School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
Sci Total Environ. 2019 Dec 20;697:134187. doi: 10.1016/j.scitotenv.2019.134187. Epub 2019 Aug 30.
Rainwater harvesting (RWH) coupled with gravity-driven membrane (GDM) filtration was used to simultaneously treat rainwater and recover energy. A pilot GDM could obtain a relatively stable level of permeate flux (4.0 L/(m·h)) under a set water head (ΔH = 0.4 m) over 140 days of operation. An increase water head (ΔH = 0.6 m) did not achieve a sharp increase in stabilized flux (2.4 L/(m·h)) over 20 days of operation until the end. It was found that GDM filtration could produce a permeate that was almost free of particles. However, only a small amount of organic matter and trace metals (i.e., Cr, Al, Fe, Cu, Al, Mn and Ca) were removed, as demonstrated by excitation-emission matrix (EEM) and energy dispersive spectrometry (EDS) analysis. Additionally, the bacterial abundance within the permeate ((8.45 ± 0.11) × 10 cells/mL) decreased compared to that within the GDM tank ((1.85 ± 0.14) × 10 cells/mL), revealing that the rejected bacteria might enhance biofilm formation. The presence of extracellular polymeric substances (EPS), adenosine triphosphate (ATP) and assimilable organic carbon (AOC) indicated a high level of microbial activity within the biofilm, which was also demonstrated by the porous cake layer morphology observed by scanning electron microscopy (SEM) and results from confocal laser scanning microscopy (CLSM) imaging of the biofilm. NH-N was removed by Nitrospira within the biofilm, which was identified by microbial community analysis. Overall, this novel approach has the potential to improve municipal water availability and stormwater management practices.
雨水收集与重力驱动膜过滤相结合，可同时处理雨水并回收能源。在 140 天的运行中，采用一个小型重力驱动膜，在设定的水头（ΔH=0.4 m）下可获得相对稳定的渗透通量（~4.0 L/（m·h））。增加水头（ΔH=0.6 m）在 20 天的运行中并没有导致通量的显著增加，直到运行结束。研究发现，重力驱动膜过滤可以产生几乎不含颗粒的渗透物。然而，通过激发-发射矩阵（EEM）和能量色散光谱（EDS）分析发现，只有少量的有机物和痕量金属（即 Cr、Al、Fe、Cu、Al、Mn 和 Ca）被去除。此外，与重力驱动膜过滤罐内的细菌丰度（（1.85±0.14）×10 cells/mL）相比，渗透物中的细菌丰度（（8.45±0.11）×10 cells/mL）有所下降，这表明被截留的细菌可能会促进生物膜的形成。胞外聚合物物质（EPS）、三磷酸腺苷（ATP）和可同化有机碳（AOC）的存在表明生物膜内的微生物活性很高，这也通过扫描电子显微镜（SEM）观察到的多孔饼层形态和生物膜的共聚焦激光扫描显微镜（CLSM）成像结果得到了证实。生物膜内的硝化菌（Nitrospira）去除了氨氮，这是通过微生物群落分析鉴定的。总的来说，这种新方法有可能改善城市供水的可用性和雨水管理实践。
