Design And Operation Of Nutrient Removal Plants Fo

Design And Operation Of Nutrient Removal Plants For Very Low Effluent ConcentrationsDESIGNANDOPERATIONOFNUTRIENTREMOVALPLANTSFORVERYLOWEFFLUENTCONCENTRATIONSBjornRusten*andHallvardØdegaard***Aquateam-NorwegianWaterTechnologyCentre,P.O.Box6875Rodelokka,N-0504Oslo,Norway**NorwegianUniversityofScienceandTechnology(NTNU),Dep.ofHydraulicandEnvironmentalEngineering,S.P.Andersensvei5,N-7491Trondheim,Norway.ABSTRACTOutofatotalofsixplantswithnitrogenremovalinNorway,fourplantsusetheMBBR(MovingBedBiofilmReactor)process.InallfourcasestheMBBRprocesswaschosenbecauseitofferedaverycompacttreatmentsolutionandbecauseithadthelowestinvestmentcostsaswellasthelowesttotalannualcosts.AlltheMBBRplantsusethecombineddenitrificationprocess(pre-denitrification+post-denitrification)fornitrogenremoval,followedbychemicalprecipitationforphosphorusremoval.Thistypeofdesignoffersalotofoperationflexibilityandenablestheplantstoproduceveryloweffluentconcentrations.Externalcarbonsourcesusedforpost-denitrificationattheseplant