进水负荷对地下渗滤系统ORP及脱氮效果的影响

Effects of Influent Loadings on ORP and Nitrogen Removal Efficiency in Subsurface Wastewater Infiltration System

以沈阳大学校园污水地下渗滤处理示范工程为研究对象,分析了进水负荷对地下渗滤系统内部氧化还原环境、脱氮微生物结构及脱氮效果的影响。结果表明:随着进水水力负荷和有机负荷的增加,地下渗滤系统中氧化还原电位(ORP)呈下降趋势,其中在20～60 cm深度区域下降明显,同时脱氮效率下降。推荐适宜的水力负荷为0.081～0.125 m3/(m2·d),有机负荷≤16.8gBOD/(m2·d)。在进水水力负荷为0.125 m3/(m2·d)、有机负荷为12.0 gBOD/(m2·d)、落干和布水时间比为8 h∶8 h的条件下,系统中氧化、还原环境分区明显,出水NH4+-N、TN、COD、BOD5、TP及SS浓度分别为4.6、14.6、23.2、5.0、0.4和0.2 mg/L,满足《城市污水再生利用景观环境用水水质》(GB/T 18921—2002)的要求。

The subsurface wastewater infiltration system （SWIS） in Shenyang University was used to investigate the effects of influent loadings on ORP values, microbial distribution and nitrogen removal efficiency. The results showed that with increase of the hydraulic and organic loadings, ORP values declined and nitrogen removal efficiency decreased, which was especially apparent in the 20 to 60 cm deep area. The optimal hydraulic loading was 0. 081 to 0. 125 m^3/（m^2 ·d） , and organic loading was equal to or less than 16.8 gBOD/（m^2 ·d）. Under the conditions of influent hydraulic loading 0. 125 m^3/（m^2· d）, organic loading 12.0 gBOD/（m^2 · d） and dry/wet ratio 8 h ： 8 h, the effluent concentrations of NH4 - N, TN, COD, BOD5 , TP and SS were 4.6, 14.6,23.2, 5.0, 0.4 and 0.2 mg/L respectively, meeting the requirement of Reuse of Urban Recycling Water--Water Quality Standard for Scenic Environmerit Use （ GB/T 18921 - 2002）.