强化供氧对低温域人工湿地脱氮及微环境的影响

Influence of aeration on nitrogen removal effect and microenvironment in constructed wetland at low temperature

在低温条件下（T〈15oC）对人工湿地进行植物地上部分收割并覆膜保温，采取强化供氧措施，探讨了湿地溶解氧分布、微生物数量及净化效率的变化规律.结果表明，强化供氧宜在湿地前段进行，最佳气水比约为4：1.最佳供氧条件下，湿地氧环境显著改善，供氧前湿地的氧浓度普遍低于0.2mg／L，中后段接近于零，供氧后湿地前段氧浓度达1.2mg／L，整体湿地氧浓度高于0.4mg／L.强化供氧使湿地前段硝化菌数量提高1个数量级，中后段反硝化菌数量提高1个数量级.强化供氧有利于有机物和氮类物质的去除，COD去除率提高了15％，TN，NH^＋4-N去除率均提高了15％～20％.

Aeration was applied to constructed wetlands at low temperature （T〈 15℃） after the above-ground part of plants was harvested and the wetlands were covered by plastic films. Then the dissolved oxygen distribution, microorganism amount and contamination removal efficiency were investigated. The results show that aeration should be carded out in the forepart of wetland and the optimum gas-flow ratio is about 4：1. Under the optimal aeration condition, the oxygen condition is ob- viously improved. The oxygen concentration is mostly lower than 0.2 mg/L before aeration. Especially in the mid and rear part, it is close to zero. After aeration, the oxygen concentration is generally over 0.4 mg/L and it can even be over 1.2 mg/L in the forepart. The nitrobacteria amount in the forepart of wetland increases one magnitude after aeration. The same occurs for denitrifying bac- teria in the middle and rear part. Moreover, the removal efficiency of COD increases by 15%, and that of TN, NH4-N increases by 15% to 20%.