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研究报告

Study on the influence of enhanced carbon resource on denitrification in the constructed wetland

摘要：反硝化是人工湿地去除硝酸盐氮的主要机制,高含氮污水中低碳氮比是导致脱氮效果低的主要原因.研究了添加碳源对人工湿地反硝化过程的强化效果,结果表明,外界温度对湿地内的反硝化影响不大,而碳源则是重要的影响因素,对湿地投加碳源可以显著提高湿地的硝氮去除能力,在进水硝氮浓度25~45 mg · L^-1,24 h水力停留时间的条件下,投加约30~50 mg · L^-1(DOC)的碳源后,夏季的去除率从30％提升至60％以上,冬季的去除率从5％提升至35％以上.但是,投加碳源会导致出水中的亚硝氮产生轻度积累.通过多种途径对反硝化进行强化后,人工湿地对硝氮的去除能力最大可在5 g · m^-2 · d^-1以上.

Abstract：Denitrification is the most important mechanism for nitrate removal in the constructed wetlands. The low C/N ratio is the major reason for the low nitrogen removal efficiency from wastewaters with high content of nitrogen. The influence of external carbon source on denitrification in constructed wetlands was studied in present study. The results showed that the external carbon source can remarkably improve the nitrate removal ability of the constructed wetlands, while temperature showed few effects on the nitrate removal. The present results indicated that nitrate removal rate can increase from 30% to more than 60% in the summer and from 5% to 35% in the winter, when the nitrate load was 25~45 mg · L^-1, the retention period was 24 hours and 30~50 mg · L^-1 DOC was ploughed into the constructed wetland. However, there was slight accumulation of nitrite in the constructed wetlands when the external carbon source was supplied. The maximum removal of nitrate by constructed wetlands was more than 5 g · m^-2 · d^-1 by means of enhanced denitrification.