Surface Water Production I

For all public water systems the MCL in mg/L for THMs is ________ and for HAAs it is ________.

0.08/0.06

All disinfecting equipment on surface water treatment plants shall include at least ________ standby unit(s) to promptly adjust necessary dosages.

1

Enclosures with more than ________ 150 lb. cylinder(s) shall have forced air ventilation.

1

If the container valve does not open by striking the wrench with the heel of the hand, loosen the packing nut (no more than ________ turn) then retighten it when the valve is open.

1/2

The maximum sustained gas withdrawal rate for 150-lb cylinders (vacuum transmission) is ________ pound(s) per ________ per degree F.

1/Day

Use a ________% ammonia solution for chlorine leak testing.

10

Facilities serving ________ or more people must continuously monitor each filter's effluent turbidity and record it every ________ minutes.

10,000/15

Systems serving ________ or more people must monitor turbidity from each filter with a continuous on-line ________ and continuous recorder.

10,000/Turbidimeter

A mixed-media filter consists of about ________% garnet, ________% sand, and ________% coal.

10/30/60

Required reports must be submitted to the Texas Commission on Environmental Quality by the ________ day of the month following the end of the reporting period.

10th

When an operator mixes 3 grams of a dry chemical in 1 liter of distilled water and uses 4 mils of this solution in a liter of raw water, a dosing solution of what strength results?

12 mg/L

Each filter must have an on-line turbidimeter and recorder able to measure turbidity every ________ minutes.

15

If 2 mg/L of chlorine is added to distilled water, ________ mg/L of residual is produced.

2

If sludge is discharged to a wastewater collection system, a velocity of ________ feet per second must be maintained to prevent floc settling.

2

Sludge regulations allow sludge to be kept ________ years on site, but then must be disposed of at a landfill or other approved site.

2

Stage ________ of the Chlorine Demand Curve indicates monochloramines are formed as chlorine combines with organics containing ammonia.

2

The capacity of rapid sand filters is based on a maximum filtration rate of ________ gallons/ft2/minute.

2

For each pound of dry lime, ________ pounds of dry sludge are produced.

2.50

Chlorine gas has a greenish-yellow color, has a pungent odor, is a strong chemical oxidizer, and is ________ 1/2 times heavier than ________.

2/Air

The rate of backwash water shall not be less than ________ of vertical rise per minute and usually not more than ________ of vertical rise per minute.

20"/35"

Each filter installed after October 1, ________ must have facilities allowing filter draining without removing other filters from service.

2000

Stage ________ of the Chlorine Demand Curve indicates increasing chlorine dosage destroys chloramines and chloro-organics.

3

Declining rate rapid sand filters start at ________ gpm/ft2 and decline to about ________ gpm/ft2.

3/1

To treat with chlorine, add ________ pounds of calcium hypochlorite for every ________ square feet of filter and let it dissolve.

4/100

For high-rate filters, a maximum rate of ________ gallons/ft2/minute must be used.

5

A system that exceeds ________ NTU in the combined effluent shall notify the public drinking water program by the next business day.

5.0

A treatment goal is chemical addition that produces less than ________ NTUs onto the filter, and less than ________ NTU in the filter effluent.

5.00/0.30

Sodium hypochlorite comes in solutions of ________% to ________% available chlorine.

5.25/15

Disinfection equipment shall have a capacity at least ________% greater than the highest expected dosage.

50

Before a new filter is placed into service, the filter must be chlorinated with a dosage of ________ mg/L and the chlorine allowed to contact the filter at least ________ hours.

50/24

Sample for mud balls from the top ________ inches of the filter.

6

The average gravel depth ranges from ________ inches.

6-24

Combined chlorine requires a ________ minute detention time while free chlorine requires ________ minutes.

60/10

Normal detention time ranges from 30 to 60 minutes for clarification and ________ to ________ minutes for flocculation and softening.

60/90

Filtering material must conform to ________ standards and be free of clay, dirt, and organic matter.

AWWA

Coagulant aids include ________.

Activated Silica

Because of the density and general particle shape, filtration characteristics of ________ are similar to ________.

Activated carbon/anthracite

Temperature and dissolved oxygen are frequently measured in ________tests.

Aeration

Factors that influence coagulation include pH, temperature, salts, turbidity, dosage, time, and ________.

Agitation

Determine pH, turbidity, and ________ of the settled water before changing feed rates, the flash-mix, or flocculation intensity.

Alkalinity

Precautions recommended for chlorine should be observed for ________.

Ammonia

A major goal of chemical treatment is to control ________ that cause taste and odor problems.

Aquatic Organisms

Surface wash systems must have a/an ________ vacuum breaker or a reduced pressure principle backflow assembly in the supply line.

Atmospheric

Remove debris from fixed structure screens and ________ if necessary.

Backwash

High-density garnet sand, called the "________" layer, supports the fine media and separates it from the gravel.

Barrier

________ is (are) used to treat water in storage tanks or distribution lines.

Batch treatment

One method to apply chlorine to water is ________.

Batch treatment/Hypochlorinators/gas-feed chlorinators

Inspect ________ and warning signs of floating intakes for obstructions and positioning.

Buoys

Replacing about 6" of sand with 6" of anthracite coal is called ________ a filter.

Capping

In softening plants, where trouble is due to calcium ________, clean the filter with hydrochloric or ________ acid.

Carbonate/Carbonic

Chloroform is a known ________ to some animals and all THMS are suspected as such.

Carcinogen

The centrifuge is essentially a sedimentation device that rotates the sludge at high velocity, settling the sludge by ________ force.

Centrifugal

Some alternatives for sludge disposal are discharge to sewers, filter presses, lagoons, sand drying beds, and ________.

Centrifugation

Hypochlorination uses a chlorine solution fed by a ________ pump.

Chemical

The jar test is used to determine the ________.

Chemical Dosage

Ammonia reacts with hypochlorus acid to form ________.

Chloramines

As pressure is applied to a plate and frame filter press, the sludge cake forms on the surface of the ________.

Cloth

Chloramines are the ________ residual.

Combined

________ is most commonly used to control algae.

Copper Sulfate

Mud balls, which cause ________ and sand clogging, indicate a need to improve washing or ________ and sedimentation.

Cracking/Coagulation

Facilities shall be provided for determining the amount of disinfectant used ________ as well as the amount remaining for use.

Daily

Routine ________ observations should be made of the coagulation-flocculation process and the finding recorded on a daily log.

Daily

The amount of chlorine used up to completely react with the water and its suspended or dissolved material is called chlorine ________.

Demand

________ time is the time water stays in a basin or the time it takes to fill a basin.

Detention

The basic disposal problem of sludge is thickening and _________.

Dewatering

Diatomaceous earth filter media is the fossil-like skeleton of microscopic plants called ________.

Diatoms

Sulfur ________ dissolves manganese, ________, or calcium carbonate.

Dioxide/Iron

Chemical feeders are classified as ________ feeders.

Dry/Solution/Volumetric/Gravimetric

A rate-of-flow controller, installed in the filter ________ line, automatically maintains filtration rate.

Effluent

All filters must have ________ taps to monitor filter effluent turbidity.

Effluent

A gas-feed chlorinator suctions chlorine gas from a cylinder, through an inlet valve, by means of a (an) ________.

Ejector

Insufficient mixing results in poor floc formation and ________ mixing breaks apart the flocculated particles that have clumped together.

Excessive

Ferric sulfate is the most widely used coagulant chemical.

Fale

A free residual of 0.5 mg/L or a chloramine residual of 0.2 mg/L at the far reaches of the distribution system are minimums for safe water.

False

A key to quality control in stratified reservoirs is destratification by chlorination.

False

A lake turns over when warm, light water develops above cold, heavy water and the layers stabilize by exchanging places.

False

A properly operated and maintained filter produces an aesthetic product, protects public health, and saves cost in backwash water and coagulation.

False

A restricted zone of 100 feet radius around the intake must be maintained.

False

A settling basin is divided into four zones: inlet zone, flocculation zone, outlet zone, and sludge zone.

False

A well-operated sedimentation basin with proper coagulant dosage and good floc formation can remove 90 to 95% of the suspended material.

False

Acid solubility should not exceed 50% by weight after treatment with 5% HCL.

False

An advantage of the sludge blanket clarifier is that mixing, flocculation, and sedimentation are incorporated into separate units.

False

At least annually, more often if softening is practiced, drain the filter and collect core samples at 1 foot depths for laboratory analysis.

False

Backwash water velocity should be 15 to 25 ft/second and 3-8 gpm/ft2.

False

Chemical storage facilities should be large enough to store a 1 week supply.

False

Chemicals used to disinfect drinking water include bromine, fluorine, iodine, ozone, chlorine dioxide, chlorine, and chlorine compounds.

False

Chlorine dioxide oxidizes chemicals, is effective against microorganisms, does not form disinfection by-products, and removes taste, odor, and color.

False

Disinfection destroys or inactivates all microorganisms.

False

Distribute reservoir influent with a goal of uniform, vertical, high velocity flow across the cross-sectional area.

False

Eight structures in the treatment process include the intake, raw water pumps, the flash mix, flocculation chamber, sedimentation tank, filters, disinfection chamber, clearwell, and high service pumps.

False

Fill the bottle to the 10 mL mark, but not completely full.

False

Filter box depth must accommodate underdrains, gravel, sand, and a water depth of 10 to 12 feet.

False

Filter sand should be durable grains of siliceous material in the hardness range of talc.

False

Filter sidewalls are roughened to encourage water to short-circuit between the filter walls and sand.

False

Filters are designed to remove dissolved matter.

False

Filtration passes treated water through media such as sand, anthracite coal or a combination using physical and chemical action to reduce color.

False

Fine sand permits longer filter runs than course sand, and fine sand is less effective than course sand in removing bacteria and turbidity.

False

Flocculation facilities for straight-flow and up-flow sedimentation basins, built after Oct. 1, 2000 must have detention time of at least 2 minutes at design capacity.

False

Giardia and Cryptosporidium are easily inactivated with normal doses of chlorine.

False

Hypolimnion aeration does not de-stratify a lake, but does disinfect it to restore desirable water characteristics.

False

If a boil water notification is required, make it within 42 hours the TCEQ format in the Chapter 290 rules.

False

If the effluent sample has the lower plate count, bacteria are growing in the sand.

False

In a rectangular sedimentation basin, the flow is vertical to the basin and effluent weirs are opposite the influent trough.

False

In the contact zone of a dissolved-air flotation basin, water containing super-saturated oxygen is introduced, and upon pressure increase, micro-bubbles are released that attach to the coagulated particles.

False

Inlet water velocity into a filter should be 20 to 30 feet per second.

False

Inspection of a filter bed is not part of a maintenance program.

False

Intakes can be within 500 feet of boat ramps, docks, marinas, or fishing piers.

False

Iodine is an effective drinking water disinfectant, but its use is limited to about 2 months.

False

Leopold underdrains eliminate a need for small gravel, increases gravel bed depth, requires laterals, and assures long life and good wash water distribution.

False

Mixed oxidants produced by an electrolytic cell include chlorine, hypochlorous acid, chlorine dioxide, ozone, bromine, and free oxygen.

False

Natural factors affecting surface water quality include rainfall, soil characteristics, watershed cover, and industry.

False

No pathogens are resistant to disinfection.

False

Particle settling depends on particle size, shape, specific gravity, water temperature, and sunlight.

False

Plants with a design capacity greater than 30 million gallons per day must provide at least two sets of flocculation equipment designed to operate in parallel.

False

Plants with single basins must be capable of draining in 12 hours.

False

Pretreatment methods include intake level, screening, destratification, and reservoir chemical treatment, presedimentation, and filtration.

False

Prior to service, sand is prepared by backwashing the sand bed once to create at least a 3% sand expansion.

False

Public notification of an acute violation is made within 14 days using the words "Possible Health Concern" and public notification of a non-acute violation is made within 24 hours using the words "Serious Health Concern."

False

Raw water quality is not measured by chemical and physical tests.

False

Recommended sampling points include outside house faucets, fire hydrants, sites with overhanging plants, and sites where mains were recently flushed.

False

Samples must be collected in sterile containers to which sodium chloride has been added.

False

Samples must be submitted within 30 days and refrigerated if mailed.

False

Sand is sized (graded) by shaking media through progressively larger wire meshes, called sieves.

False

Sedimentation is a process where suspended particles settle in water as it flows rapidly through a basin.

False

Shallow lakes do not stratify due to mixing from wind and water currents, but deep lakes can develop an anoxic zone, which is less dense.

False

Short filter runs mean less percentage of wash water is used.

False

Take the test at the inletof the clearwell or the suction of the service pumps.

False

The CPE program uses a county team to review a SWTP treatment process then recommends action that will improve the water quality.

False

The TCEQ is the federal agency responsible for regulating drinking water.

False

The TCEQ requires straight-flow or up-flow settling basins for softened water to provide, at capacity flow, at least 2.5 hours of detention time.

False

The TCEQ requires straight-flow or up-flow settling basins to provide, at capacity flow, at least 4 hours of detention time.

False

The TCEQ requires surface water to be disinfected after storage.

False

The amount of chemical necessary for the coagulation reaction is determined by pH and pH and alkalinity results.

False

The employer is responsible for the training and the employee is responsible for participating during at least 50% of the program.

False

The intake size is important in securing water of the best quality.

False

The jar test should be used at least annually.

False

The minimum number of required bacteriological samples is determined by the number of system connection.

False

The mixing intensity in multiple-stage flocculators shall increase as the coagulated water passes from one stage to the next.

False

The most common solution pump is the peristaltic pump.

False

The rate of decrease of filter head loss indicates effectiveness of pretreatment and filtration.

False

The temperature of the water is the single most important factor in effective coagulation.

False

The top of the troughs should be 36 to 48 inches above the sand, which is necessary to prevent sand loss during backwash.

False

The uniformity coefficient is the mesh size that passes 10% of the sand divided by the mesh size that passes 60% of the sand.

False

The use of shallow depth (tube) settling basins increases detention time to 4 to 6 hours instead of minutes.

False

Thermal stratification causes the upper layer of water to gain oxygen, resulting in aerobic decomposition of inorganic material.

False

Types of flocculators include paddle, impeller, turbine and diffused air.

False

Underdrains should collect filtered water uniformly and with high head loss.

False

Very fine suspended solids (turbidity) require decreased dosage.

False

Wash a filter before the rate controller is fully closed.

False

Wash water piping should provide a velocity of at least 8-12 feet per minute.

False

Wash water rise should expand the sand bed 50-70% of its depth.

False

Water with high amounts of color coagulates better at high pH.

False

When flushing a service line, open the faucet fully for 10-15 seconds.

False

With concern over disinfection by-products and chlorine hazards, UV disinfection is losing popularity.

False

Only ________ water shall be used to backwash the filters.

Filtered

Filters must have facilities to regulate the ________ rate.

Filtration

Turbidity must be removed to low levels by sedimentation and _________ to allow chlorine time to contact pathogens.

Filtration

Copper sulfate dosage must be applied evenly to prevent ________ kill.

Fish

When a coagulant reacts with alkalinity in the raw water a ________.

Floc is Formed

The ________ residual is the strongest chlorine residual achievable.

Free

Detention time in minutes is calculated by dividing the basin capacity in gallons by the flow into the basin in ________.

Gallons per minute

Sand coated with ________ material may shrink under high head loss and produce cracks an inch wide and 12 to 18 inches deep.

Gelatinous

Chlorine is available in three forms: gas, solution, and ________.

Granular

Filter ________ supports the ________ or other filter medium and distributes the wash water uniformly over the underdrains.

Gravel/Sand

During the application of copper sulfate, the chemical reaction is rapid. A color change from dark ________ to ________ indicates proper kill.

Green/Gray

For safe working conditions equip basins, walkways, and ladders with ________.

Guardrails

Hypochlorous acid (________) is the most effective disinfectant when chlorine and water mix.

HOCl

When sodium hypochlorite or calcium hypochlorite is mixed with water, the strong disinfectant produced is ________.

HOCl

The quality and quantity of chemical solids depends upon treatment requirements and removal of turbidity, iron, manganese, or ________.

Hardness

________ sludge ________ basin capacity, ________ detention time.

Increased/Reduces/Decreasing

Chlorine has the greatest degree of "________" versus cost of any disinfectant.

Kill

Disadvantages of sand drying beds are poor dewatering during cold, wet weather, length of drying time, and ________.

Labor costs

The most common and least expensive method of handling sludge is ________.

Lagooning

Look for channeling (short-circuiting) or improper flow patterns along the ________ of the basin.

Length

What is the surface area of the bottom of a rectangular storage tank 10 feet long and 5 feet wide?

Length × Width = Area ft2 10 ft × 5 ft = 50 ft2

Advantages claimed for anthracite are higher filtration rates, longer filter runs, less tendency to coat with ________, and lower backwash velocity.

Lime

Rate-of-flow controller settings are determined by water quantity demand or ________ rate measured at the filter.

Loading

Destratification influences hydrogen sulfide, phosphates, iron nitrogen, and ________.

Manganese, pH, Conductivity, Heavy Metals

There are three filter designs: gravity, pressure, and ________.

Membrane

A daily disinfectant log is used to complete the ________.

Monthly Operating Report

Most filter bed trouble is due to ________, which are roughly spherical aggregates of solid material usually less than an inch in diameter.

Mud Balls

A full-faced, self-contained breathing apparatus that meets _________ standards shall be readily available outside the chlorinator room.

OSHA

Inspect valves of fixed structures for proper operation, verifying ________ and ________ movement.

Open/Close

Calcium hypochlorite will explode or create fires if it contacts ________ material or gets too hot.

Organic

Aeration is beneficial in taste and odor control, removal of hydrogen sulfide, oxidation of iron and manganese, and oxidation of ________.

Organics

Coagulant aids may be classified as _________.

Oxidants/Adsorbents/Polymers

If a hypolimnion contains a high level of organics and destratification mixes the organics with the epilimnion, insufficient dissolved ________ can occur.

Oxygen

Raw water storage reduces fluctuation in ________ and ________ characteristics of water and may reduce ________ compounds that form trihalomethanes.

Physical/Chemical/Organic

Mud balls are caused by ________.

Poor preparation of applied water/Adherence of filtered material to sand/Faulty application of wash water

When copper sulfate is ineffective in controlling algae, ________ is used.

Potassium Permanganate

Decomposition of certain sludge is controlled by ________ or other chemical treatment.

Pre-chlorination

Residual copper is not a problem because the copper ________ and is filtered out in the plant.

Precipitates

Clearwell baffling is designed to ________.

Prevent short-circuiting

Check reels, turbines, and ________ for alignment, broken paddles, shaft leakage or other mechanical problems.

Propellers

________ filters are used by most plants.

Rapid sand

When all the demand is met, additional chlorine produces a chlorine ________.

Residual

One control method involves ultrasonic signals that measure filter water level then transfers the reading to a ________ system.

SCADA

Before entering a room containing a chlorine leak, put on a ________.

SCBA

Crushed anthracite is often added to replace some of the ________.

Sand

Cracks impact filter efficiency, allowing influent to by-pass the fine sand and create filter ________.

Short Circuts

Paddle, turbine, and propeller flocculators are often mounted in square basins (usually 3 in number) and separated by baffles to prevent ________.

Short-circuting

During filtration, clogs create uneven loading and ________ filter runs.

Shorten

Clogs occur more frequently in _________ cracks, but form anywhere within the filter that is susceptible to restricted flow.

Side Wall

Presedimentation basins or reservoirs reduce ________ load on treatment facilities.

Silt

Coagulants, coagulant aids and other chemicals influence ________ characteristics.

Sludge

Sedimentation process daily records should be recorded and maintained for plant flow, basin turbidity, V/V tests, jar tests, and ________.

Sludge volume pumped

Lagooning is not a disposal method, but a thickening, dewatering, and ________ technique.

Storage

A standard solution is one whose ________ is known.

Strength

In addition to disinfection, chlorine is used for ________.

Taste and odor control/Color removal/Iron and manganese oxidation

Sludge build up in sedimentation basins can cause ________ and ________ problems from septicity or microorganism growth.

Taste/Odor

Particle size, carbon bed depth, filtration rate, and water ________ influence head loss.

Temperature

The distribution sampling record should include the date, samples taken, location, weather conditions, and ________.

Temperature/Destination/Sampler Identity

At least a 15 day supply of ________ must be stored at a water treatment plant.

Treatment Chemicals

The adsorption properties of activated carbon include taste and odor-causing substances and impurities such as ________.

Trihalomethanes

A common wall between a filter and unfiltered water is prohibited.

True

A community water system is a public system that has a potential to serve at least 15 service connections on a year-round basis or serves at least 25 individuals on a year-round basis.

True

A disadvantage of the sludge blanket clarifier is that the operator must be more knowledgeable of treatment because each function overlaps the others.

True

A public water system (1) provides the public with piped water for human consumption (2) includes at least 15 service connections or (3) regularly serves at least 25 people at least 60 days out of the year.

True

A rapid mix is necessary for a good floc formation.

True

A sample-siting plan assures that bacteriological samples are collected from representative and active service connections.

True

A sludge blanket is maintained in a sludge blanket clarifier and the rising water is filtered through the blanket.

True

A zeta meter is used to observe the effects of electrical fields on charged colloids in the water and the effect of varied coagulant dosage.

True

About 174 million acre-feet of water evaporates annually.

True

Aeration equipment is divided into destratification systems and hypolimnion aerators.

True

After washing with distilled water and allowed to settle, sand is acceptable if the upper layer is clear and the surface is free of floating material.

True

An acute risk violation occurs when a positive fecal coliform repeat sample or a positive total coliform repeat sample follows a positive fecal coliform routine sample.

True

An advantage of presedimentation is that it removes the bulk of turbidity and reduces the load on coagulation basins.

True

Backwash when head loss is 6-10 feet.

True

Bacteriological testing determines the presence of intestinal waste in the water from warm-blooded animals or humans.

True

Because nutrients collect in filter sand, bacteria grow.

True

Chlorine application points in water treatment include pre-chlorination of raw water, chlorination prior to filtration, and terminal disinfection of the finished water.

True

Chlorine dioxide must be generated on site and produces highly regulated chlorites and chlorates.

True

Chlorine is effective for treating filters because it disinfects and aids in dissolving encrustation.

True

Coagulation is a chemical and a physical reaction.

True

Compressed air aids water in cleaning filter beds.

True

Development of a filter vacuum leads to cracks and the drawing of sand away from the filter walls.

True

Diffused air flocculators are not favored because of the inability to control an even rolling current throughout the basin length.

True

Direct monitoring involves evaluating turbidity, alkalinity, pH, hardness, and other parameters in various plant locations.

True

Disease-causing microorganisms are called pathogens.

True

Disinfectants other than chlorine must be approved by TCEQ prior to their use.

True

Disinfection is the final process of water treatment.

True

During an average year, Texas receives 413 million acre-feet of rainfall.

True

Employers must train employees about the hazards of chemicals stored or used in the workplace.

True

Filter head loss is influenced by pretreatment, sand grain size, filtration rate, water temperature, and dissolved gases.

True

Filter media characteristics influencing filter performance include head loss, filtration rate, length of filter run, amount of backwash water used, and filtered water quantity.

True

Filtration is the most important step in treating surface water.

True

Flaming is not required, but it helps reduce sample contamination.

True

Flocculation follows the flash or rapid mix and forms floc by the dissolution of coagulant, neutralizing negative turbidity charges with positive ones.

True

Flocculators are to develop floc with a weight greater than water, reduce turbidity by particle adsorption, and remove bacteria by entrapment upon settling.

True

Flow enters the center ring of a center-feed basin and flows to the outside circular weir.

True

Folded-plate stainless underdrains provides superior simultaneous air/water backwash and eliminate gravel or garnet sand.

True

Heat treatment is used under emergency conditions for small quantities because it is energy intensive and expensive.

True

If a sample is positive, and more than one sample per month is submitted, take one repeat sample at the positive point, one repeat sample five connections upstream, and one repeat sample five connections downstream, all on the same day.

True

If the Water Bacteriology form is incomplete or incorrect, credit for the sample may be withheld.

True

If the media is too course, it will not remove small turbidity and if it is too fine, filter flow is restricted causing short filter runs.

True

In the event of distribution pressure below 20 psi, water outages, repeated unacceptable microbiological samples or failure to maintain adequate chlorine residuals, special precautions must be instituted by the water system.

True

Media hardness is important because the grinding action of a backwash breaks down soft sand.

True

Media must meet AWWA filtering material standard B100-96.

True

Mixing causes surface adsorption, which is the gathering of insoluble precipitates of aluminum hydroxide or iron hydroxide that are heavier than water.

True

Most important filter design factors are sand particle size and filter bed depth.

True

Most of the raw water turbidity is removed in the sedimentation process, greatly reducing filter load.

True

Occasionally, draw the water down manually to near the top of the sand, inspect it, record findings, and investigate unusual filter action.

True

One cause of deterioration of reservoir water quality is thermal stratification.

True

Ozone must be produced on site, it is costly to generate, and the residual is short-lived.

True

Ozone rapidly inactivates microorganisms, it is a strong chemical oxidizer, and does not produce disinfection by-products.

True

Parameters used to determine when to backwash include effluent turbidity, rate controller position, head loss, filter run length, and part-time operation.

True

Percent expansion is estimated by noting the height to which the sand rises and dividing it by the sand bed depth.

True

Peripheral-feed basins are designed for flow to enter a circular weir on the outside of the basin and flow toward a collection weir at the basin center.

True

Piping, flumes and troughs connecting flocculators to sedimentation basins shall be designed to provide a flow velocity of 0.5 to 1.5 feet per second.

True

Pretreatment is determined by individual water quality.

True

Pretreatment of surface water begins at the intake structure of the water source.

True

Raw water quality is determined by geology, topography, and climate.

True

Recreational lakes, herbicides and pesticides, and industry are regulated to prevent contamination of watersheds.

True

Removal of floating debris in surface water, especially river water is accomplished by screening devices.

True

SCADA systems record turbidity of influent and effluent, filter run time, filter levels, and other data.

True

Sand particle shape, density, hardness, and porosity have a marked affect on filtration.

True

Separating the epilimnion from the lowest and coldest water layer is a transition zone called the thermocline.

True

Some factors influencing sedimentation are floc size and shape, water temperature, floc specific gravity, detention time, velocity, and short-circuiting.

True

Stirring the floc in a gentle fashion causes the particles of floc to agglomerate, or grow, increasing their settleability.

True

Sunlight increases surface temperature, which decreases oxygen content, but wind lowers surface temperature by evaporation and increases oxygen content by wave action.

True

Surface water is grouped into three broad categories: rivers with impounding reservoirs, rivers without impounding reservoirs, and natural lakes.

True

The Hazard Communication Act (HCA) of 1985 is a state law.

True

The TCEQ requires plants with capacity greater than 3 mgd to provide 2 clarifiers to operate in parallel.

True

The TCEQ requires pretreatment disinfection and post disinfection, and at additional points indicated for quality control.

True

The TCEQ requires sludge blanket and solids-recirculation clarifiers to provide, at capacity flow, at least 2 hours of detention time.

True

The chlorine residual test determines disinfection efficiency.

True

The combined filter effluent cannot exceed 1.0 NTU and must be 0.3 NTU or less in 95% of the monthly samples.

True

The correct coagulant dosage is determined by the jar test.

True

The distance troughs must be above the sand is about equal to the required maximum rise per minute of wash water.

True

The function of the mixer is to bring coagulant into contact with the raw water turbidity and dissolved matter to cause a chemical reaction.

True

The length of a straight-flow basin must be at least twice the width.

True

The most important characteristics of filter media are particle size and uniformity coefficient.

True

The purpose of a filter surface wash is to loosen suspended solids attached to the sand on the filter surface.

True

The purpose of filtration is to remove suspended matter (turbidity) for public health and aesthetic reasons.

True

The reaction of alum or iron compounds with natural alkalinity in the water will form an insoluble hydroxide.

True

The sediment in steeply inclined tubes (45°-60°) does not accumulate, but moves down the tubes into a hopper below.

True

The stagnant, colder water under the thermocline is called hypolimnion.

True

The three general categories of disinfection treatment are heat, radiation, and chemical.

True

The top stratum of warm, light water in a reservoir is called epilimnion.

True

The tubes in an essentially horizontal settling basin are declined slightly (5°) in the direction of flow to promote sludge drainage during backwash.

True

The unit of measure for large volumes of water is the acre-foot.

True

The velocity of filter influent should be 1 to 4 ft/second and 8 to 12 gpm/ft2.

True

The wash rate is important to proper scouring, which clears inorganic growth and maintains good conditions in the under-drains.

True

The water level difference before and after the filter determines head loss.

True

There is no metal in Wheeler underdrains, and only 12 inches of gravel is needed.

True

Three common, but significant laboratory tests for establishing coagulant dosages are turbidity, pH and raw water temperature.

True

Three methods of monitoring coagulation, flocculation, and sedimentation are direct monitoring, jar test, and volume over volume test.

True

Troughs must be spaced to distribute settled water without causing currents and must be level, and at the same elevation, to prevent short-circuiting during backwash.

True

Turbidity is suspended matter removed by filtration, and is an important indicator of bacteriological quality.

True

Turbidity removal is accomplished by improving chemical dosage, sedimentation and filtration.

True

UV light produces no residual; therefore, bacteriological testing determines the degree of kill.

True

Underdrains serve three purposes: support filter media, collect filtrate, and deliver uniform backwash.

True

Underdrains should be durable because they are the filter foundation.

True

Wagner block advantages are simplicity, long life, and less required gravel.

True

Wash water lines must carry ample water and drain piping must carry water away without flooding the filter.

True

Wash water volume should not exceed 3% of the water filtered.

True

When a lake turns over an algae bloom can occur resulting in taste, odor and poor quality water.

True

When a plant operates part-time, backwash the filters at the day's end or first thing the next day.

True

When inspecting a filter, look for uneven wash distribution, sand pulled away from sidewalls, cracks in the sand, air in the filter, and mud balls.

True

When the bottom layer loses oxygen, hydrogen sulfide is produced, the pH lowers iron, manganese become soluble, and carbon dioxide increases.

True

If necessary, take samples for settling tests, jar tests, temperature, pH, and ________.

Turbidity

Coagulation is affected by ________.

Turbidity/Temperature/pH

Operators should observe ________ of the water in the flash mixing channel.

Turbulence

Floc formation is determined by correct stirring time, proper stirring intensity, ________ mixing, and correct detention time.

Uniform

A mixed media filter is often called an ________ filter.

Upside down

Coagulants used in water treatment include ________.

alum, ferric sulfate, ferrous sulfate

Which of the following tests are most significant in determining coagulant dosage?

pH and Alkalinity

Factors affecting the reaction rate of chlorine include ________.

pH/Dosage/Contact time/Temperature