Nitrogen and phosphorus removal in a recirculating system for Nile tilapia (Oreochromis niloticus) culture

摘要

Themainobjectiveofthisresearchwastoevaluatetheperformanceofacolumnverticalflowsettlerandaconventionalhorizontalflowsettlerassociatedtoanaerobicthree-phasefluidizedbedreactorwithcirculationinarecirculatingaquaculturesystemforNiletilapiafarming.Thehydraulicdetentiontimesofthereactor,thehorizontalflowsettlerandthecolumnsettlerwere0.198,2.94and0.55hrespectively.Forfinalfishstockingdensitiesof33kg/m3(systemwithcolumnsettler)andwith30kg/m3(conventionalsettler)theaverageremovalefficienciesoftotalammonianitrogen,totalnitrogenandtotalphosphoruswere36.6%,26.3%,46.5%and26.2%,24.3%,32.3%,respectivelywithsignificantdifferencesfortotalammonianitrogen;thecumulativefeedburdenforthetwosystemswere:2.64and2.22kgoffeed/m3offreshwaterperday.Thetwoevaluatedsystemsdemonstratedtobefeasibleoptionstomaintainthewaterqualityintherecirculatingsystems.Thesystemwithcolumnsettlershowedbetterresultsduetothelesservolumeandarearequirements,thehigherlevelsoftotalammonianitrogenremovalefficiencyandassimilativecapacityoffeedpernbsp;unitvolume.