Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three differ...Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three different pathways,i.e.,the ammonia oxidizing bacteria(AOB)denitrification,the hydroxylamine(NH2 OH)oxidation and heterotrophic denitrifiers denitrification.N2O emission data vary significantly because of the different operational conditions,bioreactor configurations,monitoring systems and quantitative methods.Under the common operational parameter scopes of PNA,N2O emission via NH2 OH oxidation dominates at relatively low dissolved oxygen(DO),low inorganic carbon(IC),high pH or low N02-concentration,while N2O emission via AOB denitrification dominates at relative higher DO,higher IC.lower pH or higher N2O-concentration.AOB are highly enriched while nitriteoxidizing bacteria(NOB)are rarely found in partial nitritation process,and the order Nitrosomonadales of AOB is the dominant group and N2O producer.Anammox bacteria,AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process,the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria.In one-stage PNA reactors,anammox bacteria account for a large fraction of the biomass,AOB account for small portion,and NOB account for even less.The microbial community,diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors.The dominant anammox bacteria,AOB and NOB in PNA are the species Candidatus Brocadia,the genera of Nitrotoga,Nitrospira and Nitrobacter,and the genus Nitrosomonas,respectively.The relations between N2O emission pathways and microbial communities need further study in the future.展开更多
基于目前短程硝化–厌氧氨氧化(partial nitritation and anammox, PN/A)工艺处理城镇污水中反应器运行不稳定和氮去除负荷低的问题,本文设计一种新型复合生物反应器:序批式–折流板–分置膜生物反应器(sequencingbatch-baffled-separat...基于目前短程硝化–厌氧氨氧化(partial nitritation and anammox, PN/A)工艺处理城镇污水中反应器运行不稳定和氮去除负荷低的问题,本文设计一种新型复合生物反应器:序批式–折流板–分置膜生物反应器(sequencingbatch-baffled-separatemembranebioreactor,SASMBR)。将该反应器应用于PN/A工艺处理城镇污水,探究反应器的性能,并对SASMBR运行PN/A工艺的运行成本进行分析。结果表明,采用SASMBR反应器运行PN/A工艺处理城镇污水,能够实现高效稳定的脱氮效果,TN去除率达到80%~85%,氮素去除负荷(nitrogenremovalrate,NRR)达到0.20~0.22kgN/(m-3·d-1),出水TN浓度维持在8 mg/L以下。16SrRNA基因测序分析发现,短程硝化SASMBR反应器内设置的折流板能够富集氨氧化细菌(ammoniaoxidationbacteria,AOB),确保短程硝化SASMBR反应器的良好性能;厌氧氨氧化SASMBR内固定在折流板两侧的无纺布可以有效地持留厌氧氨氧化菌(ammoniumoxidizingbacteria,AnAOB),同时,厌氧氨氧化SASMBR内丰度升高的AOB可以为AnAOB提供生长的厌氧环境和NO2--N基质,使厌氧氨氧化SASMBR反应器能够快速启动和高效稳定运行。SASMBR的运行成本为0.037元/m3,比传统城镇污水处理厂的运行成本大幅度降低。展开更多
基金supported by the National Major Science and Technology Program for Water Pollution Control and Treatment (Nos. 2017ZX07401003-05-01, 2014ZX07216-001)China Scholarship Council Foundation (No. 2011911098)
文摘Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three different pathways,i.e.,the ammonia oxidizing bacteria(AOB)denitrification,the hydroxylamine(NH2 OH)oxidation and heterotrophic denitrifiers denitrification.N2O emission data vary significantly because of the different operational conditions,bioreactor configurations,monitoring systems and quantitative methods.Under the common operational parameter scopes of PNA,N2O emission via NH2 OH oxidation dominates at relatively low dissolved oxygen(DO),low inorganic carbon(IC),high pH or low N02-concentration,while N2O emission via AOB denitrification dominates at relative higher DO,higher IC.lower pH or higher N2O-concentration.AOB are highly enriched while nitriteoxidizing bacteria(NOB)are rarely found in partial nitritation process,and the order Nitrosomonadales of AOB is the dominant group and N2O producer.Anammox bacteria,AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process,the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria.In one-stage PNA reactors,anammox bacteria account for a large fraction of the biomass,AOB account for small portion,and NOB account for even less.The microbial community,diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors.The dominant anammox bacteria,AOB and NOB in PNA are the species Candidatus Brocadia,the genera of Nitrotoga,Nitrospira and Nitrobacter,and the genus Nitrosomonas,respectively.The relations between N2O emission pathways and microbial communities need further study in the future.
