两种复合人工湿地系统对东莞运河污水的净化效果

复合人工湿地系统是将不同类型的人工湿地相组合,充分发挥各类型湿地特长,实现优势瓦补的一种更有效的污水净化系统.研究采用复合垂直流-水平潜流人工湿地和复合垂直下行流人工湿地两种复合人工湿地系统对东莞运河的河道污水进行处理,分别监测了两套不同复合人工湿地系统第一、二级湿地单元的出水情况,研究了不同时间段和一定的水力负荷下复合人工湿地系统对河道污水的净化效果.结果表明,两种复合人工湿地系统的二级湿地单元出水各指标明显优于一级湿地单元,复合垂直流-水平潜流湿地对东莞运河污水COD、BOD_5和TP的平均去除率分别达到70.52%、69.21%和55.56%;复合垂直下行流湿地系统对TP的净化尤其突出,平均去除率达到72.62%,二级出水的质量浓度在0.10～0.60 mg·L~(-1)之间,对COD和BOD_5的平均去除率分别为64.74%和60.63%.两种复合系统的出水浓度均达到<城市污水处理厂污染物排放标准>(GB 18918-2002)中的一级标准.由此可见,两种复合人工湿地系统对各污染物去除效果明显优于单一的湿地系统,且更具稳定性和耐冲击能力.

Purification efficiency of wastewater in Dongguan canal by different hybrid constructed wetlands

Various types of constructed wetlands may be combined in order to achieve higher treatment effect. The two different kinds of hybrid wetlands systems in the experiment were constructed respectively by the combination of vertical-flow and horizon-tal-flow, and the combination of two vertical-flow wetlands. The purification efficiency of wastewater in Dongguan Canal by the two different kinds of hybrid constructed wetlands was monitored in different seasons and at different hydraulic loadings. The results showed that the performance of both hybrid constructed wetlands were much better than single type wetlands. The average removal rates of COD, BOD_5 and TP by the combination of vertical-flow and horizontal flow constructed wetland were 70.52%, 69.21% and 55.56%, respectively. The combination of two vertical-flow wetlands system had high purification efficiency for TP, of which the average removal rate were 72.62%, and the concentration of effluent were between 0.10 and 0.60 mg·L~(-1). The average removal rates were 64.74% for COD and 60.63% for BOD_5. It was obvious that the concentrations of COD, BOD_5 and TP in the effluent could all reach to the first rank of"Urban Sewage Treatment Plant Pollutants Drainage Standards" (GB 18918-2002).