Texas Wastewater Class A Questions with Correct Answers

Seeding of BOD samples is necessary when samples - Correct Answer (All of the above) have a chlorine residual, have a previously been chlorinated, have been subjected to high temperatures, contain high or low pH industrial wastes When is blue-green algae the most dominant on a pond treatment system? - Correct Answer Summer A 30-inch diameter wastewater interceptor is observed to be flowing half-full at about two fps. The approximate volume of wastewater flowing through the pipe is 3.14x1.25 x 1.25 x 2 = 4.9 cfs x 449 = 2,200 gpm - Correct Answer c. 2,200 gallons per minute A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-inch stroke pumps at a rate of 50 cycles per minute. How many minutes must the pump be operated to pump 5,000 gallons of sludge? 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 60 minutes If an existing centrifugal pump motor is replaced with a motor with 25 percent more speed, the motor horsepower required will increase by 1.25 x 1.25 x 1.25 = 1.95 - Correct Answer 95 percent When must TCEQ be notified about expansions of a treatment facility? - Correct Answer Before construction In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - Correct Answer 70% methane, 30% carbon dioxide The temperature of an anaerobic digester should be maintained at a minimum of - Correct Answer 95° F What type of wastewater treatment operates in the endogenous bacteria growth phase? - Correct Answer Extended air Why is recirculation needed in a trickling filter? - Correct Answer Keep the media wet Further reduce BOD All of the above (a, b, and c) What type of fire extinguisher would be used on an electrical control panel that has been de-energized? - Correct Answer Class A Class C (a and d) Disinfection with chlorine is the most effective at a pH of - Correct Answer 6.0 The biomass on a normal functioning RBC has what appearance? - Correct Answer Grey to brown and 0.05 to 0.1 inch thick