太湖流域化工园区污水处理厂尾水人工湿地深度处理实验研究

ADVANCEMENT TREATMENT OF A CONSTRUCTED WETLAND SYSTEM FOR THE TAIL-WATER OF CHEMICAL INDUSTRIAL PARK WASTEWATER TREATMENT PLANT IN TAIHU LAKE BASIN

针对化工园区污水厂尾水水质和水量波动性较大、难降解物质多、B/C低等特点,难以达到回用水要求,开展垂直流湿地-水平潜流湿地组合工艺深度处理化工园区污水厂尾水实验研究。结果表明,整个湿地系统运行稳定,进水COD为(36.68±4.30)mg/L、BOD5为(7.34±1.22)mg/L,进水NH4+-N、TN、TP质量浓度分别为(1.76±0.30)、(3.39±0.62)、(0.052±0.018)mg/L,出水COD为(21.72±2.59)mg/L、BOD5为(1.23±0.39)mg/L,出水NH4+-N、TN、TP质量浓度分别为(0.17±0.13)、(0.69±0.21)、(0.02±0.01)mg/L,其去除率分别为43.2%、83.2%、90.3%、81.2%、64%,系统出水指标均达到地表水环境质量标准(GB 3838-2002)Ⅳ类。垂直流湿地主要进行硝化作用,对氨氮去除率较高,水平流湿地主要进行反硝化作用,对硝氮去除率较高,2种工艺组合达到去除总氮最佳效果。

Owing to the volatile of quality and quantity, high refractory materials and low B/C value in tail water of chemical industrial park sewage plant, a combined process of vertical subsurface flow constructed wetland and horizontal subsurface flow constructed wetland was conducted for advanced treatment to meet the requirement of reuse water. The results showed that： under the condition that the influent of COD, BOD5, NH4＋-N, TN and TP were （36.68±4.30）mg/L, （7.34±1.22）mg/L, （1.76±0.30）mg/L, （3.39±0.62）mg/L and （0.052±0.018）mg/L, the average concentrations of COD, BOD5, NH4＋-N, TN, and TP in effluent are （21.72±2.59）,（1.23±0.39）,（0.17±0.13）,（0.69±0.21） and （0.02±0.01）mg/L, with the average removal rates being 43.2%, 83.2%, 90.3%, 81.2%, 64%, respectively. Moreover, most of removed ammonia was contributed in vertical subsurface flow constructed wetland and the removal rate of nitrate in horizontal subsurface flow constructed wetland was higher, thus total nitrogen was gradually removed during all process. The quality of COD, BODs, NH4＋-N, TN, TP in final effluent reached the class IV criteria of the environmental quality standard for surface water （GB 3838--2002）.