Recovery and Valorisation of Phosphorus compounds from Waste Water Streams using Magnetic Adsorption-Desorption (MAD)

Phosphorus compounds are scarce, cause eutrophication and should be reused in a circular economy. This project aims to develop a sustainable method for the recovery of phosphates from effluent streams with better opportunities for reuse.

P-recovery, state of the art

Currently, phosphate is mainly removed through chemical precipitation or biological processesinvolving phosphate accumulating bacteria. While these methods are efficient, the extracted phosphate is rarely reused in e.g. fertilizer products due to unwanted salt components and pollutants in theproduct stream.

Integrated solution using magnetic adsorption and desorption

In this project, we aim to demonstrate the feasibility of a novel and integrated process for removing and recovering P-compounds from municipal wastewater and process water streams from the food industry. The process is based on the reversible and selective complexation of P-compounds with magnetisable iron nanoparticles. New aspects of the process are that it allows for:

  • the recovery, in-situ, of the P-compounds,
  • the regeneration of the magnetic particles for continuous use within the process,
  • direct application in different wastewater streams, i.e., it does not require chemical precipitation onto sludge and anaerobic digestion afterward.

Additionally, the process includes an energy-efficient electrochemical process, i.e., electrodialysis, to produce in-situ the chemicals used for recovery and regeneration of the magnetic particles.

Chain collaboration

This research represents a collaborative effort between Wageningen University & Research and various companies, each playing a role in the phosphorous emission and recovery chain. Agristo, producer of potato products and specialties, and the Royal Swinkels Family Brewers, 'supply' phosphate-rich wastewater. Bakker Magnetics and Sidra Wasserchemie contribute to the magnetic separation process and magnetite synthesis, respectively. BiotaNutri plans to use the recovered phosphate in organic fertiliser products, which could be used e.g. by the potato growers of Agristo. Meanwhile, Suez SA is exploring the potential integration of the MAD-process into municipal wastewater treatment systems.