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TEXAS WASTEWATER CLASS B EXAM ACTUAL
EXAM QUESTIONS AND CORRECT ANSWERS
ALREADY GRADED A+
In an activated sludge treatment system, primary treatment processes include the: - ANSWER- Primary Clarifiers
In a washing grit remover, the grit is moved slowly by screw conveyors up an inclined channel in order to? - ANSWER-Removal of Inorganic material from grit
An efficient primary clarifier is expected to remove ? of the influent settleable solids. - ANSWER-90% or above
Proper operation of a facultative pond system requires that:, - ANSWER-Adequate DO at surface at all times
The amount of organic matter removed by a trickling filter is mostly dependent on the recirculation ratio - ANSWER-True
In an activated sludge treatment plant, a Sludge Volume Index (SVI) of 180 would indicate - ANSWER-Bulking 1 / 4
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The purpose of returning the solids from the bottom of the clarifier to the aeration tank in the activated sludge process is to - ANSWER-Reseed The AB, Remove sludge from FC
Microscopic examination of a good-settling sludge should show a predominance of: - ANSWER- Free swimmer rotifers stalked ciliates
When nitrification takes place in the activated sludge process, facultative bacteria use - ANSWER-Dissolved oxygen (DO) or oxygen obtained from food materials such as sulfate or nitrate
In an activated sludge process, the results of a mixed liquor settling test indicate that the supernatant of the mixed liquor sample is clear, but the supernatant of the plant effluent sample is turbid. These test results indicate that the problem is occurring in the? - ANSWER- Primary clarifiers
One indication that an anaerobic digestion facility is improving would be? - ANSWER-Low C02 high Methane
The terms "low rate" and "high rate" when used in reference to the anaerobic digester refer to the rate of stabilization of the raw sludge? - ANSWER-False
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3 Besides disinfection, chlorination can be used in wastewater treatment processes to? - ANSWER-Control odor, Reduce BOD ,Control foaming, Aid in sludge
If released to atmospheric pressure, one part liquid chlorine will expand to about? - ANSWER- 450ml
Anaerobically digested sludge should be applied to a drying bed to a depth of about? - ANSWER-8-12"
Sludge from a digester should be slowly drawn to a drying bed in order to? - ANSWER-Not to create a negative pressure in the anaerobic digester and to prevent coning of sludge
Direct aquifer recharge of treated effluent can be used to? - ANSWER-Recharge Water supply, keep saline out of groundwater stop ground Substance
An exemption from filing monthly effluent reports with the TCEQ may be obtained if? - ANSWER-under new construction, new plant, not running yet
A wastewater treatment plant would make use of ? to remove small concentrations of dissolved organics from wastewater effluent - ANSWER-Screens
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4 The maximum design organic loading for stabilization ponds is 35 pounds of BOD per acre per day. An industry wants to construct a facility with projected flow of 50,000 gpd and an average BOD of 450 mg/l. A stabilization pond to serve this projected loading would need to be a minimum size of? - ANSWER-5.4 acres
A sewer construction project in rocky ground will require a 2 foot wide by 350 foot long trench with an average depth of 10 feet. The new pipe and select bedding material (hauled in) will occupy the bottom third of the trench. Assuming that the rest of the soil from the trench can be used for backfill, the cubic yards of spoil dirt which must be hauled away will be about? -
ANSWER-86.41
Under average flow conditions, it takes 18 minutes for a 10-foot diameter lift station wet well to fill the 5 feet between the low water line and the level where the lead pump comes on. After the pump comes on, it runs for 11 minutes before turning off. These measurements indicate
the average discharge rate of the pump is about: - ANSWER-430G
Samples of water are taken from both the inlet and outlet ends of a clarifier and poured into separate one-liter Imhoff cones. After settling for two hours, the sample of inlet water shows a settleable solids concentration of 10 mg/l while the sample of outlet water shows a settleable solids concentration of 2 mg/l. These measurements indicate the efficiency of the clarifier for settleable solids removal is, 80% - ANSWER-80%
At a flow of 1.7 MGD, a 50-foot diameter circular clarifier has an overflow rate of about? - ANSWER-866 gpd
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