碳源对地下渗滤系统脱氮及产生N2O的影响

摘要 生活污水经沉淀预处理后投配到地下污水渗滤系统(SWIS)中进行深度脱氮处理.考察了在SWIS基质中添加有机碳源对脱氮效果、脱氮微生物活性及N2O产生量和转化率的影响.研究结果表明:碳源的添加有利于促进微生物的反硝化作用，但过量添加会促进其他菌群的生长而抑制脱氮菌群的优势活性，从而削弱系统的脱氮能力.当有机质质量分数由2.0%提高到9.5%时，SWIS对污水中COD、氨氮及总氮平均去除率分别降低了10.9%，19.5%和24%;N2O产率和转化率均随着碳源添加量的增加而下降.相关分析表明，硝化细菌、反硝化细菌数量对数值分别与N2O转化率呈显著正、负相关关系(R○2分别为0.994及0.959)，说明SWIS中微生物硝化-反硝化作用尤其上层硝化反应是N2O产生的主要途径.
Abstract：Domestic wastewater was infiltrated through a subsurface wastewater infiltration system (SWIS) for depth denitrification treatment after precipitation. Influence of carbon source addition on nitrogen removal， denitrification microbial activity， N2O generation and conversion rate was analyzed. The results showed that carbon source was conductive to the promotion of microbial denitrification， but adding excess would promote substantial growth of other bacterial groups and inhibit the advantages of denitrification activity and nitrogen removal efficiency. When the organic content increased from 2.0% to 9.5%， removal efficiency for COD， NH+4-N and TN decreased by 10.9%， 19.5% and 24%， respectively and N2O generation and conversion rate declined. Correlation analysis showed that the nitrifier and denitrifier quantity exhibited significantly positive and negative correlation with N2O conversion (R2=0.994 and 0.959)， respectively， suggesting that N2O production was the result of the interaction of nitrification and denitrification， and mainly derived from nitrification process in upper layer.