污水碳源对复合垂直流-水平流人工湿地脱氮效果的影响

Effect of internal carbon source supplement on nitrogen removal in integrated vertical-flow and horizontal-flow constructed wetland

碳源是人工湿地反硝化作用重要的限制因子,提供足够的碳源能够有效地提高湿地系统的反硝化作用,从而提高人工湿地的脱氮效果。考察了以污水碳源作为复合垂直流-水平流人工湿地水平流进水碳源,对系统去氮能力的影响。实验结果显示,添加碳源能使复合人工湿地对TN和氨氮的去除率分别由23.19%、39.57%提高到34.17%和50.4%。当碳源污水(化粪池污水)/硝化处理水(垂直流出水)体积比为1∶4(C/N=1.22∶1)时,系统对氨氮和总氮具有最好的去除效果,且在不同季节具有较强的脱氮稳定性。不同季节加碳源复合系统对氨氮和总氮去除效果差异显著,在夏季去除效果最高可到达66.79%和60.95%。在加污水碳源条件下,增加停留时间对TN去除效果无明显影响,但可以显著提高氨氮去除率;有植物系统比无植物系统去除NH+4-N和TN的效果要好,且夏季提升效果最明显。由此可见,以污水碳源作为复合垂直流-水平流人工湿地系统中水平流部分的碳源,是强化人工湿地脱氮效果的有效手段,但是添加碳源比例、保温措施及植物种植是人工湿地重要的设计参数。

Carbon source is the main limiting factor to denitrification efficiency in constructed wetlands（ CWs）.A complete denitrification function can take place when adequate degradable carbon sources are available,which improve the capacity of the CW for nitrogen removal. This study investigated the effect of an internal carbon source swage on the capacity for nitrogen removal in integrated vertical-flow and horizontal-flow constructed wetlands,when employing it as the carbon source in the horizontal-flow unit. The result showed that the addition of internal carbon source swage enhanced the removal efficiency of total nitrogen（ TN） from 23. 19% to 34. 17%,and the removal efficiency of ammonia nitrogen（ NH＋4-N） from 39. 57% to 50. 4%. When the ratio of internal carbon source swage / nitrification wastewater was 1 ∶ 4,the integrated CW had the highest and most stable removal efficiency for nitrogen. Season change had a significant effect on the mass removal rates for TN and NH＋4-N. The CW,with the addition of internal carbon source swage in summer,had the highest TN reduction rate of 60. 95%and a NH＋4-N reduction rate of 66. 79%. Increasing the hydraulic retention time had no effect on TN removal,but was favorable for the erasure rate of NH＋4-N. Planting,especially in summer,was shown to enhance the nitrogen removal capability of the constructed wetland treatment systems. This study illustrated that the addition of an internal carbon source swage could be an effective method for increasing the removal efficiency of nitrogen inintegrated vertical-flow and horizontal-flow CWs. The quantity of the internal carbon source swage,the insulation measures,and planting were important parameters in the CW design.