再生水景观回用系统富营养化污染控制技术研究

Study on Eutrophication Pollution Control Technology of Reclaimed Water Landscape Reuse System

再生水经过生态浮床和垂直流人工湿地的深度处理后,进入景观水体还是会出现藻类滋生的富营养化现象。实地调查结果表明:水力负荷为20~30 m3/(m2·d)的生态浮床对CODCr的去除效果明显,但是,对氨氮和总磷的去除作用有限;水力负荷为0.2~0.4 m3/(m2·d)的垂直流人工湿地对CODCr、氨氮和总磷均有明显的去除效果。模拟试验结果表明:缓慢流动的景观水体(流速低于1.5 m/min),即使总氮浓度低于1 mg/L、总磷浓度低于0.025 mg/L,也会出现藻类滋生叶绿素a浓度升高的现象;藻类的生长可显著降低水中氮、磷的浓度,对总氮和总磷的去除率分别达到35%~50%和60%~65%,配合物理或生物除藻的方法,可以高效地降低水体中氮和磷的浓度,从根本上解决水体富营养化的问题。

After the advanced treatment of ecological floating bed and vertical flow constructed wetland, the eutrophication of algae will still appear when the reclaimed water enters the landscape water body. The results of field investigation show that the removal effect of CODCr by ecological floating bed with hydraulic load of 20~30 m3/(m2·d) is obvious. However, the removal of ammonia nitrogen and total phosphorus is limited. The vertical flow constructed wetland with hydraulic load of 0.2~0.4 m3/(m2·d) has obvious removal effect on CODCr, ammonia nitrogen and total phosphorus. The simulation results show that in slow-moving landscape water with flow rate less than 1.5 m/min, even if the total nitrogen concentration is less than 1 mg/L and the total phosphorus concentration is less than 0.025 mg/L, the concentration of chlorophyll-a in algae breeding will also increase. The growth of algae can significantly reduce the concentration of nitrogen and phosphorus in the water, and the removal rates of total nitrogen and total phosphorus reach 35% to 50% and 60% to 65%, respectively. Combined with physical or biological algae removal methods, it can efficiently reduce the concentration of nitrogen and phosphorus in the water body, and fundamentally solve the problem of water eutrophication.