控制氧化沟工艺中的污泥沉降外文翻译三

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1、本科生毕业设计外文文献翻译ControllingsludgesettleabilityintheoxidationditchprocessK.J.HartleyABSTRACTThispaperdescribesaninvestigationaimedatdevelopinganoperatingtechniqueforcontrollingsludgesettleabilityintheoxidationditchformofthenitrificationdenitrificationactivatedsludgeprocess.Itw

2、ashypothesizedthatspecificsludgevolumeindex(SSVI)islowestatanoptimumprocessanoxicfractionandincreasesathigherandlowerfractions.Usingeffluentammonia:nitrateratioasasurrogateforanoxicfraction,itwasfoundthatasimpleempiricalmodelbasedonathreesolidsretentiontimemovingaveragenit

3、rogenratiowasabletoreplicatethelong-termSSVIvariationsintwoindependentoxidationditchesatafull-scaleplan匸OpenUingdatafromasecondoxidationditchplantduringperiodswhenaprefermenterwason-oroff-lineshowedthatSSVIalsovarieswithRBCOD,greaterRBCODgivinglowerSSVI.Itwasconcludedthatb

4、estsettleabilityoccursataboutthesameanoxicfractionaslowesteffluenttotalnitrogenconcentration,withanammonia:nitrateratioofabout1.Anoperatingruleofthumbistousedissolvedoxygencontroltomaintaineffluentammoniaandnitratenitrogenconcentrationsaboutequal.Athirdoxidationditchplantd

5、eliberatelyoperatedinthismannerachieved15-monthmedianoperatingvaluesforSSVIof60mL/gandforeffluentammonia,nitrateandtotalN,respectively,of0.2,0.3and2.0mgN/L.KeywordsSettleability；Sludgevolumeindex；SVI；Control；Nitrogen；Oxidationditch1IntroductionTheoxidationditchprocesshasth

6、ecapabilitytoreliablymeetlowtotalnitrogenstandardsbecauseofitsspecialoperatingcharacteristics.Nitrogenremovalcanbecontinuouslyoptimizedinoperationbyvaryingtheanoxicandaerobicmassfractionstomeetshort-andlong-termchangesinwastewatercharacteristics(Hartley,1997;MinesandWoods,

7、1994).Ithasalsobeenobservedthatsludgesettleabilityinoxidationditchesvarieswiththeoperatingmassfractions(VivianandHartley,1989).Sludgesettleabilityisoneofthemostimportantdesignandoperatingcharacteristicsoftheactivatedsludgeprocess.Itaffectsboththesizingoftankageandtheproces

8、scapacityactuallyachieved.Yet,nearly100yearsaftertheactivatedsludgeprocesswasinvented(Ard