低温条件下生态槽深度处理农村生活污水的日变化特性

Diurnal variation characterization of advanced treatment of rural domestic sewage by eco-tank under low temperature

针对农村生活污水处理设施出水水质偏高污染环境的现状,构建了以水生植物为主体的生态槽深度处理农村生活污水,研究了低温条件下生态槽深度处理生活污水过程中DO、pH、COD、NH4+-N、TP等指标的日变化特性。结果表明,生活污水COD为37.67～60.23 mg/L、NH4+-N为13.66～16.76 mg/L、TP为1.32～1.78 mg/L、水温为9～11℃,HRT为5 d时,生态槽出水COD、NH4+-N和TP平均为21.07 mg/L、0.99 mg/L和0.19 mg/L,均可达《地表水环境质量标准》(GB3838-2002)之Ⅳ类水标准。各级生态槽内DO浓度夜间低于昼间。夜间植物对NH4+-N和TP具有较强的吸收作用,平均去除率分别达94.83%和89.87%;而TN去除效果稍差,平均去除率为59.9%。

In accordance with environmental pollution by effluent from rural domestic sewage treatment plants, aquatic plants-based eco-tank system was constructed for advanced treatment of domestic sewage. Diurnal variation characterization of dissolved oxygen（DO） , pH value, chemical oxygen demand（COD） , ammonium ni- trogen（NH4＋-N） and total phosphorus （TP） of the sewage under low temperature was investigated. Results showed that when influent COD was 37.67 -60.23 mg/L, NH4＋ -N was 13.66 - 16.76 mg/L, TP was 1.32 - 1.78 mg/L, temperature was 9 - 11 ℃ , and hydraulic retention time （HRT） was 5 days, average COD, NH43- N, and TP of the effluent were 21.07 mg/L, 0.99 mg/L and 0.19 mg/L separately, reaching the fourth class of the national environmental quality standard of surface water. During the night DO of all tanks was lower than at daytime. The plants exhibited strong absorption capacity to NH4＋ -N and TP at night, of which the average remov- al efficiencies reached 94.83% and 89.87% separately, while that of TN was only 59.9%.