【摘要】 低污染水具有来源广、水量大、水质波动性强、污染物浓度较低等特点。人工湿地是净化低污染水的有效方法。该文阐述了潮汐流和曝气人工湿地对低污染水脱氮的不同增氧机制,并分析它们对低污染水的脱氮效果和影响因素。结果表明:在潮汐流湿地中,适当的闲置和淹没反应时间可创造良好的好氧-厌氧条件,有利于TN去除;当运行周期不大于24 h,淹没排空时间比为0.25～4和0.5～7时,湿地对低污染水中NH₃-N和TN的去除效果最好。合理曝气可使人工湿地在低温（-5～10℃）保持较高去除率;曝气人工湿地净化低污染水的最佳气水比为6∶1,最佳曝气位置是湿地底部。此外,对比2种人工湿地脱氮效果可知,曝气人工湿地的NH₃-N和TN净化效果优于潮汐流人工湿地,对COD的净化效果弱于潮汐流人工湿地。2种人工湿地虽以不同增氧机制提高了脱氮效率,但潮汐流湿地仍存在低温期脱氮效果差和易堵塞的问题,而曝气湿地则存在耗能高且易产生有害物质的问题。更多还原

【Abstract】 Low-pollution water has the characteristics of wide sources, large water volume, strong fluctuation of water quality and quantity, and relatively low concentration of pollutants. Constructed wetland is an effective measure to treat low-polluting water. In this paper, the oxygen increasing mechanisms of two typical oxygen-enhanced constructed wetlands, i.e. tidal flow constructed wetlands and aerated constructed wetlands, for nitrogen removal from low pollution water were described, and their denitrification effects and the influencing factors were analyzed. The results show that in the tidal flow constructed wetland, proper idle time and submerged reaction time can create good aerobic-anaerobic conditions, which is beneficial to the removal of TN; when the operating cycle to be less than 24 h, and the submerged～idle time ratio to be between 0.25-4 and 0.5-7, the wetland would have the best NH₃-N and TN removal effect in low-polluted water. Reasonable aeration can make the constructed wetland to maintain a high pollutant removal rate at low temperature（-5-10 ℃）; for the treatment of low-polluted water by aeration constructed wetland, the best air-water ratio is 6∶1, and the best aeration part is the bottom of the wetland. In addition, by comparing the denitrification effects of the two constructed wetlands, it shows that the treatment effect of aerated constructed wetlands on the removal of NH₃-N and TN was better than that of the tidal flow constructed wetlands, but the treatment effect of COD removal was weaker than that of tidal flow constructed wetlands. Finally, this article also points out the existing problems in the denitrification of low-polluted water in the two constructed wetlands. The results of this study could be used as a reference for similar further researches.更多还原