活性污泥体系中C/N/S对硝酸盐还原过程的影响

采用序批式活性污泥反应器（ASBR），通过调整进水C/N和S/N，在活性污泥体系中探究电子受体有限的条件下，不同电子供体（有机物或者S^2-）对反硝化和硝酸盐氮异化还原成铵（DNRA）过程的影响.结果表明：较高的C/N进水条件，有利于反硝化过程的进行；而较高的S/N进水条件，更有利于DNRA过程的发生；DNRA过程的特征产物NH₄⁺-N，在C/N/S=2：2：3、2：2：4条件下的出水中较明显，其中C/N/S=2：2：4条件下，NH₄⁺-N浓度达到最高为10.65mg/L.说明在电子受体有限时，过量的电子供体可促使反硝化向DNRA过程转变.采用16SrRNA分子生物学技术对不同C/N/S下的微生物菌群结构进行分析，发现与氮还原相关的Proteobacteria、Anaerolineae、Bacteroidia、Actinobacteria等菌群丰度较高，且Actinobacteria菌与DNRA过程相关.不同电子供体环境下氮转移途径的研究可为污水处理过程中碳，氮，硫的同步去除提供指导.

Effect of C/N/S on nitrate reduction process in activated sludge system

The effect of different electron donors (organics or S^2-) on denitrification and nitrate nitrogen reduction to ammonium (DNRA) was explored by adjusting inlet C/N and S/N ratios in an activated sequencing batch reactor (ASBR). The results showed that higher C/N ratios improved denitrification process, while higher S/N ratios were more beneficial to DNRA process. NH₄⁺-N, the characteristic product of DNRA, greatly yielded when C/N/S were 2:2:3 and 2:2:4, with the highest effluent NH₄⁺-N concentration of 10.65mg/L at C/N/S of 2:2:4. It indicated that when the electron acceptor was limited, the excess electron donor could increase the activity of DNRA and promote the conversion of denitrification to the DNRA process. 16SrRNA microbiological analysis clarified that Proteobacteria, Anaerolineae, Bacteroidia as well as Actinobacteria were closely related with nitrate reduction process, and Actinobacteria was corelated with the DNRA. Overall, this study provided alternative strategies for the simultaneous removal of carbon, nitrogen, and sulfur in the sewage treatment process.