Feasibility and simulation model of a pilot scale membrane bioreactor for wastewater treatment and reuse from Chinese traditional medicine

The lack and pollution of water resource make wastewater reuse necessary. The pilot scale long-term tests for submerged membrane bioreactor were conducted to treat the effluents of anaerobic or aerobic treatment process for the high-strength Chinese traditional medicine wastewater. This article was focused on the feasibility of the wastewater treatment and reuse at shorter hydraulic retention time （HRT） of 5.0, 3.2 and 2.13 h. MLSS growth, membrane flux, vacuum values and chemical cleaning periods were also investigated. The experimental results of treating two-phase anaerobic treatment effluent demonstrated that the CODfilt was less than 100 mg/L when the influent COD was between 500-10000 mg/L at HRT of 5.0 h, which could satisfy the normal discharged standard in China. The experimental results to treat cross flow aerobic reactor effluent demonstrated that the average value of CODfilt was 17.28 mg/L when the average value of influent COD was 192.84 mg/L at HRT of 2.13 h during 106 d, which could completely meet the normal standard for water reuse. The maximum MLSS and MLVSS reached 24000 and 14500 mg/L at HRT of 3.2 h respectively. Membrane flux had maximal resume degrees of 94.7% at vacuum value of 0.02 MPa after cleaning. Chemical cleaning periods of membrane module were 150 d. A simulation model of operational parameters was also established based on the theory of back propagation neural network and linear regression of traditional mathematical model. The simulation model showed that the optimum operational parameters were suggested as follows： HRT was 5.0 h, SRT was 100 d, the range of COD loading rate was between 10.664-20.451 kg/（m3.d）, the range of MLSS was between 7543-13694 mg/L.

透水路面-生物滞留池组合道路的城市面源污染控制效果评估

不同低影响开发（LID）技术组合对于控制城市面源污染具有重要应用价值,但是其对城市面源污染形成过程（污染物累积-冲刷-输送）的影响及污染负荷削减效果的评估鲜见报道.本研究以深圳市国际低碳城为例,分析了6场降雨事件下透水路面-生物滞留池组合对城市面源晴天污染物累积量、降雨径流冲刷量、不同LID设施的削减量、溢流的负荷量的影响.结果表明,研究区地表颗粒物平均累积量为（15.80±3.79）g·m^-2,粒径〉250μm的颗粒物质量占比约为65.14%;6场不同强度降雨对地表颗粒物的平均冲刷率为17.15%,粒径〈105μm的颗粒物冲刷率为62.71%-74.94%;降雨冲刷地表径流污染物SS、TN、TP的平均污染负荷分别为2.02、0.025、0.001 3 g·m^-2;透水路面下渗、过滤作用对污染物SS、TN、TP的去除率分别为70.26%、46.29%、19.27%;生物滞留池对径流二次净化去除率分别为85.25%、20.22%、70.27%;入河径流污染物SS、TN、TP的平均污染负荷分别为0.08、0.011、0.000 3 g·m^-2,是地表冲刷污染负荷的4.05%、43.47%、24.39%.透水路面-生物滞留池组合应用对道路径流中污染物的净化效果显著.通过定量化表征透水路面-生物滞留池组合应用道路的城市面源污染形成过程,以期为城市面源污染形成过程的污染负荷估算及LID工程绩效评估提供科学依据,为LID在国内的推广应用和海绵城市设计提供参考.

雨水花园施工过程的场地污染特征研究

当前我国海绵城市建设中低影响开发(LID)施工场地污染普遍存在,但却没有引起足够的重视与正确的认识。为此,以镇江市雨水花园施工场地为例,分析了不同施工阶段地表沉积物的静态空间分布特征与动态径流污染特征,并与未施工场地进行对比。结果表明,开挖、铺砂、填土及种植阶段的地表沉积物单位面积质量分别为(478.7±14.57)、(261.74±37.79)、(76.18±17.22)、(31.83±9.44)g/m^2,均高于未施工场地[(17.71±2.81)g/m^2],且各施工阶段的地表沉积物均以粗粒径(149~1 000μm)为主;各施工阶段地表沉积物中的重金属含量均低于未施工场地,但重金属污染负荷均高于未施工场地,由高到低依次为开挖阶段、铺砂阶段、填土阶段、种植阶段;地表沉积物的扩散迁移距离约为120 m。施工道路径流中总悬浮固体与重金属浓度均高于未施工道路,施工道路径流中总悬浮固体的场次降雨径流平均浓度(EMC)约为未施工道路的2.8倍。基于上述结果,提出了适合我国海绵城市建设的LID场地径流污染控制措施。