From liquid waste to mineral fertilizer: Recovery, recycle and reuse of high-value macro-nutrients from landfill leachate to contribute to circular economy, food security, and carbon neutrality

As nutrients shortage that will occur by the next decade could limit global fertilizer production, there are growing needs to recover macro-nutrients such as P and N from landfill leachate, which its generation and treatment have become global environmental issues. This work critically reviews the applicability and the performance of physico-chemical treatments for nutrient recovery from landfill leachate. This article also identifies recent progress and bottlenecks of nutrient recovery from landfill leachate, while providing an overview of how to apply a circular economy paradigm in the nexus of water–food–energy. Due to their ability to recover P and N from landfill leachate, specific attention is given to struvite precipitation, adsorption, and ammonium stripping. Their technological strengths and bottlenecks of each technique are evaluated based on a literature survey of 145 papers (1981–2022). By integrating anaerobic digestion and other nutrient recovery technologies, it is possible for water utilities to provide both renewable energy and nutrients, while contributing to a circular economy, global food security, and carbon neutrality. To attain a sustainable landfill management, the selection of appropriate technology for nutrient recovery from the liquid waste needs to consider the properties of waste stream, recovery performance, discharge standard, impacts, and cost-effectiveness. Overall, this work has consolidated new knowledge between technological development and demand-driven valorization.