Hydrogen sulfide causes the most serious problems at what pH range?
What is less than 5?
100
Bacteria that require free oxygen for their life processes are said to be what?
What is aerobic?
100
A BOD bottle has a volume of 300 mL. A 125 mL sample is placed in the bottle, which is then filled completely with dilution water. What is the sample volume in percent?
What is 41.7%?
100
When handling acids in the laboratory, what type of eye protection should be worn?
What is goggles?
200
Tests such as pH, temperature adn dissolved oxygen should always be performed within _____ after collection.
What is 15 minutes?
200
In dissolved air flotation thickeners, floated solids are kept out of the effluent by the use of _____?
What are effluent baffles?
200
Organisms that can't survive in the presence of free dissolved oxygen are referred to as what?
What are anaerobes?
200
If the influent to a primary clarifier has a suspended solids (SS) concentration of 280 mg/L and the effluent contains 112 mg/L of SS, what would the efficiency of the clarifier be in percent?
What is 60%?
200
When using ammonia to test for the presence of a chlorine leak, if a leak is present the reaction will create what?
What is white smoke?
300
What is the maximum holding time for a preserved total suspended solids sample?
What is 7 days?
300
According to the State of Tennessee Design Criteria for Sewage Works, all chlorinator rooms must have a means of heating and controlling the room temperature above a minimum of __________ degrees F.
What is 55?
300
As the water temperature decreases, the settling rate of particles in a clarifier do what?
What is decrease?
300
It has been decided that a 28 hp motor is needed in a pump station. If the cost of power is $0.035 per kWh, what is the cost to operate this motor for 24 hours?
What is $17.55?
300
When a permit is required to enter a confined space, who may sign the permit?
Who is the entry supervisor?
400
How does an autoclave sterilize?
What is with steam at 121 degrees C at 15 psi?
400
Which one of the following activated sludge process modes is best suited for nitrification? (complete mix, conventional or plug flow, step-feed aeration, contact stabilization OR modified aeration)
What is conventional or plug flow?
400
What do algae produce in wastewater ponds from the water molecule through photosynthesis? (oxygen, carbon dioxide or methane)
What is oxygen?
400
An 12-inch diameter pipeline has water flowing at a depth of 8 inches. If the velocity of the water is 3.1 fps, what is the flow rate, gpm?
What is 778 gpm?
400
Of chlorine gas, calcium hypochlorite or bleach, which chemical is most flammable?
What is calcium hypochlorite?
500
Chlorination of wastewater is considered adequate when the total fecal coliform count has been reduced to _____ colonies per 100 mL or less.
What is 200 cfu?
500
In the lime precipitation process for phosphorus removal, the pH of the combined wastewater and lime slurry should be _____ or above.
What is 11?
500
If gassification is noticed in the secondary clarifier and is causing rising sludge, what should be done to correct the problem?
What is increase the RAS or WAS rate?
500
If a wastewater treatment plant uses 82 lbs of chlorine to treat 1,800,000 gpd of wastewater and the residual is 0.7 mg/L, what is the chlorine demand, mg/L?
What is 4.8 mg/L?
500
Name three things that a water system must have in order to safely handle chlorine gas.
What are SCBA, adequate ventilation system with alarms; emergency repair kits