WASTEWATER GRADE 1 TEST 2025 WITH 300 PRACTICE QUESTIONS AND CORRECT ANSWERS WASTEWATER TREATMENT OPERATOR GRADE 1 CERTIFICATION TEST 2025 (BRAND NEW!)

WASTEWATER TREATMENT OPERATOR {test 2&3} CE
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RTIFICATION EXAM 2023- g g

2024 ACTUAL EXAM 160 QUESTIONS AND CORRECT D
g g g g g g g

ETAILED ANSWERS g

WITH RATIONALES|ALREADY GRADED A+
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Test2
WhatgisgthegtypicalgBODgremovalgefficiencygingagprimarygclarifier?

A) 10gtog15%

B) 40gtog60%

C) 20gtog50%

D) 95gtog99%g-ganswer-C)g20gtog50%g(v.1gpgg129)



Whatgdoesgtheg"F"gingF/Mgratiogrepresent?

A) Thegmicroorganismgpopulationgingthegaerationgtank

B) Thegamountgofgfilamentousgbacteriagingthegactivatedgsludgegprocess

C) ThegMLVSSgingthegaerationgtank

D) Thegfoodgforgthegmicroorganismsgflowinggintogthegaerationgtank,ginglbs/dayg-ganswer-
D)gThegfoodgforgthegmicroorganismsgflowinggintogthegaerationgtank,ginglbs/dayg(v.2gpgg58)



Whichgofgthegfollowinggdescribesgthegappearancegofghealthygactivatedgsludge?

A) Thick,ggreasy,gdarkgtangfoam

B) Browngwithgagmoderategamountgofgcrisp,gwhitegfoam

C) Cleargliquidgwithgcleargfoam

D) Graygliquidgwithgnogfoamg-ganswer-B)gBrowngwithgagmoderategamountgofgcrisp,gwhitegfoam



Whatgisgusedgtogcontrolgfilamentousgorganisms?

A) Polymer

B) SulfurgDioxide

C) Coagulant

,D) Chlorineg-ganswer-D)gChlorineg(v.1gpgg399)



Whatgaregcommonlygusedgtogcontrolgchlorinegfeedgrategforgdisinfection?

A) BODgandgMLVSS

B) pHgandgtemperature

C) Flowgandgchlorinegresidual

D) DOgandgTSSg-ganswer-C)gFlowgandgchlorinegresidualg(v.1gpgg356)



Whichgtoxicggasgisgcommonlygfoundgingsepticgwastewatergandgsmellsglikegrottengeggs?

A) HydrogengSulfide

B) Carbongmonoxide

C) Hydrogen

D) CarbongDioxideg-ganswer-A)gHydrogengSulfideg(v.2gpgg299)



Whatgisgthegpermissiblegexposureglimitgforgchlorineggasgvaporgduringgagnormalg8ghourgworkdaygandgag4
0ghourgworkgweek?

A) 0.1gppm

B) 0.5gppm

C) 1gppm

D) 15gppmg-ganswer-B)g0.5gppmg(v.2gpgg268)



Whatgisgagvulnerabilitygassessment?

A) Assessesgthegimpactgofghydrogengsulfidegtogagconcretegstructure

B) Analyzesgthegimpactgofgflowgandginfiltrationgproblemgtogthegplantghydraulics

C) Estimatesgthegvulnerabilitygofgaquaticgwildlifegtogexcessivegalgaeggrowth

D) Contingencygplanninggtogdeterminegthegvulnerabilitygofgthegutilitygduringgvariousgtypesgofgemergenci
esgandgidentifygcorrectivegactionsgtogreducegthegrisksg-ganswer-
D)gContingencygplanninggtogdeterminegthegvulnerabilitygofgthegutilitygduringgvariousgtypesgofgemergenc
iesgandgidentifygcorrectivegactionsgtogreducegthegrisksg(v.2gpgg722)

,Whatgisgthegdifferencegbetweengthegsettlinggrategofgactivatedgsludgegandgrawgsludge?

A) Activatedgsludgegsettlesgslightlygfastergthangrawgsludge

B) Activatedgsludgegsettlesgatgthegsamegrategasgrawgsludge

C) Activatedgsludgegsettlesgslowergthangrawgsludge

D) Activatedgsludgegsettlesgmuchgfastergthangrawgsludgeg-ganswer-
C)gActivatedgsludgegsettlesgslowergthangrawgsludgeg(v.1gpgg109)



Whatgshouldgbegmostlygfoundginghealthygactivatedgsludge?

A) Tinygflagellates

B) Amoeboids

C) ShortgFilaments

D) Freegswimmersgandgstalkedgciliatesg-ganswer-D)gFreegswimmersgandgstalkedgciliatesg(v.2gpgg120,124)



Onegtogtwogpercentgofgthegdigesterggasginganganaerobicgconsistsgof

A) Hydrogen,gNitrogen,gHydrogengsulfide,gandgotherggases

B) Methane

C) CarbongDioxide

D) CH_4g-ganswer-A)gHydrogen,gNitrogen,gHydrogengsulfide,gandgotherggasesg(v.2gpgg158)



Whatgisgtruegduringgthegcoldergwintergmonths?

A) ModifygoperationsgtogdecreasegsolidsgundergaerationgtogprovideglessgmicroorganismsgtogtreatgthegBO
D

B) Modifygoperationsgtogincreasegsolidsgundergaerationgtogprovidegmoregmicroorganismsgtogtreatgt
hegBOD

C) Biologicalgactivitygwillgincrease,gwhichgresultsgingmoregoverallgsludgegproduction

D) Microorganismsgbecomegmoregactiveg-ganswer-
B)gModifygoperationsgtogincreasegsolidsgundergaerationgtogprovidegmoregmicroorganismsgtogtreatgthegB
ODg(v.2gpgg71)



WhatgtypegofgsludgegwouldgyougexpectgingangaerationgtankgifgthegcontentgisgdarkgandghasglowgDO?

A) Sludgegthatgisgheavy

B) ChlorinatedgSludge

, C) SepticgSludge

D) HealthygSludgeg-ganswer-C)gSepticgSludgeg(v.2gpgg75)



Whatgcouldghaveghappengifgthegvolatilegacid/alkalinitygratiogstartsgtogincrease,gandgcorrectivegactiongisg
notgtakengimmediately?

A) Carbongdioxidegcontentgingthegdigesterggasgwillgdecrease

B) Carbongmonoxidegcontentgingthegdigesterggasgwillgfluctuate

C) pHgofgthegdigestergsludgegwillgincrease

D) Carbongdioxidegcontentgingthegdigesterggasgwillgincreaseg-ganswer-
D)gCarbongdioxidegcontentgingthegdigesterggasgwillgincreaseg(v.2gpgg191)



Whatgaregscreenings?

A) Colloids

B) TDS

C) Piecesgofgwood,groots,grags,gandgotherglargegdebris

D) CODg-ganswer-C)gPiecesgofgwood,groots,grags,gandgotherglargegdebrisg(v.1gpgg41)



Whatghappensgwhengtheregisgmoregfoodgingtheginfluentgtogthegaerationgtank?

A) Lessgoxygengisgrequiredgingthegaerationgtank

B) Moregoxygengisgrequiredgingthegaerationgtank

C) Lessgorganismgactivitygtakesgplace

D) Lessgoxidationgtakesgplaceg-ganswer-B)gMoregoxygengisgrequiredgingthegaerationgtankg(v.2gpgg19)



Whatgimpactgdoesgtemperatureghavegongthegreactiongrategofgmicroorganismsgingwastewater?

A) Reactiongrategdoublesgwithgeveryg18gdegreegFahrenheitgincreasegingtemperatureguntilghigh
ergtemperatureginhibitsgbiologicalgactivity

B) Reactiongrategdecreasesgbyg20%gwithgeveryg10gdegreegFahrenheitgincreasegingtemperature

C) Reactiongrategofgmicroorganismgisgnotgimpactedgbygtemperature

D) Reactiongrateggoesgtogzerog-ganswer-
A)gReactiongrategdoublesgwithgeveryg18gdegreegFahrenheitgincreasegingtemperatureguntilghigher