垂直流-水平潜流一体化人工湿地对菜地废水的净化效果

广州市番禺区东升农场菜地废水未经处理直接排入水生植物塘,最终流入附近河流,由于菜地废水水质较差,对其造成了严重的污染,严重威胁了附近居民的饮水安全。为了提高菜地出水水质,减轻对河流的污染,通过构建垂直流-水平潜流一体化人工湿地,对菜地废水进行净化处理。湿地经过9个月的运行,结果显示,湿地对COD、NH4＋-N和TP的平均去除率分别达56.40%、79.09%和79.79%以上,COD、NH4＋-N和TP出水平均浓度分别为9.45、0.47mg.L-1和0.06mg.L-1,均达到《地表水环境质量标准》（GB3838—2002）Ⅱ类水质标准。湿地对TN的平均去除率较低,仅为35.08%,通过补充甘蔗叶作为碳源,湿地对TN的平均去除率显著提高,但随着碳源投加量的增加,去除率逐渐降低。本实验碳源投加量以1.62kg.m-3为宜,TN的平均去除率最高,达80.85%,出水TN平均浓度从3.06mg.L-1降低至0.90mg.L-1。

Removal Efficiencies of Wastewater from Vegetable Land by the Integrated Vertical-flow and Horizontal-flow Constructed Wetlands

Untreated wastewater with poor quality from vegetable lands in Dongsheng Farm,Panyu District,Guangzhou City is discharged directly into macrohydrophyte ponds and eventually flows into adjacent rivers,which have seriously polluted the water resources and threatened the safety of drinking water for local residents.In this study,the integrated vertical-flow and horizontal-flow constructed wetlands were developed to treat the wastewater for water quality improvement.The nine-month operation results indicated that the average removal rates of COD,NH＋4-N,and TP were 56.40%,79.09%,and 79.79%,respectively.The average concentrations of COD,NH＋4-N,and TP from the effluent were 9.45 mg·L-1,0.47 mg·L-1 and 0.06 mg·L-1,respectively,which were all reached the Level-Ⅱ of ＂Environmental Quality Standards for Surface Water＂（GB3838—2002）.The average removal rate of TN was low with only 35.08%.By supplying plant carbon such as sugarcane leaves to the wetland system,the average removal rate of TN was improved significantly.However,as the external carbon source dosage continued to increase,the average removal rate of TN was gradually decreased.Our experiments showed that the optimal supplemental amount of plant carbon was 1.62 kg·m-3 of sugarcane leaves,which has lead to the average removal rate of TN by 80.85% and to the decrease of the effluent average concentration of TN from 3.06 mg·L-1 to 0.90 mg·L-1.