BASIC WASTEWATER OPERATOR
PRACTICE CLASS 3 LATEST
2026/2027 ACTUAL EXAM QUESTIONS
WITH CORRECT ANSWERS 100%
VERIFIED GRADED A+
1. Stalkedmciliatesm-
mCORRECTmANSWERmWhatmismthempredominantmorganismminmamhealthymActivatedmSludgem
TreatmentmPlant?
2. RepresentativemandmSub-samplesmtimemspacedmoverm15mminutesmapartm-
mCORRECTmANSWERmAmcompositemsamplemmustmbe?
3. 300mlm-mCORRECTmANSWERmWhatmismthemstandardmvolumemformamBODmsamplembottle?
4. Plugmvalvem-
mCORRECTmANSWERmIfmyoumhavemamlimemslurrymfeedmline,mwhatmismthembestmvalvemtomuse?
5. OldmSludgem-
mCORRECTmANSWERmIfmyoumnoticemampredominancemofmrotifersminmyourmactivatedmsludgem
samplemwhilemlookingmatmitmundermammicroscope,mwhatmdoesmthismindicate?
6. Settlingminmthemclarifiersm-
mCORRECTmANSWERmIfmyourmactivatedmsludgemplantmbeginsmtomnitrify,mwhatmconditionsmw
ouldmyoumexpectmtomdecrease?
7. 360mg/lm-mCORRECTmANSWERmCalculatemthemBODmgivenmtheminformation:
8. InitialmDO:m8.3
9. FinalmDO:m5.9
10. Millilitersmofmsamplemused:m2
,11. Bymmeasuringmthempumpmoutputm-
mCORRECTmANSWERmHowmdomyoumcalibratemamchemicalmfeedmpump?
12. H2SO4m-mCORRECTmANSWERmWhatmismthemchemicalmformulamformsulfuricmacid?
13. extendedmaerationm-
mCORRECTmANSWERmWhatmismthemmostmcommonmtypemofmActivatedmSludgempackagemplan
ts?
14. Increasemwastingm-
mCORRECTmANSWERmWhatmismthemmostmappropriatemmethodmofmreducingmthemF:MmRatio?
15. Unequalmairmdistributionmcausedmbymamblownmdiffuserm-
mCORRECTmANSWERmAnmoperatormnoticesmamportionmofmthemaerationmtankmwithmlargembub
blesmrisingmup.mWhatmismthemmostmlikelymproblem?
16. Thempressuremonmthemsuctionmsidemofmthempumpm-
mCORRECTmANSWERmWhatmismsuctionmlift?
17. 22.5mmg/lm-
mCORRECTmANSWERmThemprimarymeffluentmtomamRBCmsystemmism350mmg/lmBOD.mThemprim
arymunitmremovesm83%,mthemsecondarymunitmremovesm50%,mandmthemfinalmunitmremovesm2
5%.mWhatmismthemBODmleavingmthemfinalmunitmofmthemRBCmtrain?
18. Decreasemthemlagmtimemformpumpmoperationmbymmovingmthemfloatsmclosermtogetherm-
mCORRECTmANSWERmTheminfluentmtomthemtreatmentmplantmismseptic.mItmismdeterminedmtha
tmitmismcomingmfrommamliftmstationmupstreammfrommthemplant.mWhatmshouldmthemoperatorm
do?
, 19. Tomprotectmchemicalsmthatmaremsensitivemtomlightm-
mCORRECTmANSWERmWhatmismthempurposemofmambermstoragembottles?
20. 24mdaysm-mCORRECTmANSWERmCalculatemSRT
21. GIVEN:mMixedmliquormsuspendedmsolidsm(MLSS)m=m2400mg/l
22. Aerationmbasinmvolumem=m35,000mgallonsm=m0.0350mmillionmgallonsm(MG)
23. Wastemactivatedmsludgem(WAS)mconcentrationm=m3500mg/l
24. Wastemactivatedmsludgem(WAS)mflowratem=m0.001MGD
25. Horizontalm&mHorizontalm-mCORRECTmANSWERmHowmshouldmam1-
tonmchlorinemcylindermbemmoved?
26. 0.68m-mCORRECTmANSWERmCalculatemF:Mmratio
27. GIVEN:mInfluentmBOD5m=m290mg/l
28. InfluentmFlowm=m5.0MGD
29. AerationmbasinmMLSSm=m2650mmg/l
30. Aerationmbasinmvolumem=m0.8MG
31. Cloggedmimpellerm-
mCORRECTmANSWERmWhatmwouldmmostmlikelymcausemamsubmersiblempumpmtomhavemanmA
MPmreadingmthatmismabovemthemoptimummlevel?
32. Statorm-mCORRECTmANSWERmWhichmofmthemfollowingmaremnon-
movingmpartsmofmamrunningmmotor?
33. 225m-mCORRECTmANSWERmCalculatemSVI
34. GIVEN:m30mminutemsettlingmtestm=m1800mlminmam2000mlmcontainer
35. MLSS:m4000mg/L
PRACTICE CLASS 3 LATEST
2026/2027 ACTUAL EXAM QUESTIONS
WITH CORRECT ANSWERS 100%
VERIFIED GRADED A+
1. Stalkedmciliatesm-
mCORRECTmANSWERmWhatmismthempredominantmorganismminmamhealthymActivatedmSludgem
TreatmentmPlant?
2. RepresentativemandmSub-samplesmtimemspacedmoverm15mminutesmapartm-
mCORRECTmANSWERmAmcompositemsamplemmustmbe?
3. 300mlm-mCORRECTmANSWERmWhatmismthemstandardmvolumemformamBODmsamplembottle?
4. Plugmvalvem-
mCORRECTmANSWERmIfmyoumhavemamlimemslurrymfeedmline,mwhatmismthembestmvalvemtomuse?
5. OldmSludgem-
mCORRECTmANSWERmIfmyoumnoticemampredominancemofmrotifersminmyourmactivatedmsludgem
samplemwhilemlookingmatmitmundermammicroscope,mwhatmdoesmthismindicate?
6. Settlingminmthemclarifiersm-
mCORRECTmANSWERmIfmyourmactivatedmsludgemplantmbeginsmtomnitrify,mwhatmconditionsmw
ouldmyoumexpectmtomdecrease?
7. 360mg/lm-mCORRECTmANSWERmCalculatemthemBODmgivenmtheminformation:
8. InitialmDO:m8.3
9. FinalmDO:m5.9
10. Millilitersmofmsamplemused:m2
,11. Bymmeasuringmthempumpmoutputm-
mCORRECTmANSWERmHowmdomyoumcalibratemamchemicalmfeedmpump?
12. H2SO4m-mCORRECTmANSWERmWhatmismthemchemicalmformulamformsulfuricmacid?
13. extendedmaerationm-
mCORRECTmANSWERmWhatmismthemmostmcommonmtypemofmActivatedmSludgempackagemplan
ts?
14. Increasemwastingm-
mCORRECTmANSWERmWhatmismthemmostmappropriatemmethodmofmreducingmthemF:MmRatio?
15. Unequalmairmdistributionmcausedmbymamblownmdiffuserm-
mCORRECTmANSWERmAnmoperatormnoticesmamportionmofmthemaerationmtankmwithmlargembub
blesmrisingmup.mWhatmismthemmostmlikelymproblem?
16. Thempressuremonmthemsuctionmsidemofmthempumpm-
mCORRECTmANSWERmWhatmismsuctionmlift?
17. 22.5mmg/lm-
mCORRECTmANSWERmThemprimarymeffluentmtomamRBCmsystemmism350mmg/lmBOD.mThemprim
arymunitmremovesm83%,mthemsecondarymunitmremovesm50%,mandmthemfinalmunitmremovesm2
5%.mWhatmismthemBODmleavingmthemfinalmunitmofmthemRBCmtrain?
18. Decreasemthemlagmtimemformpumpmoperationmbymmovingmthemfloatsmclosermtogetherm-
mCORRECTmANSWERmTheminfluentmtomthemtreatmentmplantmismseptic.mItmismdeterminedmtha
tmitmismcomingmfrommamliftmstationmupstreammfrommthemplant.mWhatmshouldmthemoperatorm
do?
, 19. Tomprotectmchemicalsmthatmaremsensitivemtomlightm-
mCORRECTmANSWERmWhatmismthempurposemofmambermstoragembottles?
20. 24mdaysm-mCORRECTmANSWERmCalculatemSRT
21. GIVEN:mMixedmliquormsuspendedmsolidsm(MLSS)m=m2400mg/l
22. Aerationmbasinmvolumem=m35,000mgallonsm=m0.0350mmillionmgallonsm(MG)
23. Wastemactivatedmsludgem(WAS)mconcentrationm=m3500mg/l
24. Wastemactivatedmsludgem(WAS)mflowratem=m0.001MGD
25. Horizontalm&mHorizontalm-mCORRECTmANSWERmHowmshouldmam1-
tonmchlorinemcylindermbemmoved?
26. 0.68m-mCORRECTmANSWERmCalculatemF:Mmratio
27. GIVEN:mInfluentmBOD5m=m290mg/l
28. InfluentmFlowm=m5.0MGD
29. AerationmbasinmMLSSm=m2650mmg/l
30. Aerationmbasinmvolumem=m0.8MG
31. Cloggedmimpellerm-
mCORRECTmANSWERmWhatmwouldmmostmlikelymcausemamsubmersiblempumpmtomhavemanmA
MPmreadingmthatmismabovemthemoptimummlevel?
32. Statorm-mCORRECTmANSWERmWhichmofmthemfollowingmaremnon-
movingmpartsmofmamrunningmmotor?
33. 225m-mCORRECTmANSWERmCalculatemSVI
34. GIVEN:m30mminutemsettlingmtestm=m1800mlminmam2000mlmcontainer
35. MLSS:m4000mg/L