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Air flow through a trickling filter when the influent is warmer than the air temperature is
A. upward through the filter
B. downward through the filter
C. inadequate and may require forced air ventilation
D. improved by decreasing the recirculation
A. upward through the filter
An active sludge in the aeration tank with an abundant available food supply will have a relatively
A. high oxygen uptake and fast settling rate
B. high oxygen uptake and slow settling rate
C. low oxygen uptake and fast settling rate
D. low oxygen uptake and slow settling rate
B. high oxygen uptake and slow settling rate
The reaction of chlorine and ammonia produces a compound which is called
A. ammonium chloride
B. chloral hydrate
C. chloramine
D. hydrazine
C. chloramine
A malfunctioning gas chlorination system has normal gas pressure, no feed rate indicated on rotometer, and no injector vacuum. What is the most likely cause of the
problem?
A. air leak upstream of rotameter
B. gas line plugged
C. injector clogged
D. pressure reducing valve diaphragm ruptured
C. injector clogged
What is the impact of increased viscosity on the effectiveness of mixed media filters?
Mixed media filters are
A. affected only if temperature also changes
B. less effective
C. more effective
D. not affected
B. less effective
The precipitate in coagulation with alum is aluminum
A. bicarbonate
B. carbonate
C. hydroxide
D. sulfate
C. hydroxide
Given the following data, what is the most likely cause of the mechanically cleaned bar screen problem?
DATA: Above normal water differential across bar screen
Drive motor shaft turning
Drive sprocket, chain, rake not moving
Less than normal flow on bar screen downstream side
Bar screen mode selector in automatic position
Normal seasonal flow (influent) coming into bar screen
Alarm systems operating normally
A. low influent (incoming) level
B. raw wastewater pumping units out of service
C. sheared pin or disengaged clutch
D. none of the above
C. sheared pin or disengaged clutch
The least amount of chemical used to remove turbidity is known as the
A. coagulation range
B. combination dosage
C. efficiency range
D. dosage
D. dosage
The method of sludge handling resulting in a supernatant with the highest BOD is
A. aerobic digestion
B. anaerobic digestion
C. centrifugation
D. vacuum filtration
C. centrifugation
Sodium chloride is used in the low pressure wet oxidation unit's
A. water softener
B. steam generator
C. deaerator
D. chemical feed tank
A. water softener
The quantity of volatile solids in the content of the sludge is an indirect measure of the
A. amount of the sample that will evaporate upon standing
B. "food" available for the bacteria in the digester
C. number of bacteria in the digester
D. primary effluent suspended solids
B. "food" available for the bacteria in the digester
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