Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia.
School of Civil and Environmental Engineering, UNSW Sydney, NSW 2052, Australia.
Water Res. 2020 Oct 15;185:116228. doi: 10.1016/j.watres.2020.116228. Epub 2020 Jul 24.
Low energy and cost solutions are needed to combat raising water needs in urbanised areas and produce high quality recycled water. In this study, we investigated key processes that drive a unique greywater treatment train consisting of a passive green wall biofiltration system followed by disinfection using a Boron-doped diamond (BDD) electrode with a solid polymer electrolyte (SPE). In both systems, the treatment was performed without any additional chemicals and pollutants of concern were monitored for process evaluation. The green wall system removed over 90% of turbidity, apparent colour, chemical oxygen demand, total organic carbon, and biological oxygen demand, and 1 log of E. coli and total coliforms, mostly through biological processes. The green wall effluent met several proposed greywater reuse guidelines, except for E. coli and total coliform treatment (below 10 MPN/100 mL). Further disinfection of treated greywater (contained 28 mg/L Cl¯ and electrical conductivity (EC) of 181.3 µS/cm) by electrolysis at current density 25 mA/cm inactivated over 3.5 logs of both E. coli and total coliforms, in 10 - 15 min of electrolysis, resulting in recycled water with less than 2 MPN/100 mL. A synergistic effect between electrochemically-generated free chlorines and reactive oxygen species contributed to the inactivation process. Although the treated water contained diluted chloride and had low EC, estimated energy consumption was just 0.63 - 0.83 kWh/m. This is the first study to show the effectiveness of a low energy and a low cost greywater treatment train that combines green urban infrastructure with BDD electrochemical treatment process with SPE, offering a reliable and an environmentally-friendly method for greywater reuse.
需要低能耗和低成本的解决方案来应对城市化地区不断增加的用水需求，并生产高质量的再生水。在这项研究中，我们研究了驱动独特灰水处理火车的关键过程，该火车由被动绿色墙生物过滤系统组成，随后使用掺硼金刚石 (BDD) 电极和固体聚合物电解质 (SPE) 进行消毒。在这两个系统中，处理过程均无需添加任何其他化学品，并且监测了关注的污染物，以进行工艺评估。绿色墙系统去除了超过 90%的浊度、表观颜色、化学需氧量、总有机碳和生物需氧量，以及 1 对数的大肠杆菌和总大肠菌群，主要通过生物过程。绿色墙流出物符合几项提出的灰水再利用指南，除了大肠杆菌和总大肠菌群的处理（低于 10 MPN/100 毫升）。进一步通过在电流密度为 25 mA/cm 的情况下对处理后的灰水（含有 28 mg/L Cl¯和 181.3 µS/cm 的电导率 (EC)）进行电解消毒，在 10-15 分钟的电解过程中，使大肠杆菌和总大肠菌群的活性降低了 3.5 个对数，从而使再生水的含量低于 2 MPN/100 毫升。电化学产生的自由氯和活性氧之间的协同作用有助于失活动力学。尽管处理后的水中含有稀释的氯化物且 EC 较低，但估计的能耗仅为 0.63-0.83 kWh/m。这是第一项研究，该研究表明，结合绿色城市基础设施和 BDD 电化学处理过程与 SPE 的低能耗和低成本灰水处理火车的有效性，为灰水再利用提供了一种可靠且环保的方法。
