ReviewPhosphorus recovery and recycling with ecological engineering: A review

- Ecological engineers have largely focused on landscape retention systems for P management.
- Ecological engineering can play a broader role that supports a circular P economy.
- Several ecological engineering approaches to P recovery and recycling have emerged.
- Many strategies show promise for producing recovered P fertilizer and co-benefits, but challenges remain.
- A systems framework is outlined that can guide research on P recovery and recycling.

Phosphorus is essential to life on Earth and frequently limits the productivity of ecosystems, including agroecosystems. Currently, a substantial portion of the global human population relies on finite phosphate rock resources used for chemical fertilizer production. Concern over poor management of these vital resources and continued efforts to enhance soil fertility and food security have stimulated interest in phosphorus recovery and recycling. Existing heterogeneity in phosphorus waste flows, agricultural phosphorus needs, the availability of resources, and spatial patterns of land use calls for a diverse array of phosphorus recycling strategies. Ecological engineers working on phosphorus management have most commonly aimed to create phosphorus sinks on the landscape to help mitigate eutrophication. There is a growing need for ecological engineering approaches that go beyond phosphorus retention to create pathways for phosphorus recovery and recycling, supporting both eutrophication control and food security. This review includes a brief overview of human impacts on the global phosphorus cycle and a survey of existing ecological engineering techniques for phosphorus recovery and recycling discussed in the literature. A systems approach for design and feasibility assessment of phosphorus recycling with eco-technology is outlined, along with several key challenges. The importance of an interdisciplinary, multiple element, and multiple resource approach to phosphorus recycling is emphasized.