Eco-Technological Wastewater Solutions for Arid Environments: A Case Study of Vertical Flow Constructed Wetlands in Saudi Arabia

Abstract

Water scarcity, coupled with the energy-intensive nature of conventional treatment technologies, continues to hinder the pursuit of sustainable wastewater management in arid climates. To address this challenge, a pilot vertical flow constructed wetland (VFCW) was implemented at King Saud University in Riyadh, Saudi Arabia, and assessed as a nature-based solution for treating institutional wastewater. During a 16-day monitoring period, the wetland demonstrated high treatment efficiency, with removal rates of 97.1% for total suspended solids, 86.1% for chemical oxygen demand, and 92.7% for ammonia–nitrogen, alongside a moderate reduction of total phosphorus (approximately 59%). Pollutant removal followed first-order kinetics, with rate constants aligning with those reported in other warm-climate studies, thereby validating the reliability of kinetic modeling under harsh desert conditions. The treated effluent consistently satisfied World Health Organization reuse criteria, underscoring the potential of VFCWs to alleviate pressure on centralized systems while reducing dependence on desalination and energy-demanding processes. By providing transferable kinetic parameters and performance benchmarks, this study positions VFCWs as a practical and scalable ecological technology for arid regions. More broadly, the research emphasizes the strategic importance of nature-based approaches in advancing Saudi Arabia’s Vision 2030 objectives for water security, resource recovery, and the promotion of circular water economies in water-stressed environments.