低温条件下不同曝气方式对硫自养湿地脱氮效能的影响

Effect of different aeration modes at low temperature on nitrogen removal efficiency of sulfur autotrophic wetland

为提高人工湿地的脱氮效率,将硫磺与石灰石按体积1∶1的比例填充于波形潜流湿地内,辅助间歇人工曝气,探讨了在冬季低温条件下,间歇曝气时间对波形潜流人工湿地脱氮效率和反硝化作用的影响,并分析了硫自养湿地的作用机理和节能减排特性。结果表明,间歇曝气运行方式有效提高了湿地内部溶解氧水平,在湿地内部营造了一种交替的好氧和缺氧环境,可以促进硝化和反硝化作用,有效地解决了人工湿地在冬季(10℃以下)脱氮效率低的问题。湿地冬季运行时,曝气间歇时间为4 h的条件下,TN去除率高达59.4%,相比连续曝气方式提高20%~30%。与传统处理工艺相比,硫自养湿地的能耗节省率达到50%以上,且在一定程度上减少了CO^2的排放,实现了高效脱氮和节能环保。

In order to improve the nitrogen removal efficiency of constructed wetlands,the waveform subsurface flow wetland was filled with sulphur and limestone with a ratio of 1∶1 and it was intermittently aerated.The effects of different aeration interval times on the nitrogen removal rate and denitrification of this subsurface flow constructed wetland were discussed at low temperatures in winter.The mechanism and energy conservation and emission reduction of sulphur autotrophic wetland were analyzed.The results showed that the DO level inside wetland was effectively elevated through the intermittent aeration mode,an alternation of anaerobic and aerobic environments inside the wetland occurred,then the nitrification and denitrification were promoted,and a remarkable nitrogen removal efficiency was achieved at low temperatures,which effectively solved the problems of low nitrogen removal rates of the traditional constructed wetlands at low temperatures(<10℃).When the waveform subsurface flow wetland was operated in winter at the aeration interval of 4 h,TN removal rate reached 59.4%,which increased by 20%~30%in comparison with continuous aeration mode.Besides,the energy conservation rate above 50%was achieved for the sulphur autotrophic wetland compared with traditional wetlands,and the reduction of CO^2 emission was also achieved to some extent,at last,high efficient nitrogen removal,energy conservation and environment protection were realized.