Texas Wastewater Class A 2024-2025. Questions and Correct Verified Answers. Graded A, Exams of Water and Wastewater Engineering

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Texas Wastewater Class A 2024-2025.

Questions and Correct Verified Answers.

Graded A

13. What type of wastewater treatment operates in the endogenous bacteria growth phase? - ANSExtended air 15,000 gallons of sludge with 4% solids is run through a press to produce a 25% cake. How many dry metric tons of sludge will be disposed of? [Assume a conversion factor of 2200 Ibs per dry metric tons.] - ANS2.
14. What type of fire extinguisher would be used on an electrical control panel that has been de-energized? - ANSf. a class a and d class c
15. The biomass on a normal functioning RBC has what appearance? - ANSGrey to brown and 0.05 to 0.1 inch thick
16. A wastewater stabilization pond has 130,680 sq. ft. It has a three to one slope on the embankment and has an average depth of 5 ft. Approximately how many people will this pond provide wastewater treatment for? 130,680 sq ft = 3 acres x 35 lbs / BOD/ acre = 105 lbs BOD =618 0.17 lbs BOD/ person 43,560 sq ft l acre - ANSd. 600
17. 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 - ANSIncrease F/M ratio by wasting more

57. The most common pump used in the collection system is - ANSd. centrifugal
58. The major cause of wastewater line stoppages is - ANSroots and grease
59. One of the most important factors affecting the slope of a gravity wastewater line is - ANSpipe bedding A 24-inch wastewater interceptor is observed to be flowing half-full at 3 fps. The approximate volume of wastewater flowing through the line is - ANS3.14 x1x1x3 = 9.42 = cfs 9.42 x 449 = 4229.58 gpm 4229.58 = 2114.79 2,115 gpm A 30 ml wastewater sample, is incubated 5 days at 20 degrees C. The DO before was 6.0 mg/L and the DO after was 3.5 mg/L. What is the reportable BOD? - ANS(6-3.5) x 300 30 b. 25 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 3.14x1.25 x 1.25 x 2 = 4.9 cfs x 449 = 2,200 gpm - ANSc. 2,200 gallons per minute A bubbler level control system works off of what principal? - ANSdifferential pressure A chemical element is a - ANSatom

A collection system that averages 1.0 mgd or more must employ. - ANSa. at least one Class III Collection operator or a Class B Wastewater operator A confined space is defined as - ANSa. a space so configured that an employee can enter and perform work space that is not designed for continuous human occupancy space that has limited entry and exit A construction site safety evaluation checklist must include - ANSa. placement of equipment, vehicles, and spoil bank b. placement of flaggers, barricades, cones and other safety equipment c. use of warning signs A crucible and filter weigh 21.6870 grams. After filtering 50 ml of sample through the filter, and then drying, desiccating and weighing them, the crucible, filter, and sample weigh 21.7250 grams. How many mg/L of suspended solids are in the sample? - ANSb. 760 A cyclone grit separator operates on what principle? - ANScentrifugal force A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-inch stroke pumps at a rate of 50 cycles per minute. How many minutes must the pump be operated to pump 5,000 gallons of sludge? 3.14x0.416 x 0.416 x0.416 x 50 x7.48 = 84.5 gpm 5000 gal = 59,2min 84.5 gpm b. 29 - ANS60 minutes A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-inch stroke pumps at rate of 50 cycles per minute. How many minutes must the pump be operated to pump 5,000 gallons of sludge? - ANS3.14 x0.416 x0.416 x0.416 x 50x7.48 = 84.5 gpm 5000 gal = 59.2min 84.5 gpm d. 60 minutes e.

A particular construction project has a total of 3,000 feet of 12-inch pipe, 15 manholes, 50 wastewater connections. Based upon the contract unit costs shown, if the contractor has completed 2,000 feet of pipe, 12 manholes, and 30 wastewater connections, what percentage of the total project has been completed? 12 inch pipe place $85.00 per linear foot Manholes in place $1,500.00 each Wastewater connections $250.00 each - ANS3000 x 85 = 255, 15 x1500 = 22, 50x 250 = 12, 255,000 + 22,500+ 12,500 = $290, 2000 x 85 = 170, 12x1500 - 18, 30x250 =7, 170,000 + 18,000 + 7,500 = S195, 195,000/290000 =0.67 = 67% A piston pump with a 5-inch piston and a 10-inch stroke strokes 60 times a minute. How many minutes will operated to pump 6,000 gallons? - ANS5x5x0.0408x0.833x60 = 51 gpm 6,000 gal/51 gpm=117. round to 118

A pneumatic ejector is - ANSa. a lift station pumping device A predominance of filaments in an activated sludge plant indicates what? - ANSlow DO poor settling nutrient imbalance a wastewater pipe has a slope of 4 feet in 200 feet, it is referred to as - ANSc. 0. feet per foot d. two percent 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? - ANSWhat is the clarifier detention time in hours? 2,500,000 gpd - 104,167 gph 24 hrs/day 3.14 x 40 x 40 x 9 x 7.48 gal 3.14 x 36 x 36 x 3 x 7.48 = 91,318 338,216 + 91,318 429, gallons 429,534 gals = 4.1 hrs 104,167 gph 4. A"Racetrack" is what type of Activate Sludge treatment? - ANSExtended air According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure mains shall have a minimum psi pressure rating of - ANS According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a minimum psi pressure rating of - ANS According to Chapter 317, Design Criteria, a manhole can be installed within 9 feet of an existing waterline if - ANSif a. the manhole is completely watertight and tested for no leakage

According to Chapter 317, Design Criteria, a manhole can be installed within 9 feet of an existing waterline if - ANSthe manhole is completely watertight and tested for no leakage Aerobic digestion is a(n) process. - ANSendogenous An Imhoff tank is what type of treatment process? - ANSPrimary An industrial complex has a BOD discharge to the POTW of 500 pounds per day. The population equivalent of this industry is 500 lbs = 2,941 0.17 lbs BOD person - ANS An industrial complex has a BOD discharge to the POTW of 500 pounds per population equivalent of this industry is - ANS500 lbs - 2,941 0.17 lbs BOD/ person 2941 An injured person is not breathing, but has a pulse. The correct first aid response is - ANSventilate An operator must measure the current being used by a motor that is operating three phase power. The correct instrument for this measurement is: - ANSclamp- on ammeter Approved backflow devices in Texas include: - ANSair gap of two times the inlet pipe diameter testable assemblies usually an RPZ

As the complexity of an organization increases, what management function becomes most important? - ANSPlanning As the population of a collection system increases, the ratio of peak flow to average daily flow will - ANSdecrease As the population of a collection system increases, the ratio of peak flow to average daily flow will - ANSdecrease Assume that a 12% solution of a substance weighs 10.6 lbs/gal.and a 0.8% solution of the same substance weighs 8.76 lbs/gal. If 10.0 gallons of the 12% solution are mixed with 50 gallons of the 0.8% solution, the percent strength of the mixed solution would be - ANS3.0% At a construction job site, as the roadway speed increases, the spacing barricades should - ANSincrease At a construction job site, as the roadway speed increases, the spacing between cones and barricades should - ANSincrease Before making major changes in the collection system or the treatment plant, detailed designed by a professional engineer must be submitted to TCEQ before - ANSbeginning construction Carbon monoxide (CO) poisoning symptoms are - ANSa. tightness in the chest b. nausea c. drowsiness and headache d. all of the above

Carbon monoxide (CO) poisoning symptoms are - ANStightness in the chest nausea drowsiness and headache (all of the above) Cartridge respirators provide protection against: - ANSgases Chemical dechlorination can be accomplished with? - ANSa. sodium Bisulfite b. sulfur Dioxide Chlorine disinfects the best at - ANSlow pH Dangerous gases in a confined space may not be detected with the physical senses because - ANSa. some gases have no odor b. some gases may deaden the sense of smell c. some gases may displace the oxygen Dangerous gases in a confined space may not be detected with the physical senses because - ANSsome gases have no odor some gases may deaden the sense of smell some gases may displace the oxygen (all of the above) Disinfection with chlorine is the most effective at a pH of - ANS6. Disinfection with chlorine is the most effective at a pH of - ANS6. Distilled water used for the BOD analysis should not exceed mg/L oxygen depletion. - ANS0.

e. controlling When must TCEQ be notified about expansions of a treatment facility? - ANSBefore construction Effective communication depends on - ANSbeing a good listener Effective communication depends on - ANSbeing a good listener Fresh wastewater is desirable because it is much easier to treat. The physical characteristics of fresh wastewater are - ANSdishwater gray in color H,SO, is a(n). - ANSchemical compound How often must a facility conduct a TCLP on its sludge if its sludge disposal is equal to or greater than 15,000 metric tons annually? - ANSmonthly How often should pH meters be calibrated? - ANSDaily How often should pH meters be calibrated? - ANSDaily How should shoring be removed from a trench? - ANSd. from the bottom up How should shoring be removed from a trench? - ANSup from the bottom up How should trench shoring be installed? - ANSto above the top of the trench

How should trench shoring be installed? - ANSTwo above the top of the trench How would an operator increase the degree nitrification in an activated sludge plant? - ANSincrease D0 and increase sludge age If an employee is guilty of misconduct as defined by the utilities personnel policies, the supervisor should - ANSattempt to modify the employee's behavior through training and other forms of assistance inform the employee of the consequences if the behavior is not modified If an existing centrifugal pump motor is replaced with a motor with 20 percent more speed, the motor horsepower required will increase by - ANS1.2x1.2x1.2=1.728 73 percent If an existing centrifugal pump motor is replaced with a motor with 25 percent more speed, the motor horsepower required will increase by 1.25 x 1.25 x 1.25 = 1.95 - ANS95 percent If an operations company ceases its operation or is sold such that control of the company is transferred to another party, - ANSthe company's operations certificate is revoked If effluent is land applied for irrigation what tests must be run? - ANSCBOD and TSS pH and dissolved solids total nitrogen total phosphorous

If the float that turns on the lead pump in a wastewater lift station is situated above a gravity influent line, the line will - ANStend to have a grease problem In 2.5 minutes, a lift station will fill up 18" with no pumps running. In 3. minutes, both pumps will drop the level in the lift station 18". In 7 minutes, the large pump will drop the level 18". What is the capacity of the small pump? The lift station is 10' x 10 x 10'. 10x10x1.5x7.48= 1122 gal/2.5=449 gpm inflow Both 1122/3.25=345 gpm + 449 gpm = 794 gpm both Large 1122/7=160 gpm + 449 gpm = 609 gpm large Small 794 gpm - 609 gpm = 185 gpm - ANS185 gpm In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - ANS70% methane, 30% carbon dioxide In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be - ANSb. 70% methane, 30% carbon dioxide

In low pressure sewer systems where each tap must have a grinder pump lift station, station is considered to be - ANSpart of the collection system and the responsibility of the utility In low pressure sewer systems where each tap must have a grinder pump lift station, the lift station is considered to be - ANSPart of the collection system and the responsibility of the utility In Texas no disinfection of treated effluent is required if - ANSdetention time is 21 days + In Texas, an oxidation ditch treatment plant is referred to as - ANSRacetrack In Texas, pH meters are required to be calibrated on how many buffers? - ANStwo In Texas, pH meters are required to be calibrated on how many buffers? - ANStwo In the problem above, how many cubic yards of material will be required to fill the trench? 3.14x0.5 x0.5 x 4,100 =119cu yds 27 3,644 -119 = 3,525 - ANS3, In the problem above, what the sludge quality? - ANSBulking Monitoring and reporting records of a wastewater treatment plant shall be kept at the facility site for a period of - ANSd. three years

Most gas detection instruments do not latch. This means that - ANSthe instrument stops alarming when removed from the contaminated atmosphere Motivating workers to do a better job is best done by - ANSletting workers participate in setting goals Motivating workers to do a better job is best done by - ANSletting workers participate in setting goals MSDS sheets must be kept for how many years after you have stopped using the chemical? - ANSc. 30 New head in feet: 75 x 1.5 x 1.5 = 168.75 - ANS New horsepower required: - ANS750 x 170 - 43 3960 x 0.75 a. 43 On a construction job site, equipment booms must maintain at least how many feet clearance from overhead electric lines? - ANSa. 10 On a construction job site, equipment booms must maintain at least how many feet of clearance from overhead electric lines? - ANS One important element of a good communicator is - ANSbeing a good listener One important element of a good communicator is - ANSGood listener

One of the requirements of the Texas Hazard Communication Act of 1985 is that the employer must hold annual training in which the utilities' written policies and the employee's rights are explained to - ANSall employees PL 92-500 is known as the - ANSClean Water Act Water Pollution Control Act Pretreatment of industrial waste will help minimize - ANSsludge contamination interference to the treatment process safety hazards to workers discharge of industrial pollutants in the effluent problem is Testing of mixed liquor indicates the MLSS is 2500 mg/L and the settling test shows that a 1000 ml sample settles to 400 mls after 30 minutes. What is the SVI? 400 x 1000 2500 160 - ANS Proper employee motivation occurs when - ANSemployees participate in developing goals Proper safety in the water lab includes: - ANSwearing protective eyewear wearing an apron or lab coat Seeding of BOD samples is necessary when samples - ANS(All of the above) have a chlorine residual, have a previously been chlorinated, have been subjected to high temperatures, contain high or low pH industrial wastes Seeding of BOD samples is necessary when samples - ANSe. all of the above

Septic wastewater has what properties? - ANSa. dark in color b. offensive odor e. Jacks dissolved oxygen d. is harder treat than fresh wastewater e. all of the above Sewer balls or pigs are what type of wastewater cleaning equipment? - ANSmechanical cleaning equipment Standard Dimension Ratio in pvc pipe is defined as - ANSRatio of OD pipe diameter to wall thickness Standard Dimension Ratio in pve pipe is defined as - ANSRatio of OD pipe diameter to wall thickness Technology The management function of selecting and training employees of an organization is called - ANSstaffing The biomass on a normal functioning RBC has what appearance? - ANSGrey to brown and 0.05 to 0.1 inch thick The discharge from a centrifugal pump will: - ANSincrease with an decrease in head decreases with an increase head The effectiveness of an activated sludge process depends on? - ANSamount of activated solids in the system type and health of organisms in the solids acration basin detention time influent characteristics The Federal Clean Water Act - ANSrequires a permit for disposal of sludge requires a permit for ocean discharges of sewer c. requires a permit for disposal or

placement of dredge material creates a national permit system for all wastewater discharge The Federal Clean Water Act: - ANSa, requires a permit for disposal of sludge b. requires a permit for ocean discharges of wastewater c. requires a permit for disposal of dredge material d. creates a national permit system for all wastewater The following scenario is to be used in answering questions 38, 39, and 40. A pump with a 15-inch impeller is running at 1170 RPM s, with pump efficiency of 75%, and is pumping 500 gpm with 75 feet of head. If the RPM of the pump is increased to 1750 RPMS calculate the following: New output in gpm: - ANS 1770 =F = 1.5 500 x 1.5 = 750 gpm 750 The goal of a sanitary wastewater physical survey is to - ANSIdentifying problems in the system need a rehab The Hazard Communication Act of 1985 is: - ANSTexas law Federal law The incubation procedure for fecal coliform in wastewater - ANS44.5° Centigrade for 24 hours The inside diameter of a manhole must be at least wide. - ANS48 inches The major cause of wastewater line stoppages is - ANSroots and grease The management function of setting goals, policies, and procedures is called: - ANSplanning

The minimum velocity of flow in a wastewater line should be - ANS2.0 fps The minimum velocity of flow in a wastewater line should be - ANS2.0 fps The most important purpose for wastewater treatment is - ANSto remove harmful contaminants from the wastewater before it is discharged to the waters of the state The normal appearance of the biomass on an RBC is - ANSgrey to brown and. to.1 inch thick shaggy and stringy appearance The organizing management function involves: - ANSdeciding who will do what work The parameters of the BOD test are - ANS5 days at 20° Centigrade The parameters of the BOD test are - ANS5 days at 20° Centigrade The sludge from a primary clarifier should contain what percent solids? - ANS4% to 6% The sludge from a primary clarifier should contain what percent solids? - ANSb. 4% to 6%

The sludge from a primary clarifier should percent solids? - ANS4% to 6% The smallest pipe size for air recirculation of a self-priming centrifugal pump is - ANS1 inch The smallest pipe size for air recirculation of a self-priming centrifugal pump is - ANSb. 1 inch The TCEQ Design Criteria requires that deflection tests be performed on all new installed flexible or semi-rigid pipe after the final backfill has been in place for 30 days. This deflection test is usually performed using a rigid ball or mandrel that has a diameter equal to -percent of the inside diameter of the pipe. - ANSc. 95 The temperature of an anaerobic digester should be maintained at a minimum of - ANS95° F The temperature of an anaerobic digester should be maintained at a minimum of - ANS95° F Three hundred milliliters of 0.02 N H,SO, is needed for a lab test. The lab stocks a standard of 0.5 N. How many ml of the 0.5 N will be needed? 300 x0.02 = V x0. 300x0.02 0.5 - ANS To be a team player, a person must: - ANSput yourself in the place of other team members to understand their position

trench is 4,100 feet long, four 4 wide and 6 feet deep. There is a 12-inch diameter pipe in the bottom of the trench. How many cubic yards of material were removed from the trench? 4x6x4,100 3,644 27 - ANS3, Under EPA regulations utilities that store chlorine gas over what quantity are required to have a "Risk Management Plan"? 2500 Ibs - ANS2500 Ibs Under the Texas Hazard Communication Act employers must annually report chemicals stored above what limits? - ANS55 gals/500 Ibs Wastewater What are the effects of organic pollution on the receiving stream? - ANSDecomposition of organics lowers DO levels adversely affecting aquatic life Nutrients encourage the growth of aquatic organism such as algae c. Lower water quality downstream is more difficult treat for potable use d. All of the above What are the dangerous gases a collection system worker might come into contact with? - ANSa. CO2 b. CO c. H,S d. CH, e. all of the above What are the dangerous gases a collection system worker might come into contact with? - ANSCO2 CO НaS CH4 (all of the above) What are the hazards of using powered activated carbon? - ANSa. fire/explosive b. inhalation c. uncomfortable working conditions What can change a non-permit confined space entry into a permit required confined space entry? - ANSa, if an ignition source is identified b. non-sparking

tools are required c. a possible source of engulfment is identified d. a hazardous atmosphere is identified e. all of the above What compound or compounds are formed when Cl, combines with water? - ANSBoth a and d What does biomonitoring test for? - ANSeffluent toxicity What is dissolved air floatation in a wastewater plant usually used for? - ANSgrease removal What is eutrophication in a pond system? - ANSEnrichment with nitrogen and phosphorous Causes algae blooms What is eutrophication in a pond system? - ANSEnrichment with nitrogen and phosphorous Causes algae blooms (b and c) What is the definition of pH? - ANSThe logarithm of the reciprocal of the hydrogen ion concentration The negative logarithm of the hydrogen ion concentration What is the hydraulic loading on the clarifier in gal/sq ft/day? - ANS3.14 x 38 x 38 = 4,534 sq ft 2,500,000 gpd = 551 gal / sq ft I day 4,534 sq ft 551 What is the MCL for coliform? - ANSper b. 1.0 per 100 mls

What is the minimum clearance from the sidewall of a pipe to the trench wall in an excavation? - ANS4 inches What is the purpose of a capital improvement fund? - ANSreplacement fund to keep the utility operating in the future What is the purpose of biomonitoring of a plant's effluent? - ANSd. Test for toxicity What is the relationship between F/M ratio and MCRT? - ANSIndirect; if one goes up, the other goes down What is the standard chlorine residual and contact time on Texas discharge permits? - ANSe. None of the above organization increases, What is the standard pH range on Texas effluent discharge permits? - ANSb. 6.0 to 9.0 What is the velocity of water flowing through a clarifier that is 16 feet deep x 45 feet wide 135 feet long if the flow is 5,837 gpm? Q- AxV 13=720x fps - ANS0.02 fps What is the weir loading in gal/linear ft/day? 3.14 x 76 = 239 ft of weir 2,500,000 gpd = 10,460 gal / lin ft / day 239 ft weir - ANS10,460 What processes are used to check an upset activated sludge plant? - ANSBOD loadings, F/M ratio, SV 30, MCRT, DO

What substance will interfere with a DPD chlorine test? - ANSManganese What tasks does a manager perform when controlling a utility? - ANSbeing sure progress being made toward objectives What type of fire extinguisher would be used on an electrical control panel that has been de-energized? - ANSClass A Class C (a and d) What type of valve is usually used for isolation? - ANSgate What type of wastewater treatment operates in the endogenous bacteria growth phase? - ANSExtended air When chlorinating treated wastewater, what chlorine residual do we test for? - ANSChloramine and Total When chlorine used, the effective disinfectant is - ANSHOCI When connecting a public water supply to any source of potential contamination, an air gap of what size must be provided? - ANStwo times the inlet pipe diameter When designing a wastewater collection system, the engineer considers the population for how many years in the future? - ANS50

When designing a wastewater collection system, the engineer considers the population for how many years in the future? - ANS50 When designing a wastewater rehab program, the first step is to - ANSd. define the objectives of the program When fighting an electrical fire, you should - ANSUse non-conductive extinguishing methods c. Use Class A or B extinguishers if electricity to the unit has been shut-off d. Either b or e When is blue-green algae the most dominant on a pond treatment system? - ANSSummer When is blue-green algae the most dominant on a pond treatment system? - ANSSummer When laying bell and spigot wastewater - ANStrench bedding should be scooped out at joints > support pipe on the barrel the bell end should be pointed upstream When must TCEQ be notified about expansions of a treatment facility? - ANSBefore construction When setting work goals for an employee, the goals should be - ANSaccompanied by an action plan When setting work goals for an employee, the goals should be - ANSaccompanied by an action plan

When should drop manholes be utilized? - ANSwastewater velocities greater than ten fps flows entering the manhole 24 inches or greater above the floor When using a fire hydrant to flush wastewater lines, - ANSa. the hydrant should be opened and closed slowly b. if flow needs to be controlled, use an external valve not the hydrant internal c. an air gap or backflow prevention device must be utilized d. all of the above Which activated sludge process does not achieve complete nitrification? - ANSContact stabilization Which activated sludge process has 18 to 20 + hours detention time in the aeration basin? - ANSExtended air Which form of activated sludge does the better job of handling shock or toxic loads? - ANSComplete mix Which form of activated sludge must have primary clarifiers? - ANSConventional Which of activated sludge has two aeration basins per single treatment unit? - ANSContact stabilization Which temperature is more important to the operation of a trickling filter? - ANSinfluent temperature

Why is lime added to sludge? - ANSto raise the pH and assist in pathogen reduction Why is recirculation needed in a trickling filter plant? - ANSa. to keep the zoogleal mass wet during low flow periods b. to assist in flooding the filters and to increase sloughing Why is recirculation needed in a trickling filter? - ANSa. Keep the media wet b. Further reduce BOD c. Flood the filter to control ponding and filter flies Why is recirculation needed in a trickling filter? - ANSKeep the media wet Further reduce BOD All of the above (a, b, and c)