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TX Class C Wastewater Treatment License Exam Questions and Answers, Exams of Water and Wastewater Engineering

A comprehensive set of questions and answers related to the tx class c wastewater treatment license exam. It covers various aspects of wastewater treatment, including preliminary treatment, biological treatment, disinfection, effluent disposal, water quality regulations, and the role of the tceq. Valuable for individuals preparing for the tx class c wastewater treatment license exam, offering insights into key concepts and practical applications.

Typology: Exams

2024/2025

Available from 12/09/2024

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Download TX Class C Wastewater Treatment License Exam Questions and Answers and more Exams Water and Wastewater Engineering in PDF only on Docsity!

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

How much BOD will each person contribute to the wastewater treatment plant each day? - - - correct answer ✅0. 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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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%

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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%

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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 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

License Exam Questions And Answers

(Latest Update)

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- What DO levels (in aeration) are optimal to maintain health of aerobic microorganisms? - - - correct answer ✅2-4 mg/L

License Exam Questions And Answers

(Latest Update)

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%

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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

License Exam Questions And Answers

(Latest Update)

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