The study conducted by IIASA focused on assessing the feasibility of recovering phosphorus from municipal wastewater as a sustainable alternative source of this non-renewable mineral. Phosphorus is essential for human health and plant growth, making it a key ingredient in fertilizers. However, it is a finite resource obtained through mining and processing of phosphate rock, and its uneven distribution globally, coupled with increasing food demand, has raised concerns about potential future fertilizer price hikes. Therefore, there is an urgent need to improve phosphorus use efficiency.
Recovering phosphorus from municipal wastewater has been identified as a potential sustainable source of this mineral, as the majority of phosphorus consumed in urban areas ends up in sewage sludge. The current practice of land application of sewage sludge in Europe is becoming controversial due to the presence of both valuable resources and harmful substances in sludge, which can impact soil health and biodiversity. Therefore, effective recovery methods could help minimize environmental impacts, promoting healthier water systems and ecosystems.
The study by IIASA evaluated various phosphorus recovery technologies and their costs, as well as greenhouse gas emissions, to identify economically viable strategies for phosphorus recovery from municipal wastewater. The research focused on different scenarios, including individual plants and hub strategies for phosphorus recovery, as well as various sludge management options. Sweden was chosen as a case study due to its reliance on land application of sewage sludge and potential legislative shifts favoring extraction methods.
The researchers found that economic viability of phosphorus recovery varied between individual plants and strategies, with high recovery costs making it less profitable without subsidies. Hub strategies involving collaboration among multiple plants were identified as a way to reduce costs and make recovery more economically feasible. Developing hub networks and converting sludge into marketable products could generate revenue and offset disposal costs, reducing overall management expenses.
The study underscores the importance of external factors, such as regulatory mandates and long-term increases in fertilizer prices, in making phosphorus recovery economically viable. The authors caution against policies that prioritize specific recovery technologies without considering diverse conditions, highlighting the need for comprehensive environmental impact assessments to prevent unintended increases in emissions. Understanding phosphorus recovery economics is crucial for informed investments and supporting a circular economy by recycling waste into valuable resources.
Overall, the research emphasizes the significance of phosphorus recovery in ensuring a sustainable supply of this essential mineral, reducing reliance on finite resources, and supporting food security. Cost-effective methods and collaborative approaches are crucial for enhancing financial sustainability and promoting the circular economy. By implementing tailored solutions to address challenges in phosphorus recovery, as outlined in the study, policymakers and municipal wastewater treatment plant operators can work towards developing supportive regulations and promoting sustainable practices in phosphorus recovery.