进水方式对序批式深床人工湿地硝化效能的影响

针对现有人工湿地硝化效能低、占地面积大的问题,研究污水处理厂尾水人工湿地高效硝化深度处理技术,采用序批式深床人工湿地反应器(DSCW),考察进水方式及其运行工况对硝化效能的影响。结果表明,进水方式、进水时间和闲置时间对湿地硝化效能影响显著。进水方式采用"连续进水-间歇出水"较连续进出水运行工况NH_4~+-N去除率高39.69%。连续进水时间为5.5 h、7.5 h、11.5 h时,NH_4~+-N去除率分别为81.82%、88.12%、89.91%;闲置时间为0、2 h、4 h时,NH_4~+-N去除率分别为88.12%、94.46%、92.60%。反应器在水温(20±3)℃、负荷35.56 g NH_4~+-N/(m2·d)、连续进水7.5 h-间歇出水0.5 h-排空闲置2 h运行工况下,出水NH_4~+-N为0.91 mg/L,去除率为94.46%,系统NH_4~+-N去除效能大幅提高。

Influence of water feeding pattern on the nitrification efficiency of the deep sequencing constructed wetlands

This paper takes it as its objective to deal with the problems of vast-spaced and low efficient constructed wetlands in winter.For the research purpose,we have investigated the efficiency of the reactor during the set-up period and settled down NH4+-N removal efficiency successfully for 6-14 days later,when the reactor tends to increase gradually and finally reach 76.16％ till the 14th day.In so doing,we have made careful investigations over the impacts of the water feeding pattern and the operational conditions on the nitrification efficiency of the deep sequencing constructed wetlands (DSCW) in hoping to develop a kind of highly efficient nitrification technology for treating the tailing water in the sewage-processing plant.The results of our investigation and testing have shown that,the nitrification efficiency can be affected significantly by the water feeding pattern,the feeding duration,as well as the idling time.For example,when the operation is done in a "continuous influent" pattern,or in a "5.5 h continuous influent-0.5 h intermittent effluent",or in the manner of "0.25 h continuous influent-1.25 h intermittent effluent-4.5 h idling",the mass concentrations of effluent NH4+-N should be 8.70 mg/L,2.87 mg/L and 5.31 mg/L,with the average removal efficient rates being 42.34％,82.03％ and 64.67％,respectively.As compared with "the continuous influent and effluent" pattern,when operational pattern is chosen to be the "continuous influent-intermittent effluent," the removal efficiency of NH4+-N can be expected to increase by 22.33％ -39.69％.Moreover,when the sewage feeding durations were taken as 5.5 h,7.5 h and 11.5 h,the mass concentrations of effluent NH4+-N should be 2.89 mg/L,1.59 mg/L and 1.40 mg/L,respectively,with the average removal efficiency of NH4+-N being 81.82％,88.12％ and 89.91％,accordingly.On the other hand,if idling time were to last 0,2 h and 4 h,the mass concentrations of effluent NH4+-N would turn to be 1.59 mg/L,0.91 mg/L and 0.97 mg/L,with the average removal efficiency of NH4+-N being 88.12％,94.46％ and 92.60％,relatively.Thus,as compared with no idle time,the average removal efficiency of NH4+-N may rise by 6.34％ and 4.48％ for 2 h and 4 h of the idling time.But,when the reactor is operated or working under the condition of (20 ± 3) ℃ with NH4+-N load 35.56 g/(m2 · d) (7.5 h continuous influent-0.5 h intermittent effluent-2 h idle),the average mass concentration of effluent NH4+-N can be expected to reach 0.91 mg/L,with its removal efficiency of 94.46％,which suggests that NH4+-N removal efficiency has gained a substantial increase.