自然导气措施对垂直流人工湿地堵塞的影响

Influence of Natural Aeration on Clogging of Vertical-flow Constructed Wetland

为解决人工湿地堵塞问题,设计了一种自然导气型垂直流人工湿地,并采用连续运行的方式,考察了水力负荷分别为0.30、.60、.9、1.2 m3/(m2.d)的条件下,其基质孔隙率和除污效果随时间的变化。结果表明:当在低水力负荷下运行时,自然导气对垂直流人工湿地的基质堵塞有显著的改善作用,而在较高水力负荷[1.2 m3/(m2.d)]下运行时则改善作用甚微。同时自然导气可显著提高垂直流人工湿地对污染物的去除效果,其中对氨氮去除率的提高程度大于对COD的。当水力负荷<0.9 m3/(m2.d)时,对氨氮的去除率稳定保持在较高水平,在水力负荷分别为0.3、0.6和0.9 m3/(m2.d)时,对氨氮的平均去除率分别为98.38%、89.10%7、2.31%。

A natural-aeration vertical-flow constructed wetland was designed to solve the problem of clogging. The continuous operation mode was used to investigate the variation of matrix porosity and the removal efficiency of the pollutants with time at different hydraulic loads of 0.3, 0.6, 0.9 and 1.2 m3/ （m2 · d）. The results indicate that the natural aeration can significantly improve the clogging condition in the vertical-flow constructed wetland at lower hydraulic load while the improvement effect is not significant when the hydraulic load is higher than 1.2 m3/（ m2 · d）. Meanwhile, the natural aeration can also improve the removal efficiency of the pollutants significantly, in which the improvement level of ammonia nitrogen is higher than that of COD. The removal rate of ammonia nitrogen is maintained at a high level when the hydraulic loading is less than 0.9 m3/（ m2 · d）. The average removal rates of ammonia nitrogen are 98.38% , 89.10% and 72.31% when the hydraulic loads are 0.3, 0.6 and 0.9 m3/（m2 ·d） respectively.