DemoVaSA: valorisation of EPS from sewage sludge

Every wastewater treatment plant brings in a new waste stream: sludge. Water treatment plants usually have this sludge removed for a fee. Two past PWO projects (VaSA and DemoVaSA) studied how to valorise this waste stream. An extraction procedure was designed to extract EPS from this sludge. These EPS mainly consist of polysaccharides and proteins, which allows their use in various industrial applications. In this project, the extracted EPS will be validated in two applications.

Concrete

As a first application, an after-treatment product for concrete will be created that incorporates the extracted EPS. The advantage of this after-treatment product over commercially available products is the fact that this product is water-based and not an organic solvent. There are already a number of products on the market that are also water-based, but these often contain products derived from petroleum (e.g. paraffin).

Glue

Besides using EPS in an after-treatment product for concrete, the EPS can also serve as an additive in adhesives. The extracted EPS can consist of up to 70% proteins. Currently, proteins are already added to some adhesives. However, it is the case that these proteins are often of plant origin (e.g. soy, camelina), this may create a conflict as these crops are also used in food and feed. The extracted EPS come from a waste stream and are fairly easy to extract, which limits the cost of obtaining them.

On the one hand, companies with wastewater treatment plants are eager to get rid of their sludge because they often pay to have it removed. On the other hand, there are companies looking for innovations in the field of concrete and adhesives. In terms of valorisation, two sides of the market need to be considered:

1. Services will be set up around the extraction of EPS from sluice sludge.
2. The applications in concrete and glue developed in this project may be patented.