土壤过滤系统处理农村生活污水过程中污染物的变化规律

采用一种土壤过滤系统处理农村生活污水,分析了该工艺处理过程中CODCr、BOD5、NH3-N、全氮(TN)和全磷(TP)的时空变化规律。实验结果表明:去除季节效果由高到低依次为:夏季>秋季>春季>冬季。土壤过滤系统对CODCr、BOD5、NH3-N、TN和TP的最高去除率分别达到87.3%、88.2%、75.9%、59.3%和74.1%;在土壤过滤系统内,沿着水流的水平方向,各物质去除率逐渐增大。采用该技术处理后,排水中TN、TP的浓度较高,用于灌溉可减少化肥使用量和节省淡水资源。     

Effect of hydraulic retention time and pH on oxidation of ferrous iron in simulated ferruginous acid mine drainage treatment with inoculation of iron-oxidizing bacteria

The effect of hydraulic retention time(HRT) and pH on the biooxidation of ferrous iron during simulated acid mine drainage(AMD)treatment was investigated.The simulated AMD was highly acidic(pH 2.5),rich in iron(about 1700 mg/L) and copper(about 200 mg/L),and contained high concentrations of sulfate(about 4700 mg/L).The biooxidation of ferrous iron was studied in a laboratory-scale upflow packed bed bioreactor(PBR).The HRT was shortened stepwise from 40 h to 20 h,13 h,and 8 h under the acidic environment at a pH value of 2.2.Then,the influent pH value was changed from 2.2 to 1.2 at a constant suitable HRT.Physiochemical and microbial community structure analyses were performed on water samples and stuffing collected from the bioreactor under different conditions.The results indicate that the efficiency of ferrous iron oxidation gradually decreased with the decrease of HRT,and when the HRT exceeded 13 h,ferrous iron in AMD was almost completely oxidized.In addition,the best efficiency of ferrous iron oxidation was achieved at the influent pH value of 1.8.Microbial community structure analyses show that Leptospirillum is the predominant genus attached in the bioreactor,and low influent pH values are suitable for the growth of Leptospirillum.