生物质-硫磺混合营养反硝化体系对尾水中 NO 3 - -N的去除效果

生活污水经二级处理工艺处理后排放,尾水 NO 3 - -N浓度仍较高。构建了生物质-硫磺混合营养反硝化体系,对其去除 NO 3 - -N的效果进行了研究。静态试验结果表明:木屑-硫磺混合营养反硝化体系能在较短的时间内去除 NO 3 - -N,反应速率常数为0.041 6 d-1,且 NO 2 - -N、 NH 4 + -N转化量低;初始pH为6~9、木屑与硫磺配比为0.5~2.0时,对反硝化过程影响不大,铁屑的添加对体系的pH具有一定的调控作用。动态试验结果表明:含有50 g硫磺和25 g木屑的混合营养反硝化体系,对初始浓度为15 mg/L的 NO 3 - -N有较好的去除效果,去除率接近90%;通过改变木屑与硫磺配比或加入铁屑能适当提高高浓度 NO 3 - -N的去除率,其中,50 g硫磺+50 g木屑的反硝化体系在 NO 3 - -N浓度为30 mg/L时,也能维持约90%的去除率。初始NO 　 3 - -N浓度会对反应柱内微生物群落的丰度产生一定影响,但对微生物群落的结构基本没有影响。

Removal of nitrate in tail water by biomass-sulfur mixed denitrification process

Tail water containing relatively high concentration of NO 3 - -N is often discharged even after secondary treatment process. A biomass-sulfur mixed denitrification system was constructed for the treatment of elevated concentration of NO 3 - -N in tail water, and its performance for the removal of NO 3 - -N was studied. The results of static experiments showed that woodchips-sulfur mixed denitrification system had good performance for the removal of nitrate (reaction rate constant 0.041 6 d-1) with the least conversion of NO 3 - -N and NH 4 + -N. The initial pH within the range of 6-9, and the woodchip/sulfur ratio of 0.5-2.0 had insignificant effect on the mixed denitrification process. The addition of iron fillings had a certain regulating effect on the pH of the system. In the dynamic experiments, mixed denitrification system with 50 g sulfur plus 25 g woodchips had a good removal effect on NO 3 - -N with initial concentration of 15 mg/L , and the removal efficiency of NO 3 - -N could reach 90%. The removal rate of high NO 3 - -N concentration of mixed denitrification system could be improved by changing the proportion of woodchips and sulfur or adding iron sawdust. Among the trials, mixed denitrification system of 50 g sulfur and 50 g woodchips could maintain a removal efficiency of 90% even for 30 mg/L of NO 3 - -N. Different initial NO 3 - -N concentrations had some effect on the abundance of microbial community in the reaction column, but had little effect on the structure of microbial community.