Overcoming Hydraulic Limitations of the Integrated

Overcoming Hydraulic Limitations of the Integrated Fixed–Film Activated Sludge (IFAS) ProcessOvercomingHydraulicLimitationsoftheIntegratedFixed-filmActivatedSludge(IFAS)ProcessWilliamR.Leaf1,JoshuaP.Boltz2,JamesP.McQuarrie3,AdrienneMenniti4,GlenT.Daigger51CH2MHILL,Inc.,322EastFrontStreetSuite200,Boise,ID,83702USA,CorrespondingAuthor(E-mail:wleaf@ch2m.com)2CH2MHILL,Inc.,4350W.CypressStreet,Suite600,Tampa,FL,33607USA,(E-mail:jboltz@ch2m.com)3MetroWastewaterReclamationDistrict,6450YorkStreet,Denver,CO80229USA,(E-mail:jmcquarrie@mwrd.dst.co.us)4CH2MHILL,Inc.,2020SouthWest4thAvenue,3rdFloor,97201USA,(E-mail:amenniti@ch2m.com)5CH2MHILL,Inc.,9191S.JamaicaStreet,Englewood,CO,80112USA(E-mail:gdaigger@ch2m.com)ABSTRACTIn2011morethan600movingbedbiofilmreactors(MBBRs)wereoperationalin50differentcountries.Approximately20systemsincorporatinganintegratedfixed-filmactivatedsludge(IFAS)processwereoperationalin2011,15ofwhichexistintheUnitedStatesofAmerica.SimilardesignstandardsareappliedtoMBBRandIFASpro