TX Class C Wastewater Treatment License Exam Questions and Answers, Exams of Water Resources Planning and Management

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TX Class C Wastewater Treatment License

2024-2025. Questions and Correct Verified

Answers. Graded A

% reduction formula - ANSincoming - outgoing/incoming X 100 1 acre = - ANS43,560 ft squared 1 acre will treat approximately __________ lb BOD - ANS 1 day = __________ minutes - ANS 1 gallon of water weighs.. - ANS8.34 pounds 1 Liter = - ANS1000 milliliters (mL) 1 mg/L = - ANS1 parts per million (ppm) in water 1 MGAD = - ANS23 gpd/ft cubed 1 mL of water weights - ANS1 gram (g) 1,000,000 gallons per day = - ANS1 MGD

27 ft cubed = - ANS1 yard cubed 43,560 ft cubed = - ANS1 acre-ft 7.48 gal = - ANS1 ft cubed 8.34 lb in 1 MG of water = - ANS1 ppm (8.34 lb/8,340,000) A BOD test is... - ANSa major parameter in quality control A buildup of solids in the tank of the rotating biological contactor may be caused by... - ANSpoor primary clarification A cause of poor quality supernatant liquor could be... - ANSdigester overload A chemical factor influencing the efficiency of wastewater stabilization ponds is... - ANScarbon dioxide A condition(s) that adversely affect(s) the operation of a rotating biological contactor is... - ANStoxic materials from industrial wastes; hydrogen sulfide; high or low pH A conventional activated sludge process has primary clarifiers that remove about ________ percent of the organic load.. - ANS30-40%

All anaerobic digester roofs/covers should be equipped with pressure relief, vacuum relief and _________. - ANSflame-trap valves Anaerobic digester mixing methods include - ANSgas mixing and mechanical mixing Anaerobic lagoon dissolved oxygen content... - ANSnone As what materials are decomposed, their phosphorus content is converted to orthophosphate? - ANSorganic At 20'C the HOCl (hypochlorous acid) concentration will vary with the pH as follows: - ANSpH 7 - 80% HOCl Basic elements of a trickling filter are... - ANSfloor and walls; distributor arms; underdrains and media Because UV light is not a chemical, it does not alter the ______________ of the water. - ANSphysical properties Benefit of multiple inlets and outlets in treatment ponds are... - ANSprevention of short-circuiting and will assure an evenly distributed flow Benefits of removing grit - ANSwear on pump impellers, line stoppages and taking up space

Biological denitrification is accomplished under what conditions by heterotrophic bacteria that use nitrate during the fermentation of organic carbon materials? - ANSanaerobic BOD is a measure of what? - ANSoxygen used up By performing Imhoff cone tests on the clarifier inlet and outlet, the operator can determine what? - ANSthe efficiency of the clarifier and a sludge pumping schedule Cause of septic wastewater - ANSbacterial action Chlorine combines with ammonia in wastewater to form.... - ANSChloramines Chlorine contact chamber shall have at least a _____ minute detention time at peak flow - ANS Chlorine could be used as an aid in trickling filter operation to... - ANSbreakup a ponding problem Chlorine equipment shall be capable of... - ANSapplying chlorine continuously; adding highest expected dosage at any time; automatic control of feed Chlorine is a heavy, non-combustible, ______________ gas with a pungent, irritating odor and very low electrical conductivity. - ANSgreenish-yellow

Define F/M ratio - ANSfood to microorganism ratio Depth of facultative lagoons is - ANS5-8 ft deep Depth of wastewater stabilization pond - ANS3-5 ft deep Describe activated sludge... - ANSis fluffy and difficult to settle with approximately 99% moisture content Different treatment plants have different requirements for wastewater treatment (true or false). - ANSTrue Digester gas may be used to ________ digesters. - ANSheat Digester gas should contain about _____________ methane - ANS65-75% Digester trouble signs include... - ANSan increase in CO2 content and a decrease in volatile solids reduction Direct filtration of secondary effluent is often used to reduce _____ solids to low levels. - ANSsuspended Disinfection may also be accomplished by... - ANSozone, bromine and ultraviolet radiation

Dissolved oxygen is necessary in... - ANSsecondary treatment processes During normal operations, the __________ will concentrate sludge, making it 2- times denser than that of the mixed liquor. - ANSclarifier Electrons pass from the ______ source (the electron donor) to nitrate and nitrite (the electron acceptor) to promote the conversions to nitrogen gas. - ANScarbon Essential needs of an efficient wastewater stabilization pond... - ANSDO, algae and bacteria Every city with more than ________ in population needs to establish a water pollution control program and hire qualified personnel to administer it. - ANS10, Facultative lagoon dissolved oxygen content... - ANSDO on top and none at bottom Filter operational problems include... - ANSponding; filter flies (psychoda); odors Filter ponding may be caused by... - ANSpoor quality rock; excessive organic loading; inefficient primary clarifier For an activated sludge process to work properly, an operator much insure that... - ANSenough return activated sludge is sent tot he aerator to maintain the process; solids do not accumulate in the clarifier; excess solids that develop in the process are removed frequently enough to avoid build-up

How deep should the clarifier blanket be? - ANSfilling the bottom 1/ How is F/M ratio calculated? - ANSby dividing the pounds of incoming BOD (food) by the pounds of MLVSS (microorganisms) in the aeration tank How many basic cell structures are there? - ANS How many cubic feet of screenings per million gallons of wastewater will coarse screens remove? - ANS0.5 to 6. How many gallons per day will each person contribute to the wastewater treatment plant? - ANS How many times should a clarifier concentrate mixed liquor solids? - ANSat least two times How much BOD is removed in primary settling? - ANS35% How much BOD will each person contribute to the wastewater treatment plant each day? - ANS0. How much raw influent should return pumps be able to provide? - ANS50-150% How much settleable solids is removed in primary settling? - ANS90-95%

How much suspended solids is removed in primary settling? - ANS50-70% How much total organic matter is removed in primary settling? - ANS20-30% How should raw sludge be pumped to a digester? - ANSslowly when it is adequately thickened If a chlorine dosage of 12 mg/L is added to a wastewater effluent containing ammonia and the chlorine demand is 11.5 mg/L, the residual would be ________.

• ANSa monochloramine - 0.5 mg/L Important factors to a well operating trickling filter... - ANScontinuous food supply, aerobic conditions and a moist zoogleal mass In an Imhoff tank, the lower compartment serves as the... - ANSdigester In an Imhoff tank, the upper compartment serves as the... - ANSclarifier In small concentrations hydrogen sulfide has a __________ odor. - ANSrotten-egg In the removal process, what must bacteria do? - ANSgather food, digest food, utilize food and give off by-products In what ways are bacteria classified? - ANSshape, oxygen needs, temperature and metabolism

Normal range for SVI (sludge volume index) - ANS70- One of the benefits of pre-aeration is - ANSgas and grease removal Organic compounds in wastewater include - ANScarbon, hydrogen and oxygen (animal and vegetable in nature) Other than stream discharge, what are other ways to dispose of effluent wastewater? - ANSaquifer recharge, evaporation in a pond, and application to farm land by irrigation Percent (%) formula is - ANSPart/Whole X 100 pH is important in the operation of... - ANSanaerobic digesters; chlorination of wastewater; oxidation ponds Physical causes of sludge bulking are... - ANSexcessive hydraulic loading, settled sludge that is not promptly removed from the clarifier, inadequate weir lengths and improper ratio of depth to surface area of the final clarifier pie = - ANS3. Preaeration benefits - ANSfreshen wastewater, scour gases and remove grease Preliminary Treatment - ANSthe 1st stage of sewage treatment where large debris, such as sticks, grit, and rags pas through a screen followed by a grit chamber, where the flow of water is slowed enough to allow for sedimentation.

Primary volatile acids are converted by methane bacteria to... - ANSmethane and carbon dioxide Proper __________ is essential to filter performance. - ANScleaning Purpose of advanced (tertiary) treatment - ANSreduces specific contaminants such as suspended solids, ammonia or phosphorous to very low levels to achieve struct effluent standards Purpose of primary treatment - ANSremoves solids that readily settle or float Purpose of return activated sludge - ANSto reseed the biological reactor with treatment microorganisms Purpose of secondary treatment - ANSmicroscopic living creatures (microorganisms) remove additional contaminants Purpose of wasting solids from an activated sludge system is... - ANSremove excess biological solids, inert solids and old/dead microorganisms Raw wastewater anaerobic ponds are usually used by... - ANSlivestock feedlots, meat packing operations and industrial wastes generators Reclaimed water piping must be color-coded __________. - ANSpurple

Sludge conditioning is the process of removing water by thickening or by adding polymers or _________________ materials to improve the loading rate - ANSinorganic Sludge drying time is affected most by... - ANSdegree of digestion Sludge from a primary clarifier should have a moisture content of what? - ANS94- 96% Sludge types may include... - ANSactivated State law requires that reports are to be submitted no later than the ________th day of the following month. - ANS SVI Formula (Sludge Volume Index) - ANS30 min settle test/MLSS x 1000 Synergistic Effect - ANSreaction between waste streams Texas Water Code - ANSgives the TCEQ jurisdiction over discharges of waste into or adjacent to water in the state The air requirements in an activated sludge process are governed by... - ANSorganic loading on the plant

The biological growth on the disc of a rotating biological contactor should... - ANScontain approximately 50,000 mg/L solids; be 0.05-0.1 inch thick after one or two weeks; and be gray to brown in color The depth of sludge drawn to a drying bed should be... - ANSabout 9 inches The digester temperature should not change more than ______ degree C per day.

• ANS The following processes are used to dewater sewage sludge: - ANSvacuum filters, filter presses and centrifuges The following tests are important in the control of an activated sludge process... - ANS30 min setteability test; oxygen uptake rate; microscopic examination The ideal orientation of a wastewater stabilization pond would be... - ANSparallel with prevailing winds The materials found practical for phosphorus precipitation include the ionic forms of what? - ANSaluminum, iron and calcium The materials resulting from the stabilization of waste material as it passes through a trickling filter are... - ANSwater, nitrates and carbon dioxide The moisture content of sludge transported to a municipal landfill should be less than __________. - ANS80%

The TCEQ allows the reuse of treated wastewater for... - ANSgolf course irrigation; aquifer recharge; agricultural irrigation The TCEQ monthly effluent report must be submitted to the TCEQ in Austin by the ______ day of the month following the month being reported - ANS20th The TCEQ requires at least _____ mg/L residual after _____ minutes contact. - ANS 20 The test(s) that best indicate(s) the condition of an anaerobic digester is (are)... - ANSvolatile acid concentration The underdrain system of a standard rate trickling filter should be... - ANSdesigned to flow half-full The use of granular activated carbon (GAC) for ______________ removal is common. - ANSorganic The zoogleal mass on a filter is composed mainly of what? - ANSbacteria and algae To control odors at a trickling filter plant, the operator can... - ANSincrease recirculation, practice good housekeeping and chlorinate the influent Too high a velocity in a grit chamber can result in what? - ANSexcess grit in primary clarifier

Total suspended solids are... - ANSdetermined by filtration Treatment pond classifications are... - ANSwastewater stabilization ponds, aerated lagoons, facultative lagoons, anaerobic lagoons and hyacinth ponds Trickling filters may be classified as.... - ANShigh-rate; roughing; standard-rate Type of organic matter present in wastewater - ANSproteins Units commonly used to measure the rate of hydraulic loading are... - ANSlb/ft/day Units commonly used to measure the rate of organic loading include... - ANSlb BOD/acre ft/day and lb BOD/1000 ft3/day Wastewater is treated by what organisms? - ANSbacteria, fungi, algae, plants, animals and protozoa Wastewater stabilization pond dissolved oxygen content... - ANSDO throughout (top, bottom and middle) Wastewater stabilization ponds are... - ANSaerobic, dependent upon sunlight and shallower than facultative lagoons