人工湿地处理低碳氮比污染河水时的脱氮机理

针对人工湿地处理城市污染河水时出现的脱氮效果不佳的问题,以受到严重面源污染的镇江古运河水为例,采用芦苇碎石床复合垂直流人工湿地小试装置研究了人工湿地处理此类低碳氮比污水时的脱氮机理.试验结果表明,人工湿地对于污水中氮的去除主要发生在表层30cm处,其去除机理主要包括填料、植物根系等对悬浮态氮的过滤、截留作用,微生物对溶解态氮的硝化反硝化作用以及植物的吸收作用;湿地下部由于碳源缺乏抑制了反硝化过程,基本不能发挥除氮的作用;对于硝氮浓度高的污水,通过补充有机碳可以有效提高除氮效果,但对于氨氮浓度高的污水,补充有机碳没有明显的效果.

Nitrogen removal mechanism in constructed wetland used for treating polluted river water with lower ratio of carbon to nitrogen

Taken the contaminated seriously Zhenjiang Old Canal as an polluted water example of lower ratio of carbon to nitrogen, the nitrogen removal mechanism in constructed wetland with the integrated vertical-flow gravel-bed constructed wetland microcosm was investigated. Based on the experiments, three conclusions showed that nitrogen was mostly removed in surface layer (0~30cm) and the removal mechanism was composed of suspended-nitrogen filtration of medium and plant roots, while the dissolved nitrogen was removed by nitrification and denitrification of microorganisms and absorption of hydrophytes. Owing to Lack of carbon source under layer, denitrification was inhibited and little nitrogen was removed. Supplying organic carbon source was an effective method to improve nitrogen removal efficiency for nitrate-nitrogen rich wastewater, while it was not valid obviously to high ammonium concentration wastewater.