不同C/N下SBBR脱氮过程N2O释放及胞外多聚物变化  

Variation of N2O emission and EPS production during simultaneous nitrification and denitrification in SBBR under different C/N ratio

作　　者：巩有奎 赵强[1] 彭永臻[2] GONG Youkui;ZHAO Qiang;PENG Yongzhen(Department of Architecture Engineering,Yantai Vocational College,Yantai 264670,Shandong,China;National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]烟台职业学院建筑工程系,山东烟台264670 [2]北京工业大学城镇污水深度处理与资源化利用技术国家工程实验室,北京100124

出　　处：《化工学报》2019年第12期4847-4855,共9页CIESC Journal

基　　金：国家自然科学基金项目（51508008）;烟职博士科研(2018002)

摘　　要：在(20±2.0)℃条件下,利用序批式生物膜反应器(sequencing batch biofilm reactor,SBBR),考察不同碳氮比(C/N=3.0、5.0、8.0和10.0)下同步脱氮(simultaneous nitrification and denitrification,SND)过程N2O释放及胞外聚合物(extracellular polymeric substance,EPS)变化。C/N由3.0增至10.0,异养菌大量增殖,曝气阶段DO降低,系统硝化性能受到抑制,SBBR系统出水NH4+由0.5 mg/L以下增至(7.85±1.42)mg/L,N2O产量由(2.68±0.17)mg/L降至(1.02±0.12)mg/L。C/N=8.0,TN去除率最大为80.4%±3.5%。反应初期,微生物体内聚β-羟基烷酸酯(PHA)增加,可为后续反硝化过程提供电子供体。AOB好氧反硝化和低氧条件下异养菌反硝化过程均可导致N2O产生。C/N降低,SBBR内部缺氧区域减少,N2O还原过程减弱,释放量增加;C/N增加,N2O扩散进入生物膜内缺氧区域,促进其减量。C/N由3.0增至10.0,微生物EPS分泌由(57.6±5.6)mg/g VSS降至(32.7±3.2)mg/g VSS,其中,TB-EPS含量占65.8%~68.8%。低C/N下,紧密型EPS(TB-EPS)中多糖(PS)含量增加,生物膜更加密实,N2O扩散进入缺氧区阻力增加,释放量增加。At normal temperature of(20±2.0)℃,the characteristics of N2O eimssion and extracellular polymeric substance(EPS)production were studied during simultaneous nitrification and denitrification(SND)process under different C/N ratio(C/N=3.0,5.0,8.0 and 10.0).When C/N increased from 3.0 to 10.0,the heterotrophic bacteria increased rapidly,DO decreased and the nitrification process was inhibited.The effluent NH4+increased from below0.5 mg/L to(7.85±1.42)mg/L,and the N2O emission decreased from(2.68±0.17)mg/L to(1.02±0.12)mg/L.When C/N was 8.0,the maximum total notrogen removal efficiency was 80.4%±3.5%.The accumulation of PHA(poly-β-hydroxyalkanoate)increased firstly and then decreased.Both nitrifier denitrification and heterotrophic denitrification resulted in N2O production.The anoxic area located in the biofilm decreased with the decreasing of C/N ratio,which weakened the denitrification process.With the increase of C/N ratio,N2O diffused into the anoxic region of biofilm can be effectively reduced.The microbial EPS secretion decreased from(57.6±5.6)mg/g VSS to(32.7±3.2)mg/g VSS.The TB-EPS content accounts for 65.8%-68.8%of the total EPS.Under low C/N,the content of polysaccharide(PS)in compact EPS(TB-EPS)increased,the biofilm was more compact,the resistance of N2O diffusion into the anoxic zone increased,and the release increased.

关 键 词：C/N 同步硝化反硝化 N2O 胞外多聚物 

分 类 号：X703.1[环境科学与工程—环境工程]