College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge, Middlesex UB8 3PH, UK.
Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, 5 Iroon Polytechniou St., Zografou Campus, 15780 Athens, Greece.
Sci Total Environ. 2018 Oct 15;639:1268-1282. doi: 10.1016/j.scitotenv.2018.05.247. Epub 2018 May 26.
Significant growth of the human population is expected in the future. Hence, the pressure on the already scarce natural water resources is continuously increasing. This work is an overview of membrane and filtration methods for the removal of pollutants such as bacteria, viruses and heavy metals from surface water. Microfiltration/Ultrafiltration (MF/UF) can be highly effective in eliminating bacteria and/or act as pre-treatment before Nanofiltration/Reverse Osmosis (NF/RO) to reduce the possibility of fouling. However, MF/UF membranes are produced through relatively intensive procedures. Moreover, they can be modified with chemical additives to improve their performance. Therefore, MF/UF applicability in less developed countries can be limited. NF shows high removal capability of certain contaminants (e.g. pharmaceutically active compounds and ionic compounds). RO is necessary for desalination purposes in areas where sea water is used for drinking/sanitation. Nevertheless, NF/RO systems require pre-treatment of the influent, increased electrical supply and high level of technical expertise. Thus, they are often a highly costly addition for countries under development. Slow Sand Filtration (SSF) is a simple and easy-to-operate process for the retention of solids, microorganisms and heavy metals; land use is a limiting factor, though. Rapid Sand Filtration (RSF) is an alternative responding to the need for optimized land use. However, it requires prior and post treatment stages to prevent fouling. Especially after coating with metal-based additives, sand filtration can constitute an efficient and sustainable treatment option for developing countries. Granular activated carbon (GAC) adsorbs organic compounds that were not filtered in previous treatment stages. It can be used in conjunction with other methods (e.g. MF and SSF) to face pollution that results from potentially outdated water network (especially in less developed areas) and, hence, produce water of acceptable drinking quality. Future research can focus on the potential of GAC production from alternative sources (e.g. municipal waste). Given the high production/operation/maintenance cost of the NF/RO systems, more cost-effective but equally effective alternatives can be implemented: e.g. (electro)coagulation/flocculation followed by MF/UF, SSF before/after MF/UF, MF/UF before GAC.
预计未来人口将大幅增长。因此，本已稀缺的淡水资源所面临的压力持续增加。本文综述了膜过滤方法在去除地表水中的污染物（如细菌、病毒和重金属）方面的应用。微滤/超滤（MF/UF）在去除细菌方面非常有效，或可作为纳滤/反渗透（NF/RO）的预处理，以降低结垢的可能性。然而，MF/UF 膜的生产过程较为复杂，而且可以通过添加化学添加剂进行改性以提高性能。因此，MF/UF 在欠发达国家的适用性可能会受到限制。NF 对某些污染物（如药物活性化合物和离子化合物）具有较高的去除能力。RO 是海水用于饮用水/卫生用途的地区进行海水淡化所必需的。然而，NF/RO 系统需要对进水进行预处理、增加电力供应并具备较高的技术专业知识。因此，对于发展中国家来说，它们通常是一个成本高昂的附加系统。慢砂过滤（SSF）是一种简单易用的固液、微生物和重金属保留工艺，但土地利用是一个限制因素。快速砂过滤（RSF）是一种满足优化土地利用需求的替代方法，但需要在前处理和后处理阶段防止结垢。尤其是经过金属基添加剂涂覆后，砂滤可以成为发展中国家的一种高效、可持续的处理选择。颗粒活性炭（GAC）吸附在前处理阶段未被过滤的有机化合物。它可以与其他方法（如 MF 和 SSF）结合使用，以应对可能已过时的供水管网（尤其是在欠发达地区）造成的污染，从而生产出可接受的饮用水质。未来的研究可以集中在从替代来源（如城市废物）生产 GAC 的潜力上。鉴于 NF/RO 系统的高生产成本/运营/维护成本，可以实施更具成本效益但同样有效的替代方法：例如，（电）混凝/絮凝后进行 MF/UF、MF/UF 前后进行 SSF、MF/UF 前进行 GAC。
