Texas Wastewater Class A Exam Questions and Answers with Complete Solutions Graded A 2024

Seeding of BOD samples is necessary when samples - (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? - 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 - 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 - 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 - 95 percent When must TCEQ be notified about expansions of a treatment facility? - Before construction In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - 70% methane, 30% carbon dioxide The temperature of an anaerobic digester should be maintained at a minimum of - 95° F What type of wastewater treatment operates in the endogenous bacteria growth phase? - Extended air Why is recirculation needed in a trickling filter? - 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? - Class A Class C (a and d) Disinfection with chlorine is the most effective at a pH of - 6.0 The biomass on a normal functioning RBC has what appearance? - Grey to brown and 0.05 to 0.1 inch thick The sludge from a primary clarifier should percent solids? - 4% to 6% What is eutrophication in a pond system? - Enrichment with nitrogen and phosphorous Causes algae blooms (b and c) How often should pH meters be calibrated? - Daily In Texas, pH meters are required to be calibrated on how many buffers? - two An industrial complex has a BOD discharge to the POTW of 500 pounds per day. The population equivalent of this industry is 500 lbs = 2,941 0.17 lbs BOD person - 2941 The parameters of the BOD test are - 5 days at 20° Centigrade Standard Dimension Ratio in pvc pipe is defined as - Ratio of OD pipe diameter to wall thickness How should shoring be removed from a trench? - up from the bottom up In low pressure sewer systems where each tap must have a grinder pump lift station, station is considered to be - part of the collection system and the responsibility of the utility Effective communication depends on - being a good listener When designing a wastewater collection system, the engineer considers the population for how many years in the future? - 50 According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a minimum psi pressure rating of - 150