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Texas Class C Wastewater Treatment License Exam Questions and Answers, Exams of Nursing

A comprehensive set of questions and answers related to the texas class c wastewater treatment license exam. It covers various aspects of wastewater treatment, including preliminary treatment, biological treatment, disinfection, and effluent disposal. The document also includes information on relevant regulations, such as the clean water act and the texas water code. This resource can be valuable for individuals preparing for the texas class c wastewater treatment license exam.

Typology: Exams

2024/2025

Available from 01/05/2025

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Download Texas Class C Wastewater Treatment License Exam Questions and Answers and more Exams Nursing in PDF only on Docsity!

TEXAS CLASS C WASTEWATER TREATMENT LICENCE

EXAM QUESTIONS AND CORRECT ANSWERS

VERIFIED LATEST 2025 GRADE A

Preliminary Treatment - 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? - ANSWER>>>preliminary treatment Rotating Biological Contactor - ANSWER>>>a type of biological secondary treatment process How are protozoa (cause of amoebic dysentery) destroyed? - ANSWER>>>disinfection Other than stream discharge, what are other ways to dispose of effluent wastewater? - ANSWER>>>aquifer recharge, evaporation in a pond, and application to farm land by irrigation Clean Water Act - ANSWER>>>gives the basic structure for regulating discharges of pollutants into the waters of the United States Texas Water Code - 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? - ANSWER>>>TCEQ Water quality fees may be as high as ____________ per permit? - ANSWER>>>$115, Administrative penalties, up to __________ per day for each violation, may be assessed against any violator. - ANSWER>>>$25, Every city with more than ________ in population needs to establish a water pollution control program and hire qualified personnel to administer it. - ANSWER>>>10, State law requires that reports are to be submitted no later than the ________th day of the following month. - ANSWER>>> What are major surface waters classified as for the purposes of water quality management and designation of site-specific standards? - ANSWER>>>segments Inflow - 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? - ANSWER>>> 100 How much BOD will each person contribute to the wastewater treatment plant each day? - ANSWER>>>0. Cause of septic wastewater - ANSWER>>>bacterial action Classifications of solids in wastewater - ANSWER>>>fixed/ash, suspended/dissolved, organic/inorganic Organic compounds in wastewater include - ANSWER>>>carbon, hydrogen and oxygen (animal and vegetable in nature) Type of organic matter present in wastewater - ANSWER>>>proteins BOD is a measure of what? - ANSWER>>>oxygen used up Ways that oxygen can be depleted in streams - ANSWER>>>untreated waste discharges, algae masses at night, and high BOD in the effluent A gas found in treatment systems that is NOT dangerous - ANSWER>>>dissolved oxygen

Cycles of decay include - ANSWER>>>carbon, nitrogen and sulfur A flow totalizer is required when the plant design flow is more than - ANSWER>>>0.5 MGD Non-hazardous wastes include - ANSWER>>>chlorides, alkalinity, color, phosphorous and iron Hazardous wastes include - ANSWER>>>cyanide, sulfides, organics and gasoline Synergistic Effect - ANSWER>>>reaction between waste streams How many cubic feet of screenings per million gallons of wastewater will coarse screens remove? - ANSWER>>>0.5 to 6. Preaeration benefits - ANSWER>>>freshen wastewater, scour gases and remove grease Main purpose of sedimentation tank - ANSWER>>>allow scum to rise and solids to settle under quiescent (low velocity) conditions How much settleable solids is removed in primary settling?

  • ANSWER>>>90-95%

How much suspended solids is removed in primary settling? - ANSWER>>>50-70% How much BOD is removed in primary settling? - ANSWER>>>35% How much total organic matter is removed in primary settling? - ANSWER>>>20-30% What percentage of suspended solids will settle out within 2 hours? - ANSWER>>>70% Required minutes of detention time for peak flow? - ANSWER>>> Required minutes of detention time for design flow? - ANSWER>>> Benefits of removing grit - ANSWER>>>wear on pump impellers, line stoppages and taking up space Too high a velocity in a grit chamber can result in what? - ANSWER>>>excess grit in primary clarifier One of the benefits of pre-aeration is - ANSWER>>>gas and grease removal Why does grit need to be washed? -

ANSWER>>>because organic matter clings to it What is a flow equalization used for? - ANSWER>>>to reduce excessive flows or organic loads How can grease be removed before sedimentation? - ANSWER>>>by chlorination, aeration and skimming A primary clarifier should remove most of what? - ANSWER>>>settleable solids What conditions can influence settling of solids? - ANSWER>>>temperature, condition of solids and flow velocity Sludge from a primary clarifier should have a moisture content of what? - ANSWER>>>94-96% By performing Imhoff cone tests on the clarifier inlet and outlet, the operator can determine what? - ANSWER>>>the efficiency of the clarifier and a sludge pumping schedule When temperature increases, water becomes... - ANSWER>>>less dense What problem is short-circuiting in a clarifier? - ANSWER>>>flow problem

How should raw sludge be pumped to a digester? - ANSWER>>>slowly when it is adequately thickened In an Imhoff tank, the upper compartment serves as the...

  • ANSWER>>>clarifier In an Imhoff tank, the lower compartment serves as the... - ANSWER>>>digester Wastewater is treated by what organisms? - ANSWER>>>bacteria, fungi, algae, plants, animals and protozoa How many basic cell structures are there? - ANSWER>>> What factors affect biological growth? - ANSWER>>>dissolved oxygen level, temperature, pH and available food What is the most important microorganism in wastewater treatment? - ANSWER>>>bacteria In what ways are bacteria classified? - ANSWER>>>shape, oxygen needs, temperature and metabolism

In the removal process, what must bacteria do? - ANSWER>>>gather food, digest food, utilize food and give off by-products What limiting factors affect bacteria growth? - ANSWER>>>pH, temperature, moisture and food What must the operator control in order for microorganisms to do their job? - ANSWER>>>the environment What by-products are excreted by microorganisms? - ANSWER>>>CO2, H2O and NH3 and polysaccharides Treatment pond classifications are... - ANSWER>>>wastewater stabilization ponds, aerated lagoons, facultative lagoons, anaerobic lagoons and hyacinth ponds What will a wastewater stabilization pond effectively reduce? - ANSWER>>>BOD and bacteria Anaerobic lagoon dissolved oxygen content... - ANSWER>>>none Facultative lagoon dissolved oxygen content... - ANSWER>>>DO on top and none at bottom Wastewater stabilization pond dissolved oxygen content...

  • ANSWER>>>DO throughout (top, bottom and middle)

Depth of wastewater stabilization pond - ANSWER>>>3- 5 ft deep Wastewater stabilization ponds are... - ANSWER>>>aerobic, dependent upon sunlight and shallower than facultative lagoons Benefit of multiple inlets and outlets in treatment ponds are... - ANSWER>>>prevention of short-circuiting and will assure an evenly distributed flow The organic loading on wastewater stabilization ponds should not exceed - ANSWER>>>35 lb. BOD/acre/day Depth of facultative lagoons is - ANSWER>>>5-8 ft deep Raw wastewater anaerobic ponds are usually used by... - ANSWER>>>livestock feedlots, meat packing operations and industrial wastes generators Essential needs of an efficient wastewater stabilization pond... - ANSWER>>>DO, algae and bacteria The ideal orientation of a wastewater stabilization pond would be... - ANSWER>>>parallel with prevailing winds What does short-circuiting in a pond cause? - ANSWER>>>reduction in detention time

A chemical factor influencing the efficiency of wastewater stabilization ponds is... - ANSWER>>>carbon dioxide Good housekeeping around ponds includes... - ANSWER>>>keeping dike clean Control tests on pond effluents include - ANSWER>>>BOD, TSS and pH Purpose of return activated sludge - ANSWER>>>to reseed the biological reactor with treatment microorganisms Describe activated sludge... - ANSWER>>>is fluffy and difficult to settle with approximately 99% moisture content How many times should a clarifier concentrate mixed liquor solids? - ANSWER>>>at least two times Purpose of wasting solids from an activated sludge system is... - ANSWER>>>remove excess biological solids, inert solids and old/dead microorganisms Control parameters for activated sludge plants - ANSWER>>>oxygen levels, wasting rates, sludge quality, return rates and aerator solids levels The air requirements in an activated sludge process are governed by... - ANSWER>>>organic loading on the plant

Sludge bulking is corrected by.... - ANSWER>>>restoring environmental balance to favor floc-forming bacteria over filamentous organisms Rising sludge and gas bubbles can be caused by... - ANSWER>>>denitrification in the final clarifier What test can give operators a visual check on sludge quality? - ANSWER>>>30-minute settling test A conventional activated sludge process has primary clarifiers that remove about ________ percent of the organic load.. - ANSWER>>>30-40% What activated sludge process parameters can an operator change directly? - ANSWER>>>aeration rates, waste rates, and return sludge rates What happens when the return sludge rate is too low? - 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... - 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) - ANSWER>>>30 min settle test/MLSS x 1000 Normal range for SVI (sludge volume index) - ANSWER>>>70- 150 What DO levels (in aeration) are optimal to maintain health of aerobic microorganisms? - ANSWER>>>2-4 mg/L How deep should the clarifier blanket be? - ANSWER>>>filling the bottom 1/ Weir loadings should not exceed _________ gal/day/linear foot of weir at peak flow (1 MGD or less plant). - ANSWER>>>20, Weir loadings should not exceed ___________ gal/day/linear foot of weir at peak flow (1 MGD or above plant). - ANSWER>>>30, Is activated sludge aerobic or anaerobic? - ANSWER>>>aerobic Why do pumps continually send RAS to the aeration tank?

  • 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? - ANSWER>>>50- 150 % For an activated sludge process to work properly, an operator much insure that... - 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. - ANSWER>>>clarifier Define F/M ratio - ANSWER>>>food to microorganism ratio How is F/M ratio calculated? - 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? - 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? - 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? - ANSWER>>>large suspended solids Important factors to a well operating trickling filter... - ANSWER>>>continuous food supply, aerobic conditions and a moist zoogleal mass Basic elements of a trickling filter are... - ANSWER>>>floor and walls; distributor arms; underdrains and media What must be durable and provide enough surface for bacterial growth with a trickling filter? - ANSWER>>>filter media The zoogleal mass on a filter is composed mainly of what?

  • ANSWER>>>bacteria and algae The materials resulting from the stabilization of waste material as it passes through a trickling filter are... - ANSWER>>>water, nitrates and carbon dioxide What are zoogleal solids called that are washed off a trickling filter? - ANSWER>>>sloughings (which settle in the final clarifier)

Units commonly used to measure the rate of hydraulic loading are... - ANSWER>>>lb/ft/day Units commonly used to measure the rate of organic loading include... - ANSWER>>>lb BOD/acre ft/day and lb BOD/1000 ft3/day Trickling filters may be classified as.... - ANSWER>>>high-rate; roughing; standard-rate The underdrain system of a standard rate trickling filter should be... - ANSWER>>>designed to flow half-full The recirculation ratio of a trickling filter has an effect on...

  • ANSWER>>>organic matter removal; odors; filter flies What test best indicates the efficiency of a trickling filter? - ANSWER>>>percent BOD removal Filter operational problems include... - ANSWER>>>ponding; filter flies (psychoda); odors Filter ponding may be caused by... - ANSWER>>>poor quality rock; excessive organic loading; inefficient primary clarifier Methods of controlling filter flies include... - ANSWER>>>flood the filter

To control odors at a trickling filter plant, the operator can... - ANSWER>>>increase recirculation, practice good housekeeping and chlorinate the influent Clogged orifices on influent distributor arms may be corrected by... - ANSWER>>>cleaning and flushing Rotating biological contactors are usually covered to... - ANSWER>>>prevent algae growth on the media The rotating discs should be... - ANSWER>>>partially submerged in the wastewater Rotating biological contactors may be... - ANSWER>>>driven by electric motors or trapped air The biological growth on the disc of a rotating biological contactor should... - 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... - ANSWER>>>primary clarifier or fine screen A condition(s) that adversely affect(s) the operation of a rotating biological contactor is... - 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... - 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. - ANSWER>>>higher Direct filtration of secondary effluent is often used to reduce _____ solids to low levels. - ANSWER>>>suspended The most important factor affecting filter performance is the _____ of the secondary effluent applied to the filter. - ANSWER>>>quality Proper __________ is essential to filter performance. - ANSWER>>>cleaning What is the absorbent most commonly used for water treatment? - ANSWER>>>Activated carbon The use of granular activated carbon (GAC) for ______________ removal is common. - ANSWER>>>organic What can cause problems in granular activated carbon

(GAC) treatment? - ANSWER>>>biological growth What has been tried as oxidizing agents in wastewater treatment? - 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? - ANSWER>>>ozone Laboratory-scale studies have shown that the changes occurring in the settlement of the floc are greatly influenced by what? - ANSWER>>>biological activity What is a common coagulant used for chemical precipitation? - 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? - ANSWER>>>osmosis Biological denitrification is accomplished under what conditions by heterotrophic bacteria that use nitrate during the fermentation of organic carbon materials? - ANSWER>>>anaerobic

Electrons pass from the ______ source (the electron donor) to nitrate and nitrite (the electron acceptor) to promote the conversions to nitrogen gas. - ANSWER>>>carbon As what materials are decomposed, their phosphorus content is converted to orthophosphate? - ANSWER>>>organic The materials found practical for phosphorus precipitation include the ionic forms of what? - ANSWER>>>aluminum, iron and calcium The purpose of sludge digestion is... - ANSWER>>>stabilize the organic matter Sludge types may include... - ANSWER>>>activated Sludge conditioning is the process of removing water by thickening or by adding polymers or _________________ materials to improve the loading rate - ANSWER>>>inorganic What is a factor that influences the operation of sludge thickeners? - 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... - ANSWER>>>be from 6.8 to 7.

Primary volatile acids are converted by methane bacteria to... - ANSWER>>>methane and carbon dioxide The digester temperature should not change more than ______ degree C per day. - ANSWER>>> Anaerobic digester mixing methods include - ANSWER>>>gas mixing and mechanical mixing A cause of poor quality supernatant liquor could be... - ANSWER>>>digester overload Scum in a digester is mostly... - ANSWER>>>undigested grease Digester gas may be used to ________ digesters. - ANSWER>>>heat Digester gas should contain about _____________ methane - ANSWER>>>65-75% Digester trouble signs include... - 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. - ANSWER>>>aerobic

A minimum value of _________ of oxygen should be maintained in the aerobic digester at all times. - ANSWER>>>1.0 mg/L The following processes are used to dewater sewage sludge: - ANSWER>>>vacuum filters, filter presses and centrifuges Sludge drying time is affected most by... - ANSWER>>>degree of digestion The depth of sludge drawn to a drying bed should be... - ANSWER>>>about 9 inches The moisture content of sludge transported to a municipal landfill should be less than __________. - ANSWER>>>80% The most expensive method for the final disposal of sludge is... - ANSWER>>>incineration Disinfection may also be accomplished by... - ANSWER>>>ozone, bromine and ultraviolet radiation Forms of chlorine used in wastewater treatment include... - ANSWER>>>gas, granular and solution Chlorine is available as.... - 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... - ANSWER>>>HOCl (hypochlorous acid) and HCl (hydrochloric acid) At 20'C the HOCl (hypochlorous acid) concentration will vary with the pH as follows: - ANSWER>>>pH 7 - 80% HOCl Chlorine combines with ammonia in wastewater to form....

  • 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 ________. - ANSWER>>>a monochloramine - 0.5 mg/L Chlorine may be used for... - ANSWER>>>bulking control, disinfection and odor control The TCEQ requires at least _____ mg/L residual after _____ minutes contact. - ANSWER>>>1 20 Chlorine may be used to... - ANSWER>>>increase BOD; kill psychoda bacteria and destroy grease Chlorine could be used as an aid in trickling filter operation

to... - ANSWER>>>breakup a ponding problem Chlorine contact chamber shall have at least a _____ minute detention time at peak flow - ANSWER>>>20 Gas chlorination facilities should be equipped with.... - ANSWER>>>bottle of ammonium hydroxide Chlorine equipment shall be capable of... - 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. - ANSWER>>>physical properties The TCEQ allows the reuse of treated wastewater for... - ANSWER>>>golf course irrigation; aquifer recharge; agricultural irrigation Reclaimed water piping must be color-coded __________.

  • ANSWER>>>purple Reclaimed water providers must report monthly to TCEQ the _____________ and __________ of reclaimed water delivered to a user. - ANSWER>>>volume/quality The purpose of laboratory tests is to... -

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.... - ANSWER>>>chlorine residual A flow-weighted "composite" sample is a... - ANSWER>>>combination of portions of samples collected at regular intervals and combined according to flow A BOD test is... - ANSWER>>>a major parameter in quality control pH is important in the operation of... - ANSWER>>>anaerobic digesters; chlorination of wastewater; oxidation ponds Total suspended solids are... - ANSWER>>>determined by filtration Adequate chlorine residuals will... - ANSWER>>>destroy pathogenic organisms Dissolved oxygen is necessary in... - ANSWER>>>secondary treatment processes

Laboratory tests on an anaerobic digester may be used to determine... - 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... - ANSWER>>>7.0 The test(s) that best indicate(s) the condition of an anaerobic digester is (are)... - ANSWER>>>volatile acid concentration The following tests are important in the control of an activated sludge process... - ANSWER>>>30 min setteability test; oxygen uptake rate; microscopic examination The SVI should range from... - ANSWER>>>70- 150 A low SVI may indicate... - ANSWER>>>sludge is settling too fast A low oxygen uptake rate might indicate... - ANSWER>>>toxic waters, low DO or low BOD Good activated sludge will contain... - ANSWER>>>a high percentage of stalked ciliates and large numbers of rotifers The TCEQ monthly effluent report must be submitted to