A recent study evaluated the possibility of extracting phosphorus from municipal wastewater as a sustainable alternative to this non-renewable mineral.
Focusing on Sweden, a new study from IIASA has examined the potential of reclaiming phosphorus from municipal wastewater as a sustainable alternative to this essential but non-renewable mineral.
Phosphorus is a vital mineral found in many common foods and is essential for human health. It also plays a critical role in plant growth, making it a key component in fertilizers. Phosphorus is mainly sourced from the mining and processing of phosphate rock, but it is a limited resource. Experts warn that its uneven availability globally, combined with increasing food demands, may lead to higher fertilizer prices in the future. This situation underscores the urgent need to enhance phosphorus utilization efficiency.
Research has indicated that recovering phosphorus from municipal wastewater could serve as a sustainable alternative source since nearly 98% of phosphorus consumed in urban areas is sent to sewage sludge. At present, land application is the most common method of managing sewage sludge in Europe. This approach involves spreading treated sludge onto land to enrich soil and supply nutrients to crops, but it is becoming more contentious. The presence of valuable resources alongside harmful substances in sludge raises concerns, as land application can introduce both phosphorus and dangerous contaminants into the environment. Efficient recovery techniques could help mitigate these environmental issues, promoting healthier water systems and enhancing biodiversity.
In their research, Marzieh Bagheri, a former participant in the IIASA Young Scientists Summer Program (YSSP), along with colleagues from IIASA, assessed various phosphorus recovery technologies, their associated costs, and greenhouse gas emissions to find economically feasible methods for extracting phosphorus from municipal wastewater.
The study explores different scenarios, including the application of phosphorus recovery technologies in individual plants and hubs, as well as various sludge management strategies such as land application, incineration, and hydrochar production based on current market conditions. Sweden was chosen as a case study due to its heavy reliance on land application for sewage sludge and the potential for legislative changes that could support extraction methods.
“Our research looks into the economic feasibility of phosphorus recovery in Swedish municipal wastewater treatment facilities and identifies the potential challenges that could arise. We also suggest tailored solutions for municipal treatment operators and advocate for future policies to create supportive frameworks for phosphorus recovery,” Bagheri explains.
The widespread presence of smaller municipal wastewater treatment plants in Sweden has been identified as a significant barrier, creating major economic and logistical challenges that deter investment in phosphorus recovery.
The team found that the economic prospects for phosphorus recovery vary greatly across different plants and approaches. Individual facilities face high recovery expenses, making the process less profitable without financial support. In contrast, hub strategies, which involve partnerships among several plants, can help lower costs. Furthermore, the study highlights that establishing hub networks and transforming sludge into sellable products can generate income and offset disposal expenses, thereby reducing overall management costs.
The study’s findings stress the importance of external factors, such as regulatory requirements or long-term fertilizer price increases, in determining the economic viability of phosphorus recovery. However, the authors caution that promoting specific phosphorus recovery technologies through policy may limit flexibility to adapt to varying conditions, potentially favoring costly infrastructure investments while neglecting more sustainable practices. They also emphasize the need for thorough environmental impact assessments for each technology to prevent unintended emissions increases.
“Phosphorus is critical for food production, and efficiently recovering this mineral from wastewater is essential for ensuring a sustainable supply while decreasing dependence on limited resources and supporting food security,” states Adriana Gomez Sanabria, a researcher in the IIASA Pollution Management Research Group. “Understanding the economics of phosphorus recovery is crucial for making well-informed investment decisions. Cost-effective strategies and collaborative initiatives could significantly improve financial sustainability and bolster the circular economy by recycling waste into valuable resources.”
