International recognition for sustainable flocculant

The criteria for the Best Practice Award for recovering resources from water are strict. They cover the level of innovation, replication potential, the positive impact on the environment, the positive potential of the business case and active collaboration in the sector. The award is an initiative from Allied Waters and AquaMinerals. The aim is to draw attention to exemplary solutions for resource recovery in the water cycle that can be used in full-scale applications or in pilot projects. Recovery practices are attracting worldwide interest because of the benefits for the environment and society as a whole. And, of course, they fit in perfectly with the ambition of a circular economy, which is the ultimate goal of the two initiators of the Best Practice Award. The winner receives a trophy and a certificate.

Environmental gains

The six-member jury thought that the quality of all nineteen candidates was excellent but the HerCauWer project convinced them with respect to all criteria. This project resulted in a circular flocculant that has been shown to be more effective than commercial iron pyrites, with lower costs and a significant reduction in the environmental impact. In particular, the jury very much appreciated the fact that the project was based on the question of whether using iron pyrites recovered from drinking water sludge would result in environmental gains. “The environmental impact of the flocculant from drinking water sludge is just 1 to 2 percent of the commercial product,” explains KWR researcher Roberta Hofman, who received the award online. “Moreover, the commercial flocculant is increasingly difficult to obtain. So the circular flocculant is a welcome alternative for water authorities.”

Consortium and follow-up research

The HerCauWer project was executed by a broad-based consortium consisting of KWR, Feralco, the Brabantse Delta water authority, AquaMinerals and the five drinking water utilities Evides, WML, Vitens, Waternet and PWN. With the inclusion of all the links in the sector, the sustainable flocculant really did progress from a desk study to use in practice. According to Hofman, the Best Practice Award is a recognition for all the hard work. “It also shows that, at KWR, we are doing useful and interesting work on resource recovery. There is already a proposal in place to follow up on the HerCauWer project with the partners who have already been involved, possibly expanding to include more water authorities. For example, a careful assessment is still needed to determine the best arrangements for managing operations with aquafer from drinking water treatment. And we want to have a clearer understanding of why not every sludge type is equally suitable for dissolving all the iron it contains. These questions are relevant for further research.”

Jury members

The international jury for the IWA Award consisted of:

• Willy Verstraete (University of Ghent, Belgium)
• Korneel Rabeay (University of Ghent, Belgium)
• Ana Soares (Cranfield University, United Kingdom)
• Heather Kerr (Isle Utilities, United Kingdom)
• Olaf van der Kolk (AquaMinerals)
• Kees Roest (KWR)

Obviously, candidates for the award did not vote for their own proposals.

The HerCauWer project has already won awards in the past. Earlier this year, an article on this project won the award for the best H2O paper in 2022.