Considering all existing and new challenges imposed on the treatment process of (municipal) wastewater, there are convincing arguments for rethinking the system. A key element is the concentration of wastewater early in the process. What are the reasons for concentrating wastewater first?

  • As a general rule in water technology, the more concentrated the liquid stream, the more efficient treatment processes are
  • The concentrate can be treated anaerobically (generation of methane)
  • Recovery of valuable compounds (e.g. nutrients) and energy from the concentrate are favoured
  • Trace organics (e.g. pharmaceuticals) are managed more efficiently
  • The emission of greenhouse gases (esp. N2O) is significantly reduced
  • And last but not least: the clean water flow can be reused in high-end applications


The principle of Forward Osmosis (FO) is a general part of natural biological systems. In our engineered FO process, a semi-permeable membrane is placed between the pre-clarified wastewater and the ‘draw solution’ (typically a concentrated salt solution). The osmotic gradient between the two flows generates a water flow through the membrane, resulting in a concentrated feed stream and a diluted draw solution. Next, the diluted draw solution and clean water are recovered, and the concentrate stream is further treated.

Due to substantial flow and quality variations, wastewater is a challenging application for FO technology. Over the past years, we have upscaled the process to a capacity of 50 m3/day. A patent application for an optimized configuration has been filed.


The CoRe Water team is a cooperation of Allied Waters and BLUE-tecRoyal HaskoningDHV and KWR: an all Dutch team that combines a strong track record in innovation and FO expertise with design and operational expertise in wastewater practice. We are happy to work together to evaluate the potential of the CoRe Water concept in any specific case.

Allied Waters: driving the circular economy.

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