运用无动力人工湿地分散式处理农村生活污水的研究

Application of the non-powered constructed wetland system on rural domestic sewage treatment

针对农村生活污水排放分散、难以集中处理等特点,以长沙市望城区光明村3户典型家庭为例,采用无动力人工湿地系统分散式处理农村生活污水,并比较冬、夏两季人工湿地对居民生活污水的净化效果。结果表明,构建的无动力人工湿地对农村生活污水净化效果明显,冬季生活污水COD、TP、TN、氨氮、SS的平均去除率分别达71.83%、97.20%、83.52%、55.34%、71.79%;夏季COD、TP、TN、氨氮、SS平均去除率分别达91.52%、93.99%、83.22%、75.15%、65.04%。经人工湿地净化处理后,TP、TN、氨氮可以达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A或一级B标准,COD可以达到GB 18918—2002二级标准,但人工湿地对COD及氨氮的去除受冬季低温影响十分显著,且出水SS不能达到GB 18918—2002相关标准,建议增加拦截设施或在冬季设置保温措施以提高人工湿地对农村生活污水的净化效果。

Focused on the characteristics of rural domestic sewage,such as scattered distribution and difficult to concentrated disposition,the non-powered constructed wetland system was employed to treat the domestic sewage from three typical families in Guangming Village,Wangcheng District,Changsha City.Moreover,the purification efficiencies of the local non-powered constructed wetland system in the summer and winter were compared.The result showed that the constructed wetland system had obvious purification effect on the rural domestic sewage,the average removal rates of COD,TP,TN,ammonia nitrogen and SS were 71.83%,97.20%,83.52%,55.34%and 71.79%in winter,and 91.52%,93.99%,83.22%,75.15%and 65.04%in summer,respectively.In particularly,the effluent TP,TN and ammonia nitrogen could meet the“Discharge standard of pollutants for municipal wastewater treatment plant”(GB 18918-2002)classⅠA or B after purified by constructed wetland system.And the effluent COD could reach to the classⅡof GB 18918-2002.However,the low temperature in winter cause a significant effect on the removal efficiencies of COD and ammonia nitrogen,and the effluent SS could not meet the standard of GB 18918-2002.Therefore,it was suggested to increase interception facilities or set up thermal insulation measures in winter to improve the purification efficiency of constructed wetland system on rural domestic sewage.