu ft/day

Oxygen Depletion

Secondary Treatment = Organic Reduction of Wastewater. "Non-stable" organic based waste (like untreated domestic sewage) causes DO to be depleted out of natural water. Most natural waters (rivers and lakes) contain less than 0.001% DO (<10 ppm) [THE RULE OF TEN THOUSAND]. Most fish (like salmon and trout) require at least 4+ ppm to survive and propagate. When high levels of organic material are allowed to enter the environment, nature will begin working in the stream/lake. Bacteria will grow, aerobic treatment begins, DO concentrations will deplete (go down↓). If the levels of organic contamination overwhelm the aerobic treatment in the environment (i.e. DO = 0 ppm), then the anaerobic bacteria begin to use combined chemical oxygen (i.e. SO4-2) to decompose the waste. Hydrogen Sulfide (H2S) gas will result with the "rotten egg" smell and the natural environment is in jeopardy. H2S in air can paralyze your respiratory system, signifies that the DO is near 0 ppm so that fish are dying, and can form an explosive mixture.

Bar Screens

Seies of parallel bars that are generally spaced 3/8" - 2". ***Flow rate ~1.5 ft/sec (if 1 ft/sec grit removed=bad) *** Placed vertically in the influent flow channel. These screens can be manually cleaned several times per day, or mechanically cleaned within in the headworks area. Manually cleaned bar screens are usually set at a 45-degree angle. This makes it easier to rake the debris from the screen. Automatically cleaned bar screens are designed with a set of rakes that are chain-driven. Mechanical bar screen angle is usually between 60 and 90 degrees on an automatically cleaned screen system.

SEPTIC

Septic is a condition produced by anaerobic bacteria. If severe, the wastewater produces hydrogen sulfide (H2S), turns black in color, gives off foul (rotten egglike) odors, contains little or no dissolved oxygen, and gives the wastewater a high demand for oxygen (O2).

Volumetric Solids

Settleable Solids

What does an Imhoff cone measure

Settleable Solids

what are the typical ranges in the "settling compartment" lab testing process?

Settleable Solids 3-10 ml/l 75-90% removal rate Total Suspended Solids: 200-400 mg/l 45-65% removal rate BOD5: 200-500 mg/l 25-35% removal rate PH: 6.7-7.3 Alkalinity: 1-300 mg/l

An Imhoff cone is used to measure_______ solids

Settleable solids

Describe "septic tanks"

Sewage or untreated household waste will quickly clog all but the most porous gravel formations. The septic tank conditions sewage waste to allow percolation (sifting downward) of the liquid portion into the subsoil.

Wastewater is the same as ____________.

Sewage/Spent Water

With primary clarifiers, WHAT ARE THE FORCES YOU MUST CONSIDER? Part 4

Short Circuiting. o Bad clarifier design allows for "dead pockets" of solids to accumulate, and not providing "active" volume to allow newly inputted solids to settle out. (HDT is decreased). o Weir plates and baffles on the inlet end (or center, if circular design) of the clarifier must be correctly positioned to diffuse the entry velocity, and disperse the influent load evenly across the "moving wedge" of water being treated. o Effluent weirs must be perfectly level. If not level, water will seek the lowest part of the weir and all the water will flow to that point. o Thermal Stratification causes short circuiting. Warm water will "scoot" across the surface of the denser cold water. Cold and warm temperatures must be mixed at or before the inlet to the primary clarifiers.

SHORT-CIRCUITING

Short-circuiting is a condition that occurs in tanks or basins when some of the water travels faster through the basin than the rest of the flowing water. This condition is usually undesirable, since it may result in shorter contact, reaction, or settling times in comparison with the theoretical (calculated) or presumed hydraulic detention times (HDT). Thermal stratification (warm water versus cold water) can create a short-circuiting event.

COMMINUTION

Shredding. Comminution is a mechanical treatment process that cuts large pieces of waste material into smaller pieces; purpose, so they won't plug pipes or damage equipment. COMMINUTION and SHREDDING usually mean the same thing.

PURPOSE OF SEDIMENTATION AND FLOTATION

Simply put the purpose is to "clear up" the wastewater by allowing gravity to settle solid particles that are heavier than water (SG >1.0), while providing a mechanism to capture those solid particles that are lighter than water (SG <1.0). The single physical wastewater treatment unit that accomplishes both of these tasks is called a clarifier. Wastewater facilities use clarifiers, whereas water treatment facilities usually use sedimentation tanks.

Combined Sewers

Single network of piping that is intended to carry both sanitary wastewater and storm runoff. When the rain comes, the network is overloaded and the combination of sanitary wastewater and storm runoff is by-passed to the nearest natural waterway.

Scum Skimmer

Skims or collects floating material from the surface of the wastewater and moves it to the scum trough. (Main Sludge Coll.)

Scum Skimmer Arm

Skims or floating material from the water surface and moves it to the scum trough.

MAINTENANCE CONSIDERATIONS part 2

Sludge & scum suction piping must be kept short with no 90° elbows. Primary sludge piping should never be smaller than 6"N,while secondary sludge piping should never be smaller than 4"N.Never use reducers. Ensure that pipe-pumping velocities exceed 3 fps. o Ensure that you can clean sludge and scum pipelines with "tools of the trade", i.e. sewer rods, vacu-jets, and hydraulic highpressure cleaners. This equipment should be able to clean without taking the clarifier out-of-service.

Provide a few examples of the "Sludge Handling" processes

Sludge Centrifuges Vacuum filters belt presses sludge lagoons sludge drying beds *Filters that allow gravity to separate (thicken) the sludge from the water are known as GBTs *Filters that press water out of the sludge are known as Belt Filter Press *Systems that vacuum the water from the sludge are known as Vacuum Filters

_______________ is the process of changing the organic matter contained within sludge into gasses and liquids and a more stable solid form. These changes take place as microorganisms feed on sludges in either anaerobic (more common) or aerobic digesters.

Sludge digestion

SLUDGE GASIFICATION

Sludge gasification is a process in which both soluble and suspended organic matters are converted into gas by anaerobic decomposition. The resulting gas bubbles can become attached to the settled sludge and cause large clumps of sludge to rise and float on the water surface. Both nitrogen gas (N2) and carbon dioxide (CO2) formation can result from this anaerobic decomposition, resulting in sludge rising to the surface of a clarifier.

Hand-cleaned grit chambers are typically used in what size plants?

Small plants with flows generally between 3 and 5 mgd.

What is the purpose of Solids Handling and Disposal?

Solids and scum that have been removed during wasteater treatment have been "wasted" over to solids handling and treatment. Solids thickening, volatile solids reduction, liquid/solids separation, solids stabilization and "bio-friendly" disposal. The single most important handling step in the stabilization of solids is done with the help of an ANAEROBIC DIGESTER: This unit process "digests" solids under conditions WITHOUT DISSOLVED OXYGEN (Anaerobically). After 50% of the colatile solids matter has been stabilized, the sludge can be moved from the "active" tank to the "storage" tank where the digested sludge is allowed to separate by gravity with the non-solid (watery: material (supernatant) flowing to the surface. This process allows the watery portion of the separated solids to be metered back into the treatment process (water side) with the solids being further treated. ****It is worth of noting here that the digester gas is mixed with air (about 5-15% digester gas) can form a very explosive mixture**** Anaerobic digesters can be classified by the type of roof that they have. There are "floating" roofs and "fixed" roofs.

Target Baffle

Spreads the wastewater evenly across the width of the clarifier for even distribution and prevents short-circuiting.

Screening of the wastewater

Stop and remove the "trash" from the wastewater. This includes logs, dogs, and money. Mechanical debris removal is much easier than manually getting out there and raking the bars. ( upwards)

NUTRIENTS

Substances required to support living plants and organisms. Major nutrients are carbon, hydrogen, oxygen, sulfur, nitrogen and phosphorus. Nitrogen and phosphorus are difficult to remove from wastewater by conventional treatment processes because they are water-soluble and tend to recycle. Also see NUTRIENT CYCLE.

Which of the following refers to the liquid above the settleable solids but below the top layer of scum in an anaerobic digester?

Supernatant Supernatant is the liquid removed from settled sludge. Supernatant commonly refers to the liquid between the sludge on the bottom and the scum on the surface of an anaerobic digester. This liquid is usually returned to the influent wet well or to the primary clarifier.

Sprocket

Supports chain, adjusts tension, or forces the chain to move. A Wheel with teeth around the outside that fit in the chain link.

SURFACE LOADING & SURFACE LOADING RATE (SLR)

Surface Loading is just one of the guidelines for the design of settling tanks and clarifiers in within treatment plants. It is an important process variable used by operators to determine if tanks and clarifiers are hydraulically (flowrate) over- or under-loaded. Surface Loading is flowrate to a process. When this Surface Loading is divided by the Surface Area of the tank to which the water flow is being applied, the result is called overflow rate (OR), or surface overflow rate (SOR) or surface loading rate (SLR) and is calculated by: Surface Loading Rate, gpd/ft2 = Flowrate, gpd/Surface Area, ft2

Total Suspended Solids (TSS, mg/L)

Suspended Solids include "all solids" that will not pass through a "standard" filter as defined above (5Fm). The Suspended Solids may be organic or inorganic in nature, either a piece of lettuce or a grain of sand. Further, the Suspended Solid may be either Settleable or non-Settleable. The TSS test is done after filtration with the non-filtrate (material that is retained on the filter) being dried at 103EC. Settleable Solids (Set Sols) can be tested using the Imhoff Cone and reported as a "volume settled in milliliters with respect to 1Liter of wastewater available in the test". Settable Solids Test is the only test to be reported in mL/L.

Suspended Film Systems

Suspended film systems stir and suspend microorganisms in wastewater. As the microorganisms absorb organic matter and nutrients from the wastewater they grow in size and number. After the microorganisms have been suspended in the wastewater for several hours, they are settled out as a sludge. Some of the sludge is pumped back into the incoming wastewater to provide "seed" microorganisms. The remainder is wasted and sent on to a sludge treatment process. Activated sludge, extended aeration, oxidation ditch, and sequential batch reactor systems are all examples of suspended film systems.

Vacuum Filters

Systems that vacuum the water from the sludge

Which process is performed at 180 C?

TDS Total Dissolved Solids

Which process is performed at 103 C?

TS Total Solids TSS Total Suspended Solids

Total Solids Testing Method?

TS at 103 C = TSS at 103 C + TDS at 180 C

Which Processes are done volumetrically?

TSS TS TDS

With primary clarifiers, WHAT ARE THE FORCES YOU MUST CONSIDER? Part 3

Temperature of the water (T,°F or T,°C). o As water warms over 4°C , the mass density of 8.34 #/gallon will take more room than one gallon volume. o As water cools under 4°C, the mass density of 8.34 #/gallon will take up less room than one gallon volume. The fun thing to remember here is that water can cool only down to 0°C before it freezes, then it reverses itself and begins to take up more room than one gallon of volume, but this is something we need not go into now. o Temperature affects solids settling rates. o Warm water molecules are expanded (more volume) thereby allowing solids to settle easily. o Conversely, cold-water molecules are denser (less volume thereby restricting the settleability of solids.

Advanced WasteWater treatment is also called:

Tertiary Treatment

TRICKLING FILTER (TF)

The "trickling filter" is a secondary treatment process in which the wastewater trickles over media (rocks). This media provide the opportunity for the formation of slimes (biomass). The biomass contains organisms that feed upon and remove wastes from the water being treated.

How to Imhoff Tanks work?

The Imhoff Tank contains an upper chamber for sedimentation and a lower chamber for unheated digestion. A simple floor with one "slot" separates the chambers. The detail of the "slot" is important since its unique design will not allow for the digesting gasses to pass back into the sedimentation chamber.

What does NPDES stand for?

The National Pollutant Discharge Elimination System (NPDES)

NPDES PERMITS

The National Pollutant Discharge Elimination System (NPDES) is a nationwide management practice designed to inventory, maintain a database, and detect pollution violations through a comprehensive permitting system. These permits are required by the USEPA based on the FWPC Act Amendments of 1972. This system was created to regulate "point source" discharges into the nation's waterways. One, if not the single most important, duty that you will perform in the treatment plant is filling out the NPDES. Though not complicated, this form is used to validate your treatment plant's performance, document laboratory results, and establish your credibility as an operator.

OSHA

The Williams-Steiger Occupational Safety and Health Act of 1970 (OSHA) is a federal law designed to protect the health and safety of industrial workers and treatment plant operators. It regulates the design, construction, operation and maintenance of industrial plants and wastewater treatment plants. The Act does not apply directly to municipalities, EXCEPT in those states that have approved plans and have asserted jurisdiction under Section 18 of the OSHA Act. HOWEVER, CONTRACT OPERATORS AND PRIVATE FACILITIES DO HAVE TO COMPLY WITH OSHA REQUIREMENTS. Wastewater treatment plants have come under stricter regulation in all phases of activity as a result of OSHA standards. OSHA also refers to the federal and state agencies, which administer the promulgated OSHA regulations, i.e. Oregon OSHA.

Density in a nutshell

The density of water under normal circumstances is 1kg/L (1g/mL) • Objects or substances with a greater density will sink in water • Objects or substances with less density will float in water

HEADWORKS

The facility (or area) where wastewater enters a wastewater treatment plant. The headworks may consist of bar screens, comminutors, flumes with flowrate indicators, a flow equalization basin, a wet well and various pumps.

Grit

The heavy material present in wastewater, such as sand, coffee grounds, eggshells, gravel and cinders.

POLLUTION

The impairment (reduction) of water quality by agricultural, domestic or industrial wastes (including thermal and radioactive wastes) to a degree that the natural water quality is changed to hinder any beneficial use of the water or render it offensive to the senses of sight, taste, or smell or when sufficient amounts of wastes create or pose a potential threat to human health or the environment. Compare with CONTAMINATION.

MEDIA

The material found within a trickling filter on which slime accumulates and organisms grow. As settled wastewater trickles over the media, organisms contained in the slime remove certain types of wastes thereby partially treating the wastewater. Also, the material found in a rotating biological contactor or in a gravity or pressure filter.

FACULTATIVE POND(S) aka FACULTATIVE LAGOON(S)

The most common type of pond currently used for domestic waste treatment in the United States. The upper pond portion (supernatant) is aerobic, while the bottom layer is anaerobic. Algae supply most of the oxygen to the supernatant.

NATURAL CYCLES

The number of "Natural Cycles" that occur in the Biosphere (on earth) would be too numerous to count. Within the Hydrosphere (things that have to do with water) we are interested in the "Natural Purification Cycles" and "Nutrient Cycles" (See Figure 2.2). Remember: The simplified Water Purification Cycle was shown in Chapter 1 Below you will see a simplified Nitrogen (one of the Nutrients) Cycle.

Which would provide better chlorine contact, a 10000gallon cubical tank or a length of 10-inch pipe flowing full and containing the same volume as the cubical tank?

The pipe would provide better chlorine contact because water cannot short circuit through a pipe (take a short route), while it might move evenly through a tank and thus some of the water would have a shorter contact time

TRANSPIRATION

The process by which water vapor is released to the atmosphere by living plants. This process is similar to people sweating. This process is also called evapotranspiration (ET).

DISINFECTION

The process designed to kill or inactivate most microorganisms in wastewater, including essentially all pathogenic (disease causing) bacteria. There are several ways to disinfect, with chlorination (and now UV light) being the most frequently used in water and wastewater treatment plants. Compare with STERILIZATION.

BIOCHEMICAL OXYGEN DEMAND (BOD)

The rate at which organisms use the oxygen in water or wastewater, while stabilizing decomposable organic matter under aerobic conditions. In decomposition, organic matter serves as food for the bacteria and energy results from its oxidation. BOD measurements are used as a measure of the organic strength of wastes in water.

BIOCHEMICAL OXYGEN DEMAND [BOD]

The rate at which organisms use the oxygen in water or wastewater, while stabilizing decomposable organic matter under aerobic conditions. In decomposition, organic matter serves as food for the bacteria and energy results from its oxidation. BOD measurements are used as a measure of the organic strength of wastes in water. Polluted Water: BOD HIGH Clean Water: BOD LOW

Transpiration refers to:

The release of water vapor to the atmosphere by living plants

STERILIZATION

The removal or destruction of all microorganisms, including pathogenic and other bacteria, vegetative forms and spores. Compare with DISINFECTION.

INFILTRATION

The seepage (leaking) of groundwater into a sewer system to include seepage through service connections. Seepage frequently occurs through defective or cracked pipes, pipe joints, connections or manhole walls. Often this is used in conjunction with INFLOW, as Infiltration & Inflow (I&I).

Activated Sludge

The single most popular, reliable, and cost effective secondary biological treatment alternative in the US today is Activated Sludge. Its a suspended film process=growing microorganisms are suspended in the wastewater being treated. AS has the ability to reduce up to 99% both BOD and TSS from the wastewater. 1. Primary clarifier effluent is piped into a swimming tank. Bugs and air are pumped into the tank 2. Allows microorganisms to stabilize the waste out of the wastewater so that they are can be separated/settled from the clarified water. This mixture of microorganisms, air, and wastewater in this tank is refereed to as MIXED LIQUOR (ML)

DETENTION TIME [DT], or HYDRAULIC DETENTION TIME [HDT]

The time (T) required to fill a tank or a basin of known Volume (V) at a given flowrate (Q). Or the theoretical time required for a given flow of wastewater to pass through a tank. Detention time usually refers to WATER, while the term Retention time will normally refer to SLUDGE.

DETENTION TIME and HYDRAULIC DETENTION TIME

The time required to fill a tank at a given flowrate. Or it is the theoretical time (T) required for a given Flowrate (Q) of wastewater to pass through a tank of known Volume (V). Detention Time is also known as Hydraulic Detention Time (HDT).

NUTRIENT CYCLE

The transformation or change of a nutrient from one form to another until the nutrient has returned to the original form, thus completing the cycle. The cycle may take place under either aerobic or anaerobic conditions.

supernatant)

The upper pond portion

Provide some examples of Effluent disposal

The water is returned to the environment; to surface waters, sub-surface aquifers, spray irrigated onto land, sold/given to industry, or allowed to evaporate out of large ponds.

TOXIC

The word "toxic" implies a substance that is poisonous to a living organism.

EFFECTS OF WASTE DISCHARGES

There are substances not removed by the wastewater treatment process that can cause problems in the receiving waters. Often times a treatment plant becomes either overloaded, or receives an industrial waste that ends up killing the ability of the facility to treat wastes naturally; trouble will result.

Acid Formers:

They begin eating the organic fraction of the sludge and produce organic acids

Methane Formers:

They convert the organic acids produced by the Acid Formers into stable organic forms and volatize gas into both methane 70% and carbon Dioxide 30%

SEPTICITY

This is the condition in which organic matter decomposes to form foul-smelling products associated with the absence of free dissolved oxygen. If severe, the wastewater produces hydrogen sulfide, turns black in color, gives off foul odors, contains little or no dissolved oxygen, and the wastewater will exert a high demand for oxygen.

Conventional Sanitary Sewer:

This system carries wastes from households, commercial establishments, and industrial wastes from origin to treatment facility. These sewers are designed to transfer the water at a velocity of at least 2.0 feet per second (scour velocity) during the peak use of the sewer each day (morning and early evening). Pump Stations/Lift Stations are installed to "lift" the wastewater to a higher elevation so that it can run freely downhill, again. The figure below shows a "conventional" collection system with pumping station followed by a "force" main that will take the pumped wastewater to a higher elevation before allowing it to fall under the influence of gravity

WEIR DIAMETER

This term applies to circular center-feed clarifiers fitted with peripheral weirs. Many circular clarifiers have a circular weir within the outside edge of the clarifier, or in other words the length of the weir is equal to the circumference of the circular clarifier. All the water leaving the clarifier flows over this weir. The diameter of the weir is the length of a line from one edge of a weir to the opposite edge and passing through the center of the circle formed by the weir.

ANAEROBIC DIGESTER

This unit process "digests" solids under conditions WITHOUT DISSOLVED OXYGEN (Anaerobically).

Influent Control Gate

Throttles or stops the flow to the sedimentation basin or clarifier.

STABILIZE

To convert wastes into a form that resists further natural change. Organic material is stabilized by bacteria that convert the organic to gases and other relatively inert substances. Stabilized organic material generally will not give off obnoxious odors.

Define Total Dissolved Solids (TDS)

Total Dissolved Solids (TDS) are those "salts" so fine that they will pass through a 5 nm pore opening standard filter.

Nitrate-Nitrogen, NO

Total Nitrogen 26 - 75 mg/L 60 mg/L Total Phosphorus 6 - 12 mg/L 10 mg/L

Gravimetric Solids Profile

Total Solids TS Total Suspended Solids TSS Total Dissolved Solids TSD

Total Solids (TS, mg/L)

Total Solids include "all solids" found in wastewater; Suspended and Dissolved, either Organic or Inorganic based. The test is done by evaporation to dryness at 103 EC.

What does TDS stand for (ABC)?

Total dissolved solids Total dissolved solids (TDS) comprise inorganic salts (principally calcium, magnesium, potassium, sodium, bicarbonates, chlorides and sulfates) and some small amounts of organic matter that are dissolved in water.

Which of the following factors must be added together to find total solids?

Total dissolved solids and total suspended solids.

Vertical Drive Cage

Transmits power from drive unit to the sludge collector mechanism.

Influent Channel or Pipe

Transports wastewater to the clarifier.

Trash Racks (TR)

Trash racks (TR) are simply bar screens (this includes manual bar screens and mechanical bar screens) with larger space openings. TR= Proceed bar screens which have more narrow openings, TR = Primarily used in combined sewer overflow (CSO) conduits Designed to prevent logs, timbers, stumps, 2X4, and other large debris from entering treatment processes. Opening size: 38 to 150 mm (1.5 - 6 in)

"Sludge dewatering is typically the final step for industrial wastewater treatment processes and plants. After pH adjustment if needed, wastewater chemicals addition, liquid solids separation or a biological process, the remaining sludge is high in water content that can be reclaimed through sludge dewatering."

True

A wastewater treatment plant operators job is to keep the plant running?

True

An operator becomes involved with public relations by explaining the operation, purpose, and reasons for operation of the facility to visitors, civic organizations, reporters, city or district representatives.

True

As an operator you must recognize and respond to many process variables. Clarifiers present a unique set of problems and each problem has several solutions. Solutions may not be 100%, but collaboration with peers, and corrective measures based on good science and analysis will move your career along very rapidly.

True

As with other structures at a wastewater treatment plant, the approach channel should be straight in order to promote evenly distributed screening over the area of the bar screen. With a minimum approach velocity of 0.4 m/s (or 1.25 ft/sec) to avoid grit deposition. The velocity through the bar screen should not exceed 0.62 ms (or 2 ft/sec) at average flow. Exceeding this flow may minimize the amount of available screening surface area for collecting solids in between cleaning (1).

True

Clarifiers come in three (3) shapes, and 3 shapes only?

True

Clarifiers remove both Settleables and Floatable?

True

Clarifiers will not "catch" all solids in the wastewater?

True

Combined Sewer System (CSS) is a a wastewater collection system which conveys sanitary wastewaters (domestic, commercial and industrial wastewaters) and stormwater through a single pipe to a publicly owned treatment works for treatment prior to discharge to surface waters.

True

Depending on head, pump wear or general usage, the actual gpm delivered by a pump will vary more of less from the gpm pump design or pumping rate?

True

Fats, oils, and grease (FOG) can be classified as polar or nonpolar?

True

Grease from the kitchen is detrimental to septic tank functions. Effluent from grease traps must go through septic tanks before being discharged to drainfields to prevent soil plugging.

True

Great sums of public and private funds are now being invested in large, complex municipal and industrial wastewaters treatment and collection system.

True

Grit includes sand, gravel, cinder, or other heavy solid materials that are "heavier" (higher specificgravity) than the organic biodegradable solids in the wastewater?

True

Grit is removed by maintaining a constant upstream velocity of 0.3 m/s (1 ft/s).

True

Grit removalfacilities typically precede primary clarification, and follow screening and comminution?

True

Hoppers are for sludge blanket removal

True

Hydrogen sulfide is a gas with a rotten egg odor. This gas is produced under anaerobic conditions. Hydrogen sulfide gas is particularly dangerous because it dulls the sense of smell so that you don't notice it after you have been around it for a while. In high concentrations, hydrogen sulfide gas is only noticeable for a very short time before it dulls the sense of smell. The gas is very poisonous to the respiratory system, explosive, flammable, colorless and heavier than air.

True

If bar spacing in the screening process is too narrow, organics that should be treated by subsequent processes will be captured and removed?

True

If the condition of the activated sludge deteriorates to a SVI of 500 (undesirable), then the solids settling takes on the shape of a bowl.?

True

If the solids fill the tank and enter the drainfield, the solids can clog the soil in the drainfield.

True

In aerated grit chambers, air is introduced in the grit chamber along one side, causing a perpendicular spiral velocity pattern to flow through the tank. Heavier particles are accelerated and diverge from the streamlines, dropping to the bottom of the tank,while lighter organic particles are suspended and eventually carried out of the tank?

True

In aerated grit chambers, grit is removed by causingthe wastewater to flow in a spiral pattern?

True

In general you tend to make more more with higher licensure. For example a level 4 operator will make more then a level 1. The quickest way to move up the licensure scale is with expereince and an Associates Degree from CCC. Together they will move you to the highest pay scale in the shortest amount of time....

True

Is this salary (take hourly rate and double it to determine annual salary range) reasonable (click true if you want points)?

True

It important that the operator be present during the construction of new facilities; plant, pump station, so that they can become familiar with the specific facility, its wiring, mechanical requirements, etc. before the facility comes 'on-line'".

True

Manual bar screens have been replaced with more robust mechanical bar screens, comminutors, and grinder pumps. The shift away from the manual bar screens can be attributed to the inefficiencies and manual labor requirements.

True

Many types of grit removal systems exist, including aerated grit chambers, vortex-type (paddle or jet induced vortex) grit removal systems, detritus tanks (short-term sedimentation basins), horizontal flowgrit chambers (velocity-controlled channel), and hydrocyclones (cyclonic inertial separation)?

True

Municipal and Industrial wastewaters must recieve adequate treatment to protect recieving waters.

True

Not only is maintaining the manual bar screen lab intensive, but when removal of screenings from the bar screen is infrequent, flooding and overflow occurs due to clogging.

True

Other types of comminutors have stationary slotted screens with oscillating cutters mounted on a shaft. Cutting teeth are mounted in rows on the drum?

True

Preliminary treatment occurs at the headworks where the operator gets the "first" glance at the waste about to be treated. Here is where the "big stuff" is shredded, or removed; wastewater flowrates are measured and logged in; and grit that will interfere with the longevity of pumps will often times be removed.

True

Primary clarifiers are large round tanks with concave bottoms where the solid matter or sludge settles out of the wastewater.Oftentimes, there is a large arm that rotates around the tank very slowly which skims the floaties off of the top of the waste water.

True

Rakes are for skimming the top?

True

Removal of gritprevents unnecessary abrasion and wear of mechanical equipment, grit deposition in pipelinesand channels, and accumulation of grit in anaerobicdigesters and aeration basins?

True

SVI of 500 indicates that the activated sludge will settle very slowly, thereby impacting near the edge of a circular clarifier (hopefully not go over the weirs).

True

Settleable solids in surface and saline waters as well as domestic and industrial wastes may be determined and reported on either a volume (mL/L) or a weight (mg/L) basis?

True

Settleable solids is a "Volumetric" Test (Procedure 3a) and is conducted in an Imhoff Cone over a 60 minute period of time?

True

Shredding devices are installed after the bar screen or as alternatives to screening. Shredding devices reduce solids to a size that can enter the plant without causing mechanical problems or clogging ?

True

Sludge Volume Index (SVI) A SVI of 100 will usually produce a bell shape pattern of settled sludge?

True

Solids Loading Rates require the operator to know the flowrate (Q) to the unit in MGD, the Total Suspended Solids (TSS) concentration being fed to the unit in mg/L, and the surface area (SA) of the unit being fed in ft^2?

True

Solids are classified by their size and whether they are organic or inorganic.

True

Surface overflow rate (SOR) depends on solids characteristics?

True

TDS normally does not create much of a problem. These are typical salts found in wastewater. However, TDS can include the likes of Lead, Copper, DDT, etc. If you can document abnormal concentrations of TDS that contain waste from an "industrial" origin, you must investigate and implement your Industrial Waste Permit System?

True

The bar screen channel should be designed in such a way as to reduce the build up of grit and other debris directly upstream and downstream of screen. For example, the floor of the channel should be flush with or sloped downward through the bar screens with a crevice where solids can be trapped.

True

The bar screen may be coarse (2-4 inch openings) or fine (0.75-2.0 inch openings). The bar screen may be manually cleaned or mechanically cleaned. Manual or mechanical cleaning is performed frequently enough to prevent solids buildup and reduce flow into the plant?

True

The basic components of wastewater grit material consists of such materials as sand, cinders, rocks, coffee grounds, cigarette filter tips, and other relatively nonputrescible organic and inorganic substances

True

The best approach is to put kitchen grease in old milk jugs and place in the garbage rather than into the drain. Small amounts of kitchen grease can go into the septic tank without damaging the system.

True

The entrapped solids rise with the dissolved air and are skimmed from the surface. The process of AIR FLOTATION is generally associated with sludge and solids processing. It will be studied further during Spring Term

True

The first step in the treatment of wastewater is known as Preliminary Treatment, which screens out, grinds up, or separates debris in the wastewater ?

True

The horizontal flow grit chamber is the oldest type of grit removal system.

True

The most common shredder is the comminutor? ?

True

The most important function of septic tanks is to protect the absorption ability of the subsoil.

True

The operator becomes involved in public relations by explaining the purpose and operation of the plant to visitors, civic organizations, school classes, news reporters, etc.

True

The operator should be present during the construction of a new plant in order to become familar with the plant before the operator begins operating it.

True

The term "wastewater" is preferred over the term "sewage" to describe a community's used water and "water-carried solids" that flow to the wastewater treatment plant

True

The term "wastewater" is preferred over the term "sewage" to describe a community's used water and "water-carried solids" that flow to the wastewater treatment plant.

True

The use of fine screens in preliminary treatment hasexperienced a resurgence in the last 20 years.

True

The vortex-type grit chamber consists of acylindrical tank in which the flow enterstangentially, creating a vortex flow pattern. Gritsettles by gravity into the bottom of the tank (in agrit hopper) while effluent exits at the top of thetank. The grit that settles into the grit hopper maybe removed by a grit pump or an air lift pump?

True

There are three primary components to a wastewater treatment facility: 1. Collection 2. Treatment 3. Discharge (re-use)

True

Total Suspended Solids (TSS) are solids in water that can be trapped by a filter. TSS can include a wide variety of material, such as silt, decaying plant and animal matter, industrial wastes, and sewage. High concentrations of suspended solids can cause many problems for stream health and aquatic life

True

Treatment equipment such as bar screens, comminutors (a large version of a garbage disposal that shreds material), and grit chambers are used on the wastewater as it first enters a treatment plant ?

True

Typical bar screens are between 10 mm (or 3/8 inch) to 50 m (or 2 inches) thick, by about 50 mm (2 inches) deep. For these bar screens, the bars are positioned at a 30 to 75 degree angel from the horizontal, with the more common configuration being 35 to 45 degrees.

True

Wastewater chemical analysis usually involves assessing the oxygen content, organic and inorganic contents of the wastewater?

True

Wastewater treatment plants usually contain clarifiers in two different locations within the facility. Water is "clarified" in a Primary Treatment phase, and again after Secondary Treatment?

True

Water velocity through the screen is very important and should be around 1.5 ft/s (1) ?

True

Water velocity through the screen is very important and should be around 1.5 ft/s. ?

True

When selecting a grit removal process, the quantityand characteristics of grit and its potential toadversely affect downstream processes areimportant considerations.

True

With the flow into the wet well stopped during a pumping test, all the pump to begin pumping wastewater from the wet well. Measure the drop in water at the end of the test (2-5 minutes). The pumping rate can be calculated (PR= Volume/ time)?

True

You need a license to be an operator?

True

Wastewater from sewage treatment plants often contains organic materials that are decomposed by microorganisms, which use oxygen in the process. The amount of oxygen consumed by these organisms in breaking down the waste is known as the biochemical oxygen demand or BOD.

True "Biochemical oxygen demand, or BOD, measures the amount of oxygen consumed by microorganisms in decomposing organic matter in stream water. BOD also measures the chemical oxidation of inorganic matter (i.e., the extraction of oxygen from water via chemical reaction). A test is used to measure the amount of oxygen consumed by these organisms during a specified period of time (usually 5 days at 20 C)."

Excess nutrient loading can lead to algal blooms.

True "Freshwater algal blooms are the result of an excess of nutrients, particularly phosphorus.[1] The excess of nutrients may originate from fertilizers that are applied to land for agricultural or recreational purposes, these nutrients can then enter watersheds through water runoff.[2] Excess carbon and nitrogen have also been suspected as causes." http://en.wikipedia.org/wiki/Algal_bloom

A SANITARY SEWER carries waste from households, commercial establishments and some industrial wastes

True "Properly designed, operated, and maintained sanitary sewer systems are meant to collect and transport all of the sewage that flows into them to a publicly owned treatment works (POTW). However, occasional unintentional discharges of raw sewage from municipal sanitary sewers occur in almost every system. These types of discharges are called sanitary sewer overflows (SSOs). SSOs have a variety of causes, including but not limited to blockages, line breaks, sewer defects that allow storm water and groundwater to overload the system, lapses in sewer system operation and maintenance, power failures, inadequate sewer design and vandalism."

In some cities a combined sewer system exists where sanitary sewers and storm sewers are collected.

True "What are CSOs, and why are they important? Combined sewer overflows, or CSOs, are remnants of the country's early infrastructure. In the past, communities built sewer systems to collect both stormwater runoff and sanitary sewage in the same pipe. During dry weather, these "combined sewer systems" transport wastewater directly to the sewage treatment plant. In periods of rainfall or snowmelt, however, the wastewater volume in a combined sewer system can exceed the capacity of the sewer system or treatment plant. For this reason, combined sewer systems are designed to overflow occasionally and discharge excess wastewater directly to nearby streams, rivers, lakes, or estuaries. Combined sewer overflows (CSOs) contain not only stormwater but also untreated human and industrial waste, toxic materials, and debris. This is a major water pollution concern for cities with combined sewer systems. CSOs are among the major sources responsible for beach closings, shellfishing restrictions, and other water body impairments. "

The solution to pollution is dilution was first said at a mid 1970's Michigan Water Resources Commission meeting when it issued a "Permit to pollute" to a large power facility. We now know that this is statement has numerous drawbacks?

True Dilution was the solution to pollution when populations were small. Everything people wanted to get rid of went into the water. These wastes were typically organic, such as human wastes and animal carcasses

Pre-liminary treatment usually occurs at the headworks. It involves bar racks mechanical screens and grit channels.

True Preliminary treatment seeks to remove grit, rags and solids that float which may harm the operation of the rest of the plant. Bar racks or mechanical screens remove paper, rags and other large solids. Sand and grit are removed by gravity settling in a grit chamber.

Following preliminary treatment, the water moves on to a clarifier or settling tank. This is Primary Treatment in a wastewater plant and it is designed to remove sludge and scum.

True Primary wastewater treatment, the second step in the wastewater treatment process beyond the preliminary treatment of a headworks, involves the physical separation of suspended solids from the wastewater flow using primary clarifiers. This separation reduces total suspended solids as well as the biological oxygen demand (BOD) levels and prepares the waste stream for the next step in the wastewater treatment process.

Following primary treatment, the water moves on to an aeration tank where the activated sludge process comences. This is secondary treatment which is designed and operated to use natural organisms such as bacteria in the plant for stabilization and removal of organic material.

True Secondary or biological treatment is performed in a tank containing a "soup" of starved microbes called activated sludge. Like us, these microbes require air to live (they are aerobic organisms) and thus air is pumped into the tank

"Secondary wastewater treatment is the second stage of wastewater treatment that takes place after the primary treatment process. The process consists of removing or reducing contaminants or growths that are left in the wastewater from the primary treatment process"

True Secondary treatment processes can remove up to 90 percent of the organic matter in wastewater by using biological treatment processes

The wastewater treatment plant has a responsibility to protect the environment and ensure that they are not contaminating our river supplies?

True The clean water act is a critical piece of legislation that regulates wastewater plant effluents.

To measure TSS, the water sample is filtered through a pre-weighed filter. The residue retained on the filter is dried in an oven at 103 to 105° C until the weight of the filter no longer changes.

True The settleable solids test is the measurement of the volume of solids in one liter of sample that will settle to the bottom of an Imhoff cone during a specific time period. The test indicates the volume of solids removed by settling in sedimentation tanks, clarifiers or ponds. The settleable solids test indicates whether the primary and secondary processes are functioning properly.

The National Pollutant Discharge Elimination System - NPDES is a nationwide management practice designed to inventory, maintain a database, and detect pollution violations through a comprehensive permitting system.

True These permits are required by the USEPA based on the FWPC Act Amendments of 1972.

There are really two common ways to "cut up" wastewater solid materials; either by horizontal slicing or vertical dicing.

True To do this task you use a comminutor to horizontally shred and a barminutor to vertically shred. Both units accomplish the same task, but operators say that the barminutor is better in that the "cutters" can be replaced while they are out of the waste stream. To do this task you use a comminutor to horizontally shred and a barminutor to vertically shred. Both units accomplish the same task, but operators say that the barminutor is better in that the "cutters" can be replaced while they are out of the waste stream.

Total Solids includes both total suspended solids, the portion of total solids retained by a filter and total dissolved solids, the portion that passes through a filter.

True To measure TDS, the water sample is filtered, and then the filtrate (the water that passes through the filter) is evaporated in a pre-weighed dish and dried in an oven at 180° C, until the weight of the dish no longer changes. The increase in weight of the dish represents the total dissolved solids, and is reported in milligrams per liter (mg/l).

Racks have larger spacing between them than a typical screen?

True Trash/Bar racks typically have 2- to 6-in. (50- to 150-mm) spacing. Fine screens have 0.06- to 0.25-in. (2- to 6-mm) spacing, Coarse/large screens 1"-2"

Wastewater can be analyzed for its origins and or content? T or F

True Wastewater is analyzed based on where it is from (source) or based on what it contains

During storm events sewer systems can become overloaded; this can lead to wastewater discharge into a watercourse.

True Where are the cities with CSO problems? "Combined sewer systems serve roughly 772 communities with about 40 million people. Most communities with CSOs are located in the Northeast and Great Lakes Regions, particularly in Pennsylvania, Indiana, Ohio, Illinois, Michigan, New York, West Virginia, and Maine. Although large cities like New York, Philadelphia, and Atlanta have combined sewer systems, most communities with CSO problems have fewer than 10,000 people. " http://cfpub.epa.gov/npdes/search.cfm

Influent to a wastewater treatment plant can be variable?

True Yes, it varies throughout the day, etc. Some companies discharge at night and other discharge during the day. Thus, its a 24 hr a day job.

Combined Sewer Overflow (CSO) is a discharge of untreated wastewater from a combined sewer system at a point prior to the headworks of a publicly owned treatment works. CSOs generally occur during wet weather (rainfall or snowmelt). During periods of wet weather, these systems become overloaded, bypass treatment works, and discharge directly to receiving waters.

True http://cfpub.epa.gov/npdes/search.cfm

Anaerobic bacteria can survive and grow without the presence of free oxygen in their immediate environment. The genera vary morphologically, being spheric (cocci), rod-shaped (bacilli), spiral (spirochetes), or comma-shaped (vibrios).

True anaerobic bacteria derive energy from fermentative processes in the absence of oxygen.

WHAT IS PURE WATER?

Truly, pure water does not exist. If it did, it would simply be the molecule made from two parts hydrogen and one part oxygen (H2O). All water contains impurities. As soon as water is introduced into the environment it becomes "impure" (contaminated). The micro-electronic industry spends millions of dollars each year (for equipment, technology, and operator's wages) just to attempt to obtain the purest of water. "Purest" of water is a must in this industry when it is used in wafer manufacturing. We try to remove traces of Ca, Mg, Na, Cl, SO4, Fe, N, P along with trace organics that are derived from plants and animals (in some cases pesticides/herbicides).

How to avoid strains and exertion

Use proper tools And equipment for: Z Lifting Z Un-sticking Valves

A wet well is a wastewater collection pit. In it a pump will be started when sewage levels rise. Wastewater is then moved upward through a pressurized pipe system called a sewer force main. A wet well is 13 ft long, 10 ft wide, and 10 ft deep. What is the gallon capacity of the wet well?

V gal = (length ft) (width ft) (depth ft); (1 cu ft= 7.48 gal) V= (13 ft)(10ft)(10 ft) = 1300 cu ft 1300 cu ft (7.48 gal / 1 cu ft) = 9724 gal

A wet well is a wastewater collection pit. In it a pump will be started when sewage levels rise. Wastewater is then moved upward through a pressurized pipe system called a sewer force main. A wet well is 18 ft long, 10 ft wide, and 25 ft deep. What is the million gallon capacity of the wet well?

V gal = (length ft) (width ft) (depth ft); (1 cu ft= 7.48 gal) V= (18 ft)(10 ft)(25 ft) = 4500 cu ft 4500 cu ft (7.48 gal / 1 cu ft) = 33,660 gal 33,660 gal (1 MG / 1,000,000 g) = 0.0336 MG

A circular wet well has a diameter of 15 ft, and a depth of 25 ft. What is the million gallon capacity of the wet well?

V gal = 0.785 (D)(D)(depth ft); (1 cu ft= 7.48 gal) V= 0.785 (15 ft)(15 ft)(25 ft) = 4415 cu ft 4415 cu ft (7.48 gal / 1 cu ft) = 33,028 gal 33,028 gal (1 MG / 1,000,000 g) = 0.033 MG

The circular wet well for WES has a diameter of 25 ft, and a depth of 40 ft. What is the million gallon capacity of the wet well?

V gal = 0.785 (D)(D)(depth ft); (1 cu ft= 7.48 gal) V= 0.785 (25 ft)(25 ft)(40 ft) = 19625 cu ft 19625 cu ft (7.48 gal / 1 cu ft) = 146,795 gal 146,795 gal (1 MG / 1,000,000 g) = 0.146 MG

Barminutor

Vertically shredding ***Operators sat the barminuter is better because the "Cutters" can be replaced while they are out of the waste stream

Preparing for a public open house, what following in-plant arrangements must be made (ABC)?

Visitor safety is ensured Safety takes precedence for all water and wastewater operators.. The correct answer is: Visitor safety is ensured.

Why remove scum not-so-ofter?

WHY? • Allow for the scum to "thicken" within the clarifier before skimming it. • When skimming methods are "manual", the operation can be labor intensive. o Skimming must be done "by hand". o Valving operation between sludge and scum must be done "by hand".

INORGANIC WASTE

Waste material such as sand, salt, iron, calcium, and other mineral materials that are only slightly affected by the action of organisms. Inorganic wastes are chemical substances of mineral origin; whereas organic wastes are chemical substances usually of animal or plant origin.

A community's used water and water carried solids that flow to a treatment plant are called?

Wastewater

A community's used water and water carried solids that flow to a treatment plant are called __________.

Wastewater

INFLUENT

Wastewater or other liquid - raw (untreated) or partially treated - flowing INTO a reservoir, basin, treatment process, or treatment plant.

EFFLUENT

Wastewater or other liquid - raw (untreated), partially or completely treated - flowing FROM (OUT OF) a reservoir, basin, treatment process, or treatment plant.

EFFLUENT

Wastewater or other liquid - raw (untreated), partially or completely treated - flowing FROM a reservoir, basin, treatment process, or treatment plant.

Other Effects

Water clarity (solids discharges), color (dyes), increased algae blooms (nutrients), high/low pH killing natural flora (industries), toxic substance releases (mines in N. Idaho), and uncontrolled high concentrations of excess chlorine disinfectant (any wastewater treatment plant) can all lead to the degrading of the receiving water into a condition where it is unfit for its intended use

INFLOW

Water discharged into a sewer system and service connections from sources other than regular connections. This includes flow from yard drains, foundation drains and around manhole covers. Inflow differs from infiltration in that it is a direct discharge into the sewer rather than a leak in the sewer itself.

How does water pick up dissolved substances?

Water picks up dissolved substances as it falls as rain flows over land and is used for domestic, industrial, agriculture and recreational purposes

What can happen when nutrient cycles are disrupted and there is no dissolved oxygen in the receiving waters?

When nutrient cycles become disrupted and there is no dissolved oxygen in the receiving waters, these waters become septic, stink and look terrible

Sewers are hydraulic conveyance structures that carry wastewater to a treatment plant or other authorized point of discharge. A typical method of conveyance used in sewer systems is to transport wastewater by gravity along a downward-sloping pipe gradient. Why are many collection systems designed to convey flows by gravity (Chapter 3) ?

When properly designed and constructed, conventional gravity systems perform reliably. Pumping wastewater is costly and requires more maintenance than gravity lines

Where Does the Treatment Plant Operator Work?

With credentials (Operator's License I - IV) you can work virtually anywhere; USA, overseas.

Public relations are important because we (ABC)?

Work for the public Correct

"typical" grit will settle out in a grit channel when the velocity is between 0.7 and 1.4 fps with 1.0 fps being the "ideal" velocity?

Yes

Combined sewer systems are most preferable because they are the most economical and allow for more efficient wastewater treatment. Yes or No.

Yes

Flumes (Parshall or Palmer-Bowlus) are reliable and accurate flowrate measuring devices. Yes or No.

Yes

Heavier grit particles settle to the bottom of the channel?

Yes

IN grit Channels, do the particles settle out before the channel ends?

Yes

Lighter organic particles remain suspended or are resuspended and transported out of the channel?

Yes

Preliminary treatment takes place in the collection system prior to wastewater reaching the plant. Yes or No.

Yes

The purpose of a V-notch weir is to slow down the flowrate to allow for the settling of solids. Yes or No

Yes

If wastewater from a secondary treatment plant were coagulated with alum or lime and settled in a clarifier, would this be considered a method of advanced treatment?

Yes Tertiary treatment

For a particle to settle before it leaves the tank, the vertical settling time must be equal to or less than the horizontal settling time?

Yes, Its really important to understand cause Matt put it in BIG BOLD LETTERING. Highly probably question on final

Provide examples of Solids Disposal

You can send bio-solids to: *landfill *ocean dump them *compost them *burn them

Who Does the Treatment Operator Work For?

You would work for any entity or corporation. Cities, Counties, Sanitary Districts, Companies (i.e. Siltronics, Intel, LSI Logic, etc.)

Slow it down and to about 1.0 fps, then the sand, eggshells, small rock, and cinders will fall out?

Yup

A combined sewer would be best defined as which of the following:

a sewer intended to receive both wastewater and storm and/or surface water

A circular primary clarifier has a diameter of 80 ft and an average depth of 10 ft. The flow of wastewater is 4.0 MGD and the suspended solids concentration is 190 mg/L. What is the weir overflow rate in gpd/ft?

a. 15,923 gpd/ft of weir

Most "sludge" digesters in use today. a. Are sealed tanks. b. Depend upon the action of anaerobic digesters. c. Produce a gas that can be used elsewhere in the plant. d. Present no serious hazards to the operators. e. Require approximately 30 days to produce a properly digested product.

a. Are sealed tanks. b. Depend upon the action of anaerobic digesters. c. Produce a gas that can be used elsewhere in the plant.

Sludge digestion tanks are mixed continuously to: a. Bring food to the "bugs". b. Help maintain an even temp. c. Keep digester gas "dissolved" d. Concentrate the scum to thick blankets covering the supernatant. e. Add the proper oxygen needed by the bacteria.

a. Bring food to the "bugs". b. Help maintain an even temp. c. Keep digester gas "dissolved"

Which of the following would be part of an Operation and Maintenance Manual for a circular clarifier?

a. Control Gates operating properly b. Look for sand/debris & obstructions. c. Check Collector Drive mechanism for oil/alignment/completeness d. Look at gaskets/gears/sprockets/drive motor for installation & proper rotation. e. Squeegee blades on collector plows for distance from floor of the tank. f. Look at all "below water" mechanisms for proper installation/operation g. Inspect sumps/hoppers and piping for debris/obstructions

If the residue remaining on a filter paper is the suspended solids, these are the solids that pass through the filter.

a. Dissolved (TDS)

Inflow is water discharged into a sewer system and service connections from sources other than regular connections. This includes flow from yard drains, foundation drains and around manhole covers. How does inflow differ from infiltration?

a. Inflow differs from infiltration in that it is a direct discharge into the sewer rather than a leak in the sewer itself.

Natural cycles could refer to which of the following? a. Life cycles of aquatic organisms b. Nutrient cycles c. Sludge cycles d. Effluent cycles e. Natural purification cycles

a. Life cycles of aquatic organisms b. Nutrient cycles e. Natural purification cycles

This is a written or electronic booklet that describes detailed procedures for operators to follow when operating and maintaining a specific wastewater treatment or pretreatment facility and the equipment found only in that plant or facility.

a. O&M (Multi-media Form) b. O&M (Written Form) c. O&M (Web Based) d. O&M (Animation Files) O and M = Operation and Maintenance Manual, they come in many forms..

Which of the following would be some suggestions that may help workers in this field to stay healthy on the job?

a. Open cuts or wounds should be protected, be sure to replace contaminated dressings. b. Workers at wastewater facilities should wash their hands frequently with anti-bacterial soap. c. Avoid direct contact with wastewater, always wear rubber gloves and protective clothing when working with wastewater. d. Keep your fingernails short and DO NOT bite your nails! e. DO NOT stick your fingers or hands in your mouth, nose, eyes or ears. f. Be careful of the many dangers associated with confined spaces with one of the primary hazards being atmospheric. g. Chemical hazards are also present at wastewater treatment facilities. In some cases (such as chlorine), the chemical hazard may be deadly. Be sure to read and understand the MSDS for the chemical product you are working with

Which of the following would be part of an Operation and Maintenance checklist for a rectangular clarifier inspection?

a. Perform the same inspections (tank hoppers, channels, control gates, weirs, b. Check the wooden cross pieces (FLIGHTS) that each is properly attached to c. Check the wearing shoe (a flat metal plate) that is attached to each end d. Check the clearance between the edge of the metal shoe and the vertical

POTW is the short version for _________________________ ?

a. Publicly Owned Treatment Works This term is used by the US Environmental Protection Agency to designate treatment works which are owned by a state, municipality, city, town, special sewer district or other publicly owned and financed entity. This is opposed to similar treatment facilities which are privately (i.e. industrial) owned. This definition includes any devices and systems used in the storage, treatment, recycling and reclamation of municipal sewage (wastewater) or industrial wastes of a liquid nature. POTW also includes sewers, pipes, pumping stations and other conveyances only if they carry wastewater to a POTW treatment plant.

Why screen wastewater?

a. Separate the organic from inorganic wastes. b. Remove large objects and debris from the influent. c. Keep small rodents and vermin from entering the treatment plant. d. Recover valuable waste components that can be recycled. e. Identify the types of waste reaching the treatment plant.

What does TDS stand for?

a. Total dissolved solids Correct

Preliminary treatment to screen out, grind up, or separate debris is the first step in wastewater treatment. Sticks, rags, large food particles, sand, gravel, toys, etc., are removed at this stage to protect the pumping and other equipment in the treatment plant. Treatment equipment includes?

a. bar screens b. comminutors (a large version of a garbage disposal) c. grit chambers

Pre-liminary Treatment can by done by?

a. bar screens b. mechanical screen c. grit chambers

In grit channels, what is the solids settling velocity?

about 0.075fps

What are two basic types of bacteria are present in an anaerobic digester?

acid formers gas formers

The primary treatment process in a wastewater treatment plant is normally found:

after preliminary treatment but before secondary

The addition of __________ at the initial stages of waste treatment to freshen the wastewater, remove undesirable gases, add oxygen, promote flotation of grease and aid in the coagulation of solids.

air

___________ bacteria live and reproduce in an environment containing no "free" or dissolved oxygen. ___________ bacteria obtain their oxygen supply by breaking down chemical compounds, which do contain a "combined" oxygen source, such as sulfate (SO 4) or nitrate (NO3-).

anaerobic

We know that the flow velocity in a sanitary sewer system is about 2 ft/sec. In the preliminary treatment process we remove obstructions from the wastewater. As water enters a sedimentation basin, grit settles out. This process requires flow to be about ?

b. 0.03 ft/sec Correct

The flow is 5.0 MGD in a circular tank with a 75 ft weir diameter. What is the weir overflow rate in gallons per dat oer foor of weir length?

b. 21,231 gpd/ft of weir

Results of the settleable solids test run using Imhoff cones may be used to ___________.

b. Calculate the pounds of primary solids pumped to the digester Correct

According to Chapter 2 and VTech ONLINE Water and Wastewater COURSE, ______________ solids, are extremely fine particles that you can see but will not settle (non setteable) from the liquid portion. They can *usually* be filtered from the liquid to a 0.45-um membrane filter (ABC). Hint: They want the specific answer not the general one...

b. Colloidal Correct

Total solids can be divided into suspended solids and ________ solids (ABC)

b. Dissolved

According to our textbook (Chapter 2) and Standard Methods For Water and Wastewater Analysis , total solids can be divided into suspended solids and ________ solids (ABC).

b. Dissolved Correct

Clarification of water by sedimentation and filtration removes (ABC):

b. Suspended solids Correct

Bacteria which will live and reproduce only in an environment containing oxygen (specifically Dissolved Oxygen or DO). DO is available for their respiration (breathing). The source for this DO is the atmosphere (about 20% Oxygen). The air is compressed and the DO is dissolved in water (due to decompression). Oxygen combined chemically, such as in water molecules (H 20) is referred to as "combined" oxygen and cannot be used for respiration by _________ bacteria.

b. aerobic

Where do the disease causing bacteria in wastewater come from?

bacteria that comes from the body wastes of humans and animals that have a disease

Infiltration may result from

bad joints

Preliminary treatment may include (but not limited to) which of the following unit operations:

bar screens, barminutor, grit chamber

Why is grit removed early in the treatment process?

because it is abrasive and will wear out pumps and other equipment

Why are weirs not frequently used to measure the influent to the plant?

because solids may collect behind the wier causing odors and inaccurate measurements

What is the typical hydraulic detention time for a primary clarifier?

c. 1.5 - 2 hrs Correct

___________ solids remain in liquid solution and are defined as the solids that will pass through a 0.45um membrane filter (ABC).

c. Dissolved Correct

The total solids in water would be a combination of (ABC):

c. Dissolved solids and suspended solids

_____________ ensures equal (even) effleunt flow over all weirs and eliminates short circuiting. Designed for small surface elevation (water level) adjustments in the clarifier provided the plate is designed for vertical movement (up or down). Leads the water to the launder region.

c. Effluent Weir

Sedimentation is improved by:

c. Uniform, horizontal, low-velocity flow across the basin Correct

List some examples or compatible inorganics?

calcium magnesium iron

Give examples of Tertiary Treatment

chemical addition-precipitation reverse osmosis chemical oxidation polymer precipition electrodialysis

Which of the following are considered inorganic wastes

chromium, copper, zinc

Which of the following is not an example of a flow measuring device?

d. Manometer Correct prssure meter

The liquid that stands above a sediment precipitate is referred to as the (ABC):

d. Supernatant

Solids turbidity generally indicates the quantity of _________ material in a water, particularly at low solids concentrations (ABC).

d. Suspended

So you just finished reading my feedback to the last question. Which of the following secondary wastewater treatment process are correctly matched?

d. Suspended film systems =Activated sludge, extended aeration, oxidation ditch, and sequential batch reactor systems Correct

Advantages of rectangular clarifiers over circular clarifiers a. Occupy less space when multiple units used b. Provide longer travel distance for settling to occur c. Less short circuiting d. All of the above

d. all the above

Comparison of Rectangular and Circular Clarifier a. Regulation and preference of regulatory authorities b. Size of installation c. Local site condition d. All of the above

d. all the above

Which of the following is/are true about clarifiers? a. is a tank or basin in which wastewater is held for a period of time b. A clarifier can also be called a Settling Tank, or Sedimentation Basin c. During a "holding period" the heavier solids settle to the bottom and the lighter materials float e. Contain a "clarified zone" of wastewater that lies between "settleables" and unsettleables d. all the above

d. all the above

List some of the ways to dewater and dispose of digested sludge

digested sludge may be dewatered by using sand drying beds, lagoons, centrifuges, vacuum filters, or filter presses. Ultimately the dried sludge may be used as a soil conditioner or it may be buried

Effluent from a wastewater treatment plant may be disposed of by:

discharging onto land evaporating into the atmosphere discharging into receiving water reclaiming and reusing recharging the groundwater

Give examples where you can find significant quantities of organic matter:

domestic wastewater, paper mills, and tanning wastes NOT cooling water from thermal station (radioactive) NOT Metal Plating wastes (non organic)

Activated sludge (a whole bunch of microorganisms) is added to wastewater and resulting in a thick mixture (raw activated sludge, RAS) is constantly de-aerated and agitated (mixed). After some time in the aeration tank (a condominium for microorganisms), the activated sludge is pushed out and allowed to settle (due to gravity) by sedimentation.

f

Inorganic wastes are chemical substances of organic origin.

f

Raw wastewater is plant influent, or wastewater after any treatment.

f

The HDT is a theoretical measurement. The actual HDT is always more than the theoretical HDT. It can be measured using dyes, a float, tracers, etc.

f

Weirs measure flow inside a pipe?

f

Aerated grit basins utilize air to remove all organics during the pretreatment process?

false

The purpose of primary clarifiers is to separate solid particles in the wastewater mixture from the liquid. After passing through the primary clarifiers, the solids and liquid streams are treated by the same processes?

false

Bar racks are sloped at an angle between 50° and 75° from vertical.

false Trash/Bar racks typically have an angle of the slope between 30° and 45°.

Wet Oxidation

high pressure and high temperature sludge treatment Was popular at one time It became too odiferous, smelled bad and grew disfavor with operators and treatment plant neighbors

What is the "ideal velocity" for "typical" grit to settle out in a grit channel?

ideal 1fps "typical" grit will settle out in a grit channel when the velocity is between 0.7 and 1.4 fps with 1.0 fps being the "ideal" velocity?

What term is used to describe water that enters the collection system from sources such as foundation drains, holes in manhole covers, surface runoff, and cross connections between sanitary and storm sewers?

inflow

preliminary treatment process that are in the correct order for proper wastewater treatment plant operation?

influent, screening, grit removal, pre-aeration, sedimentation,.

In a treatment plant, the term "headworks" usually relates to an area that:

is a location where influent enters the treatment plant

A sewer manhole is used, or needed, for which of the following best purpose?

it is a point in a pipeline, which provides access to maintain the system

List some examples of incompatible inorganics?

mercury copper nickel chromium zinc lead

Disinfection implies the killing of all microorganisms. Yes or No.

no

PRESSURE FLOTATION.

o Air is forced above 1 atm. (14.7 psig) into the wastewater inside a pressure chamber. The air becomes dissolved in the liquid. o Pressure is released back to 1 atm. o This process allows the dissolved air to be released to the surface, and out of the liquid.

MAINTENANCE CONSIDERATIONS part 3

o Auxiliary service lines (air, electrical, chemical feed) should be provided (buried) along with the sludge piping. Increased computerization allows us to closely monitor operations, therefore accessing and threading the new cables becomes important. o As clarifiers become covered (for odor control purposes),ensure that easy access is provided for continued maintenance of the basic units.

OPERATIONAL CONSIDERATIONS

o Control gates and isolation valves will isolate clarifiers. o Baffles and weirs will properly guide clarifier velocities. o Protective devices are on the collector mechanisms. o Scum removal can be done efficiently. o Hose bibs located near units needing routine maintenance. o Sampling equipment and locations are accessible and safe for routine operation. o Clarifier weirs have provision to be vertically adjusted.

Colloids and/or Emulsions can usually be removed by:

o DISSOLVED AIR FLOTATION (DAF). Flotation is very simple. Inject air (under pressure) into the wastewater, the result will be the suspended "culprits" will float to the surface and can be skimmed off. o DAF WITH CHEMICAL ADDITION. Adding chemicals to wastewater containing large amounts of colloids and/or emulsions aids in their removal. Chemical addition will electrically alter the "culprits" making the flotation and skimming processes a very effective method of removal.

WHICH SOLIDS ESCAPE?

o Dissolved Solids (TDS) o Colloids o Emulsions

MAINTENANCE CONSIDERATIONS part 1

o Drive mechanisms, lube points, gear box locations, and ensure that all inspection points are accessible. o Weirs, launders, and control points need to be accessible for cleaning, painting, and eventual replacement. o Conveniently locate sludge pumps and fit the piping with back flushing access; make it convenient. o Provide for portable pumps to be easily brought in and hooked up. Emergency backup on pumps is a MUST. o Ensure that you can isolate channels and pipelines so that they can be dewatered and cleaned.

How to be drown-proof

o Place handrails and walkways by all clarifiers. o Cover open pits with grating & deck plates. o Have life preserves and lifelines handy to throw. o Use the "buddy" system when working around/near water.

SAFETY CONSIDERATIONS part 2

o Provide for directional lighting, subdued to the neighborhood, yet bright enough to allow safe access to work areas at all hours of the day. o Place pulley-guards and belt-covers over chain drives, belt drives, and other moving parts. o Place safety hooks, poles, and floats in strategic locations around the clarifiers. o Do not allow placement of pipes or conduits overhead, or on top of bridge walkways.

VACUUM FLOTATION

o Saturate the wastewater with dissolved oxygen (DO). o Turn off the air; larger bubbles escape the surface. o Wastewater flows into a vacuum chamber. o Pressure is reduced below 1 atm. (14.7 psig). o Tiny bubbles are "evacuated" to the surface where the solids have been encapsulated within the bubbles. o Water flows out of the chamber and is skimmed.

HOW DOES THE "Sedimentation-digestion" UNIT WORK? part 3

o Solids settle to the bottom (tray section) of the clarifier and are scraped to the center of the unit. A slot in this area allows for the solids to pass out of the clarifier and into the digestion section of the unit. Here the "boot" prevents generated anaerobic gasses from re-entering the clarifier section and also prevents any "floating" solids from re-entering the clarifier. In the "unheated" digester section of this unit sludge undergoes anaerobic digestion. o "Digested" sludge (we do not know the extent of digestion) is removed from the bottom of the digester by pumping using theservices of a SEPTIC HAULER.

REVIEW PLANS & SPECS. OPERATION, MAINTENANCE & SAFETY

o Study the plans and specifications along with the O&M manual for the facility. Sometimes, the Supervisor tests you on these items before being promoted. o Pay attention to expansion plans. o Involve yourself with the design staff and if appropriate offer suggestions when asked.

HOW DOES THE "Sedimentation-digestion" UNIT WORK? part 2

o Treated wastewater leaves the unit via conventional weirs and effluent launder system. The wastewater can be distributed to an underground drainage system, spray irrigated (potato waste), or moved on to more conventional secondary treatment.

HOW DOES THE "Sedimentation-digestion" UNIT WORK? part 1

o Wastewater is collected from a number of homes, campsites, or combination of domestic sources. o The water is conveyed to the "dedicated land" on which the sedimentation-digestion unit is located. o The wastewater passes minimal preliminary treatment which includes a bar screen (bar rack), flow metering, and in-channel aeration (minimizes odor complaints). o From preliminary treatment the wastewater flows into the circular shaped sedimentation chamber of the unit. Here, conventional separation of water/solids occurs.

• CLEANING WEIRS & TROUGHS. Algae, and attaching-microorganisms are big problems in "slow-moving" wastewater. elaborate please

oChlorine solution can be piped (through PVC pipes) to the entrance area of the clarifier overflow weir to control algae growth both at the weirs and in the launders. oHigh pressure water jetting can be effective as a weekly "upkeep" duty. Too many "stringy" algae are ugly and detract from the clarifier's appearance. oBrushes can be attached to the moving scraping mechanism of circular clarifiers. These brushes will scrape the build-up from the walls and/or the weir surfaces.

List 4 types of pollution:

organic inorganic thermal radioactive

pH

pH is an expression of the intensity of the basic or acidic condition of a liquid. Mathematically, pH is the logarithm (base 10) of the reciprocal of the hydrogen ion activity. pH = Log10 1 H + The pH may range from 0 to 14, where 0 is most acidic, 14 most basic, and 7 neutral. Natural waters usually have a pH between 6.5 and 8.5.

Activated sludge can be pumped from the secondary clarifier to______ or _________

primary clarifier waste sludge handling facilities

Name the three "types" of sewers.

sanitary storm combined

secondary treatment process are in the correct order for proper wastewater treatment plant operation?

sedimentation and floatation, biological, chemical, and physical processes, disinfection, effluent

Storm Sewer

system that carries storm water runoff from streets, land, and building roofs in a separate conveyance system. Most ofter the "storm runoff" goes from your street directly to the nearest natural waterway and no treatment is accomplished en-route. This practice is slowly chaging with the installation of wetlands areas to slow/treat the storm water. ***ONLY RAIN DOWN THE DRAIN***

"Secondary Treatment Technology-based requirements for direct discharging municipal sewage treatment facilities. Standard is based on a combination of physical and biological processes typical for the treatment of pollutants in municipal sewage. Standards are expressed as a minimum level of effluent quality in terms of: BOD 5 , suspended solids (SS), and pH (except as provided for special considerations and treatment equivalent to secondary treatment)."

t

"Secondary wastewater treatment is the second stage of wastewater treatment that takes place after the primary treatment process. The process consists of removing or reducing contaminants or growths that are left in the wastewater from the primary treatment process. Usually biological treatment is used to treat wastewater in this step because it is the most effective type of treatment on bacteria, or contaminant, growth."

t

"Sedimentation is a solid-liquid separation that utilizes gravity to remove suspended solids used in water and wastewater treatment. These suspended solids, or particles, are important to remove from water for several reasons. Some of these reasons include: visibility impairment (aesthetic & safety reasons), disease transmission (bugs attach to particles that can then be ingested), and lastly because toxic materials can either exist as particles or can absorb to the particles."

t

"Sewage is the wastewater released by residences, businesses and industries in a community. It is 99.94 percent water, with only 0.06 percent of the wastewater dissolved and suspended solid material. "

t

"Sewage is the wastewater released by residences, businesses and industries in a community. It is 99.94 percent water, with only 0.06 percent of the wastewater dissolved and suspended solid material."

t

"Sludges are generated through the sewage treatment process. Primary sludges, material that settles out during primary treatment, often have a strong odor and require treatment prior to disposal. Secondary sludges are the extra microorganisms from the biological treatment processes. The goals of sludge treatment are to stabilize the sludge and reduce odors, remove some of the water and reduce volume, decompose some of the organic matter and reduce volume, kill disease causing organisms and disinfect the sludge. "

t

"Some of the solids collected in the secondary clarifier (return activated sludge) are sent back to the aeration tank to treat more wastewater and the excess (waste activated sludge) is pumped to another location in the plant for further treatment. Its thinner.."

t

A colloid is defined as very small, finely divided solids (particles that do not dissolve) that remain dispersed in a liquid for a long time due to their small size and electrical charge. These particles have negligible settling velocity because their small mass has a low gravitational force compared to surface frictional forces

t

A weir is a wall or plate placed in an open channel and used to measure the flow of water. The depth of the flow over the weir can be used to calculate the flowrate, or a chart or conversion table may be used to convert depth to flow. It can also be a wall or obstruction used to control flow (from settling tanks and clarifiers) to ensure a uniform flow rate and avoid short-circuiting.

t

About 10,000-20,000 gpd/ linear foot of CWOR is acceptable

t

Activated sludge (a whole bunch of microorganisms) is added to wastewater and resulting in a thick mixture (mixed liquor, ML) which is constantly aerated and agitated (mixed). After some time in the aeration tank (a condominium for microorganisms), the activated sludge is pushed out and allowed to settle (due to gravity) by sedimentation.

t

Actual settling basins are affected by the dead spaces in the basins, eddy currents, wind currents and thermal currents. In the ideal settling basin all of the fluid elements pass through the basin at equal time to the theoretical detention time, t, which is equal to V/Q. Actual basins, however, have most of the fluids passing at a time shorter than the theoretical detention time. Dead spaces and eddy currents have rotational flow and do very little sedimentation since the inflow and outflow from these spaces is very small. As a result, the net volume available for settling is reduced and the mean flow-through time for the fluid element is decreased. Also, wind and thermal currents create flows that pass directly from the inlet to the outlet of the basin, which decreases the mean flow-through time. The magnitude of the effects of the dead spaces, thermal currents, etc. and the hydraulic characteristics of a basin may be measured using tracer studies.

t

Bar screens are typically at the **headworks= entrance** of a wastewater treatment plant (WWTP), bar screens are used to remove large objects such as rags, plastics bottles, bricks, solids, and toy action figures (again with the action figures!) from the waste stream entering the treatment plant.

t

Bar screens are vital to the successful operation of a plant, they reduce the damage of valves, pumps, and other appurtenances.

t

Clarifiers allow gravity to settle solid particles that are heavier than water (SG >1.0), while providing a mechanism to capture those solid particles that are lighter than water (SG <1.0).

t

Clarifiers remove Settleables & Floatables.

t

Coarse bar screens (or bar screens) are distinguished from fine screens by the space opening. Coarse screens usually have a spacing of 6 mm (or 0.25 in [metric system conversion]). and larger, whereas fine screens spacing is usually between 1.5 mm (or 0.059 in) through 6 mm (or 0.25 in [metric to inches]).

t

Hydrogen sulfide is a gas with a rotten egg odor. This gas is produced under anaerobic conditions. Hydrogen sulfide gas is particularly dangerous because it dulls the sense of smell so that you don't notice it after you have been around it for a while. In high concentrations, hydrogen sulfide gas is only noticeable for a very short time before it dulls the sense of smell. The gas is very poisonous to the respiratory system, explosive, flammable, colorless and heavier than air.

t

Often times scrubbers or scrapers remove sludge from the bottom of basins.

t

Secondary treatment is a biological treatment process to remove dissolved organic matter from wastewater. Sewage microorganisms are cultivated and added to the wastewater. The microorganisms absorb organic matter from sewage as their food supply. Three approaches are used to accomplish secondary treatment; fixed film, suspended film and lagoon systems

t

Secondary treatment processes can remove up to 90 percent of the organic matter in wastewater by using biological treatment processes (its true!).

t

Secondary wastewater treatment process are used to convert dissolved or suspended materials into a form more readily separated from the water being treated. Usually the secondary process follows the primary treatment process. The secondary treatment commonly is a type of biological process followed by secondary clarifiers that allow the solids to settle out from the water being treated.

t

Sedimentation is the process used in both primary and secondary wastewater treatment that slows down the flow and allows particulate matter to settle out of the wastewater.

t

Sewage treatment is a multi-stage process to renovate wastewater before it reenters a body of water, is applied to the land or is reused. The goal is to reduce or remove organic matter, solids, nutrients, disease-causing organisms and other pollutants from wastewater. Each receiving body of water has limits to the amount of pollutants it can receive without degradation.

t

Sludge are the settleable solids and scum is what floats on top.

t

Solids are classified by their size and whether they are organic or inorganic.

t

Some WWTPs plants still use manually cleaned bar screens, but because they are so labor intensive, the trend is to move toward mechanical bar screens. Mechanical bar screens are the more routinely used type because of their ability to operate automatically.

t

Standard Methods Total solids, as the term implies, includes all of the solid constituents of a wastewater. Total solids are the total of the organic and inorganic solids or the total of the suspended and dissolved solids. In an average domestic wastewater, total solids are about half organic and half inorganic, and about two-thirds in solution (dissolved) and

t

Sticks, rags, large food particles, sand, gravel, toys, plastics, and other objects can be removed during preliminary treatment via screens, shredding, communitors, and grit chambers?

t

Suspended solids are those which are visible and in suspension in the water. They are the solids which can be removed from the wastewater by physical or mechanical means, such as sedimentation or filtration.

t

The BOD5 test is the most important test for finding the polluting strength of a wastewater.

t

The TS and TSS fractions are dried at 104º C while the TDS fraction is dried at 180º C. Total solids are important to measure in areas where there are discharges from sewage treatment plants, industrial plants, or extensive crop irrigation. Total solids are dissolved solids plus suspended and settleable solids in water. Higher concentrations of suspended solids can serve as carriers of toxics, which readily cling to suspended particles.

t

The settleable solids test is the measurement of the volume of solids in one liter of sample that will settle to the bottom of an Imhoff cone during a specific time period. The test indicates the volume of solids removed by settling in sedimentation tanks, clarifiers or ponds. The settleable solids test indicates whether the primary and secondary processes are functioning properly.

t

The settleable solids test on wastewater can tell the operator a lot about what kind of wastewater is coming into the plant and how the solids are settling. Also, the settleable solids test can help the operator estimate the volume of sludge to be expected in the clarifier.

t

The surface loading rate of a primary clarifier is generally between 300 and 1200 gpd/sq ft.

t

The term "total solids" refers to matter suspended or dissolved in water or wastewater, and is related to both specific conductance and turbidity. Total solids (also referred to as total residue) is the term used for material left in a container after evaporation and drying of a water sample. Total Solids includes both total suspended solids, the portion of total solids retained by a filter and total dissolved solids, the portion that passes through a filter (American Public Health Association, 1998).

t

To run the test, the amount of oxygen is measured in a portion of diluted wastewater, and another portion like the first one is stored at 20°C for 5 days. The glass bottles shown in figure 10-1 are used for this test. During the 5 days, the microorganisms eat the organic matter in the wastewater and use oxygen at the same time. At the end of 5 days, the amount of oxygen con- sumed by the microorganisms times the dilution factor of the sample gives the sample's 5-day BOD. The dilution factor is the number of milliliters of dilution water added to a given number of milliliters of sample.

t

Total Dissolved Solids (TDS) are solids in water that can pass through a filter (usually with a pore size of 0.45 micrometers). TDS is a measure of the amount of material dissolved in water. This material can include carbonate, bicarbonate, chloride, sulfate, phosphate, nitrate, calcium, magnesium, sodium, organic ions, and other ions. A certain level of these ions in water is necessary for aquatic

t

Total Suspended Solids (TSS) are solids in water that can be trapped by a filter. TSS can include a wide variety of material, such as silt, decaying plant and animal matter, industrial wastes, and sewage. High concentrations of suspended solids can cause many problems for stream health and aquatic life.

t

Total dissolved solids (TDS), also referred to as filterable residue, represents the portion of the sample (water, wastewater, effluent) that passes through a filter of a particular size. Generally, a pore size of 0.45 mm is considered to be adequate to differentiate between microscopic particulate and dissolved material. The final result, after evaporation and drying to constant weight at 180oC, represents the total dissolved solids. (1)

t

Total solids, as the term implies, includes all of the solid constituents of a wastewater. Total solids are the total of the organic and inorganic solids or the total of the suspended and dissolved solids. In an average domestic wastewater, total solids are about half organic and half inorganic, and about two-thirds in solution (dissolved) and one-third in suspension. The organic solids, which are subject to decay, constitute the main problem in wastewater treatment.

t

Wastewater or other liquid - raw (untreated), partially or completely treated - flowing from a reservoir, basin, treatment process, or treatment plant in called plant influent.

t

c. Effluent Weir Correct

t

supernatant [ˌsuːpəˈneɪtənt] adj 1. floating on the surface or over something 2. (Chemistry) Chem (of a liquid) lying above a sediment or settled precipitate

t

the time it takes for the plows to make one revolution inside the clarifier. Keep this for reference. Check and RECORD the electrical amperage that the drive motor draws.

t

The time (T) required to fill a tank or a basin of known Volume (V) at a given flowrate (Q). Or the theoretical time required for a given flow of wastewater to pass through a tank.

t Detention time usually refers to WATER, while the term Retention time will normally refer to SLUDGE. T= V/Q Q=V/T V=QT

Why is a Parshall Flume widely used for measuring wastewater flow?

they have no obstructions

A Manhole provides for a method to access the wastewater collection system. Why??

to allow for access to the piping system for routine maintenance

Why is a secondary clarifier needed after a trickling filter, rotating biological contactor, or aeration tank?

to allow organisms in treated wastewater to be removed by settling

Why are digesters mixed?

to bring food and organisms together, provide a uniform temperature and prevent the formation of a scum blanket

Why is it necessary to measure settleable solids?

to determine efficiency of settling basins. able to calculate loads on settling basins, sludge pumps, and sludge handling facilities for design and operational purposes

What is the purpose of tertiary (advanced treatment)?

to reduce as much nitrate, phosphate, and trace organics as practical given todays technology Allows for the wastewater to be fully reclaimed for such uses as water reservoir recreation, deep aquifer recharging, and reuse as irrigation water

1.0 fps is consideredideal for grit removal because it allows organic solids to move downstream fortreatment.

true

A screening compactor isusually situated close to the mechanically cleanedscreen and compacted screenings are conveyed to adumpster or disposal area?

true

Air in an aerated grit chamber is introduced near the bottom of the liquid depth through diffusers located to one side of the basin. As the air bubbles rise on the one side of the basin they induce a horizontal rolling motion to the liquid contained in the basin. The liquid travels upward near one wall of the basin, across the top towards the other side, and downward near the opposing wall.

true

All tank piping, channels,inlets, outlets and weirs will be designed to accommodate peak flows.

true

As the solids settle downward in a PC, the liquid flows upward and over a weir.

true

At 1.0 fps grit settles. Velocity can be controlledby using flow-proportional weirs

true

At treatment plants with less than 0.1 million gallons per day treatment capacity, one unit is acceptable when an equalization tank or holding basin is constructed with adequate volume to dampen out peak inflow rates?

true

Clarifiers can be designed for the average daily flow or daily flow equivalent to the peak hourly flow that requires the largest surface area.

true

Comminuting and grinding devices are installed inthe wastewater flow channel to grind and shredmaterial up to 6 to 19 mm (0.25 to 0.75 in) in size.?

true

Comminutors and grinders are used primarily atsmaller treatment facilities (less than 5 MGD) toprocess material between 6 and 19 mm (0.25 to0.75 in)

true

Comminutors consist of a rotating slotted cylinder through which wastewater flow passes. Solids that are too large to pass through the slots are cut by blades as the cylinder rotates, reducing their size until they pass through the slot openings (2).

true

For every one (1) foot of vertical water distance it takes a 0.2 mm sand particle 13.33 seconds to complete the journey?

true

Grit classifiers remove organics from the grit?

true

Grit is defined as heavy inorganic matter such as sand and gravel.

true

Heavier grit and suspended solids collect on the sides and bottom of the cyclone due to induced centrifugalforces, while scum and lighter solids are removed from the center through the top of the cyclone.

true

Hydrocyclone systems are typically used to separategrit from organics in grit slurries or to remove gritfrom primary sludge.

true

Hydrocyclones can remove both grit and suspendedsolids from wastewater. A hydrocyclone canpotentially remove as many solids as a primaryclarifier.

true

Inlets to a settling tank will be designed to dissipate the inlet velocity, to distribute the flow uniformly, and to prevent short circuiting.

true

Other types of comminutors have stationary slotted screens with oscillating cutters mounted on a shaft. Cutting teeth are mounted in rows on the drum?

true

Preliminary treatment begins with screening. Screens remove large solids such as rags, sticks, plastics and similar materials from the wastewater.?

true

Primary clarifiers are designed to provide a quiescent volume where solids are allowed to settle by gravity over a relatively long period of time (usually 2 to 4 hours).

true

Raw wastewater delivered from the collection system to the treatment plant is first received at the headworks facility.

true

Screening presses and vacuum containers are used at wastewater treatment plants to remove the liquid from the screenings before transport to reduce excess water, volume, and weight.

true

Settled solids collect on the floor of the clarifier to form what is known as a sludge blanket.

true

Shredding devices are installed after the bar screen or as alternatives to screening. Shredding devices reduce solids to a size that can enter the plant without causing mechanical problems or clogging ?

true

Some refer to the headworks as a pretreatment facility because no biological treatment occurs

true

The bar screen may be coarse (2-4 inch openings) or fine (0.75-2.0 inch openings). The bar screen may be manually cleaned or mechanically cleaned. Manual or mechanical cleaning is performed frequently enough to prevent solids buildup and reduce flow into the plant?

true

The basic components of wastewater grit material consists of such materials as sand, cinders, rocks, coffee grounds, cigarette filter tips, and other relatively nonputrescible organic and inorganic substances

true

The chains used in chain-driven bar screens tend to stretch from wear.

true

The goal of an aerated grit chamber is to keep the finer and lighter organic solids in suspension so that they pass through to further treatment and to allow the coarser and heavier inorganic solids (grit) to settle. As grit settles and accumulates, it is removed by pumping, dewatered in a screw type conveyor called a grit classifier, and transported by conveyor to a dumpster?

true

The minimum length of flow from inlet to outlet of a rectangular tank will be 10 feet in order to prevent short circuiting of flow in the tank.

true

The purpose of the headworks is to condition the wastewater for treatment through the processes of screening and grit removal

true

Units performing primary treatment are known as primary clarifiers?

true

Wastewater treatment is usually characterized as consisting of four sequential processes: preliminary, primary, secondary and tertiary (sometimes called "advanced") treatment).

true

What is the next step after inspection of a circular clarifier is complete?

turn on the mechanism RECORD the time it takes for the plows to make one revolution inside the clarifier. Keep this for reference. Check and RECORD the electrical amperage that the drive motor draws.

What is usually done with grit that has been removed from the wastewater?

usually buried

What happens to the sludge and scum collected in a primary clarifier?

usually pumped to sludge handling facilities such as digesters

List some examples of compatible organics?

vegetable oil chicken fat butter sugars lipids

When there is a collection system failure, what would you suspect is the most likely to happen? ?

wastewater could flow back into people's homes

A ______________ is a special-shaped water blockage in which the flowrate (Q) discharged through the designed blockage is directly proportional to the head (or height of water H) located upstream of the blockage.

weir

Wet Well Pump Rates

wet well size and control setting shall be appropriate and in accordance with the pump manufacturer's recommendations to avoid heat buildup in pump motor due to frequent starting and to avoid septic conditions due to excessive detention time Suitable devices for measuring sewage flow and/or run time should be considered at all pump stations.

In a primary clarifier, the scum and settled sludge are pumped over the effluent weirs to sludge handling processes. Yes or No.

yes

Lagoons have either aerobic, anaerobic, or both types of bacteria working on the waste. Yes or No.

yes

Sterilization implies the killing of all microorganisms. Yes or No.

yes

Tertiary treatment is designed to remove nutrients and traces of organics. Yes or No.

yes

The average hydraulic detention time (HDT) in a primary clarifier is 1½ to 2 hrs. Yes or No.

yes

What should you do when check scum?

• Check scum trough often. • Clean scum ramp/beach/trough areas frequently using a brush, water, and steam if needed. • Dispose of scum by: o Burning in an incinerator o Burial in a landfill o Digestion (Aerobic and Anaerobic) • Scum troughs and scum pits provide a breeding ground for vectors (flies, etc). Spray with chlorine solution as needed.

What are the daily operation and maintenance of clarifiers? 1 part

• INSPECT. At least once per shift. • CLEANUP. Pressure wash exposed surfaces of the clarifier(s) and the walkways around them. Weekly. • LUBRICATION. Grease, change/add oil, per the manufacturer's instruction. • PERFORM PREVENTIVE MAINTENANCE. Look at the clarifier manufacturer's O&M for specific PM instructions. Follow the instructions and interval times. • FLIGHTS. Look for looseness, corrosion, and excessive wear. Do this daily on parts above the waterline. • CHAIN & SPROCKETS (Rectangular Clarifiers). Closely check for wear, as 5/100" wear on 240 link pins will cause 1 extra foot of chain length. • KEEP BOOK. Record observations over time. This will allow you to "trend" change over the "long haul".

What should you do to remove sludge often?

• Listen to the Sludge Pump. (Thick from thin sounds different) • Read the Pressure/Combination gauges. Note any changes. • Take a pumped sample and visually examine it. • While pump is on, look at consistency of material (through a site glass). Turn off the pump if water is being pumped.

What are the daily operation and maintenance of clarifiers? 2nd part

• PERFORM SAMPLING & LAB ANALYSIS. BOD, Solids profiles, temperatures, sludge depths are just to name a few. Often, DEQ regulations will dictate "minimum" sampling standards. • SLUDGE & SCUM PUMPING. Discussed under section 5.3, however 4.0 - 8.0% solids concentration in the primary sludge and ½ - 2% in secondary sludge is appropriate. • CLEANING WEIRS & TROUGHS. Algae, and attaching-microorganisms are big problems in "slow-moving" wastewater.

What are the steps in operation and maintenance of rectangular clarifiers?

• Perform the same inspections (tank hoppers, channels, control gates, weirs, bearings, grease fittings, and drive alignments), as you would have for the circular clarifiers cited previously. • Check the wooden cross pieces (FLIGHTS) that each is properly attached to the chain collector mechanism. o Check the wearing shoe (a flat metal plate) that is attached to each end of the flight. Excessive shoe wear will allow the flight to become worn. o Check the clearance between the edge of the metal shoe and the vertical wall. You should measure between 1 and 2 inches, no more, no less. *Do not turn on the collector mechanism when the tank is empty, if the lower shaft bearings depend on water lubrication.

Why remove sludge often?

• Reduces the chance of gasification • Reduces the chance of septicity • Eliminates opportunity of pH reduction • Reduces the chance of sludge pipe plugging • Reduces the chance for foul odors & smells • Increases consistency of (thickness) of sludge.

BIOCHEMICAL OXYGEN DEMAND [BOD] TEST

A laboratory procedure that measures the rate of oxygen used under controlled conditions of time and temperature, and darkness. Standard test conditions include dark incubation at 20°C for a specified time (usually five days); you may therefore see results as BOD5.