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TX CLASS C WASTEWATER TREATMENT LICENSE EXAM 2025 LATEST QUESTIONS AND CORRECT ANSWERS, Exams of Nursing

TX CLASS C WASTEWATER TREATMENT LICENSE EXAM 2025 LATEST QUESTIONS AND DETAILED CORRECT ANSWERS| ALREADY GRADED A+

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2024/2025

Available from 11/24/2024

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Download TX CLASS C WASTEWATER TREATMENT LICENSE EXAM 2025 LATEST QUESTIONS AND CORRECT ANSWERS and more Exams Nursing in PDF only on Docsity!

TX CLASS C WASTEWATER

TREATMENT LICENSE EXAM 2025

LATEST QUESTIONS AND DETAILED

CORRECT ANSWERS| ALREADY

GRADED A+

A conventional activated sludge process has primary clarifiers that remove about ________ percent of the organic load.. Correct Answer 30 - 40% What activated sludge process parameters can an operator change directly? Correct Answer aeration rates, waste rates, and return sludge rates What happens when the return sludge rate is too low? Correct Answer there will be insufficient organisms to treat the waste load entering the aeration basin and the sludge blanket in the secondary clarifier could become too high Physical causes of sludge bulking are... Correct Answer excessive 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 SVI Formula (Sludge Volume Index) Correct Answer 30 min settle test/MLSS x 1000

Normal range for SVI (sludge volume index) Correct Answer 70 - 150 What DO levels (in aeration) are optimal to maintain health of aerobic microorganisms? Correct Answer 2 - 4 mg/L How deep should the clarifier blanket be? Correct Answer filling the bottom 1/ Weir loadings should not exceed _________ gal/day/linear foot of weir at peak flow (1 MGD or less plant). Correct Answer 20, Weir loadings should not exceed ___________ gal/day/linear foot of weir at peak flow (1 MGD or above plant). Correct Answer 30, Is activated sludge aerobic or anaerobic? Correct Answer aerobic Why do pumps continually send RAS to the aeration tank? Correct Answer to reseed the biological reaction in the aeration tank and remove accumulating sludge from the clarifier How much raw influent should return pumps be able to provide? Correct Answer 50 - 150% For an activated sludge process to work properly, an operator much insure that... Correct Answer enough 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 During normal operations, the __________ will concentrate sludge, making it 2-4 times denser than that of the mixed liquor. Correct Answer clarifier Define F/M ratio Correct Answer food to microorganism ratio How is F/M ratio calculated? Correct Answer by dividing the pounds of incoming BOD (food) by the pounds of MLVSS (microorganisms) in the aeration tank What conditions should an operator observe in a well controlled activated sludge process? Correct Answer surface turbulence/uniform roll pattern; foam/small amount of light-colored, crisp foam; odors/mild, earthy; color/medium-brown What conditions should an operator observe in a well controlled clarifier? Correct Answer very little surface scum; a sludge blanket covering 1/4 of the bottom; uniform weir flow (all the way around); almost no rising solids and overflow should be clear and free of floc What type solids cannot go onto a trickling filter? Correct Answer large suspended solids

Important factors to a well operating trickling filter... Correct Answer continuous food supply, aerobic conditions and a moist zoogleal mass Basic elements of a trickling filter are... Correct Answer floor and walls; distributor arms; underdrains and media What must be durable and provide enough surface for bacterial growth with a trickling filter? Correct Answer filter media The zoogleal mass on a filter is composed mainly of what? Correct Answer bacteria and algae The materials resulting from the stabilization of waste material as it passes through a trickling filter are... Correct Answer water, nitrates and carbon dioxide What are zoogleal solids called that are washed off a trickling filter? Correct Answer sloughings (which settle in the final clarifier) Units commonly used to measure the rate of hydraulic loading are... Correct Answer lb/ft/day Units commonly used to measure the rate of organic loading include... Correct Answer lb BOD/acre ft/day and lb BOD/1000 ft3/day

Trickling filters may be classified as.... Correct Answer high-rate; roughing; standard-rate The underdrain system of a standard rate trickling filter should be... Correct Answer designed to flow half-full The recirculation ratio of a trickling filter has an effect on... Correct Answer organic matter removal; odors; filter flies What test best indicates the efficiency of a trickling filter? Correct Answer percent BOD removal Filter operational problems include... Correct Answer ponding; filter flies (psychoda); odors Filter ponding may be caused by... Correct Answer poor quality rock; excessive organic loading; inefficient primary clarifier Methods of controlling filter flies include... Correct Answer flood the filter To control odors at a trickling filter plant, the operator can... Correct Answer increase recirculation, practice good housekeeping and chlorinate the influent Clogged orifices on influent distributor arms may be corrected by... Correct Answer cleaning and flushing Rotating biological contactors are usually covered to... Correct Answer prevent algae growth on the media

The rotating discs should be... Correct Answer partially submerged in the wastewater Rotating biological contactors may be... Correct Answer driven by electric motors or trapped air The biological growth on the disc of a rotating biological contactor should... Correct Answer contain 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 RBC (rotating biological contactor) unit must be preceded by a... Correct Answer primary clarifier or fine screen A condition(s) that adversely affect(s) the operation of a rotating biological contactor is... Correct Answer toxic materials from industrial wastes; hydrogen sulfide; high or low pH A buildup of solids in the tank of the rotating biological contactor may be caused by... Correct Answer poor primary clarification Advanced treatment processes strive to provide a ______________ removal level of specific compounds, suspended solids, and oxygen-demanding materials than cannot be achieved through secondary treatment alone. Correct Answer higher

Direct filtration of secondary effluent is often used to reduce _____ solids to low levels. Correct Answer suspended The most important factor affecting filter performance is the _____ of the secondary effluent applied to the filter. Correct Answer quality Proper __________ is essential to filter performance. Correct Answer cleaning What is the absorbent most commonly used for water treatment? Correct Answer Activated carbon The use of granular activated carbon (GAC) for ______________ removal is common. Correct Answer organic What can cause problems in granular activated carbon (GAC) treatment? Correct Answer biological growth What has been tried as oxidizing agents in wastewater treatment? Correct Answer chlorine dioxide (ClO2) Ozone (O3) Chlorine (Cl2) Many over look what kind of oxidizing agent as an oxidant because of its relative ineffectiveness in conventional waste treatment? Correct Answer ozone

Laboratory-scale studies have shown that the changes occurring in the settlement of the floc are greatly influenced by what? Correct Answer biological activity What is a common coagulant used for chemical precipitation? Correct Answer aluminum sulfate; sodium aluminate and ferric sulfate What occurs when solutions of two different concentrations are separated by a semipermeable membrane such as cellophane? Correct Answer osmosis Biological denitrification is accomplished under what conditions by heterotrophic bacteria that use nitrate during the fermentation of organic carbon materials? Correct Answer anaerobic Electrons pass from the ______ source (the electron donor) to nitrate and nitrite (the electron acceptor) to promote the conversions to nitrogen gas. Correct Answer carbon As what materials are decomposed, their phosphorus content is converted to orthophosphate? Correct Answer organic The materials found practical for phosphorus precipitation include the ionic forms of what? Correct Answer aluminum, iron and calcium

The purpose of sludge digestion is... Correct Answer stabilize the organic matter Sludge types may include... Correct Answer activated Sludge conditioning is the process of removing water by thickening or by adding polymers or _________________ materials to improve the loading rate Correct Answer inorganic What is a factor that influences the operation of sludge thickeners? Correct Answer solids surface loading, temperature of the sludge entering the unit and biological activity of the sludge The proper pH for anaerobically digested sludge will... Correct Answer be from 6.8 to 7. Primary volatile acids are converted by methane bacteria to... Correct Answer methane and carbon dioxide The digester temperature should not change more than ______ degree C per day. Correct Answer 1 Anaerobic digester mixing methods include Correct Answer gas mixing and mechanical mixing A cause of poor quality supernatant liquor could be... Correct Answer digester overload

Scum in a digester is mostly... Correct Answer undigested grease Digester gas may be used to ________ digesters. Correct Answer heat Digester gas should contain about _____________ methane Correct Answer 65 - 75% Digester trouble signs include... Correct Answer an increase in CO2 content and a decrease in volatile solids reduction Since the majority of _______ digesters are open tanks, digester liquid temperatures are dependent on weather conditions and can fluctuate extensively. Correct Answer aerobic A minimum value of _________ of oxygen should be maintained in the aerobic digester at all times. Correct Answer 1.0 mg/L The following processes are used to dewater sewage sludge: Correct Answer vacuum filters, filter presses and centrifuges Sludge drying time is affected most by... Correct Answer degree of digestion The depth of sludge drawn to a drying bed should be... Correct Answer about 9 inches

The moisture content of sludge transported to a municipal landfill should be less than __________. Correct Answer 80% The most expensive method for the final disposal of sludge is... Correct Answer incineration Disinfection may also be accomplished by... Correct Answer ozone, bromine and ultraviolet radiation Forms of chlorine used in wastewater treatment include... Correct Answer gas, granular and solution Chlorine is available as.... Correct Answer pure chlorine in a cylinder; sodium hypochlorite solutions from 5% to 15% chlorine; calcium hypochlorite of about 65% effective chlorine When gas chlorine is added to water, the following is formed... Correct Answer HOCl (hypochlorous acid) and HCl (hydrochloric acid) At 20'C the HOCl (hypochlorous acid) concentration will vary with the pH as follows: Correct Answer pH 7 - 80% HOCl Preliminary Treatment Correct Answer the 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. What stage of treatment is grit removal usually accomplished in? Correct Answer preliminary treatment Rotating Biological Contactor Correct Answer a type of biological secondary treatment process How are protozoa (cause of amoebic dysentery) destroyed? Correct Answer disinfection Other than stream discharge, what are other ways to dispose of effluent wastewater? Correct Answer aquifer recharge, evaporation in a pond, and application to farm land by irrigation Clean Water Act Correct Answer gives the basic structure for regulating discharges of pollutants into the waters of the United States Texas Water Code Correct Answer gives the TCEQ jurisdiction over discharges of waste into or adjacent to water in the state Who reviews plans and specifications for new construction projects before construction begins? Correct Answer TCEQ Water quality fees may be as high as ____________ per permit? Correct Answer $115,

Administrative penalties, up to __________ per day for each violation, may be assessed against any violator. Correct Answer $25, Every city with more than ________ in population needs to establish a water pollution control program and hire qualified personnel to administer it. Correct Answer 10, State law requires that reports are to be submitted no later than the ________th day of the following month. Correct Answer 20 What are major surface waters classified as for the purposes of water quality management and designation of site-specific standards? Correct Answer segments Inflow Correct Answer direct discharges of storm water or surface water into a wastewater collection system (storm drains, roof gutters, yard drains, basement sump pumps and broken manholes and wastewater lines). How many gallons per day will each person contribute to the wastewater treatment plant? Correct Answer 100 How much BOD will each person contribute to the wastewater treatment plant each day? Correct Answer

Cause of septic wastewater Correct Answer bacterial action

Classifications of solids in wastewater Correct Answer fixed/ash, suspended/dissolved, organic/inorganic Organic compounds in wastewater include Correct Answer carbon, hydrogen and oxygen (animal and vegetable in nature) Type of organic matter present in wastewater Correct Answer proteins BOD is a measure of what? Correct Answer oxygen used up Ways that oxygen can be depleted in streams Correct Answer untreated waste discharges, algae masses at night, and high BOD in the effluent A gas found in treatment systems that is NOT dangerous Correct Answer dissolved oxygen Cycles of decay include Correct Answer carbon, nitrogen and sulfur A flow totalizer is required when the plant design flow is more than Correct Answer 0.5 MGD Non-hazardous wastes include Correct Answer chlorides, alkalinity, color, phosphorous and iron

Hazardous wastes include Correct Answer cyanide, sulfides, organics and gasoline Synergistic Effect Correct Answer reaction between waste streams How many cubic feet of screenings per million gallons of wastewater will coarse screens remove? Correct Answer 0.5 to 6. Preaeration benefits Correct Answer freshen wastewater, scour gases and remove grease Main purpose of sedimentation tank Correct Answer allow scum to rise and solids to settle under quiescent (low velocity) conditions How much settleable solids is removed in primary settling? Correct Answer 90 - 95% How much suspended solids is removed in primary settling? Correct Answer 50 - 70% How much BOD is removed in primary settling? Correct Answer 35% How much total organic matter is removed in primary settling? Correct Answer 20 - 30% What percentage of suspended solids will settle out within 2 hours? Correct Answer 70%

Required minutes of detention time for peak flow? Correct Answer 54 Required minutes of detention time for design flow? Correct Answer 108 Benefits of removing grit Correct Answer wear on pump impellers, line stoppages and taking up space Too high a velocity in a grit chamber can result in what? Correct Answer excess grit in primary clarifier One of the benefits of pre-aeration is Correct Answer gas and grease removal Why does grit need to be washed? Correct Answer because organic matter clings to it What is a flow equalization used for? Correct Answer to reduce excessive flows or organic loads How can grease be removed before sedimentation? Correct Answer by chlorination, aeration and skimming A primary clarifier should remove most of what? Correct Answer settleable solids What conditions can influence settling of solids? Correct Answer temperature, condition of solids and flow velocity

Sludge from a primary clarifier should have a moisture content of what? Correct Answer 94 - 96% By performing Imhoff cone tests on the clarifier inlet and outlet, the operator can determine what? Correct Answer the efficiency of the clarifier and a sludge pumping schedule When temperature increases, water becomes... Correct Answer less dense What problem is short-circuiting in a clarifier? Correct Answer flow problem How should raw sludge be pumped to a digester? Correct Answer slowly when it is adequately thickened In an Imhoff tank, the upper compartment serves as the... Correct Answer clarifier In an Imhoff tank, the lower compartment serves as the... Correct Answer digester Wastewater is treated by what organisms? Correct Answer bacteria, fungi, algae, plants, animals and protozoa How many basic cell structures are there? Correct Answer 2

What factors affect biological growth? Correct Answer dissolved oxygen level, temperature, pH and available food What is the most important microorganism in wastewater treatment? Correct Answer bacteria In what ways are bacteria classified? Correct Answer shape, oxygen needs, temperature and metabolism In the removal process, what must bacteria do? Correct Answer gather food, digest food, utilize food and give off by-products What limiting factors affect bacteria growth? Correct Answer pH, temperature, moisture and food What must the operator control in order for microorganisms to do their job? Correct Answer the environment What by-products are excreted by microorganisms? Correct Answer CO2, H2O and NH3 and polysaccharides Treatment pond classifications are... Correct Answer wastewater stabilization ponds, aerated lagoons, facultative lagoons, anaerobic lagoons and hyacinth ponds What will a wastewater stabilization pond effectively reduce? Correct Answer BOD and bacteria

Anaerobic lagoon dissolved oxygen content... Correct Answer none Facultative lagoon dissolved oxygen content... Correct Answer DO on top and none at bottom Wastewater stabilization pond dissolved oxygen content... Correct Answer DO throughout (top, bottom and middle) Depth of wastewater stabilization pond Correct Answer 3 - 5 ft deep Wastewater stabilization ponds are... Correct Answer aerobic, dependent upon sunlight and shallower than facultative lagoons Benefit of multiple inlets and outlets in treatment ponds are... Correct Answer prevention of short-circuiting and will assure an evenly distributed flow The organic loading on wastewater stabilization ponds should not exceed Correct Answer 35 lb. BOD/acre/day Depth of facultative lagoons is Correct Answer 5 - 8 ft deep Raw wastewater anaerobic ponds are usually used by... Correct Answer livestock feedlots, meat packing operations and industrial wastes generators Essential needs of an efficient wastewater stabilization pond... Correct Answer DO, algae and bacteria

The ideal orientation of a wastewater stabilization pond would be... Correct Answer parallel with prevailing winds What does short-circuiting in a pond cause? Correct Answer reduction in detention time A chemical factor influencing the efficiency of wastewater stabilization ponds is... Correct Answer carbon dioxide Good housekeeping around ponds includes... Correct Answer keeping dike clean Control tests on pond effluents include Correct Answer BOD, TSS and pH Purpose of return activated sludge Correct Answer to reseed the biological reactor with treatment microorganisms Describe activated sludge... Correct Answer is fluffy and difficult to settle with approximately 99% moisture content How many times should a clarifier concentrate mixed liquor solids? Correct Answer at least two times Purpose of wasting solids from an activated sludge system is... Correct Answer remove excess biological solids, inert solids and old/dead microorganisms

Control parameters for activated sludge plants Correct Answer oxygen levels, wasting rates, sludge quality, return rates and aerator solids levels The air requirements in an activated sludge process are governed by... Correct Answer organic loading on the plant Sludge bulking is corrected by.... Correct Answer restoring environmental balance to favor floc-forming bacteria over filamentous organisms Rising sludge and gas bubbles can be caused by... Correct Answer denitrification in the final clarifier What test can give operators a visual check on sludge quality? Correct Answer 30 - minute settling test Chlorine combines with ammonia in wastewater to form.... Correct Answer Chloramines 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 ________. Correct Answer a monochloramine - 0.5 mg/L Chlorine may be used for... Correct Answer bulking control, disinfection and odor control The TCEQ requires at least _____ mg/L residual after _____ minutes contact. Correct Answer 1

Chlorine may be used to... Correct Answer increase BOD; kill psychoda bacteria and destroy grease Chlorine could be used as an aid in trickling filter operation to... Correct Answer breakup a ponding problem Chlorine contact chamber shall have at least a _____ minute detention time at peak flow Correct Answer 20 Gas chlorination facilities should be equipped with.... Correct Answer bottle of ammonium hydroxide Chlorine equipment shall be capable of... Correct Answer applying chlorine continuously; adding highest expected dosage at any time; automatic control of feed Because UV light is not a chemical, it does not alter the ______________ of the water. Correct Answer physical properties The TCEQ allows the reuse of treated wastewater for... Correct Answer golf course irrigation; aquifer recharge; agricultural irrigation Reclaimed water piping must be color-coded __________. Correct Answer purple

Reclaimed water providers must report monthly to TCEQ the _____________ and __________ of reclaimed water delivered to a user. Correct Answer volume/quality The purpose of laboratory tests is to... Correct Answer determine the overall efficiency of the plant; determine the effect of the discharge on the receiving stream; determine the characteristics of the waste being treated Grab samples must be used to determine.... Correct Answer chlorine residual A flow-weighted "composite" sample is a... Correct Answer combination of portions of samples collected at regular intervals and combined according to flow A BOD test is... Correct Answer a major parameter in quality control pH is important in the operation of... Correct Answer anaerobic digesters; chlorination of wastewater; oxidation ponds Total suspended solids are... Correct Answer determined by filtration Adequate chlorine residuals will... Correct Answer destroy pathogenic organisms Dissolved oxygen is necessary in... Correct Answer secondary treatment processes

Laboratory tests on an anaerobic digester may be used to determine... Correct Answer digester loading and quality of supernatant and digested sludge For anaerobic digesters, good sludge, supernatant and gas production is realized at a pH of about... Correct Answer 7.0 The test(s) that best indicate(s) the condition of an anaerobic digester is (are)... Correct Answer volatile acid concentration The following tests are important in the control of an activated sludge process... Correct Answer 30 min setteability test; oxygen uptake rate; microscopic examination The SVI should range from... Correct Answer 70 - 150 A low SVI may indicate... Correct Answer sludge is settling too fast A low oxygen uptake rate might indicate... Correct Answer toxic waters, low DO or low BOD Good activated sludge will contain... Correct Answer a high percentage of stalked ciliates and large numbers of rotifers

The TCEQ monthly effluent report must be submitted to the TCEQ in Austin by the ______ day of the month following the month being reported Correct Answer 20th What substances should NOT be dumped into the collection system? Correct Answer acids; caustics; chemical fertilizers All anaerobic digester roofs/covers should be equipped with pressure relief, vacuum relief and _________. Correct Answer flame-trap valves Hazardous gases can be composed of... Correct Answer combustibles and explosive gases; asphyxiation- producing gases; poisonous or toxic gases In small concentrations hydrogen sulfide has a __________ odor. Correct Answer rotten-egg Methane is a ____________________ and highly flammable gas which acts to deprive body tissues of oxygen and will not support life. Correct Answer colorless, odorless, tasteless Chlorine is a heavy, non-combustible, ______________ gas with a pungent, irritating odor and very low electrical conductivity. Correct Answer greenish-yellow 1 Liter = Correct Answer 1000 milliliters (mL) 1 mL of water weights Correct Answer 1 gram (g)