水力负荷对污水地下渗滤系统处理效果的影响

采用人工模拟的方法,研究了0.04、0.06、0.10、0.14和0.18 m3/(m2·d)5个水力负荷下污水地下渗滤系统对生活污水处理效果的影响。实验期间,SS、BOD5、COD、TN、NH4+-N和TP的进水浓度分别处于69.74~79.62、40.75~64.81、211.56~250.72、48.94~87.36、31.25~59.04和2.88~4.05 mg/L之间,出水平均浓度分别为13.63、9.66、31.53、21.08、1.90和0.10 mg/L。结果表明,地下渗滤系统对生活污水具有良好的处理效果,除TN外,其余各项指标均满足《城镇污水处理厂污染物排放标准》(GB/18918-2002)一级处理要求;当水力负荷为0.14和0.18 m3/(m2·d)时,BOD5 与TN去除率降低,出水浓度升高,受水力负荷影响明显;水力负荷对SS与COD影响作用微弱,去除率降幅较小;NH4+-N与TP则基本不受水力负荷变化影响。综合考虑渗滤系统的出水水质与日处理能力,推荐适宜水力负荷为0.10~0.14 m3/(m2·d)。

Effect of hydraulic loading rate on sewage treatment efficiency of subsurface wastewater infiltration system

A simulation experiment was carried out to study the effect of subsurface wastewater infiltration system(SWIS) on sewage treatment efficiency by different hydraulic loading of 0.04, 0.06, 0.10, 0.06 and 0.10 m3/(m2·d). During the experiment, the concentrations of SS, BOD5, COD, TN, NH4+-N and TP in the influent were 69.74-79.62, 40.75-64.81, 64.81-250.72, 48.94-87.36, 87.36-59.04 and 2.88-4.05 mg/L, and the average effluent concentrations were 13.63, 9.66, 31.53, 21.08, 1.90 and 0.10 mg/L, respectively. The results showed that the SWIS had a good effect on sewage treatment and the concentrations excluding TN could reach the primary standard of GB/18918-2002. When the hydraulic loading was raised to 0.14 and 0.18 m3/(m2·d), the removal efficiency of BOD5 and TN reduced and the effluent concentrations increased, which showed that the hydraulic loading had obvious effects on BOD5 and TN. Besides, the removal efficiency of SS and COD decreased slightly; the hydraulic loading had no effect on NH4+-N and TP basically. Considering the effluent quality and the capacity of wastewater treatment in the SWIS, the optimum hydraulic loading was between 0.10-0.14 m3/(m2·d) in this or similar experiment.