CampusSewageTreatmentSystemBasedonProgramLo

CampusSewageTreatmentSystemBasedonProgramLogicControlTechnology1.INTRODUCTIONWiththecontinuedexpansionofUniversityCollege,theproblemofcampussewagemustbeurgentlyresolvedduetotheincreasingsewageproblemsfromuniversityofcampusonthesurroundingenvironment.Accordingtodifferentprinciplesofwastewatertreatmenttechnologies,wastewatertreatmenttechnologywasdividedintophysicalmethod,chemicalmethodandbiologicalmethod.Among,biologicalmethodwasdefinedthatorganicpollutantsfromsewagewaterwereconvertedandabsorbedbythedegradationrolesofmicrobialbiological.Incommon,biologicalmethodscanbedividedintoactivatedsludgemethod,ABmethod,biofilmmethod,oxidationditchmethod,andsoon.SBRmethodisthesequencingbatchreactoractivatedsludgeprocess,whichisanactivatedsludgewastewatertreatmenttechnologybycontinuousfeeding,intermittentdrainageandcycleintermittentaeration.SBRisapredecessorofFill-and-Drawsystembyintermittentoperation,whichisanimprovementofactivatedsludgereactorfullyproducedbytheearlytwentiethcentury[1].In1912,ClarkandGageformtheUnitedKingdomhadfoundthatlongtimeaerationofthewastewaterwillproducesludge,andwaterqualitywillbeimproved.In1914,AldenandLocketthadfoundthattheaerationofthesewagewerestaticprecipitated,thecleanwaterweretossedawayandthesludgewereleavedinthebottomforthenextwastewatertreatment.Thetimeusedinthewastewatertreatmentwassignificantlyreducedbyabovemethod[2].However,duetosometechnologyproblemscouldnotbesolvedtechnicalsuchascumbersomemanualmanagement,monitoringtechnologybackward,aerationequipmentblockedetc.,wefounditdifficulttoexpandtheThisworkissupportedbyCentralUniversityspecialfundbasicresearchandoperatingexpenses˄JD1201B˅.applicationsatthattime.Intheearlyseventies,R.IrvineandotherresearchersfromNaMeDameUniversityintheUnitedStateshadproposedthatSBRcanbeusedasabetteralternativetechnologyinthecontinuousflowactivatedsludgeprocess(CFS)bycomparedandresearchedthecharacteristicsofSBRandCFSintheexperiments[3].Inthe80sof20thcentury,duetotherapiddevelopmentandapplicationofautomationandcomputertechnologyinthefieldofwastewatertreatment,theactivatedsludgewastewatertreatmenttechnologyhadgainsignificantprogress[4].Sincemid-90s,theresearchandapplicationofSBRtechnologywerebeguninourcountry,butmostSBRtechnologywasinthepilotstageorintheapplicationstageofsmallsewagetreatment.2.SBRPROCESSFLOWSBRisabiologicalmethod,whichisanactivatedsludgewastewatertreatmenttechnologyunderintermittentaeration.Differentfromthetraditionalwastewatertreatmentprocess,theoperationmodeofspacepartitioningwasplacedbytimedivisiontechnology,steady-statebiochemicalreactionswasplacedbynon-stablealternativetechnology;thetraditionaldynamicprecipitationwasplacedbyidealstandingprecipitationtechnologyintheSBRtechnology.SBRprocesstechnologyisanadvancedsewagetreatmentsystems,whichincludingthefollowsteps[5],thatis,regulation,primarysedimentation,aeration,secondarysedimentationandbiologicalnitrogenremovalprocessinonepool.Accordingdifferenttimetooperatevarioussteps,thewholeprocesswereruninapoolagainandagain,simpleprocess,compactandreasonable.TheabovetechniquecaneffectivelyremoveBOD5andsuspendedsolids(SS)inthewastewater.Nitrogencompoundswereconvertedtonitrateinthewastewater,andthenbeconvertedtoammonia,sotheconcentrationofammonia(NH3-N)willbesignificantlyreducedintheoutputwater.SBRwasmainlyusedinsmall-scaleJIANGJing1,2,ZHANGXuesong31.NorthChinaInstituteofScienceandTechnology,Beijing101601,[e-mail]-mail:2.ChinaUniversityofMiningandTechnology,Beijing100083,China3.NationalLaboratoryofElectro-OpticsSystemTechnology,Hebei065201,ChinaE-mail:[e-mail]:Sewagefromourcampuswasneededtotreaturgentlyduetheaffectofsewageontheenvironmentbecomingmoreandmoreseriously.ThispaperproposesamethodofSequencingBatchReactorActivatedSludgeProcesstomeettheneedsofcampus.Therefore,themethodissocomplicatedthatonlyautomaticcontrolpartwasrealized.StrengthsofSequencingBatchReactorActivatedSludgeProcesswereplayed.PLCcontrollerfromMitsubishiFX2NSerieswasusedintheautomaticcontrolsystemofsewagetreatmentwithstableoperation,lowcost,goodeffectandsoon.KeyWords:Sewagetreatment;Sequencingbatchreactoractivatedsludgeprocess;Programlogiccontrol2788978-1-4577-2074-1/12/$26.00c2012IEEEwastewatertreatmentprocess.Inthispaper,theautomaticcontrolsystemofsewagetreatmentfromcampuswasdesigned.ApartitionwallwasplacedintheSBRreactiontank,whichdividedreactiontankintotwoparts,pre-reactionzoneandthemainreactionzone.Therewasaconnectedholeinthebottomofthewall.Water,reaction,sedimentation,drainageandidlefiveprocesses[6]intheeachcyclearecarriedoutinthesamepoolagainandagain,showninfigure1.Fig1.FiveprocessesofSBR3.DESIGNOFELECTRICALCONTROLSYSTEMSBRtechnologyisamoreadvancedprocesstechnologyduethatSBRmeetsthebasicneedsofsewagetreatmentinthecampus.However,thetypicalshortcomingsofSBRmethodisoperatedcomplexity,SBRmethodcouldplaytoitsstrengthsafterachieveautomaticcontrol.Althoughsomesewagetreatmentplanthaveautomatedtosomeextent,mostofthetraditionalcontrolmethodswereused,namely,controlineffective.Timeprocesscontrolare