Texas Wastewater Class A Exam Questions and Answers 100% Score, Exams of Water Resources Planning and Management

Download Texas Wastewater Class A Exam Questions and Answers 100% Score and more Exams Water Resources Planning and Management in PDF only on Docsity! Texas Wastewater Class A Exam Questions and Answers 100% Score What is TCEQ doing to control "point source" pollution of the Texas waterways? *Permitting of domestic wastewater plants *Permitting of industrial wastewater plants Describe proper design of force main wastewater lines. Minimum two fps velocity with the smallest pump operating alone. Minimum four inch diameter pipe with 150 psi rating. What is Standard Dimension Ratio? Ratio of outside pipe diameter (OD) to wall thickness (PVC) Describe proper design of gravity wastewater lines. Designed to flow half full ,under normal conditions, at a minimum of two fps and a maximum of ten fps. Manholes should have a minimum opening of? 24 inches and be at least 4 feet wide. pH meters should be calibrated how often? What standards should be used for calibration purposes? Daily with at least two buffers. What is the standard chlorine residual and minimum contact time on Texas wastewater permits? a. 1.0 mg/L for a minimum 20 minutes detention time at peak flow b. No chlorine residual needed if detention time is greater than 21 days As the complexity of an organization increases, what management function becomes most important? Planning What is the effective chlorine disinfecting agent? Hypochlorous Acid (HOCl) Does pH affect the chlorination process? Explain your answer. When using free chlorine the disinfectant is HOCl acid. As such it is much more effective at pH's below 7.0. Above 7.0 pH the acid begins to be neutralized. What is the effluent chlorine residual in Texas that is standard on permits and the minimum detention time? What is the maximum residual allowed? Texas standard is 1.0 mg/L for a minimum 20 minutes detention time at peak flow. Maximum residual allowed is 4.0 mg/L. A treatment plant has a clarifier that is 60 feet in diameter and is 10 feet deep. The weir is 2 feet inside the outer clarifier wall. The flow is 1.0 MGD. The weir and outflow channel is 3 feet deep. a. What is the detention time in hours? Formula What activated process cannot nitrify in a single stage? Contact Stabilization 150 psi The oxygen depletion of BOD dilution water should not exceed 0.2 mg/L. What is the minimum air gap when making water and wastewater connections? Minimum of one inch or twice the inlet pipe size whichever is greater. What is the minimum useful size pipe to prime a centrifugal pump? 1 inch An anaerobic digester must maintain an average year round temperature of 95 degrees F. How do you remove shoring from a trench? From the bottom up Which of the following methods would you use to increase the degree of nitrification in an activated sludge plant? increase dissolved oxygen levels and increase the sludge age Which of the following are considered normal operator controls on an activated sludge plant? aeration rates return and wasting rates Reducing the return sludge flow rate for an activated sludge system which has a good settling sludge will ________. increase the RAS concentration and the clarifier sludge blanket thickness An extended air activated sludge plant has a fast settling sludge and high amounts of pin floc leaving the clarifier. One way to correct this problem is to ________. * reduce the MCRT by wasting more * increase the F/M ratio by wasting more The primary causes of wastewater stoppages are ________. roots and grease The inside diameter of a manhole must be how wide? 48 inches On a construction job site, equipment booms must maintain at least how many feet of clearance from overhead electric lines? 10 feet Digester gas should contain about ________. a. 65% - 75% methane A treatment plant has two primary clarifiers. Each has a diameter of 40 feet and a depth of 12 feet. If the design flow is 1.2 mgd, find the surface loading on each clarifier in gallons/ft2/day. Assume the flow is equally split between the two clarifiers. 3.14 x 20 x 20 = 1256 1,200,000 /2 = 600,000 gallons each 600,000/ 1256 b. 478 gallons/ft2/day Distilled water used for the BOD analysis should not exceed ________. 0.2 mg/L depletion One element of being an effective communicator is to ________. a. be a good listener In order to promote a collaborative management style, one thing a supervisor can do is ________. join the team as a member rather than as boss One thing an employee can do to be a good team member is to ________. try to understand other people's needs and desires Seeding of BOD samples is necessary when samples ________. a. have a chlorine residual b. have previously been chlorinated c. have been subjected to high temperatures d. contain high or low pH industrial wastes 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 ________. survival rate of aquatic organisms 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 ________. 95ᵒ F What type of wastewater treatment plant operates in the endogenous growth phase? Extended air Disinfection with chlorine is the more effective at a pH of 9 rather than 6. a. True b. False b. False The biomass of a normal functioning RBC has what appearance? Grey to brown and 0.05 to 0.1 inch thick A complete mix activated sludge plant has a fast settling sludge and high amounts of pin floc leaving the clarifier. One method of correcting the problem is to ________. Increase F/M ratio by wasting more How often should pH meters be calibrated? Daily A wastewater treatment plant has a clarifier that is 80 feet in diameter and is 12 feet deep. The flow is 2.5 mgd. The single weir is two feet inside the outer wall and is 3 feet deep What is the clarifier detention time in hours? a. 3.9 b. 3.5 c. 5.3 d. 4.2 Formula A wastewater treatment plant has a clarifier that is 80 feet in diameter and is 12 feet deep. The flow is 2.5 mgd. The single weir is two feet inside the outer wall and is 3 feet deep What is the hydraulic loading on the clarifier in gal/sq. ft/day? a. 598 b. 698 c. 551 d. 614 Formula A wastewater treatment plant has a clarifier that is 80 feet in diameter and is 12 feet deep. The flow is 2.5 mgd. The single weir is two feet inside the outer wall and is 3 feet deep. What is the weir loading in gal/linear ft/day? a. 10,000 b. 10,460 c. 11,276 d. 11,400 Formula How should shoring be removed from a trench? from the bottom up Effective communication depends on ________. being a good listener According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure mains shall have a minimum psi pressure rating of ________. 150 If an operations company ceases its operation or is sold such that the control of the company is transferred to another party, ________. the company's operations certificate is revoked The sludge from a primary clarifier should contain what percent solids? 4% to 6% What are the hazards of using powdered activated carbon? *fire/explosive *inhalation *uncomfortable working conditions How often must a facility conduct TCLP on its sludge if its sludge disposal is equal to or greater than 15,000 metric tons annually? monthly Most gas protection instruments do not latch. That means that________. the instrument stops alarming when removed from the contaminated atmosphere A. What are the three major characteristics of "point source" water pollution in Texas? a. Can be easily identified. For example, "This is where they discharge." b. Can be monitored for effluent characteristics. c. Can be permitted by regulators. What is TCEQ doing to control "point source" pollution of the Texas waterways? a. Permitting of domestic wastewater plants b. Permitting of industrial wastewater plants c. Permitting of storm water run-off. d. Assessment of fines and penalties for violators. How does a "non-point source" of water pollution differ from a "point source"? Point source is easily to identify, monitor, and permit. A non-point source, while we may know it exists, it difficult to identify where it is discharged. In most cases the discharge may be gradual over a very large area at multiple locations. Therefore it is also hard if not impossible to monitor. D. Give three examples of "non-point source" pollution. a. Storm water run-off in areas not under storm water permitting. b. Run-off from agricultural land c. Run-off from a mining operation d. Run-off from cattle, hog, or chicken operation Your activated sludge plant has thick blackish brown foam on it. What are the possible problems and possible solutions? This is characteristic of Nocardia filamentous bacteria. This filament and its relatives will be predominate when sludge is old and food supply does not match the organisms available. Operating conditions that support Nocardia are low food to microorganism ratio (F/M) and high mean cell residence time (MCRT). Proper operational response would be to increase wasting and get F/M and MCRT in line with the activated sludge process being utilized. If the problem is extremely severe, chlorine may need to be applied to kill some of the filamentous bacteria. List at least six control tests which should be used to optimize the activated sludge process. Provide a brief explanation of the purpose of each control test. a. Dissolved oxygen b. Return activated sludge (RAS) flows and MLSS concentration c. Waste Activated sludge (WAS) flows and concentrations d. pH e. 30 Minute settleability test (SV30) f. COD (BOD5 or CBOD5) required for permit compliance g. MLSS and MLVSS concentration in the aeration basin h. Influent flow, BOD and TSS concentration i. Calculate F/M ratio, MCRT, and SVI List and discuss three reasons why lift stations are used in a collection system. a. When the gravity line is so deep that we cannot go any deeper and have to pump. b. When we have to convey wastewater from a gravity line over a hill or rise where we can gravity flow again. c. Where we have to transport the wastewater a substantial distance such as an outfall line to the treatment plant.