微氧同步产甲烷反硝化系统颗粒污泥形成特性

Formation characterization of granular sludge in a micro-oxygen system for simultaneous methanogenesis and denitrification

采用微氧改良膨胀颗粒污泥床(EGSB)反应器处理高浓度有机含氮废水(COD 4000 mg/L,NO3--N质量浓度300 mg/L),通过预曝气和逐步缩短水力停留时间(HRT)的方式,经过89 d运行成功培养出具有同步产甲烷反硝化(SMD)功能的颗粒污泥。当HRT为12 h时,甲烷产量可达(9054.9±1261.2)mL/d,同时COD去除率为92.4%±1.5%,TN去除率为88.1%±3.3%,SMD处理效能最佳。污泥由最初的絮状污泥转变为圆润紧实的大粒径颗粒污泥。污泥胞外聚合物(EPS)分析显示,蛋白质和多糖含量显著增加。三维荧光光谱表征发现,成熟微氧颗粒污泥具有旺盛的EPS分泌和代谢能力。高通量测序证实,成熟颗粒污泥中产甲烷菌和反硝化菌均得到了快速增殖。

A micro-oxygen modified expanded granular sludge bed(EGSB)reactor was used to treat high concentration organic nitrogenous wastewater with 4000 mg/L of COD and 300 mg/L of NO3--N mass concentration.The granular sludge with simultaneous methanogenesis and denitrification(SMD)function was successfully developed after 89-day operation through pre-aeration and stepwise reduction of HRT.At an HRT of 12 h,the SMD performance was optimal with the methane production up to(9054.9±1261.2)mL/d,COD removal rate of 92.4%±1.5%,and TN removal rate of 88.1%±3.3%.The sludge was transformed from original flocculated sludge to fruity and tight large-sized granular sludge.Analysis of sludge extracellular polymer(EPS)shows that the content of protein and polysaccharide increased significantly.Three-dimensional fluorescence spectrum(3D-EEM)indicates vigorous EPS secretion and metabolism capacity of the mature microaerobic granular sludge.High-throughput sequencing results confirm the rapid proliferation of both methane-producing and denitrifying bacterial genus in the mature granular sludge.