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1、An Introduction to Urban Water and Wastewater Treatment Technologies1 1Contents1. Contaminants in Water 2. Contaminant Sources and Treatability 3. Best Available Technologies 4. Trend of Development2 21. Contaminants in Water1.1 Target of Water Quality ControlWastewater Discharge RegulationKey point
2、: Protection of human health 3 31.2 Capacity of Water EnvironmentAsimplecalculationCi : Concentration of contaminant iMi : Mass of contaminant i in waterV : Water volumeMi0 : Mass of contaminant i receivedMir :Mass of contaminant i assimilated (removed) by the water body itself (self purification)4
3、41.2 Capacity of Water EnvironmentWaterqualitycriteriaThisisequivalenttoMirisameasureoftheenvironmentalcapacityCis : Standard for contaminant iMis : Maximum permissible mass of contaminant i in water5 51.3 Water Environmental StandardAmerican standard: Clean Water Act (CWA)uAmbient Water Quality Cri
4、teria for the Protection of Human HealthuAquatic Life CriteriauNutrient Criteria6 61.3 Water Environmental StandardAmerican standard: Clean Water Act (CWA)TheNRWQC 2002includesuCriteriaforprioritytoxicpollutants:120items(15forinorganic,105fororganicpollutants)uCriteriafornonprioritypollutants:45item
5、suCriteriafororganoleptic(tasteandodor)effects:23itemsDownloadableathttp:/www.epa.gov/waterscience/criteria/ wqcriteria.html7 71.3 Water Environmental StandardChinese standard:EnvironmentalQualityStandardsforSurfaceWater(GB3838-2002)uFundamentalparameters(地表水环境质量标准基本项目标准限值):24itemsuSupplementalparam
6、etersforsourcewaterforcommunitywatersupply(集中式生活饮用水地表水源地补充项目标准限值):5itemsuSpecificparametersforsourcewaterforcommunitywatersupply(集中式生活饮用水地表水源地特定项目标准限值):80items8 8表1地表水环境质量标准基本项目标准限值(单位:mg/L)9 9表1地表水环境质量标准基本项目标准限值(单位:mg/L)1010表1地表水环境质量标准基本项目标准限值(单位:mg/L)1111表2集中式生活饮用水地表水源地补充项目标准限值(单位：mg/L)1212表3集中式生活
7、饮用水地表水源地特定项目标准限值(单位：mg/L)1313表3集中式生活饮用水地表水源地特定项目标准限值(单位：mg/L)1414表3集中式生活饮用水地表水源地特定项目标准限值(单位：mg/L)15151.4 Pollutants of Public ConcernIndicative parametersuSuspendedsolids:SSuDissolvedsolids:TDS(salinity)uOrganicsubstances:COD,BOD,TOC,UVuDissolvedoxygen:DOuAcidity:pHNutrientsuNitrogen:TN,NH3-N,NO3-N,
8、NO2-NuPhosphorous:TP,Portho,Ppoly,Poranic16161.4 Pollutants of Public ConcernSynthetic organic chemicals (SOCs)uIndustrialproductssuchasPCBs(Polychlorinatedbiphenyls)uIndustrialbyproductssuchasDioxinuPesticidesandherbicidesDBP precursorsuNaturalorganicmatter(NOM)suchashumicacidsetc.Persistent organi
9、c pollutants (POPs)uDDT,PCBs,PAHs,Hexachlorobenzene,Dioxins,Furans17171.4 Pollutants of Public ConcernEndocrine disruptive chemicals (EDCs) uHeavymetalssuchasCr,Pbetc.uPCBs,hormones,dioxinsuOrgano-chlorinatedpesticidesMicroorganismsuGiardiauCryptosporidiumuVirusesandbacteria18182. Contaminant Source
10、s and Treatability2.1 Contaminant SourcesPoint sources:Sourcesofpollutantsfromadiscretelocationsuchasapipe,tank,pit,orditch.Non-point sources:Sourceofpollutantsfromanumberofpointsthatarespreadoutanddifficulttoidentifyandcontrol.Non-pointsourcesattributeagreatdealtowaterpollution:lNutrients,pesticide
11、s,NOMlCertainPOPsandEDCs19192.2 Treatability of PollutantsThetreatabilityofpollutantsdependsontheirSizelSuspendedlColloidallSolubleChemical propertieslOrganiclInorganicBiodegradabilitylBiodegradablelBio-non-degradable2020Water quality and treatability matrix2121Domestic wastewater as an exampleMetho
12、dsofpollutantsclassificationuSuspended and soluble:usinga0.45mmfilteruSettleable and non-settleable:plainsettlingfor2hoursuCoagulable and non-coagulable:coagulationandsettlinguSecondary treatment:activatedsludgeprocess(oxidationditch)222223232.3 Limitation of Conventional TreatmentConventional treat
13、mentuTypicalprocessforwatertreatment:CoagulationsedimentationfiltrationchlorinationuTypicalprocessforwastewatertreatment(activatedsludgeprocess):Screeningprimarysettlingbiologicalunitsecondarysettlingchlorination24242.3 Limitation of Conventional TreatmentPollutants that can be removeduSuspendedsoli
14、dsuColloidalmatteruBiodegradableorganicmatteruBacteriaandvirusesPollutants that cannot be removeduMostofthedissolvedsolidsuBio-non-degradableorganicmatteruChlorinepersistentmicroorganisms(e.g.Cryptosporidium)25253. Best Available Technologies3.1 Strategic Considerations on the Selection of Available
15、 TechnologiesuConventionaltechnologiesarefundamentaltechnologiesandtheirenhancementshouldbethefirstchoiceuConversionofthepropertyofpollutantsissometimesmoreimportantthanacompleteremovalofthepollutantsuCombinationofdifferenttechnologiesisthekeyforeffectiveremovalofpollutants26263.2 Enhancement of Con
16、ventional TechnologiesEnhanced coagulationuFortheremovalofNOMindrinkingwatertreatmentuFortheenhancementofprimarytreatmentinwastewatertreatmentTakingNOMremovalasanexampleUSEPA Enhanced Coagulation Rule27273.2 Enhancement of Conventional TechnologiesEnhanced coagulationuRequirementsforenhancedcoagulat
17、ion:EnhancedcoagulationrequiredasTOC2mg/LuStep1:percentremovalrequirements2828uStep2:0.3/10slope2929upHadjustmentisthekeypoint30303.2 Enhancement of Conventional TechnologiesEnhanced filtrationuForthesafeguardofdrinkingwaterqualityespeciallythecontrolofGiardiaandCryptosporidiumlGiardialamblia:cystsi
18、ze8-12mmx7-10mmlCryptosporidiumparvum:oosystsize4.5-5mmuFortertiarywastewatertreatmenttoacquirehighqualityeffluent31313.2 Enhancement of Conventional TechnologiesEnhanced filtrationuRelationshipbetweenturbidityandparticlesize3232ExampleofturbidityandCryptosporidiumoocystdata33333.2 Enhancement of Co
19、nventional TechnologiesEnhanced filtrationuIronoxide-coatedmediaforNOMsorptionandparticulatefiltrationuIronandaluminumhydroxide-coatedmediafortheremovalofCryptosporidium3434Breakthrough curves for NOM sorption onto coated sand 3535Zeta potential of uncoated sand and sand coated with iron and aluminu
20、m hydroxide3636Improvement of the removal of Cryptosporidium oocysts in sand filters37373.2 Enhancement of Conventional TechnologiesEnhancement of biological processuFluidizedpelletbed(FPB)bioreactorasanexamplethroughacombinationofphysicochemicalprocessandbiologicalprocesslHRTreducedtolessthan1hourl
21、PrimarysettlingandsecondarysettlingomittedlOrganicremovalequivalenttoactivatedsludgeprocesslHighTPremovalachieved3838Flow diagram of the FPB bioreactor3939 Pellets (granule sludge) formed in the bioreactor SEM image of microbes on the surface of the pellets 4040 Distribution of aerobic and anaerobic
22、 bacteria4141 Removal of SS, COD, TP and TN by the bioreactor42423.3 Ozone and Advanced Oxidation ProcessesReactivity of ozone in aqueous solutionInanaqueoussolution,ozonemayactonvariouscompoundsbylDirectreactionwiththemolecularozonelIndirectreactionwiththeradicalspeciesthatareformedwhenozonedecompo
23、sesinwaterAdvanced oxidationOxidationbyfreeradicalreaction4343Pathways of ozonationPseudo first-order kinetic equation of ozone decomposition4444Ozone decomposition process4545Initiators, promotors, and inhibitors of free-radical reactionsuInitiators:thecompoundscapableofinducingtheformationofasuper
24、oxideionO2-fromanozonemoleculeuPromotors:allorganicandinorganicmoleculescapableofregeneratingtheO2-superoxideanionfromthehydroxylradicaluInhibitors:compoundscapableofconsumingOHradicalswithoutregeneratingthesuperoxideanionO2-4646Mechanism of ozone decomposition4747Ozone decomposition process by hydr
25、operoxide ions4848Ozone decomposition process by UV radiation49493.3 Ozone and Advanced Oxidation ProcessesOzonation of synthetic organic chemicalsTwoozonolysispathwaysofozonation:uDirectattackbyelectrophilicordipolarcycloadditionuIndirectattackbyfree radicalsproducedbyreactionwithwaterandwaterconst
26、ituents5050Kinetics of ozonation of dissolved organic micropollutantsuOzonationpathwaysuLet5151uTheOHradicalsaregeneratedbyozoneattackonorganicandinorganicinitiators,andthereexistsarelationasuThetotaloxidationrateoftheparticularsubstrateicanbewrittenas5252Characteristics of ozonation of organic comp
27、oundsuDecreaseofaromaticityuUnsaturatedstructuretosaturatedstructureuGenerationofintermediateproductsuTotaldegradationoftenneedsveryhighozonedoseandtakeslongertime5353 Example: Ozonation of aromatic compounds54543.3 Ozone and Advanced Oxidation ProcessesOzonation of natural organic matter (NOM)Aquat
28、ichumicsubstances(AHS):uIsolationmethod:microfiltrationofthewaterandadsorptionoforganicsonXAD-8resinatpH=2,followedbyNaOHelutionandseparationbyprecipitationatpH=1.uTwomaingroups:Humic acidprecipitatedfractionFulvic acidremainingpartinthesolution5555Possible reaction of zone consumption in a natural
29、aquatic environment d inhibitorsi initiatorsp promotorss - scavengers5656Ozone action on AHS5757The effects of ozonation on AHSuFormationofhydroxyl,carbonylandcarboxylgroups;uIncreaseofpolarityandhydrophilicity;uLossofdoublebondsandaromaticity;uShiftinthemolecularweightdistributiontowardlower-molecu
30、lar-weightcompounds.5858Py-GC-MS analysis results5959THMs and HPLC analysis results6060Specific UV adsorption (SUVA) as a parameter showing the biodegradability of AHSuTOCorDOC:totalamountoforganiccarbonuUV254:concentrationoforganicswithunsaturatedstructureuSUVA:UV-to-TOCratiowhichrepresentsthefract
31、ionofunsaturatedfunctionalgroupsinunitconcentrationoforganicmatteruHighSUVAvalue:lessbiodegradableuLowSUVAvalue:morebiodegradable61613.4 Membrane TechnologiesSpectrum of impurities in water and applicable filtration processes 62623.4 Membrane TechnologiesMembrane operation63633.4 Membrane Technologi
32、esPressure-driven membrane operationuRO:atleasttwicetheosmoticpressuremustbeexerted5to8MPaforseawateruNF:osmoticbackpressuremuchlowerthanROtypically0.5to1.5MPauUF:operatingpressure50to500kPauMF:operatingpressuresimilartoUF64643.4 Membrane TechnologiesPermeation behavioruDarcyslawuToaccountfortheeffe
33、ctsofosmoticpressure65653.4 Membrane TechnologiesReduction in Permeate FluxRc:resistanceofconcentrationboundarylayerRcp:resistanceofconcentration-polarizationlayerD:diffusivity66663.4 Membrane TechnologiesReduction in Permeate FluxTheaccumulationofmaterialson,in,andnearamembraneinthepresenceofacross
34、flowReductionsinpermeatefluxovertime67673.4 Membrane TechnologiesMechanism of membrane foulinguCakeformationuPoreblockageuAdsorptivefoulinguBiofoulingSEMimageofabiofilmformedonamembrane6868Conventional UF or MF process6969Conventional NF or RO process70703.4 Membrane TechnologiesMembrane bioreactor
35、(MBR)uPrincipleofMBR(a) MBR(b) Membrane for tertiary treatment71713.4 Membrane TechnologiesMembrane bioreactor (MBR)uMBRconfiguration(a) Recirculated MBR(b) Integrated MBR72723.4 Membrane TechnologiesMembrane bioreactor (MBR)uAdvantagesofMBRlGreaterbiomassconcentrationandgreaterloadslHighremovaleffi
36、ciencylLesssludgeproductionlGreaterreliabilityandflexibilityofapplicationlAbilitytoabsorbvariationsandfluctuationsintheappliedhydraulicandorganicloadlCompletecontrolofthesludgeagetoallowthedevelopmentofslow-growingmicroorganisms(suchasnitrifyingbacteria)73734. Trend of Development4.1 Integration of
37、Water and Wastewater SystemFundamental considerationsuWatersupplyandwastewatersystemsaresubsystemsintheseriesofurbanmetabolicsystemofwateruWatersupplyaccordingtothepurposesofuseregardingbothquantityandqualityuDesignofwaterandwastewatersystemsasonecomprehensivewatersystem7474Future urban water system
38、 with application of membrane technology75754.2 Decentralized Systems for Wastewater Treatment and ReusePhilosophy of decentralizationuNon-mixinglGrey water:Largevolumes,CODdiluted,littlenutrients,pathogens,nopharmaceuticals,personalcareproductslBlack water:Littlevolumes,possibilitiestominimisetheme
39、venfurther,highCODandnutrients,pathogens,pharmaceuticalsandhormonesuSeparatetreatmentlTreatmentdependsontheobjectiveuRecoveryofusefulresourceslWater,energy,fertilizer76764.3 Control of Micropollutants in Water and Wastewater TreatmentuControlofpollutantsourceuUtilizationofhybridprocesslAdvancedoxidationandcarbonadsorptionuUtilizationofhybridmembraneprocesslMembrane-powderedactivatedcarbonreactorlIonexchangemembranereactor7777
