1、RATIFIED EUROPEAN TEXT EN12255-13:2002 European Standards only exist formally as national transpositions (i.e. a BS EN for the UK) of a commonly agreed “ratified” text. This document will shortly be published as a British Standard. It is being made available in advance of its formal publication to g
2、ive interested parties early access to the technical information which the British Standard will contain. When the British Standard is formally published it will be supplied to you automatically, without any additional charge. Purchasers of this document should be aware of the following limitations
3、when using the document. The British Standard may contain additional information in the national foreword or national annex, Full rights conferred by compliance with the standard may only be granted by reference to the formal national transposition of the text as a British Standard. This document wa
4、s approved by CEN/CENELEC in its three official languages on the date given below. Under CEN/CENELEC rules, BSI is obliged to publish its national transposition within six months of this date. This ratified text was approved on 2002-11-01EUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN1225513 Decem
5、ber2002 ICS13.060.30 Englishversion WastewatertreatmentplantsPart13:Chemicaltreatment Treatmentofwastewaterbyprecipitation/flocculation StationsdpurationPartie13:Traitementchimique Traitementdeseauxusesparprcipitation/flocculation KlranlagenTeil13:ChemischeBehandlung AbwasserbehandlungdurchFllung/Fl
6、ockung ThisEuropeanStandardwasapprovedbyCENon1November2002. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational stand
7、ardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe officia
8、l versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROP
9、ISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2002CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN1225513:2002EEN1225513:2002(E) 2 Contents page Foreword3 1 Scope 4 2 Normativereferences 4 3 Termsanddefinitions. .4 4 Requirem
10、ents .5 4.1 General5 4.2 Chemicalbackgroundandprocessoptions. 5 4.2.1 Chemicalprocess 5 4.2.2 Precipitationprocesses . .6 4.2.3 Selectionofprecipitationchemicals .7 4.3 Storageofchemicals .7 4.3.1 General7 4.3.2 Aluminumsalts 8 4.3.3 Ironsalts .8 4.3.4 Calciumsalts. .8 4.4 Dosingequipment 8 4.4.1 Ge
11、neral8 4.4.2 Aluminiumsalts . 9 4.4.3 Ironsalts .9 4.4.4 Calciumsalts. .9 4.5 Silosandtanks. 10 4.6 Mixingsystems 10 4.7 Flocculators10 4.8 Sedimentationtanks. .10 4.8.1 General10 4.8.2 Designconsiderations . .10 4.8.3 Chemicalsludgewasting. .10 4.9 Flotation10 4.10 Physicalfiltration .11 4.11 Sludg
12、e .11 4.11.1 Sludgeproduction .11 4.11.2 Sludgecharacteristics. 11 AnnexA (normative) Precipitationchemicals 12 A.1 Aluminiumsalts . 12 A.2 Ironsalts .12 A.2.1 Ferroussalts. 12 A.2.2 Ferroussulphate,monohydrate. 12 A.2.3 Ferroussulphate,heptahydrate .12 A.2.4 Ferricsalts 12 A.3 Calciumsalts. .13 A.3
13、.1 General13 A.3.2 Calciumoxide. 13 A.3.3 Calciumhydroxide. 13 Bibliography 14EN1225513:2002(E) 3 Foreword Thisdocument(EN1225513:2002)hasbeenpreparedbyTechnicalCommitteeCEN /TC 165“Wastewater engineering“,thesecretariatofwhichisheldbyDIN. ThisEuropeanStandard shallbegiventhestatusofanationalstandar
14、d,eitherbypublicationofanidenticaltextor byendorsement,atthelatestbyJune2003,andconflictingnationalstandardsshallbewithdrawnatthelatestby June2003. ItisthethirteenthpartpreparedbytheWorkingGroupsCEN/TC165/WG42and43relatingtothegeneral requirementsandprocessesforwastewatertreatmentplantsforatotalnumb
15、erofinhabitantsandpopulation equivalents(PT)over50.Thepartsoftheseriesareasfollows: Part1:Generalconstructionprinciples Part3:Preliminarytreatment Part4:Primarysettlement Part5:Lagooningprocesses Part6:Activatedsludgeprocess Part7:Biologicalfixedfilmreactors Part8:Sludgetreatmentandstorage Part9:Odo
16、urcontrolandventilation Part10:Safetyprinciples Part11:Generaldatarequired Part12:Controlandautomation Part13:ChemicaltreatmentTreatmentofwastewaterbyprecipitation/flocculation Part14:Disinfection Part15:Measurementoftheoxygentransferincleanwaterinactivatedsludgeaerationtanks Part16:Physical(mechani
17、cal)filtration 1) NOTE Forrequirementsonpumpinginstallationsatwastewatertreatmentplants,providedinitiallyaspart2“Pumping installationsforwastewatertreatmentplants“,seeEN7526“DrainandsewersystemsoutsidebuildingsPart6:Pumping installations. ThepartsEN122551,EN122553toEN122558andEN1225510andEN1225511we
18、reimplemented togetherasaEuropeanpackage(ResolutionBT152/1998). WARNING TheuseofthisEuropeanStandardmayinvolvehazardousmaterials,operationsand equipment.ThisEuropeanStandarddoesnotpurporttoaddressallofthesafetyproblemsassociatedwith itsuse.ItistheresponsibilityoftheuserofthisEuropeanStandardtoestabl
19、ishappropriatesafetyand healthpracticesanddeterminetheapplicabilityofregularitylimitationspriortouse(seealsoEN1225510). AnnexAisnormative. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,Cze
20、chRepublic,Denmark,Finland, France,Germany,Greece,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain, Sweden,SwitzerlandandtheUnitedKingdom. 1) inpreparationEN1225513:2002(E) 4 1Scope ThisEuropeanStandardspecifiestherequirementsforchemicaltreatmentofwastewaterby precipitation/f
21、locculationforremovalofphosphorusandsuspendedsolids. TheapplicationofpolymersisnotdescribedinthisEuropeanStandard. DifferencesinwastewatertreatmentthroughoutEuropehaveledtoavarietyofpracticesbeingdeveloped.This standardgivesfundamentalinformationaboutthepractices;thisstandardhasnotattemptedtospecify
22、allavailable practices. Detailedinformationadditionaltothatcontainedinthisstandardmaybeobtainedbyreferringtothebibliography. 2 Normativereferences ThisEuropeanStandardincorporatesbydatedorundatedreference,provisionsfromotherpublications.These normativereferencesarecitedattheappropriateplacesinthetex
23、t,andthepublicationsarelistedhereafter.For datedreferences,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplytothisEuropean Standardonlywhenincorporatedinitbyamendmentorrevision.Forundatedreferencesthelatesteditionofthe publicationreferredtoapplies(includingamendments). EN7526, Drainands
24、ewersystemsoutsidebuildingsPart6:Pumpinginstallations. EN1085:1997, WastewatertreatmentVocabulary. EN100882, StainlesssteelsPart2:Technicaldeliveryconditionsforsheet/plateandstripforgeneralpurposes. EN122551, WastewatertreatmentplantsPart1:Generalconstructionprinciples. EN122556, Wastewatertreatment
25、plantsPart6:Activatedsludgeprocess. EN1225511, WastewatertreatmentplantsPart11:Generaldatarequired. EN12518:2000, ChemicalsusedfortreatmentofwaterintendedforhumanconsumptionHighcalciumlime. 3 Termsanddefinitions ForthepurposesofthisEuropeanStandard,thetermsanddefinitionsgiveninEN1085:1997andEN12518:
26、2000 andthefollowingapply. 3.1 chemicaltreatmentofwastewater treatmentofwastewaterbychemicalcoagulation/precipitationwithmetalsalts(includinglime)ororganicpolymers inordertoremoveinorganicandorganicphosphoruscompoundsandsuspendedsolidsandcolloidsEN1225513:2002(E) 5 4Requirements 4.1General Chemicalt
27、reatmentofwastewatercanbedividedintotwoprocesses:areactionphase,thatconsistsof precipitationofdissolvedphosphates,destabilisationofcolloidsandtheformationofflocs,andaseparationphase, inwhichtheflocsareseparatedfromthewater. Thereactorsandflocseparators(sedimentationtanks,flotationunitsetc.)fortheche
28、micaltreatmentcanbe integratedwiththeotherpartsofthewastewatertreatmentplant(preprecipitation,simultaneousprecipitation,see 4.2.2.2and4.2.2.3)orbeaseparatepartofthetreatmentplant(postprecipitation,directprecipitation). Thewaterlevelinthechemicalreactorsandtanksmaybecontrolledbyfixedoradjustableweirs
29、.Itisparticularly importantwheretherearemultipleparallelreactors. ThedesignoftheprocessshalltakeintoaccountvariationsinflowandloadasstipulatedinEN122551and EN1225511. 4.2 Chemicalbackgroundandprocessoptions 4.2.1 Chemicalprocess Inordertoobtaincoagulation/precipitationacationicchemicalhastobeaddedto
30、thewastewater.Mostcommonly thisisasaltofaluminiumoriron.Limemayalsobeused.Ifonlycoagulation(removalofparticles)isaimedat,a cationicpolymermaybeaddedaloneorinadditiontoametalsalt. Phosphoruscanbepresentinthewastewaterinthefollowingforms: a) organicallyboundphosphorus, b)inorganic phosphorus, polyphos
31、phate, orthophosphate. Polyphosphatesareeventuallyconvertedtoorthophosphatesandtheorganicallyboundphosphorusisconverted toorthophosphateduringbiologicaltreatment. Inprimarytreatment,phosphorusfixedtosettleableparticlesisremoved(5 %to15 %ofthetotalinfluent phosphorusdependingonthecharacterofthewastew
32、ater).Inthebiologicaltreatmentacertainamountof phosphorusisconsumedatthemicrobialsynthesisofnewcellularmaterial(10 %to30 %oftheinfluent phosphorus).Byintroducingananaerobicstagewherevolatilefattyacidsareproducedandphosphatesare releasedanincreasedbiologicalremovaloftotalphosphoruscanbereachedwithout
33、additionofchemicals (60%to90%oftheinfluentconcentration). Inthechemicalprecipitation,aprecipitationagent(suchasaluminiumsulphate,ferroussulphate,ferricchlorideor calciumhydroxide)isaddedtothewastewater.Theorthophosphatephosphorusisprecipitatedasmetal orthophosphate.Al 3+ andFe 3+ alsoformcolloidalhy
34、droxides.ThesolubilityoftheprecipitatesispHdependent. Organicpolyelectrolytesareusedasflocculationagentsforcolloidalandsuspendedmatter. Chemicalcoagulation/precipitationcanbecarriedoutinsixdifferentways,namely direct precipitation, preprecipitation,EN1225513:2002(E) 6 simultaneous precipitation, pos
35、tprecipitation, multipoint precipitation, precipitation on filters. 4.2.2 Precipitationprocesses 4.2.2.1 Directprecipitation Directprecipitationisusedinwastewatertreatmentplantswithoutabiologicalstage. Inadirectprecipitationplant,theprecipitationagentshouldbeaddedafterthepreliminarystage(screen,grit
36、 chamberandpossiblyaprimarysettlementtank). Theprecipitationagentshouldbeaddedinawaythatassuresrapidandcompletemixingofthechemical. Aftermixingflocculationtakesplaceinaflocculationtank.Thechemicalflocsarethenseparatedinafinal sedimentationtankoranotherflocseparationdevice. 4.2.2.2Preprecipitation Pr
37、eprecipitationcanbeusedinwastewatertreatmentplantshavingbothmechanicalandbiologicaltreatment. Withpreprecipitation,theadditionoftheprecipitationagentiseffectedbeforethebiologicalstage,oftenbeforethe aeratedgritchamber,preaerationtanks,orflocculationtanks.Thechemicalflocsareseparatedtogetherwiththe p
38、rimarysludgeintheprimarysettlementtanks. Chemicalflocswhicharenotremovedintheprimarysettlementtankaretransportedwiththewastewaterand separatedinthesecondarysettlementtanktogetherwiththebiologicalsludge. 4.2.2.3 Simultaneousprecipitation Simultaneousprecipitationcanbeusedinwastewatertreatmentplantswi
39、thbiologicaltreatmentdependingonthe activatedsludgeprocessused. Withsimultaneousprecipitationtheadditionoftheprecipitationagentiseffectedintheaerationtank,attheendof theaerationtankortogetherwiththereturnsludge,wherebothabiologicalandachemicalprocesstakesplace. Themixedbiologicalandchemicalsludgeiss
40、eparatedinthesecondarysettlementtankoraflotationunit.The returnsludge,theexcesssludgeandthemixedliquorsuspendedsolidscontainalargerpartofinorganicmaterial ascomparedtothesludgesinanormalactivatedsludgeplant. 4.2.2.4Postprecipitation Postprecipitationcanbeusedinwastewatertreatmentplantswithbiological
41、treatment(activatedsludge,trickling filteretc.). Withpostprecipitationtheadditionoftheprecipitationagentisdoneinamixingtankafterthesecondary settlement.Flocformationtakesplaceinaflocculationtankfollowedbyafinalclarificationtankwherethechemical sludgeisseparated.Alternativelylamellasedimentationorflo
42、tationcanbeusedforseparation. 4.2.2.5 Multipointprecipitation Theefficiencyoftheprecipitationmaybeincreasedbyaddingthechemicalsattwoorthreedifferentpoints,e.g. thegritchamber,theaerationtank,thefinalsandfilter.EN1225513:2002(E) 7 4.2.2.6 Precipitationonphysicalfilters Precipitationonfiltersisnormall
43、yacomplementtobiologicalphosphorusremovalortoapreprecipitationora simultaneousprecipitation.Thechemicalisaddedinthechannelorpipeleadingtothefilter.Aneffectivemixing shallbearranged. 4.2.3 Selectionofprecipitationchemicals DetailsofchemicalsoftenusedaregiveninannexA.Apartfromthatsomewasteproductsorbyproductsand productsreadyforusecanbeusedasprecipitationorflocculationchemicals. Carefulconsiderationoftheheavymetalconcentrationandotherpollutantsshallbemade. NOTE Detailsaboutlimitscanbeobtainedfromrelevan
