Center for Microbial Ecology & Technology (CMET), Ghent University, Frieda Saeysstraat 1, Ghent 9052, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium.
Center for Microbial Ecology & Technology (CMET), Ghent University, Frieda Saeysstraat 1, Ghent 9052, Belgium; Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Ghent, Belgium; Center for Water and Sustainable Development, Facultad de Ciencias Naturales y Matemáticas, ESPOL Polytechnic University, Guayaquil, Ecuador.
Water Res. 2023 May 15;235:119818. doi: 10.1016/j.watres.2023.119818. Epub 2023 Feb 28.
Greywater is an attractive source for water reuse at the household or building level, particularly for non-potable applications. Two greywater treatment approaches are membrane bioreactors (MBR) and moving bed biofilm reactors (MBBR), yet, their performance has not been compared so far within their respective treatment flowsheets, including post-disinfection. Two lab-scale treatment trains were operated on synthetic greywater: a) MBR with either polymeric (chlorinated polyethylene, C-PE, 165 days) or ceramic (silicon carbide, SiC, 199 days) membranes coupled with UV disinfection; and b) single-stage (66 days) or two-stage (124 days) MBBR coupled with an electrochemical cell (EC) for in-situ disinfectant generation. Water quality was constantly monitored, and Escherichia coli log removals were assessed through spike tests. Under low-flux operation of the MBR (<8 L·m ·h ), the SiC membranes delayed the onset of membrane fouling and needed less frequent cleaning compared to C-PE membranes. Both treatment systems met most water quality requirements for unrestricted greywater reuse, at a 10-fold lower reactor volume for the MBR than the MBBR. However, neither the MBR nor the two-staged MBBR allowed adequate nitrogen removal, and the MBBR did not consistently meet effluent chemical oxygen demand and turbidity requirements. Both EC and UV provided non-detectable E. coli concentrations in the effluent. Although the EC provided residual disinfection, scaling and fouling decreased its energetic and disinfection performance over time, making it less efficient than UV disinfection. Several outlines to improve the performance of both treatment trains and disinfection processes are proposed, thus, allowing a fit-for-use approach that leverages the advantages of the respective treatment trains. Results from this investigation will assist in elucidating the most efficient, robust, and low-maintenance technology and configurations for small-scale greywater treatment for reuse.
灰水是家庭或建筑物层面上再利用水的一个有吸引力的来源，特别是对于非饮用用途。有两种灰水处理方法，即膜生物反应器（MBR）和移动床生物膜反应器（MBBR），但迄今为止，它们在各自的处理流程图中，包括消毒后，尚未进行比较。我们使用合成灰水运行了两个实验室规模的处理系统：a）MBR 与聚合膜（氯化聚乙烯，C-PE，165 天）或陶瓷膜（碳化硅，SiC，199 天）相结合，并辅以紫外线消毒；b）单级（66 天）或两级（124 天）MBBR 与电化学电池（EC）相结合，用于原位消毒剂生成。我们持续监测水质，并通过加标试验评估大肠杆菌对数去除率。在 MBR 的低通量运行（<8 L·m -2·h -1）下，SiC 膜延迟了膜污染的开始，与 C-PE 膜相比，需要更频繁地清洗。两种处理系统均满足无限制灰水再利用的大多数水质要求，与 MBBR 相比，MBR 的反应器体积低 10 倍。然而，MBR 和两级 MBBR 都不能充分去除氮，并且 MBBR 也不能始终满足出水化学需氧量和浊度要求。EC 和 UV 都在出水处提供不可检出的大肠杆菌浓度。尽管 EC 提供了残留消毒效果，但结垢和污染会随着时间的推移降低其能量和消毒性能，使其效率低于 UV 消毒。我们提出了一些改进两种处理系统和消毒过程性能的方案，从而可以采用一种适合使用的方法，利用各自处理系统的优势。本研究的结果将有助于阐明用于小规模灰水处理再利用的最有效、最稳健和低维护的技术和配置。
