分级进水对阶梯垂直流人工湿地污水处理效果的影响

本文研究了分级进水对阶梯垂直流人工湿地处理生活污水效果的影响.在保持总水力负荷为100 mm/d的情况下,分别将总进水量的0%、10%、20%和30%用于湿地第2级阶梯的进水,分析了系统对化学需氧量(COD)和氮、磷的总去除率和沿程变化.结果表明,不同分级进水比例条件下人工湿地对COD和总磷(TP)的去除率差异不明显,COD和TP的最高去除率分别为87.80%和81.17%,COD的去除主要集中在第1级,其贡献率平均为82.18%,TP的去除主要集中在第3级,贡献率平均为54.37%.分级进水对总氮(TN)去除率影响显著(P0.05),当2级进水比例为20%时,TN去除率最高,为61.70%±4.48%,且3个梯级对TN的去除贡献率分别为36.52%、42.11%和21.37%.相同组合形式的垂直流人工湿地处理生活污水的工程应用中,可根据需求设置20%左右的2级进水比例,以提高人工湿地对污染物的去除效果.

Effect of step feeding on the performance of multi-stage vertical flow constructed wetland for municipal wastewater treatment

To investigate the effect of step feeding on the performance of multi-stage vertical flow constructed wetland (MS-VFCW) for municipal wastewater treatment,raw wastewater with four step feeding ratios (0%,10%,20% and 30%) were dosed to the second stage of the MS-VFCW plots at a total hydraulic load of 100 mm/d.The results showed no significant differences in removal of chemical oxygen demand (COD) and total phosphorus (TP) among the four step feeding ratios,and the highest removal rates of COD and TP reached up to 87.80% and 81.17%,respectively.Most COD was removed in the first stage,with an average contribu-tion of 82.18%.While the most TP was removed in the third stage,with an average contribution of 54.37%.In contrast,the differ-ences in total nitrogen (TN) removal rates among the four step feeding ratios were significant,with the highest TN removal rates (61.70%±4.48%) under the ratio of 20%,in which the average removal contribution of each stage was 36.52%,42.11% and 21.37%,respectively.The step feeding ratio was recommended as 20% in application of the hybrid VFCWs so as to achieve sound pollutant removal performance.