微氧生物接触氧化法联合尾水农灌处理农村生活污水

Treatment of Rural Domestic Sewage by Micro-oxygen Biological Contact Oxidation Combined with Tail Water Irrigation

为探究农村生活污水资源化处理的可行性,采用微氧生物接触氧化法联合尾水农灌对模拟农村生活污水中的氮磷及有机物进行处理,测定了运行参数对微氧生物接触氧化法处理效果的影响,并探讨了尾水农灌对农作物品质、地下水、土壤的影响。结果表明,在系统溶解氧为微氧条件(0.5±0.2 mg/L)时,水力停留时间(HRT)和温度均对生物接触氧化法的处理效果有明显的影响,当HRT为4 h以上以及温度在30℃或20℃时,COD去除率大于73.32%,出水COD浓度均能满足所有作物灌溉要求(<100 mg/L),而NH_(4)^(+)-N、TN和TP的去除率均低于50%,有效保存了部分氮磷资源。利用尾水灌溉可有效提高作物产量,同时维生素C含量、还原性糖含量并未发生明显降低,硝酸盐氮含量未超出食用标准。灌溉下渗水不会对地下水造成污染,另外农灌后土壤质地相较灌溉前有所改善,pH由4.96上升至5.78,电导率由1.925 mS/cm降低至1.803 mS/cm,土壤酸化改善且盐渍化程度降低,土壤肥力仍维持在一级水平。利用微氧生物接触氧化池尾水进行灌溉,不但能有效去除其中的污染物质,而且可以利用其中的氮磷资源,为农村生活污水的资源化处理提供理论依据。

In order to explore the feasibility of resource treatment of rural domestic sewage,this study employed the micro-oxygen biological contact oxidation method in combination with tail water agricultural irrigation to address nitrogen,phosphorus,and organic matter in simulated rural domestic sewage.The influence of operating parameters on the treatment effect of micro-oxygen biological contact oxidation method was measured,and the influence of tail water agricultural irrigation on crop quality,groundwater and soil was discussed.The results showed that when the dissolved oxygen of the system was micro-oxygen(0.5±0.2 mg/L),the hydraulic retention time(HRT)and temperature had significant effects on the treatment effect of biological contact oxidation method.When the HRT was more than 4 h and the temperature was 30℃or 20℃,the COD removal rate was greater than 73.32%.The COD concentration of effluent met all crop irrigation requirements(<100 mg/L),while the removal rates of NH_(4)^(+)-N,TN and TP were lower than 50%,which effectively preserved part of nitrogen and phosphorus resources.Tail water irrigation improved crop yield,while vitamin C content and reducing sugar content did not decrease significantly and nitrate nitrogen content did not exceed the edible standard.In addition,soil texture improved after irrigation,pH increased from 4.96 to 5.78,electrical conductivity decreased from 1.925 mS/cm to 1.803 mS/cm,soil acidification improved and salinization decreased,and soil fertility remained at the first level.The use of micro-oxygen biological contact oxidation tank tail water for irrigation can not only effectively remove the pollutants,but also harness the nitrogen and phosphorus resources in it,which provides a theoretical basis for the resource treatment of rural domestic sewage.