Nitrogen removal enhanced by intermittent operation in a subsurface wastewater infiltration system
Nitrogen removal enhanced by intermittent operation in a subsurface wastewater infiltration system
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DOI：
10.1016/j.ecoleng.2005.06.011
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发表时间：
2005-11
影响因子：
3.8
通讯作者：
Jian Zhang;Xia Huang;Chaoxiang Liu;Han-chang Shi;Hong-Ying Hu
中科院分区：
文献类型：
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作者：
Jian Zhang;Xia Huang;Chaoxiang Liu;Han-chang Shi;Hong-Ying Hu
在滇池流域某村庄，采用红粘土+25%煤渣混合土填充地下污水渗透试验系统处理农村污水。首先，系统以2cm - 1的水力负荷连续输入农村污水4个多月。运行期间COD、T-P、NH4+-N和T-N的平均去除率分别为82.7%、98.0%、70.0和77.7%。与T-P去除率相比，较低的氮去除率归因于系统中的还原性土壤条件，这对硝化过程不利。采用间歇操作提高脱氮效果。在间歇运行模式下，COD和T-P的去除效果相同。NH4+-N去除率由连续进料时的70%提高到90%以上，即使平均水力负荷高达8cmd−1，T-N去除率也提高到80%以上。氮平衡计算表明，硝化-反硝化是脱氮的主要机制，可去除57-76%的进料T-N。土壤氧化还原电位测定表明，间歇操作增加了氧化环境，促进了硝化作用。相应的，土壤硝化电位由连续投料模式下的小于0.8mg-Nkg−1h−1增加到间歇投料模式下的约1.6mg-Nkg−1h−1。
A pilot subsurface wastewater infiltration system filled with a mixed soil of red clay+25% cinder was constructed in a village located in Dianchi valley in south west China to treat rural sewage. At first, the system was continuously fed with rural sewage at a hydraulic loading of 2cmd−1for over 4 months. The removal of COD, T-P, NH4+-N, and T-N over the operation period was achieved at average rates of 82.7, 98.0, 70.0, and 77.7%, respectively. Compared to T-P removal, the lower nitrogen removal rates were attributed to reductive soil condition in the system, which was unfavorable for the nitrification process. An intermittent operation was adopted to improve nitrogen removal. The same performances of COD and T-P removal were achieved in the intermittent operation mode. NH4+-N removal was increased from 70% in the continuous feeding mode to over 90%, and T-N removal rate was elevated over 80% even with the average hydraulic loading as high as 8cmd−1. Nitrogen balance calculation suggested that nitrification–denitrification was the main mechanism of nitrogen removal that eliminated 57–76% of the fed T-N. Soil redox potential measurement showed that the oxidative environment was increased through intermittent operation, encouraging nitrification. Correspondingly, soil nitrification potential was increased from less than 0.8mg-Nkg−1h−1in the continuous feeding mode to about 1.6mg-Nkg−1h−1in the intermittent operation mode.