潜流人工湿地对农村生活污水氮去除的研究

NITROGEN REMOVAL FROM RURAL SEWAGE BY SUBSURFACE HORIZONTAL-FLOW IN ARTIFICIAL WETLANDS

作者研究了潜流水平人工湿地处理农村生活污水中氮的去除效果,结果表明湿地进水TN负荷与出水TN负荷去除之间有较好的线性关系,随着水力停留时间的延长TN去除率也升高,停留时间为4d时,芦苇湿地和菖蒲湿地的脱氮效率可以达到60%以上。从脱氮效果看,芦苇湿地的略好于菖蒲湿地的,有植物系统明显好于无植物系统。在进水NO-2-N浓度小于0.062mg/L、N-3O-N浓度小于1.982mg/L的情况下,无论是连续运行还是间歇运行,大多数情况下,出水浓度都分别低于0.631mg/L和1.00mg/L,两者一般不会有较大的积累。试验分析了湿地脱氮的途径,微生物硝化/反硝化是人工湿地脱氮的主要途径,植物吸收、存储仅占湿地总氮去除量的10%左右,但是植物的存在间接地影响湿地脱氮的其它途径,对提高湿地氮去除率具有重要作用。

Nitrogen removal by subsurface horizontal-flow in artificial wetlands for rural sewage treating was studied. The results showed that TN exhibited a strong linear relationship between load removal in influent and load removal in effluent, with removal rate increasing as HRT increasing. Phragmites australis wetland and Acorus calamus wetland gained removal rate of above 60% when HRT was 4 days. Regarding removal rate, Phragmites australis wetland performed a bit better than Acorus calamus wetland, and macmphyte systems performed better than non-plant system. Under conditions of NO2^--N concentration and NO3^--N concentration below 0.062 mg/L and 1.982 mg/L, regardless of continuous or intermittent running, concentration in effluent was below 0.631 mg/L and 1.00 mg/L respectively and the both did not accumulate much. Experiment analyzed the approaches of TN removal in constructed wetlands. The results indicated that nitrification and denitrification were main mechanism of TN removal, the amount of plants uptake accounted for about 10% of TN removal by wetland. But the existence ofmacrophyte in constructed wetland plays important role in TN removal rate of wetland through influencing indirectly other TN removal mechanisms.