漂浮植物塘处理农村分散生活污水的强化措施研究

Research on the effect of enhanced measures in floating aquatic macrophytes systems for treatment of rural decentralized domestic wastewater

利用漂浮植物与园沟宅河构建漂浮植物塘,配合化粪池处理农村分散生活污水,对改善水乡地区农村水环境质量具有重要意义。针对自然条件下的漂浮植物塘对NH4+-N等污染物的去除速率较低的局限,考察了曝气和搅拌等人工强化措施对提高漂浮植物塘净化效果的作用。结果表明:(1)曝气和搅拌可显著提高模拟漂浮植物塘中NH4+-N的去除率,但是不能改善TN的去除效果。(2)只要保证一定的DO,曝气方式对NH4+-N的去除效果影响不大。(3)模拟化粪池出水以接近连续流方式进入模拟漂浮植物塘,在平均DO大于2mg/L、水温20℃左右的条件下,停留时间为7d,NH4+-N能达到良好的硝化效果,持续运行没有发生NH4+-N积累。进水NH4+-N平均负荷为1.6g/(m2.d)下,曝气模拟漂浮植物塘出水NH4+-N平均值均可达到《地表水环境质量标准》(GB3838—2002)中Ⅴ类标准(2.0mg/L)。

Application of floating aquatic macrophytes systems （FAMS） which composed by floating aquatic a- quatic macrophytes and septic tanks for the treatment of rural domestic wastewater is of great importance in the rive side areas. However, the removal rate of NH4＋-N in natural FAMS is low. Lab-scale experiments were conducted to investigate effects of aeration and mixing on treatment performance of FAMS. The results indicate that aeration and mixing can improve the removal rate of NH4＋ N, while TN removal rate was not improved. The aeration patterns would have little effects on NH/-N removal when DO concentration of FAMS maintained at certain level; keep the in- flow of FAMS in a semi-continuous mode, the FAMS presented perfect nitrification activity when water temperature is nearly 20 ℃ ,hydraulic retention time is 7 d and average DO concentration is above 2 mg/L. When the loading rate of NH4＋ -N is 1.6 g/（m2·d）, the concentration of effluent NH＋ -N is steadily below 2.0 mg/L, which lower the V class of surface water environment quality standard （GB 3838-2002）.