Texas Wastewater Class A Questions and Answers.

Texas Wastewater Class A Questions and
Answers




Seeding of BOD samples is necessary when samples - Correct Answer - (All of the above) have a chlorine
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residual, have a previously been chlorinated, have been subjected to high temperatures, contain high or
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low pH industrial wastes
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When is blue-green algae the most dominant on a pond treatment system? - Correct Answer - Summer
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A 30-inch diameter wastewater interceptor is observed to be flowing half-full at about two fps. The
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approximate volume of wastewater flowing through the pipe is 3.14x1.25 x 1.25 x 2 = 4.9 cfs x 449 =
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2,200 gpm - Correct Answer - c. 2,200 gallons per minute
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A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-inch stroke pumps at a rate of 50
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cycles per minute. How many minutes must the pump be operated to pump 5,000 gallons of sludge?
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3.14x0.416 x 0.416 x0.416 x 50 x7.48 = 84.5 gpm 5000 gal = 59,2min 84.5 gpm b. 29 - Correct Answer -
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60 minutes
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If an existing centrifugal pump motor is replaced with a motor with 25 percent more speed, the motor
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rhorsepower required will increase by 1.25 x 1.25 x 1.25 = 1.95 - Correct Answer - 95 percent
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When must TCEQ be notified about expansions of a treatment facility? - Correct Answer - Before
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construction
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In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - Correct
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rAnswer - 70% methane, 30% carbon dioxide r r r r r r




The temperature of an anaerobic digester should be maintained at a minimum of - Correct Answer - 95°
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F
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What type of wastewater treatment operates in the endogenous bacteria growth phase? - Correct
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Answer - Extended air
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Why is recirculation needed in a trickling filter? - Correct Answer - Keep the media wet Further reduce
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BOD All of the above (a, b, and c)
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, What type of fire extinguisher would be used on an electrical control panel that has been de-energized? -
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Correct Answer - Class A Class C (a and d)
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Disinfection with chlorine is the most effective at a pH of - Correct Answer - 6.0
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The biomass on a normal functioning RBC has what appearance? - Correct Answer - Grey to brown and
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0.05 to 0.1 inch thick
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The sludge from a primary clarifier should percent solids? - Correct Answer - 4% to 6%
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What is eutrophication in a pond system? - Correct Answer - Enrichment with nitrogen and phosphorous
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Causes algae blooms (b and c)
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How often should pH meters be calibrated? - Correct Answer - Daily
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In Texas, pH meters are required to be calibrated on how many buffers? - Correct Answer - two
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An industrial complex has a BOD discharge to the POTW of 500 pounds per day. The population
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equivalent of this industry is 500 lbs = 2,941 0.17 lbs BOD person - Correct Answer - 2941
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The parameters of the BOD test are - Correct Answer - 5 days at 20° Centigrade
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Standard Dimension Ratio in pvc pipe is defined as - Correct Answer - Ratio of OD pipe diameter to wall
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thickness
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How should shoring be removed from a trench? - Correct Answer - up from the bottom up
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In low pressure sewer systems where each tap must have a grinder pump lift station, station is
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rconsidered to be - Correct Answer - part of the collection system and the responsibility of the utility
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Effective communication depends on - Correct Answer - being a good listener
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When designing a wastewater collection system, the engineer considers the population for how many
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years in the future? - Correct Answer - 50
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According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a minimum
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psi pressure rating of - Correct Answer - 150
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The minimum velocity of flow in a wastewater line should be - Correct Answer - 2.0 fps
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At a construction job site, as the roadway speed increases, the spacing between cones and barricades
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should - Correct Answer - increase
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The major cause of wastewater line stoppages is - Correct Answer - roots and grease
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Carbon monoxide (CO) poisoning symptoms are - Correct Answer - tightness in the chest nausea
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drowsiness and headache (all of the above)
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