SynchUp! is initiated by REWIN

Valorisation of sodium sulfate

Challenge closes in:

2021-05-21 17:00


How can we convert an aqueous sodium sulfate solution into something useful?

A wastewater stream (2m3/hour) produced by our plant in Veenendaal contains 2% sodium sulfate and 0.3% fatty acids. We dilute this wastewater with used cooling water from our production department before discharging it into the sewers.

The water used to dilute the wastewater is extracted groundwater. We expect that we will no longer be allowed to pump up groundwater in the future, at which point we will no longer be able to dilute the saline wastewater. We are not permitted to discharge undiluted saline wastewater, as the salt may affect the municipal sewage system. For this reason, we would prefer processing the sodium sulfate (approx. 100 tonnes annually in a circular manner).

An additional problem is posed by the presence of fatty acids derived from lanolin, which complicates food applications. In concentrated form, these fatty acids emit an unpleasant odour. The challenge now is to clean up and process this waste stream, without causing nuisance smells for the surrounding area. Since saline wastewater streams are common in the industry, we expect that any solution to our problem is also likely to help other companies.

We have illustrated the process in the diagram below.

What are we looking for?

The goal of the challenge is to find an efficient circular solution for processing a sodium sulfate wastewater stream. For these purposes, all circular solutions with an annual below EUR 50,000 are considered interesting. It would be even better, of course, if the solution turned a profit. For us, the ideal solution would be for a third party to purchase our wastewater and process it elsewhere into a useful product.

One solution we are currently investigating is to reduce the sodium sulfate to caustic soda and sulfuric acid using electrodialysis, after which these chemicals can be reused. If you are a supplier of electrodialysis equipment or other equipment that would make this process possible, please sign up for the challenge


What aren’t we looking for?

We were already experimenting with some possible solutions ourselves. Mixing the wastewater stream with a different high-potassium stream was found to be too expensive. We also tried upgrading the salt to Glauber’s salt (Na₂SO₄), but its sales potential has thus far been limited.

We are not looking for solutions like incineration and landfill, because they are very expensive, for starters, as well as being the opposite of green and circular.


What’s in it for you?

We can offer companies that come up with a good proposal the opportunity to research and test their solution at our plant. Our R&D department and our professional Technical Services department will give you the necessary support. We also have a pilot budget.

We may be interested in buying a tried & tested solution on contract. We will also help you explore whether your solution can be applied by other companies in our network and will gladly help you inform other potential customers of the opportunities and benefits offered by your solution.


How can BioVoice benefit you?

  • An innovation contract with a launching customer/partner!
  • Funding (€10,000 vouchers, to be spent in the regional ecosystem for e.g. testing, lab and demo facilities, IP consulting, etc.)
  • Coaching and counselling
  • A stage and free publicity
  • Knowledge and contact with experts
  • Access to a network of potential partners & customers, resources and research facilities


The BioVoice programme

BioVoice is an initiative of REWIN West-Brabant, Green Chemistry Campus, the joint Rabobanks of Southwest Netherlands and the province of North Brabant. Dockwize, Impuls Zeeland, Centre of Expertise Biobased Economy and Midpoint Brabant have also joined as implementation partners. Together, we want to give innovative entrepreneurs and up-and-coming biobased/circular talents the space and opportunities to develop and market their idea/product, so as to achieve our common goal: accelerating the transition to a sustainable economy.

BioVoice is made possible by financial contributions from the Regional Deal for Central and Western Brabant, the Province of North Brabant, the Province of Zeeland and Rabobank.  


Conditions of participation

We would preferably work with a dedicated company that can offer us the certainty & security of a successful solution based on a technology or techniques with a proven track record. However, our technical team will give due consideration to any new ideas that may lead to an attractive solution.


Your pitch (max 6 pages / 18 slides)

  • Concept description: Describe your concept in as much detail as possible.
  • Pilot description: Please provide a brief description of what it will take to prototype and/or pilot and what you will need from us to do so.
  • Team description: Provide a brief description of the company and team that plans to work on the pilot.

There are no formal requirements for the pitch (presentations, slide decks & letters are all allowed), apart from the fact that it must be uploaded as a PDF file (A4, landscape or portrait) with a max. size of 30MB. Videos, example websites and so on can be included as links.  



  • 29 March ’21: Challenge launch – open for applications
  • 21 May ’21 – 5:00 pm: Challenge deadline – sign up no later than 5 pm
  • 4 June ’21: Longlist announced – A longlist of start-ups/scale-ups that are invited to meet the challengers is announced
  • 14-25 June ’21: Digital introduction meetings with challengers & participants + information session about confidentiality and IP
  • 2 July ’21: Shortlist announced based on interviews – A shortlist of start-ups/scale-ups that will be given the opportunity to work on an innovation contract is announced
  • 5-11 July ’21: Make schedule & working agreements + coordinate NDA if necessary
  • 12 July through 6 October ’21: Challenge weeks – sessions with challengers, participants & coaches to arrive at an innovation contract
  • 29 September ’21: Apply for vouchers – submit draft innovation contract + apply for vouchers
  • 6 October ’21: Vouchers awarded – submit final innovation contract + vouchers are awarded
  • 14 October ’21: Match event – celebrating the innovation contracts and partnerships + presentation of vouchers
  • 15 October ’21: Start of development & collaboration (pilot)



If you have any questions about this challenge, please head to the contact options below. For more information about the challenge program, click here.  


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