摘要
人工湿地作为新兴的污水生态处理技术在村镇污水处理中得到广泛使用,系统中氮去除的最主要途径是微生物的硝化-反硝化作用。研究湿地污水处理系统微生物硝化-反硝化作用,对湿地污水处理工艺的优化及运行管理具有重要意义。2013年分春、夏、秋、冬四季对贵州草海污水湿地处理工程进行采样,研究了长期运行的湿地污水处理系统中氮循环菌数量、硝化-反硝化作用时空分布特征和系统内氮的空间分布规律。结果表明,草海污水人工湿地处理系统对TP和COD的处理效果较好,去除率分别达到57.8%和80.8%,但对TN和NH_4^+-N的去除率仅为43.3%和38.6%;硝化-反硝化作用在草海人工湿地系统中同时发生,硝化作用强度为0.9 mg·kg^(-1)·h^(-1),反硝化强度为30.5 mg·kg^(-1)·h^(-1),反硝化强度是硝化强度的30倍;硝化-反硝化作用在季节上均表现为夏季最高、春季最低,水平空间上呈逐级降低趋势;硝化-反硝化作用强度与总氮去除率呈现显著负相关(P<0.05);4类脱氮细菌中,氨化细菌数量最大,高达10~9 MPN·g^(-1),反硝化菌次之,亚硝化菌最低,仅10~2 MPN·g^(-1);脱氮细菌数量与总氮去除率相关性不显著,脱氮过程可能受亚硝化菌的限制。总之,由于长期运行的人工湿地系统缺乏氧气,导致反硝化作用远大于硝化作用,硝化-反硝化作用的失衡最终影响湿地脱氮效率。因此,针对长期运行的人工湿地系统可以通过强化供氧促进硝化作用从而提高湿地脱氮效果。
Constructed wetland as a new sewage ecological treatment technology are widely used in rural sewage,and it was considered that the nitrogen removal by nitrification and denitrification was the main pathway in the system.The study on microbial nitrification/denitrification has important practical significance for the system optimization and operation management.Thus,the samples were captured from Caohai artificial wetland sewage treatment system the in spring,summer,autumn and winter,2013.And the temporal-spatial distributions of the abundance of nitrogen cycle bacteria,nitrification/denitrifiction and spatial variations of N were studied.The results showed the TP and COD removal rate were 57.8%and 80.8%,respectively.However,TN and NH_4^+-N removal rate only for 43.3%and 38.6%.The coincidence of nitrification and denitrifiction in constructed Caohai wetland,with the denitrifiction ability 30 mg·kg^(-1)·h^(-1),which was 30 times the nitrification(only 0.9 mg·kg^(-1)·h^(-1)).Both nitrification and denitrification were highest in summer,lowest in spring,and gradually decreased in horizontal space.Significantly negative correlation exists between nitrification/denitrifiction ability with TN remove rate(P<0.05).Among all four kinds of nitrogen-removing bacteria,the number of ammonifving bacteria,up to 10~9 MPN·g^(-1),was largest,then was denitrifying bacteria,and the least was nitrifying bacteria,with the number of only 10~2 MPN·g^(-1).The correlation between the number of denitrifying bacteria and the TN removal rate was insignificant,it might be effected by the limited nitrifying bacteria in denitrification process.All in all,the long term hypoxia in constructed wetlands brings about denitrification far beyond nitrification,and finally lower the nitrogen-removal rate for the imbanlance.Therefore,the nitrogen-removal efficiency in long term running wetland could be improved by increasing the supplication of oxygen.
出处
《生态环境学报》
CSCD
北大核心
2015年第12期2045-2049,共5页
Ecology and Environmental Sciences
基金
国家科技支撑计划项目(2011BAC02B02)
贵州省社会发展攻关项目(SY20133136
SY20133145)
关键词
人工湿地
硝化作用
反硝化
constructed wetland
nitrification
denitrification
