Research Programmes

TKI-watertechnology programme

































Phase 1 Desk study

2015: Implementation of the Power-to-Protein concept in the Amsterdam urban water cycle.

Partners: Waternet, AEB Amsterdam, Avecom and KWR.
Objective: Research the technical and economic feasibility of the Power-to-Protein concept in the water cycle of the city of Amsterdam.
Status: Complete

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In 2014-2015, a survey study was conducted in the framework of the TKI Water Technology programme to assess the feasibility of coupling the Power-to-Protein concept to the wastewater cycle, and to test it for the case of the ‘urban zone of Amsterdam’ (phase 1). The study showed the enormous potential of the concept, which could annually produce 6,300 tons of protein from the ammonium in the reject water of the sludge treatment at the Amsterdam West WWTP. This could satisfy the (net) protein requirements of 36% of the residents of Amsterdam. It also concluded that the production of single-cell protein () had economic potential, which moreover depends greatly on the production costs of the raw materials – ammonium and hydrogen – and on the market price of the end product.

On the basis of the phase 1 study, a number of recommendations were made which will be taken up in the phase 2 research:

  1. Closer research is needed into the risk that – in the case of the ammonium, carbon dioxide and hydrogen (via bio-methane) sources – undesirable substances, including organic micropollutants and pathogens, might be introduced to the SCP reactor. This research is crucial for the necessary reprocessing steps, and therefore constitutes an important factor in the SCP production costs.
  2. The recommendation was made to carry out a pilot research project in which the coupling to the wastewater cycle is done for only one of the raw materials, and to add the other raw materials in the form of high-grade industrial gases or products. This would provide insights into the effects on the microbiology and toxicology of the microbiome in the reactor. It is evident that this pilot work should initially concentrate on the ammonia/ammonium raw material.
  3. The process of bringing SCP to the market as a novel food should be clarified in more detail with regard to the timeframe and costs.

Phase 2 Pilot research


Partners: Waternet, Waterkracht, AEB Amsterdam, Barentz Foods, Avecom and KWR.

Technology supplier: Nijhuis Water Technology provides the pilot for ammonia recovery (NAR-pilot) that will produce the ammoniasulphate as input for the Power-to-Protein pilot

Objective: Scaling up the Power-to-Protein concept to the production level of 1 kg per day, in which a direct coupling is made to the wastewater cycle, followed by an assessment of the quality of the protein produced and of the concept’s economic and environmental benefits.

Status: started in November 2015

The Wetsus programme

Parallel with TKI Water Technology

In parallel with the TKI Water Technology project, Wetsus conducts research into the development of the microbiome in the Power-to-Protein reactor, with a focus on safeguarding the growth process. A second Wetsus project concentrates on the process aspects, particularly on the development, over the long term, of an alternative to the air stripping of NH3 – for example, ammonia stripping through membrane electrolysis.

Partners: Avecom, DC Water (Washington, DC), University of Ghent
Status: First PhD project started in March '16, second PhD project is still to start.
Contact: Raquel Barbosa MSc., Tom Sleutels


The aim of the first PhD project at Wetsus, executed by Raquel Barbosa with supervision of Nico Boon from UGhent, is to compose in vitro synthetic hydrogen oxidising multispecies communities/collaboromes (HOC) consisting of hydrogen oxidising bacteria as core populations and heterotrophic bacteria as satellites, that are selected towards interesting biotechnological endpoints, such as single cell protein, polyunsaturated fatty acids, polyhydroxybuteric acid, vitamins, amino acids and biopolymers, and to elucidate the crucial members and interaction mechanisms.

Initially, isolation will be used to dissect a mixed microbial community (enrichment of original sample) into culture collections of heterotrophs and hydrogen oxidising bacteria. Subsequently, different sets of isolates will be assembled and the best performing HOC will be selected by evaluating the performance (specific metabolite production) of the HOC in high-throughput essays.