电流对三维电极生物膜耦合硫自养脱氮工艺的影响

针对污水处理厂尾水TN去除问题,研究了电流对三维电极生物膜耦合硫自养脱氮工艺(3DBER-S)脱氮性能及菌群结构的影响.运行结果表明:在进水pH为7.0~7.5,ρ(NO_3~--N)为35 mg/L,ρ(C)/ρ(N)为1,HRT为12h条件下,电流由60 mA增大到800 mA,NO_3~--N和TN去除率变化不明显,分别稳定在87%和76%左右;随电流增大,体系氢自养反硝化作用所占比例由22.8%逐渐上升到74.4%.基于nirS基因的克隆文库结果表明:3DBER-S中与异养、硫自养和氢自养反硝化功能菌属相似的细菌均占有一定比例;随电流增大,与氢自养反硝化功能菌属相似的细菌所占比例增大.该体系中存在异养、氢自养和硫自养反硝化协同去除硝酸盐氮的作用,维持了稳定高效的脱氮效果,且增大电流利于氢自养反硝化作用的增强.

Influence of Electric Current on Coupling 3-dimensional Biofilm-electrode With Sulfur Autotrophic Denitrification

To strengthen the removal of TN for wastewater treatment plant ( WWTP ) effluent, the performance and bacterial community of a coupling 3-dimensional biofilm-electrode with sulfur autotrophic denitrification technology (3DBER-S) were investigated at different electric current conditions. The operating result indicates that there are no significant impacts of electric current on denitrification performance in 3DBER-S. When electric current increases from 60 to 800 mA at a HRT of 12 h in 3DBER-S, the proportion of hydrogen autotrophic denitrification process increases from 22. 8% to 74. 4%. An average NO3--N and TN removal rate of 87% and 76% respectively is obtained atρ( COD)/ρ( TN) (ρ( C)/ρ( N) ) ratio of 1 and NO3--N concentration of 35 mg/L as well as pH=7. 0-7. 5 in the influent. The nirS gene clone library suggests that the bacteria similar to heterotrophic, hydrogen or sulfur autotrophic denitrifying bacteria occupy a certain proportion respectively in 3DBER-S, and the proportion of the bacteria similar to hydrogen autotrophic denitrifying bacteria increases with electric current increasing. It illustrates that there is a composite among heterotrophic, hydrogen and sulfur autotrophic denitrification process leading to a stable and high-performance nitrogen removal in 3DBER-S, and the increase of electric current contributes to hydrogen autotrophic denitrification.