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; School of Civil and Environmental Engineering, University of New South Wales, Sydney 2052, Australia; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Guangdong University of Technology, Guangzhou 510006, PR China.
Sci Total Environ. 2022 Dec 10;851(Pt 1):158197. doi: 10.1016/j.scitotenv.2022.158197. Epub 2022 Aug 20.
The collected roofing rainwater with high water quality and large water volume, can alleviate the crisis of water resources and fit the Low-Impact Development (LID) concept. In this work, a novel water purification technology, Electro-Coagulation coupled with Gravity-Driven Ceramic Membrane Bio-Reactor (EC-GDCMBR) was developed for the roofing rainwater purification under long-term operation (136 days). EC-GDCMBR system not only exhibited the better effluent quality, but also obtained the greater flux (32 LMH). The reason contributed to the high permeability of ceramic membrane and large porosity of biofilm formed by floc growth (36 μm) during the EC process, which was also proved by SEM image. The coagulation, adsorption, biodegradation, and coprecipitation of EC-GDCMBR was able to synergistically remove the particulate matter, ammonia nitrogen (NH-N), Total Phosphorus (TP), organic substances, and heavy metal (i.e., Cr, Zn, and Cu). In particular, via the analysis of bacterial abundance, Extracellular Polymeric Substances (EPS), Assimilable Organic Carbon (AOC), Adenosine Tri-Phosphate (ATP) and Confocal Laser Scanning Microscopy (CLSM), EC could sweep most free bacteria on the ceramic membrane surface, enhancing the biological purification efficiency. Furthermore, a large amount of Pseudomonas (12.4 %-66.7 %) and Nitrospira (1.46 %-3.16 %) in the aggregates formed the biofilms, improved the NH-N removal. During the long-term operation, there are some unavoidable problems, such as the thick and ripened biofilm of EC-GDCMBR would crack and fall off. Based on this, the current work also studied the reliability of GDCMBR under "extreme operating case", and the results showed that neither the biofilm detachment nor the biofilm breakup had a significant impact on the effluent quality. Overall, the findings of this study suggest the reliability of EC-GDCMBR for the sustainable operation of roofing rainwater purification and improve the application value of decentralized rainwater harvest device.
收集的雨水水质好、水量大，可以缓解水资源危机，符合低影响开发（LID）理念。在这项工作中，开发了一种新型的水净化技术，即电絮凝与重力驱动陶瓷膜生物反应器（EC-GDCMBR）联用技术，用于长期运行（136 天）下的屋面雨水净化。EC-GDCMBR 系统不仅表现出更好的出水水质，而且获得了更大的通量（32 LMH）。这是由于电絮凝过程中陶瓷膜的高渗透性和絮体生长形成的生物膜的大孔隙率（36μm）所致，这也通过 SEM 图像得到了证明。EC-GDCMBR 的絮凝、吸附、生物降解和共沉淀协同作用可以去除颗粒物、氨氮（NH-N）、总磷（TP）、有机物和重金属（即 Cr、Zn 和 Cu）。特别是通过细菌丰度、胞外聚合物（EPS）、可同化有机碳（AOC）、三磷酸腺苷（ATP）和共聚焦激光扫描显微镜（CLSM）的分析，EC 可以清除陶瓷膜表面的大部分游离细菌，提高生物净化效率。此外，大量的假单胞菌（12.4%-66.7%）和硝化螺旋菌（1.46%-3.16%）在形成的生物膜中聚集，提高了 NH-N 的去除率。在长期运行过程中，EC-GDCMBR 会出现一些不可避免的问题，如电絮凝-GDCMBR 上的生物膜变厚、成熟后会破裂和脱落。基于此，本工作还研究了 GDCMBR 在“极端运行情况下”的可靠性，结果表明生物膜的脱落和破裂对出水水质没有显著影响。总体而言，本研究结果表明 EC-GDCMBR 用于屋面雨水净化的可持续运行是可靠的，提高了分散式雨水收集装置的应用价值。
