序批式深床人工湿地冬季处理效能

针对连续流人工湿地脱氮效果差、占地面积大、冬季效能低的问题,以提高人工湿地冬季低温运行效能、减小人工湿地占地面积为目标,在前期序批式深床人工湿地研究基础上,重点考察其冬季低温条件下的处理效能。结果表明,温度对序批式深床人工湿地效能影响显著,8~10℃下城镇污水进水COD、NH_4~+-N和TN质量浓度为261mg/L、60 mg/L和70 mg/L时,各自平均去除率分别为72.6%、36.7%和40.2%,较20~25℃时分别下降9.8%、15.4%和10.6%;水温8-10℃时,2级序批式深床人工湿地系统COD、NH_4~+-N和TN去除率分别为95.1%、74.7%和78.7%,较单级系统的72.0%、38.9%和41.1%分别提高了23.1%、35.8%和37.6%。

On efficiency of deep sequence constructed wetlands in winter

This paper is aimed to solve the problem of the low efficiency of wetland construction and utilization particularly in winter days.For the aid purpose,we have first of all investigated the two operational conditions (for the first operational condition:8 min influent-24 h reaction-8 min drainage-12 h idle time;whereas for the second operational condition:8 min influent-12 h reaction-8 min drainage-12 h idle time) under the temperature of 20-25 ℃ and that of 8-10 ℃ differently.The results of our study show that,when the temperature was 8-10 ℃,the average mass concentration of COD,NH4+-N and TN in the effluent is equal to 71 mg/L,34 mg/L and 38.3 mg/L,with the average removal efficiency of COD,NH4+-N and TN being 72.6％,36.7％ and 40.2％,respectively.However,as compared with the temperature condition of 20-25 ℃,the average removal efficiency of COD,NH4+-N and TN may decrease by 9.8％,15.4％ and 10.6％,under the temperature condition of 8-10 ℃ respectively.Nevertheless,from the point of view of the DSCW operation,such an effluent fails to meet the national standard B of the first class (GB 18918-2002) at 8-10 ℃.Therefore,we have managed to build up a two-stage DSCW operation version to solve the problem of the low efficiency in winter days.If such a two-stage DSCW engineering project can be made to come into being,the mass concentration of COD,NH4+-N and TN in the effluent from the two-stage system under 8-10 ℃ can be made to achieve 12.4 mg/L,15 mg/L and 14.8 mg/L,respectively,with the removal efficiency of being 95.1％,74.7％ and 78.7％.In addition,the removal efficiency for the COD,NH4+-N and TN by way of the two-stage DSCW can be heightened by 23.1％,35.8％ and 37.6％ in comparison with one-stage of DSCW under the same temperature condition of 8-10 ℃.Effluent from two-stage DSCW operating under 8-10 ℃ successfully meet the national standard B of the first class (GB 18918-2002).Meanwhile,student's t test has been applied in the result analysis.The result proves that system efficiency has significant difference under different temperatures and wetland stages.On the other hand,comparing to continuous constructed wetlands,the removal load of the two-stage DSCW could improve by 45.3 g COD/(m3 · d) or 12.6 g TN/(m3 · d),and the area load of the two-stage DSCW improve by 114.9 g COD/(m2 · d) or 24.1 gNH4+-N/(m2·d).