生物膜微环境和传质现象研究进展温沁雪pdf

Macroscaleandmicroscaleanalysesofnitrificationanddenitrificationinbiofilmsattachedonmembraneaeratedbiofilmreactors附着在曝气生物膜反应器中的生物膜硝化和反硝化的宏观与微观分析AbstractAmembraneaeratedbiofilmreactor(MABR),inwhichO2wassuppliedfromthebottomofthebiofilmandNH4+andorganiccarbonweresuppliedfromthebiofilmsurface,wasoperatedatdifferentorganiccarbonloadingrates加载速率andintra-membrane内膜airpressurestoinvestigatetheoccurrenceofsimultaneouschemicaloxygendemand(COD)removal,nitrificationanddenitrification.ThespatialdistributionofnitrificationanddenitrificationzonesinthebiofilmswasmeasuredwithmicroelectrodesforO2,NH4+,NO2,NO3andpH.WhentheMABRwasoperatedatapproximately1.0g-COD/m2/dayofCODloadingrate,simultaneousCODremoval,nitrificationanddenitrificationcouldbeachieved.TheCODloadingratesandtheintra-membraneairpressuresappliedinthisstudyhadnoeffectonthestartupandthemaximumratesofNH4+oxidationintheMABRs.MicroelectrodemeasurementsshowedthatO2WassuppliedfromthebottomoftheMABRbiofilmandpenetratedthewholebiofilm.Becausethebiofilmthicknessincreasedduringtheoperations,ananoxiclayerdevelopedintheupperpartsofthematurebiofilmswhileanoxiclayerwasrestrictedtothedeeperpartsofthebiofilms.Thedevelopmentoftheanoxiczonesinthebiofilmscoincidedwithincreaseinthedenitrificationrates.Nitrificationoccurredinthezonesfrommembranesurfacetoapointofca.60mm.Denitrificationmainlyoccurredjustabovethenitrificationzones.TheCODloadingratesandtheintra-membraneairpressuresappliedinthisstudyhadnoeffectonlocationofthenitrificationanddenitrificationzones.r2004ElsevierLtd.Allrightsreserved.摘要：曝气生物膜反应器（MABR）的氧气是由生物膜的底部提供，铵离子和有机碳由生物膜表层提供。它根据不同的有机碳负荷率和内膜的空气压力来研究同步去除COD，硝化以及反硝化作用的发生。硝化与反硝化区域生物膜的空间分布可以用微电极来测量氧气，铵离子，二氧化氮，硝酸根离子和ph值。当MABR处于适当的COD负荷率（1.0g-COD/m2/d）时，同步去除COD，硝化与反硝化就会实现。研究证明COD负荷率和内膜空气压力在MABR中对铵离子氧化的启动和最大氧化率没有影响。微电极测量说明氧气是由MABR生物膜的底部提供的，而且穿透整个生物膜。因为在操作时增加生物膜厚度，在成熟生物膜上部会形成一个缺氧层，而减小生物膜厚度时，缺氧层会在生物膜比较深的地方形成。生物膜的形成与反硝化速率的增加相一致，硝化反应发生在离膜层表面60mm的区域。反硝化反应主要发生在硝化区域上面。在该研究中，COD的去除和膜内空气压对硝化和反硝化作用的发生区域位置没有影响。Keywords:Membraneaeratedbiofilmreactors;CODremoval;Nitrification;Organiccarbonloadingrate;Intra-membraneairpressure;Microelectrodes关键词：曝气生物膜反应器；COD去除；硝化作用；有机碳去除率；膜内空气压；微电极Conclusions(1)SimultaneousCODremoval,nitrificationanddenitrificationcouldbeachievedintheMABRs.TheefficienciesofnitrificationandCODremovalwere95%and90%,respectively.Theintra-membraneairpressuresappliedinthisstudyhadnoeffectonthestart-upandthemaximumratesofNH4+oxidationintheMABRsatalowCODloadingrate,whereasatahighCODloadingratetheMABRhadtobeoperatedwithahighintra-membraneairpressureforstablenitrification.总结：（1）同步去除COD，硝化和反硝化反应可以在MABR中实现。硝化反应效率为95%，COD去除率为90%。MABR处于较低COD负荷率时，研究表明膜内空气压对铵离子氧化反应的启动和最高氧化率；相反当处于较高COD负荷率时，MABR会发生一个高膜内空气压的稳定硝化反应。(2)MicroelectrodemeasurementsdirectlyrevealedO2profilesintheMABRbiofilms.O2wasdiffusedthroughthemembraneandutilizedbymicroorganismsinthebiofilm.ThedevelopmentofanoxiczonesinthebiofilmscoincidedwiththeincreaseinthedenitrificationratesoftheMABRs.(2)微电极测量可以直接显示MABR生物膜中氧气的剖面结构。氧气利用生物膜中的微生物扩散穿过薄膜。生物膜中缺氧层的形成与MABR中的反硝化速率的增加相一致。(3)MicroelectrodemeasurementsofO2,NH4+,NO2,NO3
andpHinthebiofilmsdemonstratedthatnitrificationoccurredinthezonesfrommembranesurfacetoapointofca.60mmanddenitrificationmainlyoccurredjustabovethenitrificationzones.ThelowCODloadingrates(o1.1g-COD/m2/day)andtheintra-membraneairpressures(0.01and0.04MPa)hadnoeffectonthelocationofthenitrificationanddenitrificationzones.(3)微电极测量出生物膜中的氧气，铵离子，二氧化氮，氧化氮离子以及ph值证明硝化反应发生在距离薄膜表面60mm的区域，而且反硝化反应主要发生在硝化反应上面的区间。较低的COD去除率（o1.1g-COD/m2/day）以及较低膜内空气压（0.01and0.04MPa）对硝化和反硝化作用的区间位置没有任何影响。