摘要
研究了不同水力停留时间(HRT)和农药污染负荷(PPL)下,"生态沟渠+水平流人工湿地"和"生态沟渠+垂直流人工湿地"系统对农田退水中常规污染物和噻虫嗪的去除效果。结果表明,"生态沟渠+垂直流人工湿地"系统对COD、NH+4-N、NO-3-N、TN、TP及噻虫嗪的去除率均优于"生态沟渠+水平流人工湿地"系统,分别为76%、97%、92%、95%、88%和40%(HRT=2 d),其中噻虫嗪在沟渠段的去除率为17%,在垂直流人工湿地段的去除率为23%。延长HRT、降低PPL均有利于噻虫嗪在组合系统中的去除。对垂直流人工湿地各基质层出水噻虫嗪浓度检测结果表明,运行前期,噻虫嗪在空心砖层去除率最高(8%),主要是由于空心砖对于噻虫嗪的吸附优于沸石和钢渣,随着系统运行,土壤+细沸石层和粗沸石层的去除效率增加,植物吸收与微生物降解作用逐渐占据主导地位。微生物群落结构分析结果显示,生态沟渠段β-变形菌纲和厌氧绳菌纲丰度分别为11%和10%。垂直流人工湿地自上而下芽孢杆菌逐渐增多成为优势菌,β-变形菌和厌氧绳菌逐渐减少。厌氧、好氧交替环境有利于常规污染物和噻虫嗪的去除。
The removal of conventional pollutants and thiamethoxam from farmland runoff by ＂ecological ditches＋ horizontal flow constructed wetland＂ and ＂ecological ditches ＋ vertical flow constructed wetland＂ system was investigated with different hydraulic retention time （HRT） and pesticide pollution load （PPL）. The results show that the removal efficiency of COD,NH4＋-N,NO3--N,TN,TP and thiamethoxam in vertical flow constructed wetland were better than that in horizontal flow constructed wetlands,which were 76%,97%,92%,95%,88% and 40%, respectively（HRT=2 d）.The removal rate of thiamethoxam in eco-ditches was 17%, and that in the vertical flow wetland was 23%. Prolonging HRT and lowering PPL were beneficial to the removal of thiamethoxam. The test results of effluent thiamethoxam in the vertical flow wetland showed that the removal rate of thiamethoxam in hollow brick layer was the highest in the initial operation period, which was mainly due to its better adsorption capacity than the zeolite and the steel slag. While the removal of thiamethoxam in the soil and zeolite layer increased gradually, which showed plants absorbability and microbial degradation played an increasingly important role. The microbial community structure analysis indicated that the abundance of Betaproteobacteria and Anaerolineae in eco-ditches were 11% and 10%, respectively. Bacillus gradually increased and became a dominant, while Betaproteobacteria and Anaerolineae gradually decreased from top to down in vertical flow artificial wetlands. The changeover of aerobic and anaerobic favored the removal of conventional pollutants and thiamethoxam.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第12期6532-6539,共8页
Chinese Journal of Environmental Engineering
基金
北京林业大学青年教师科学研究中长期项目(2015ZCQ-HJ-01)
国家水体污染控制与治理科技重大专项(2014ZX07305003)
关键词
生态沟渠
人工湿地
噻虫嗪
水力停留时间
农药污染负荷
ecological ditch
constructed wetland
thiamethoxam
hydraulic retention time
pesticide pollution load
