Utility Partners - Georgia Wastewater Certification Study Questions
The population equivalency for BOD is...
.20 lb/day/BOD/person
What nutrient ratio must be met to support bio mass?
100 lbs of bod/5lbs notrogen/1 lb phosphorus
What should the velocity of the gravity sewer coming into the plant be?
2 ft/second
According to OSHA, What is the lowest concentration of oxygen for humans to breath that is not considered oxygen deficiency?
21%
How long mist lab records be kept?
3 years
How many lbs of oxygen are needed to remove one lb of ammonia nitrogen?
4.6
Primary clarification generally removes what percentage of TSS?
40-60%
What is the incubation time and temperature for a BOD-5?
5 days at 20 C
How long must bio solids record be kept?
5 years
How long must sludge records be maintained?
5 years
How many lbs of alkalinity are consumed to convert 1 lb of ammonia nitrogen?
7.1
A well operated digester receives sludge at _______ % volatile solids, and reduces it to about ______ % volatile solids.
70-75 %, 25-30%
What does a GFCI do?
A GFCI monitors the current flowing from the hot to the neutral and opens (trips) the circuit if an imbalance occurs
Observation which indicates that a pond is well operated is...
A definite green color of the pond
Where is the best location to collect a sample?
A location that represents the entire basin
Define "as-built" plans.
A set of drawings or maps that indicates structures as they are currently built.
Define endrogenous respiration.
A situation where living organisms oxidize some of their own cellular mass instead of new organic matter they adsorb or absord from their environment.
The natural biological progression in an anaerobic digester is...
Acid formers then methane formers
What is the best way to control filamentous bacteria?
Addition of chlorine to the RAS
Facultative ponds are...
Aerobic on the top and anaerobic on the bottom
A pump and pump motor should be...
Aligned
Most nitrogen entering the plant in in the for of what?
Ammonia and organic nitrogen
When potable water and wastewater are used within close proximity what should you have?
An air gap device
Chlorine leaks can be detected with...
An ammonia solution
What is the first action for a polymer spill?
Apply an absorbent to the spill such as sand or kitty litter and then sweep up the material.
Where should air relief valves be located in the collection system?
At the highest point of the force mains.
What test best measures trickling filter efficiency?
BOD
What is the predominant organism responsible for stabilizing the waste in a trickling filter?
Bacteria
The purpose of flow equalization, in general, is to...
Balance flows, dilute strong waste, and impound excessive flows temporarily
What is the first thing you should do before performing a pH analysis?
Calibrate the probe
What does hydrogen sulfide do to the system?
Cause corrosion
When receiving chemicals what should you do before accepting the load?
Check the drivers credentials
Chlorine and ammonia combine to form what?
Chloramines
Maintenance of a v-notch weir involves...
Clean and brush off deposits that accumulate on the weir and keep upstream and down stream channels clear
The best way to prevent accidental releases of untreated waste is to...
Clearly mark all pipes and valves
What is coning?
Development of a cone shaped flow of liquid, like a whirlpool, through sludge. This can occur in a sludge hopper during sludge withdrawl when the sludge becomes too thick. Part of the sludge remains in place while the liquid rather than the sludge flows out of the hopper.
Total Discharge Head includes...
Discharge pressure head + Static discharge head + velocity head (outlet) + Friction Head (discharge line)
The rakes in the primary clarifier jerks, skips, or hangs. What should be done?
Drain the clarifier and determine the problem
At what time of day would DO in a pond be at its lowest?
Early morning
What is the disadvantage of using a constant percentage RAS flow control?
F/M varies more than a constant rate RAS control
Organisms that are both aerobic and anaerobic are what?
Facultative
Barminutors and comminutors are installed for different purposes? (T/F)
False
Floatable solids are easy to measure? (T/F)
False
Turbidity in wastewater is caused by...
Finely divided suspended material
Which direction does electrical current travel in cathodic protection?
From anode to pipe
For safety purposes, what should be installed on the gears and other moving parts of clarifiers?
Guards must be installed over moving parts that could be accidentally contacted
What are the end products of the aerobic biochemical reaction?
H2O and CH4
What can cause a demand for more oxygen in an aeration basin?
Increase in microorganisms
The grit from the grit chamber contains a large amount of organic material that begins to settle in the chamber, the best remedy is to...
Increase the velocity in the grit chamber
What gases are formed during anaerobic digestion?
Initially hydrogen sulfide is formed at start up and then methane and carbon dioxide
When the DO drops below 1, what happens to nitrification?
It decreases
What material is added to wastewater in the form of a slurry?
Lime
Most extended aeration processes have...
Longer sludge ages
The best thing (tool) to have during a chemical spill is...
MSDS
What type of meter is used to measure primary sludge?
Magnetic meter
What heavy metal is the most stringent for land application requirements?
Mercury
Chlorine is corrosive when it mixes with what?
Moisture
EPA 600 refers to what?
Monitoring organic chemicals/pollutants
The conversion of ammonia to nitrate is called what?
Nitrification
What happens if the flow to the grit chamber is too low?
Organic material will be deposited
What piece of equipment is required to enter a confined space?
Oxygen meter
Disease causing organisms are called...
Pathogenic
What is the term for the protection of potentially hazardous material from entering the plant?
Pretreatment
Oxygen transfer in an oxidation ditch is increased by...
Raising the effluent weir so that the depth of the water in the ditch increases
What micro-organisms are found in good settling mixed liquor?
Rotifers, stalked ciliates, and free swimming ciliates
How is flow of chlorine controlled from the chlorinator?
Rotometer
What should be worn to enter an area with a large chlorine leak?
SCBA
Results from a settleability test are used to calculate...
SVI
What is required to calculate the SVI?
Settleability and MLSS
If packing is not maintained properly
Shaft or shaft sleeve will be damaged
The fusible plug in all chlorine cylinders:
Should never be removed or tampered with
What must be on the warning tag attached to a switch that has been locked out?
Signature of the person who is the only person authorized to remove it.
Coning refers to...
Sludge that is removed too quickly from a sludge blanket
Why are some chemicals stored in amber bottles?
The chemicals may be sensitive or reactive to light
Define BOD
The rate at which organisims use oxygen while stabilizing decomposable organic matter under aerobic conditions.
A positive displacement pump should never be operated against a closed valve because...
The resulting pressure may damage the line, pump, and motor
Where does the term activated in activated sludge process come from?
The sludge in the process are teaming with bacteria, protozoa, and fungi
Pump packing should be...
Tightened down to a drip
Why is a pump allowed to run temporarily without a relief plug after lubrication?
To allow excess grease to drain out
What is the purpose of a dessicator?
To allow residual samples to cool prior to weighing.
Why is wastewater disinfected?
To destroy or disable pathogenic organisms
What is the purpose of a thermal control on a motor?
To open the circuit if the motor starts to over heat
What is the goal of a secondary/final clarifier?
To remove biological solids from wastewater
Why is sodium thiosulfate added to a microbiological sample?
To remove chlorine from the sample
What should be done FIRST when a problem develops in a mechanically cleaned screen?
Turn off the power and lock out tag out
What test is the meaningful when operating an anaerobic digester?
VA ALK
What is the most important physical characteristics of pump lube?
Viscosity
A piton pump should be operated when?
When the suction and discharge valves are open.
How does the operator control the suspended solids in an activated sludge basin?
With return and wasting rates
The best way to record when maintenance is performed.
Work order system
What is the acceptable rate of leakage from a mechanical seal?
Zero, mechanical seals shouldn't leak
Chlorine is commonly applied to the effluent of a treatment plant for...
disinfection
Coliform bacteria are...
indicators
What is the preservation temperature and hold time for BOD samples?
less than or equal to 6 C for 48 hours
The outlet for a forced ventilation system for a chlorinator room should be located...
near the floor
Disease causing bacteria are called...
pathogenic
The dissolved oxygen content of a pond is a direct result of...
photosynthesis
The treatment that always precedes an RBC or a trickling filter is...
primary clarification
Sludge bulking is a condition in which sludge becomes...
too light to settle
How does the operator know when the air filters needs to be changed?
when the differential pressure increases between the inlet and outlet side.
