Sustainable Wastewater Management in Gotland: A System Dynamics Model for Urine Diversion and Resource Recovery

Sanitation systems are integral to urban infrastructure but face critical challenges, including inadequate coverage, sustainability issues, and environmental impacts exacerbated by population growth and urbanization. Innovative approaches, such as urine diversion, have emerged as promising solutions for resource recovery and sustainable nutrient management in wastewater treatment. This study develops a system dynamics model to evaluate the potential of urine
diversion in enhancing the sustainability of urban wastewater management, with a case focus on Visby, Gotland, Sweden. Gotland’s seasonal tourism, coupled with the Baltic Sea’s status as a highly eutrophic and vulnerable water body, intensifies the region’s water and wastewater management challenges. Using the STELLA software, the system dynamics model incorporates two modules: (1) the Visby WWTP module, which simulates the operations of Visby’s wastewater treatment plant, accounting for seasonal tourism fluctuations, and (2) the Urine Diversion module, which examines urine collection during peak tourist seasons for fertilizer production. Data were derived from environmental reports and secondary sources to simulate environmental indicators, including marine eutrophication potential, carbon footprint, and water footprint. The results will provide valuable insights into how urine diversion can enhance long-term sustainability in urban wastewater management by reducing environmental impacts and promoting resource efficiency. This study underscores the importance of integrating circular economy principles into sanitation systems to address global environmental challenges, particularly in regions experiencing seasonal population dynamics