Adopting the circular model: opportunities and challenges of transforming wastewater treatment plants into resource recovery factories in Saudi Arabia

Abstract

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 resource 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.

Are Rainwater and Stormwater Part of the Urban CE Efficiency?

“…Already at that time, there was the perception that the linear model of economic development was unsustainable from the point of view of resource productivity and eco-efficiency, and that the strategy defined, using a CE model policy, promised to be the appropriate response, despite not yet having the necessary policies, institutions, and regulation requirements for its implementation [13]. Thus, in this way, in China, they thought that it would be possible to achieve sustainable development, i.e., without the exaggerated consumption of its resources.…”

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Performance Evaluation of a Pilot-Scale Aerobic Granular Sludge Integrated with Gravity-Driven Membrane System Treating Domestic Wastewater

“…By 2030, the global demand for energy and fresh water is expected to increase by 40 and 50%, respectively . To augment these depleting resources, municipal wastewater cannot be regarded anymore as merely a “waste” but as a valuable resource of water for reuse, energy, and materials/minerals. − Globally, more than 360 billion m 3 of wastewater is produced annually, out of which ∼50% is treated and only ∼10% is reused. , Currently, the most widely used biological wastewater treatment process is the conventional activated sludge (CAS) process, and it has been employed in most wastewater treatment plants (WWTPs) for over a century, where organic matter is aerobically converted to biomass and carbon dioxide. , In the CAS process, biological wastewater treatment is carried out by small microbial aggregates (size around 0.2 mm), also referred to as a floc or activated sludge, which typically grows in suspension in the treatment reactor. A subsequent settling tank (secondary clarifier) is used to separate activated sludge from the treated water by the sedimentation process.…”

Water demand in university: rainwater harvesting system and COVID-19 crisis influence on water demand

“…Many are the challenges due to the rapidly growing human population, leading to increased resource how energy, food, chemicals, and water (Ali et al, 2022). Furthermore, because of rapid urbanization, population growth, climate change, desertification, and the uneven distribution of water resources in some parts of the world, water demand has increasingly outgrown its supply (Akpan et al, 2020).…”