Clean Water Production from Urban Sewage by Algae-Based Treatment Techniques, a Reflection of Case Studies

The inadequate collection and treatment of urban wastewater continue to pollute built environments, threaten public health, and contribute to epidemic outbreaks in many densely populated, underdeveloped regions. This study investigates whether algae-based wastewater treatment offers an optimal and efficient solution for drought-prone and underdeveloped cities. Given recent global challenges, such as the COVID-19 pandemic, nature-based wastewater treatment methods—particularly algae-based systems—have regained attention due to their feasibility, cost-effectiveness, and sustainability. Algae-based wastewater treatment presents an innovative approach to sustainable urban development, offering environmental, resource-efficient, energy-saving, and biodiversity benefits while supporting circular economy principles. This study evaluates recent advancements in wastewater treatment technologies and applies a case study methodology to Zahedan City, analyzing sewage canal networks, wastewater composition, and treatment feasibility. Three algae-based techniques were assessed, with waste stabilization ponds (WSPs) identified as the most suitable solution based on technical, economic, and environmental indicators. Key factors such as climate conditions, land-use policies, and cost-effectiveness were incorporated into the comparative analysis, enhancing the scientific rigor of this study compared to prior research. The findings provide actionable insights for urban planners, engineers, and policymakers to address simultaneous challenges in wastewater management, public health, and water scarcity.