wastewater operator certification practice
test with correct answers 2025
Invthevenhanced-biological-nutrient-
controlvactivatedvsludgevsystemvforvthevprocessvcontrolvofvphosphorusvremoval,vwhatvarevthevprim
aryvcontrollingvvariablesvforvthevdesiredvmicrobialvpopulation?v
a.vvolatilevfattyvacidsvb.vsolublevBOD5vandvphosphatevc.vpHvandvalkalinityvd.voxidizedvnitrogenvandv
DOv-vcorrectvanswers-d.voxidizedvnitrogenvandvDO
Invthevfour-
stagevBardenphovprocess,vammoniavfromvthevinfluentvisvconvertedvtovnitratevinvwhichvarea?v
a.vanoxicvzonevb.vaerationvbasinvc.vanaerobicvzonevd.vaerobicvzonev-vcorrectvanswers-
b.vaerationvbasin
.vWhatvisvthevtheoreticalvamountvofvoxygenvinvmilligramsvrequiredvtovconvertv1vmgvofvammoniavnit
rogenvtovnitratevnitrogen?v
a.v2.5vmgvb.v3.3vmgvc.v4.6vmgvd.v7.1vmgv-vcorrectvanswers-c.v4.6vmg
,Whatvisvthevoperatingvguidelinevinvthevfour-
stagevBardenphovprocessvforvthevmeanvcellvresidencevtime?
a.v15vtov20vdaysvb.v20vtov25vdaysvc.v20vtov30vdaysvd.v20vtov40vdaysv-vcorrectvanswers-
v
c.v20vtov30vdays
ThevoptimumvpHvrangevinvthevenhancedvchemicalvnutrientvcontrolvreactionsvforvphosphorusvremo
vedvbyvFe3+vadditionvis
v a.v4.0vtov6.0vb.v4.5vtov6.0vc.v4.5vtov6.5vd.v5.0vtov6.5v-vcorrectvanswers-a.v4.0vtov6.0
WhatvisvthevdesiredvDOvlevelvforvanvanaerobicvselector?
v a.v0.05vmg/Lvb.v0.10vmg/Lvc.v0.15vmg/Lvd.v0.20vmg/Lv-vcorrectvanswers-b.v0.10vmg/L
Whichvonevofvthevfollowingvtypesvofvfoamvisvthevmostvpersistentvandvmostvdifficultvtovcontrol?
a.vsolidsvfromvthevdewateringvprocessvb.vfilamentousvorvNocardiavorganismsvc.vpolymervoverdosin
v
gvd.vnutrientvdeficienciesv-vcorrectvanswers-b.vfilamentousvorvNocardiavorganisms
Invthevreactionvofvhydrogenvsulfidevwithvchlorinevtovformvsulfuricvacid,vitvtakesvonevpartvhydrogenvs
ulfidevforveveryv_______vpartsvofvchlorine.
v a.v2.5vb.v4.5vc.v6.5vd.v8.5v-vcorrectvanswers-d.v8.5
.vDichloraminevwillvbevpresentvinvwastewatersvatvpHvvaluesvbelowvwhat?v
, a.v5.5vb.v5.0vc.v4.7vd.v4.3v-vcorrectvanswers-a.v5.5
Whatvisvthevrecommendedvwithdrawalvofvchlorinevfromvav100-vorv150-
lbvcylindervforveachvdegreevFahrenheitvambientvtemperaturevsuchvthatvfreezingvdoesvnotvoccur?
v a.v1vlbvb.v2vlbvc.v3vlbvd.v4vlbv-vcorrectvanswers-a.v1vlb
Whatvchlorinevemergencyvrepairvkitvisvusedvtovstopvleaksvonlyvatvthevvalvesvofvtankvcars?
a.vemergencyvrepairvkitvAvb.vemergencyvrepairvkitvBvc.vemergencyvrepairvkitvCvd.vemergencyvrepairv
v
kitvTv-vcorrectvanswers-c.vemergencyvrepairvkitvC
Ifvavliquidvsulfonatorvwasvmisting,vwhatvwouldvmostvlikelyvbevthevcause?
va.vlossvofvwatervpressurevb.vwrongvsizevinjectorvvalvevc.vdirtyvinjectorvvalvevd.vdefectivevevaporator
v-vcorrectvanswers-d.vdefectivevevaporator
Tovpreventvreliquefactionvofvsulfurvdioxidevgasvinvavconductingvpipe,vwhatvshouldvthevtemperaturev
rangevofvthevroomvbe?v
a.v60vtov80°Fvb.v70vtov85°Fvc.v80vtov90°Fvd.v90vtov100°Fv-vcorrectvanswers-c.v80vtov90°F
Ifvthevflocvisvtoovsmallvinvthevsolidsvremovalvphysical-
chemicalvtreatmentvprocess,vwhatvisvthevmostvprobablevcause?
a.vpaddlevspeedvofvflocculatorsvtoovslowvb.vnotvenoughvdilutionvwatervc.vimpropervorvmisalignedvb
v
afflingvd.vchangevinvpHv-vcorrectvanswers-d.vchangevinvpH
test with correct answers 2025
Invthevenhanced-biological-nutrient-
controlvactivatedvsludgevsystemvforvthevprocessvcontrolvofvphosphorusvremoval,vwhatvarevthevprim
aryvcontrollingvvariablesvforvthevdesiredvmicrobialvpopulation?v
a.vvolatilevfattyvacidsvb.vsolublevBOD5vandvphosphatevc.vpHvandvalkalinityvd.voxidizedvnitrogenvandv
DOv-vcorrectvanswers-d.voxidizedvnitrogenvandvDO
Invthevfour-
stagevBardenphovprocess,vammoniavfromvthevinfluentvisvconvertedvtovnitratevinvwhichvarea?v
a.vanoxicvzonevb.vaerationvbasinvc.vanaerobicvzonevd.vaerobicvzonev-vcorrectvanswers-
b.vaerationvbasin
.vWhatvisvthevtheoreticalvamountvofvoxygenvinvmilligramsvrequiredvtovconvertv1vmgvofvammoniavnit
rogenvtovnitratevnitrogen?v
a.v2.5vmgvb.v3.3vmgvc.v4.6vmgvd.v7.1vmgv-vcorrectvanswers-c.v4.6vmg
,Whatvisvthevoperatingvguidelinevinvthevfour-
stagevBardenphovprocessvforvthevmeanvcellvresidencevtime?
a.v15vtov20vdaysvb.v20vtov25vdaysvc.v20vtov30vdaysvd.v20vtov40vdaysv-vcorrectvanswers-
v
c.v20vtov30vdays
ThevoptimumvpHvrangevinvthevenhancedvchemicalvnutrientvcontrolvreactionsvforvphosphorusvremo
vedvbyvFe3+vadditionvis
v a.v4.0vtov6.0vb.v4.5vtov6.0vc.v4.5vtov6.5vd.v5.0vtov6.5v-vcorrectvanswers-a.v4.0vtov6.0
WhatvisvthevdesiredvDOvlevelvforvanvanaerobicvselector?
v a.v0.05vmg/Lvb.v0.10vmg/Lvc.v0.15vmg/Lvd.v0.20vmg/Lv-vcorrectvanswers-b.v0.10vmg/L
Whichvonevofvthevfollowingvtypesvofvfoamvisvthevmostvpersistentvandvmostvdifficultvtovcontrol?
a.vsolidsvfromvthevdewateringvprocessvb.vfilamentousvorvNocardiavorganismsvc.vpolymervoverdosin
v
gvd.vnutrientvdeficienciesv-vcorrectvanswers-b.vfilamentousvorvNocardiavorganisms
Invthevreactionvofvhydrogenvsulfidevwithvchlorinevtovformvsulfuricvacid,vitvtakesvonevpartvhydrogenvs
ulfidevforveveryv_______vpartsvofvchlorine.
v a.v2.5vb.v4.5vc.v6.5vd.v8.5v-vcorrectvanswers-d.v8.5
.vDichloraminevwillvbevpresentvinvwastewatersvatvpHvvaluesvbelowvwhat?v
, a.v5.5vb.v5.0vc.v4.7vd.v4.3v-vcorrectvanswers-a.v5.5
Whatvisvthevrecommendedvwithdrawalvofvchlorinevfromvav100-vorv150-
lbvcylindervforveachvdegreevFahrenheitvambientvtemperaturevsuchvthatvfreezingvdoesvnotvoccur?
v a.v1vlbvb.v2vlbvc.v3vlbvd.v4vlbv-vcorrectvanswers-a.v1vlb
Whatvchlorinevemergencyvrepairvkitvisvusedvtovstopvleaksvonlyvatvthevvalvesvofvtankvcars?
a.vemergencyvrepairvkitvAvb.vemergencyvrepairvkitvBvc.vemergencyvrepairvkitvCvd.vemergencyvrepairv
v
kitvTv-vcorrectvanswers-c.vemergencyvrepairvkitvC
Ifvavliquidvsulfonatorvwasvmisting,vwhatvwouldvmostvlikelyvbevthevcause?
va.vlossvofvwatervpressurevb.vwrongvsizevinjectorvvalvevc.vdirtyvinjectorvvalvevd.vdefectivevevaporator
v-vcorrectvanswers-d.vdefectivevevaporator
Tovpreventvreliquefactionvofvsulfurvdioxidevgasvinvavconductingvpipe,vwhatvshouldvthevtemperaturev
rangevofvthevroomvbe?v
a.v60vtov80°Fvb.v70vtov85°Fvc.v80vtov90°Fvd.v90vtov100°Fv-vcorrectvanswers-c.v80vtov90°F
Ifvthevflocvisvtoovsmallvinvthevsolidsvremovalvphysical-
chemicalvtreatmentvprocess,vwhatvisvthevmostvprobablevcause?
a.vpaddlevspeedvofvflocculatorsvtoovslowvb.vnotvenoughvdilutionvwatervc.vimpropervorvmisalignedvb
v
afflingvd.vchangevinvpHv-vcorrectvanswers-d.vchangevinvpH
