改良A/O-垂直流人工湿地组合工艺深度处理畜禽养殖废水研究

Research on the advanced treatment of livestock and poultry breeding wastewater using the improved A/O-vertical flow constructed wetland combination process

针对畜禽养殖废水成分复杂较难处理问题,将传统A/O工艺与人工湿地装置进行改良并组合,利用人工湿地进行深度脱氮除磷,探究了单独启动时各因素的影响作用,确定和讨论了组合工艺最佳处理能力,并分析了人工湿地系统中微生物群落的功能与结构变化.结果表明:改良A/O工艺HRT为12 h,回流比为150%,气水比为5∶1时,处理效果最为理想;人工湿地在HRT为48 h达到最佳去除效果;在最佳工况条件下,组合工艺处理后出水COD、NH_(4)^(+)-N、TN、TP的分别为10.34 mg/L、1.63 mg/L、13.70 mg/L、0.39 mg/L,出水浓度均达到《陕西省黄河流域污水综合排放标准》(DB 61/224-2018)B标标准;根据物种丰富度及层次聚类分析结果可知,人工湿地第二级上行流优势类群Chloroflexi(绿弯菌门)丰富度为16.7%,表明人工湿地形成局部厌氧环境;第三级下行流优势菌群Firmicutes(厚壁菌门)丰富度为18.2%,其主要担负脱氮除磷作用.

In response to the complex and difficult to treat components of livestock and poultry breeding wastewater,the traditional A/O process is improved and combined with the constructed wetland device,and the artificial wetland is used for deep nitrogen and phosphorus removal,and the influence of various factors when starting alone is explored.The optimal treatment capacity of the combined process was determined and discussed,besides the functional and structural changes of microbial communities in the artificial wetland system were analyzed.The results showed that the most ideal treatment effect was achieved when the improved A/O process had an HRT of 12 hours,a reflux ratio of 150%,and a gas water ratio of 5∶1.The artificial wetland achieves the most excellent removal effect at an HRT of 48 hours.Under the optimal operating conditions,the concentrations of COD,NH_(4)^(+)-N,TN,TP in the effluent after combined process treatment are 10.34 mg/L,1.63 mg/L,13.70 mg/L,and 0.39 mg/L,and the effluent concentrations all meet the B standard of″Integrated wastewater discharge standard of Yellow river basin in Shaanxi province(DB 61/224-2018)″.According to the species richness and hierarchical cluster analysis,the richness of Chloroflexi,the dominant group of the second upwelling flow in constructed wetlands,was 16.7%,indicating that the constructed wetlands formed a local anaerobic environment.The abundance of Firmicutes was 18.2%,which was mainly responsible for nitrogen and phosphorus removal.