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Phosphorus flow mapping to identify opportunities for recovery and reuse

Farm fields

The need to look for more local sources of phosphorus (P), such as recycling of P in waste, becomes increasingly important as rock-phosphate quality declines. Moving towards a closed P cycle has the potential to decrease cost, increase sustainability, reduce pollution, and improve local and worldwide food security through long-term access to P. In line with the EU “Roadmap to a Resource Efficient Europe” and the “Circular Economy Action Plan”, resource recycling is important to the Scottish Government’s growth strategy, resource efficiency plans and developing a closed loop circular economy.

Although there has been a significant amount of research on P flows through natural and managed water systems, the spatial patterns of P-rich waste generation, recycling opportunities, and the economic costs associated with these remain unclear. This project seeks to build on the outputs of previous studies to pilot spatial P flow maps for large Scottish catchments with contrasting land use (urban vs rural land use). Ultimately, this may be upscaled to create a regional scale map of Scotland’s P flows. This work will allow the identification of opportunities for innovation in capture and reuse of P by assessing the economic costs associated with these steps as well as locating potential links between currently untapped sources of recoverable P (e.g. wastewater treatment) and users of P (e.g. agriculture).

Previous CREW projects relevant to this project:

Project Objectives

This project aims to map out existing P flows for two Scottish catchments of contrasting land use. The project aims to develop an improved P management strategy and highlight areas where this strategy is likely to produce the most significant results.

Specific objectives include:

  1. Produce a short review of P flows at a Scottish level, including:
    • How spatial coupling concepts (e.g. P source locations compared to P use locations) are tackled in countries where this practice is advanced (e.g. Netherlands).
    • P recovery methods appropriate to Scotland’s dominant P waste sources.
    • The major/minor P usage opportunities (e.g. fertiliser replacement in different sectors); products/forms available for reuse.
  2. Produce a P flow map for two Scottish catchments of contrasting land use.
  3. Analyse a number of scenarios (e.g. P recapture using different strategies, reuse in various locations) for the two catchments and identify areas that deliver best practise in P management and offer opportunities for generating value. Explicitly consider the costs associated with the proposed opportunities (e.g. transport, capture, and processing costs).
  4. Provide recommendations for the potential future project upscaling the results to create a P-flow map for Scotland.