With the ever-growing population, water, energy, and resources need to be used carefully, reused, and renewed. There is an increasing global interest in resource recovery from ‘waste’, which is driven by sustainability and environmental concerns and motivated by the potential for economic benefits. A new era in waste (water) management is being realized where wastewater treatment is becoming part of the circular economy by integrating the production of reusable water with energy and resource recovery. In this new perspective, wastewater is no longer seen as a waste to be treated with energy expenditure but rather as a valuable source of freshwater, energy, nutrients (nitrogen and phosphorous), and materials (e.g., bioplastics, cellulose fibres, and alginate). In this review paper, the conversion of wastewater treatment plants (WWTPs) into resource recovery factories (RRFs) is presented as one of the ways forward to achieve a circular economy in the water sector for the Kingdom of Saudi Arabia (KSA). The advanced technologies, some highlighted in the article, can be installed, integrated, or retrofitted into existing WWTPs to create RRFs enabling the recovery of freshwater, cellulose, alginate-like exopolymers (bio-ALE), and biogas from municipal wastewater achieving climate neutrality, decarbonization, and production of new and promising resources. The article highlights the need for modular, adaptive, and/or decentralized approaches using sustainable technologies such as aerobic granular sludge (AGS)-gravity-driven membrane (AGS-GDM), anaerobic electrochemical membrane bioreactor (AnEMBR), and anaerobic membrane bioreactor (AnMBR) for conducive localized water reuse. The increase in reuse will reduce the pressure on non-renewable water resources and decrease dependency on the energy-intensive desalination process. This article also outlines the water challenges that are arising in KSA and what are the major water research programmes/themes undertaken to address these major challenges.

随着人口的不断增长，水、能源和资源需要谨慎使用、再利用和更新。全球对从“废物”中回收资源越来越感兴趣，这是由可持续性和环境问题驱动的，并受到经济利益潜力的推动。废水（水）管理的新时代正在实现，废水处理通过将可重复使用水的生产与能源和资源回收相结合，成为循环经济的一部分。在这个新的视角下，废水不再被视为需要消耗能量来处理的废物，而是作为淡水、能量、营养物质（氮和磷）和材料（例如生物塑料、纤维素纤维和藻酸盐）的宝贵来源. 在这篇评论文章中，将污水处理厂 (WWTP) 转变为资源回收厂 (RRF) 被认为是沙特阿拉伯王国 (KSA) 在水行业实现循环经济的途径之一。文章中强调的一些先进技术可以安装、集成或改装到现有的污水处理厂中，以创建 RRF，从而能够从城市废水中回收淡水、纤维素、藻酸盐类外聚合物 (bio-ALE) 和沼气，实现气候中和，脱碳和生产新的和有前途的资源。本文强调了使用可持续技术的模块化、自适应和/或分散方法的必要性，例如好氧颗粒污泥 (AGS)-重力驱动膜 (AGS-GDM)、厌氧电化学膜生物反应器 (AnEMBR)、和厌氧膜生物反应器（AnMBR）有利于局部水的再利用。再利用的增加将减少对不可再生水资源的压力，并减少对能源密集型海水淡化过程的依赖。本文还概述了沙特阿拉伯面临的水资源挑战，以及为应对这些重大挑战而开展的主要水资源研究计划/主题是什么。