Statistics for Texas Waste Water Treatment Final Exam Review

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This quiz has been taken 17 times
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The average score is 21 of 30

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Question	Answer	% Correct
Testing of mixed liquor indicates the MLSS is 3,500 mg/L, and the settling test shows that a 1,000 mL sample settles to 350 mL after 30 minutes. What is the SVI and sludge quality?	100 and good	100%
Wastewater stabilization ponds will effectively reduce ________.	BOD and bacteria	100%
Which type of activated sludge process must have primary clarification?	Conventional	100%
The TCEQ requires a chlorine residual of at least ________.	1.0 mg/L residual after 20 minute contact	83%
The moisture content of sludge transported to a municipal landfill should be less than ________.	80%	83%
The moisture content of sludge from a primary clarifier should be which of the following?	94%–96%	83%
Rotating biological contactors may be ________.	driven by electric motors or trapped air	83%
Too high a velocity in a grit chamber can result in ________.	excess grit in the primary clarifier	83%
Which type of bacteria adapts best to changing environmental oxygen conditions?	Facultative	83%
A contact stabilization activated sludge plant has a fast settling sludge and high amounts of pin floc leaving the clarifier. One way to correct this problem is to ________.	increase the F/M ratio by wasting more	83%
Septic wastewater ________.	is the result of bacterial decomposition in the absence of oxygen	83%
Which of the following materials should not go onto a trickling filter?	Large suspended solids	83%
The purpose of the microorganisms that are present in biological treatment processes is to ________.	trap and consume contaminants in wastewater	83%
The extent of treatment required for a waste discharge depends on ________.	water quality standards set for the receiving stream	83%
What will be the detention time in days in a pond that is 850 ft. long, 250 ft. wide with an average depth of 4 ft. that is receiving a flow of 0.2 MGD and has a net evaporation loss of 8 in. per 30 day month?	38.65 days	67%
A POTW has a flow of 3.5 MGD and an influent BOD of 220 mg/L. Find the pounds of BOD in the influent.	6,422 lb.	67%
Which of the following should digester gas contain?	65%–75% methane	67%
Bacteria may be classified by which of the following?	All of the above	67%
BOD is a measure of ________.	amount of oxygen used up	67%
Total suspended solids are ________.	determined by filtration	67%
Which activated sludge process has 20+ hours detention time in the aeration basin?	Extended Air	67%
Which of the following is formed when gas chlorine is added to water?	HCL AND HOCL	67%
Which of the following is true of trickling filter media?	Must be durable and provide enough surface area for bacterial growth	67%
Whoever violates any part of the ________ or any permit or order of the TCEQ can be fined up to $25,000 per day per violation.	water code	67%
A treatment plant has two primary clarifiers. Each has a diameter of 40 ft. and a depth of 12 ft. If the design flow is 1.2 MGD, find the surface loading on each clarifier in gal./ft.2/day. Assume the flow is equally split between the two clarifiers.	478 gal./ft.2/day	50%
The organic loading on wastewater stabilization ponds should not exceed ________.	35 lb. BOD/acre/day	33%
If 200 lb./day of gas chlorine is added to 2.8 MGD, what is the dosage in mg/L?	8.6 mg/L	33%
A good sludge volume index should range from ________.	95 to 125	33%
What is the detention time in hours of a tank 50 ft. long, 25 ft. wide, and 10 ft. deep, with a flow of 2 MGD?	1.12 hrs	17%
A standard rate rock trickling filter is 120 ft. in diameter and 8 ft. deep. What is the hydraulic loading in MG per acre per day if 1.0 MGD is treated?	3.85 MGAD	0%