7/30/2019 F-M Ratio - Activated Sludge

1/2

7/30/2019 F-M Ratio - Activated Sludge

2/2

FLORIDAWATERRESOURCESJOURNAL MARCH199921

Equation3,is2500x8.34x0.25=5210lb.TheF/Mratioisthen992/5210=0.19,which

isbelowthestandardrangeof0.25to0.50.Theprocesshastoomuchsludge(weightofmicro-organisms)underaerationforthefoodbeingprovided.TheoperatorshouldwastesludgetolowertheMLTSSinaeration.DeterminingOptimalMLTSSTheoptimalMLTSSisbasedontheratio-

proportionformula,R1:R2::P1:P2,wheretheproductofthemeansisequaltotheproduct,or:

(R1xP2)=(R2xP1) (Equation4)whereR1 =thedesiredF/Mratio

=0.25fortheaboveexample.R2 =theMLTSScorrespondingto

thedesiredF/Mratio,or1.0pounds for an F/M ratio of0.25.

P2 =optimalMLTSSP1 =weightoffoodinaerationfrom

Equation3,or992lb/day intheaboveexample.

Therefore,fortheexampleplant:(0.25xP2)=(1.0x992)or,P2=(1.0x992)/0.25=3968lbsMLTSS.TheoptimalaerationMLTSSconcentration

canbefoundbyrewritingEquation3as:ppm=(poundsperdayMLTSS)/(8.34xMG)ppm=(3968lb/day)/(8.34x0.25MG)=1900.Therefore,1900ppmisthemaximumcon-

centrationofMLTSStoachieveaF/Mratioof0.25.

AnumberofyearsagowhenIwasayoungbuckinthewaterandwastewaterindustry,Iwrotesomearticlesonactivatedsludgeopera-tionfortheOverflowMagazine.Iamnowanold-timer, but I still see a need for someemphasisonunderstandingactivatedsludgeprocessoperation.

January WaterTreatment:Membranes.FSAWWAOfficers.

FebruaryWaterDistribution.FWPCOAOfficers

March WastewaterCollection.April AnnualConferenceIssue.Misc.technicalarticles.

May WaterTreatmentJune FSAWWA&FWEAAwards.

Miscellaneoustechnicalarticles.July Disinfection.

August Conservation.

September IndustrialWastewater/ResidualsManagement.

October WaterResourcesManagement/FWPCOAAwards.FSAWWAConference.

November Reuse.December WastewaterTreatment.FWEA

Officers.

EditorialCalendar