好氧颗粒污泥的培养过程

附件2论文中英文摘要作者姓名：倪丙杰论文题目：好氧颗粒污泥的培养过程、作用机制及数学模拟作者简介：倪丙杰，男，1981年11月出生，2006年9月师从于中国科学技术大学俞汉青教授，于2009年7月获博士学位。中文摘要好氧颗粒污泥是活性污泥微生物通过自固定最终形成的结构紧凑、外形规则的生物聚集体。它具有相对密实的微观结构、优良的沉淀性能、较高浓度的生物体截留和多样的微生物种群。因此，好氧颗粒污泥技术作为一种新型的废水生物处理形式，在城市污水和工业废水处理中具有非常广阔的应用前景。好氧颗粒污泥的形成过程非常复杂，它的作用机制涉及到微生物的生长与竞争、氧的传质、底物的扩散及微生物产物的形成等各个方面。本论文系统地研究了好氧颗粒污泥的形成过程、作用机制和数学模拟，探索了颗粒污泥在好氧和缺氧条件下的胞内储存过程机理，深入阐明了颗粒污泥中胞外聚合物和溶解性微生物产物的形成规律，并首次成功地以低有机物浓度城市污水为基质在中试规模反应器中培养出性能优良的好氧颗粒污泥。主要研究内容和研究结果如下：分别采用豆制品加工废水和混合酸废水在SBR反应器中培养好氧颗粒污泥，基于实验结果和形成机理的分析，实现了好氧颗粒污泥形成过程的定量描述。粒污泥在形成过程中粒径逐渐增大，沉降速度提高到40mh-1,污泥体积指数SVI减小至20mLg〔，COD去除效率高于98%；模型能够很好地定量描述好氧颗粒污泥的形成过程及基质在颗粒内部的扩散；好氧颗粒污泥的形成过程可分为适应期、快速生长期和成熟期。通过好氧颗粒污泥的间歇实验，探索了颗粒中自养微生物和异养微生物的生长与竞争；根据实验结果修正了ASM3模型，用以描述好氧颗粒SBR反应器中自养菌和异养菌的同时生长，并分析两类微生物对于溶解氧的竞争和在颗粒中的空间分布；发现氨氮和COD在颗粒SBR反应器运行周期的前1.5小时内分别被自养菌和异养菌消耗完毕，且异养菌消耗更多的溶解氧；自养菌主要位于颗粒的外层，而异养菌则分布于颗粒的外层或者中心。通过McCarty建立的生物热能学方法估算出活性污泥的微生物产率，分析了反应器中关键化学和生物组分的总体计量学；与生化反应和电子平衡相耦合，建立了分析反应器中各种重要化学组分的动态变化的热力学新方法，并同修正后的ASM1模型相结合，解析了豆制品废水活性污泥处理系统中C16H24O5N4、CH20、细胞(C5H7O2N)、H+、NH4+、HCO3「和C02浓度的动态变化规律。通过不同初始条件下的颗粒污泥储存实验，探索了好氧条件下颗粒污泥的胞内储存机制和电子转移途径，实现了好氧颗粒污泥胞内储存过程的准确描述。当系统中外源底物过剩时，底物被微生物快速利用并形成一定量的储存物质；在外源底物消耗完之后，微生物则会利用胞内储存物质进行生长。采用好氧和缺氧条件下的呼吸速率实验结果对反硝化条件下颗粒污泥的储存机理进行了探索，发现其生化机理过程主要包括反硝化条件下的水解、缺氧同时储存和生长、缺氧维持以及生物衰减。动力学分析结果表明，好氧颗粒污泥的反硝化胞内储存过程NUR包括4个不同的硝酸盐利用线性阶段；根据缺氧储存机理，建立了缺氧校正系数的估算方法，并解析出好氧颗粒污泥在反硝化条件下的胞内储存过程。采用凝胶渗透色谱(GPC)和三维荧光光谱(EEM)对活性污泥胞外多聚物(EPS)的产生过程进行了表征。EPS的形成量及其组分分子量分布依赖于外源底物的利用， EPS量在底物利用过程中逐渐增加；EPS中的荧光物质主成分有两种:最大激发发射波长位于280/340nm的蛋白类物质和最大激发发射波长位于320/400nm的类富里酸物质。提出了一套估算活性污泥EPS形成动力学参数的新方法。在该方法中利用非线性最小二乘法建立目标函数，而采用蒙特卡罗法优化目标函数；参数估计结果表明，此方法能够准确、简便地获得活性污泥微生物降解有机物过程中 EPS的形成动力学参数值及其相应的可靠性信息；外源底物电子的分布途径为：61%的电子用于细胞生物量的合成，21%的电子转移到电子受体溶解氧用于生物呼吸产生能量，而剩下的 18%的电子则用于EPS的形成。集成运用凝胶渗透色谱、耗氧速率分析、多糖和蛋白测定、三维荧光光谱、傅立叶变换红外光谱和溶解性有机碳测定等技术，全面分析了活性污泥SMP的分子量分布、化学特性及其分类，对污泥微生物降解底物过程中SMP的形成及其分类划分进行了定性和定量研究。发现UAP产生于底物利用阶段，其分子量低于290kDa,而BAP为290-5000kDa范围内的生物大分子物质，BAP则可进一步分为生长相关BAP(GBAP)和内源相关BAP(EBAP)。提出了分析SMP、UAP和BAP产生动力学的新方法，并建立了描述SMP形成过程及其划分的数学模型。基于底物利用积分方程分别建立了UAP和BAP目标函数，运用规划求解法优化目标函数使其最小化，从而得到活性污泥SMP形成的相关速率系数、Ks、kBAP以及产率系数Yh、kuAP的最佳估计值；在此基础上描述了3种SMP的产生与底物利用之间的联系以及SMP的形成机理。采用实验分析和数学模拟相结合的方法阐明了好氧颗粒污泥系统中 EPS、SMP和XSTO的形成和消耗过程，在将这3种不同微生物代谢产物的电子转移途径相耦合的基础上，建立一套统一的EPS、SMP和XSTO的形成动力学模型，分析了反应器污泥停留时间(SRT)对EPS、SMP和XSTO形成的影响，并提出了基于EPS、SMP和XSTO动力学模型调控颗粒反应器的新方法。对好氧颗粒污泥自养菌微生物产物的产生规律、成分特性及数学模拟进行了系统的研究，阐明了自养菌微生物代谢产物的形成机理，并对自养微生物体系中产生的EPS和SMP进行了表征；探索了自养微生物体系中异养微生物利用自养微生物代谢产物的生长规律；发现NoB在好氧条件下以亚硝酸盐作为电子供体进行生长，并产生新的NoB细胞、UAP、EPS和硝酸盐；这些自养微生物的代谢产物是自养体系中异养菌细胞合成的唯一电子供体来源。首次利用低浓度实际城市污水在中试规模反应器中培养出性能优良的好氧颗粒污泥，探索了低浓度有机废水作为底物条件时污泥颗粒化的关键因素，并且实现了中试颗粒污泥反应器的数学模拟。好氧颗粒污泥粒径适中、沉降性良好、生物活性高；颗粒污泥主要以丝状菌为骨架，由结构密实地杆状细菌和球菌组成；分析表明体积交换率和沉降时间是低浓度废水条件下SBR反应器中污泥颗粒化的关键参数。采用好氧颗粒污泥为接种物，在上流式厌氧污泥反应器(UASB)中实现厌氧氨氧化(ANAMMoX)过程的快速启动，并对所形成ANAMMoX颗粒污泥的结构和物化特性以及反应器运行工况进行表征；在此基础上，采用16SrRNA基因扩增和PCR-DGGE等分子生物学技术对启动过程中颗粒污泥的微生物种群结构变化进行定量分析，为拓展好氧颗粒污泥的应用领域提供了新的思路。关键词：好氧颗粒污泥；数学模拟；微生物产物；序批式反应器(SBR)；中试颗粒污泥反应器Formationprocess,functionmechanismandmathematicalmodelingof

theaerobicgranularsludgeNiBing-JieABSTRACTAerobicgranularsludgeisatypeofmicrobialaggregatethroughself-immobilizationandgranulationofthemicroorganismsinactivatedsludge.Aerobicgranuleusuallyhasregularshape,goodsettlingability,compactstructure,highbiomassretention,anddiversityofmicrobialpopulation.Itensuresahighersubstrateremovalefficiency,lessexcesssludgedisposal,lessareaconsumptionandlowercostsforcapitalconstruction,comparedwithactivatedsludgeflocs.Therefore,thisprocesshasbeenregardedasapromisingwastewatertreatmentsystem.However,aerobicgranulationisaverycomplexphenomenon.Therearenumerousinternalinteractionsamongprocessvariables,suchasgrowth,storage,microbialproductsformationandendogenousrespiration,andsludgecharacteristics,includingbiomassdetachment,oxygentransferanddiffusion.Inthisthesis,theformation,thefunctionmechanismandthemathematicalmodelingofaerobicgranularsludgeweresystematicallyexplored.Thestorageprocessesofaerobicgranulesunderbothaerobicandanoxicconditionswereinvestigated.Theproductionofextracellularpolymericsubstances(EPS)andsolublemicrobialproducts(SMP)inaerobicgranularsludgewerealsoexplored.Furthermore,thisworkwasthefirstattempttocultivateaerobicgranulesonlow-strengthmunicipalwastewaterinapilot-scalesequencingbatchreactor(SBR).Maincontentsandresultsareasfollows:AerobicgranulesweresuccessfullycultivatedinSBRsfedwithbothsoybean-processingandfatty-acids-richwastewaters.Basedonexperimentalobservationsandformationmechanismanalysis,theaerobicgranulationprocessintermsofmeanradiusprofileswasquantitativelycharacterized.Inthegranulationprocess,themeandiameterofbioparticlesgraduallyincreased.Theirsettlingvelocityincreasedto40mh-1whiletheirsludgevolumeindex(SVI)decreasedto-i20mLg.Thechemicaloxygendemand(COD)removalefficiencyincreasedto98%.Thedevelopedmodelisapplicabletodescribingtheaerobicsludgegranulationprocessandsubstratediffusionwithingranulesappropriately.Threephasesinthegranuleformationprocesscouldbeclearlydistinguished:initialexponentialgrowthphase,lineargrowthphaseafterwardsandfinalstablephase.Theautotrophicandheterotrophicgrowthandcompetitioninaerobicgranularsludgewereexploredusingabatchexperimentalapproach.TheactivatedsludgemodelNo.3(ASM3)wasmodifiedbasedonexperimentalresultsinordertodescribethesimultaneousautotrophicandheterotrophicgrowthinaerobicgranules.Thedistributionwithingranulesandcompetitionfordissolvedoxygenofautotrophsandheterotrophswereanalyzed.ItwasfoundthatfulloxidationofammoniaandCODbyautotrophsandheterotrophsoccurredwithin1.5h.Theheterotrophsaccountedformajoroxygenconsumptionthantheautotrophs.Theautotrophsweremainlylocatedontheouterlayerofgranules,whereastheheterotrophswerepresentinthecenterofgranules,orontheouterlayerofgranules.WiththebioenergeticmethodologyestablishedbyMcCarty,themicrobialyieldwaspredictedandtheoverallstoichiometricsforbiologicalreactionsinvolvingthekeychemicalandbiologicalspeciesinactivatedsludgewereestablished.ThebioenergeticmethodologywasintegratedwithamodifiedactivatedsludgemodelNo.1(ASM1)toformulateanewapproachtoanalyzetheactivatedsludgeprocess,withthetreatmentofsoybean-processingwastewaterasanexample.ThisapproachwasabletoapproximatelydescribethetreatmentofsoybeanwastewaterbyactivatedsludgeintermsoftheconcentrationdynamicsofC16H24O5N4,CH2O,cell(C5H7O2N),H+,+NH4+,HCO3-andCO2.Theinternalstoragemechanismsandelectronflowsfromtheexternalsubstrateoccurringinaerobicgranulesludgewereexploredwithextensivestorageexperimentsunderdifferentinitialconditions.Thesimultaneousgrowthandstorageprocessesinaerobicgranuleswereaccuratelymodeled.AerobicgranulesinanSBRweresubjectedtoalternativefeastandfamineconditions,andwereabletorapidlytakeupcarbonsubstrateinwastewaterandtostoreitasintracellularstorageproductswhenthesubstratewasinexcesAs.fterthedepletionoftheexternalsubstrate,theaccumulatedstoragepolymerwasutilizedforheterotrophicgrowth.Theinternalstoragemechanismsinaerobicgranulesludgeunderanoxicconditionswereinvestigatedwithrespirometricexperimentalresults.Hydrolysis,simultaneousanoxicstorageandgrowth,anoxicmaintenance,andendogenousdecaywerefoundtobethemainbioreactionprocessesgoverningtheanoxicstorageintheaerobicgranules.Kineticanalysisofnitrateutilizationrate(NUR)indicatesthattheNURofgranules-baseddenitrificationprocessincludedfourlinearphasesofnitratereduction.Furthermore,themethodologyfordeterminingthemostimportantparameterinanoxicstorage,i.e.,anoxicreductionfactor,wasestablishedbasedonananalysisofanoxicstoragemechanisms.Theperformanceofstorageprocessinagranule-baseddenitrificationsystemwasaccuratelymodeled.EPSproducedbymixedmicrobialcommunitywerecharacterizedusinggel-permeatingchromatography(GPC)and3-dimensionalexcitationemissionmatrix(EEM)fluorescencespectroscopymeasurement.TheproductionofEPS,aswellasitsmolecularweight(MW),dependedontheexternalsubstrateutilization.ThequantityofproducedEPSincreasessignificantlyinthesubstrateutilizationprocess.Withtheparallelfactoranalysis(PARAFAC)approach,twocomponentsofthepolymermatrixareidentifiedbytheEEManalysis,oneasproteinsatEx/Em280/340nmandonematrixassociatedasfulvic-acid-likesubstancesat320/400nm.AnovelandconvenientapproachtoevaluatetheEPSproductionkineticswasdeveloped.Theweightedleast-squaresanalysiswasemployedtocalculateapproximatedifferencesinEPSconcentrationbetweenmodelpredictionsandexperimentalresults.AniterativesearchroutineinMonteCarlosimulationwasutilizedforoptimizingtheobjectivefunctionbyminimizingthesumofsquaredweightederrors.ParametersestimationresultsindicatethatthekineticcoefficientsofEPSproductionbyactivatedsludgeandtheirpracticalidentifiabilityinformationcouldbeobtainedaccuratelyandconvenientlywiththisapproach.Electronsfromtheexternalsubstrateweredistributedinthefollowingorder:newbiomasssynthesisof61%,oxygenforrespirationof21%,andEPSof18%.Thesub-fractionsoftheSMP,i.e.,utilization-associatedproducts(UAP)andbiomass-associatedproducts(BAP),excretedbyactivatedsludgewerecharacterizedintermsofformationsequence,MWandchemicalnatures,usingMWanddissolvedorganiccarbon(DOC)measurements,coupledwithoxygenutilizationratedetermination,polysaccharideandproteinmeasurement,3-dimensionalEEMfluorescencespectroscopyandFouriertransforminfraredspectroscopy(FTIR)analysis.TheUAP,producedinthesubstrateutilizationprocess,werefoundtobecarbonaceouscompoundswithanMWlowerthan290kDa.TheBAPweremainlycellularmacromoleculeswithanMWinarangeof290-5000kDa,andwerefurtherclassifiedintothegrowth-associatedBAP(GBAP)andtheendogeny-associatedBAP(EBAP).AnewapproachfordeterminatingSMP,UAPandBAPandtheirproductionkineticswasestablished.Amathematicalmodelwasdevelopedtofurtherquantitativelyandqualitativelydescribetheproductionkineticsandsub-fractionationofSMP.TheobjectivefunctionsofUAPandBAPwereconstructedbasedontheintegratedsubstrateutilizationequation.Aspreadsheetprogramwasutilizedtooptimizetheobjectivefunctionbyminimizingthesumofsquaredweightederrors.Inthisway,thebestestimationsoftheratecoefficients曲,KSandkBAPandthetwoyieldcoefficientsforactivebacteria(YH)andUAP(kUAP)weredetermined.Furthermore,therelationshipsamongtheformationofthethreesub-fractionsoftheSMPandthesubstrateutilization,aswellastheSMPformationmechanisms,wereelucidated.TheformationofEPS,SMPandinternalstorageproducts(XSTO)inaerobicgranularsludgewasinvestigatedusingexperimentalandmodelingapproaches.AnexpandedunifiedmodeldescribingtheproductionandtheconsumptionofEPS,SMP,andXSTOwasformulatedafterintegratingtheelectronflowsfromtheexternalsubstratetoEPS,SMP,andXSTO.Theeffectofthesludgeretentiontime(SRT)ofthereactorontheformationofEPS,SMP,andXSTOintheaerobicgranularsludgewasanalyzed.Thenewmodelcouldbeusedforprocesscontrolandthusfortheoptimizationofaerobic-granule-basedreactors.Theformationmechanism,componentcharacterization,andmathematicalmodelingofthemicrobialproductsofautotrophsintheaerobicgranularsludgewereinvestigatedsystemically.TheformationmechanismofEPSandSMPbyautotrophswasclarified.InformationontheMWandchemicalnaturesofmicrobialproductsinthenitrifyingsludgewasexploredusingEEMfluorescencespectroscopyandGPCmeasurement.Theheterotrophicgrowthonthemicrobialproductsinthenitrifyingsludgefeedingwithnon-organiccarbonsourcewasalsoevaluated.TheaerobicgrowthoftheNOBoccurredattheexpenseofnitriteasanelectrondonorandresultedintheproductionofnewbiomass,UAP,EPS,andnitrate.Theseautotrophicmicrobialproductscouldbeutilizedasthesoleelectronsandcarbonsourcefortheheterotrophicgrowthinautotrophicsystems.Forthefirsttime,aerobicgranuleswithanexcellentsettlingabilitywerecultivatedinapilot-scale