Arnoud de Wilt receives the Jaap van der Graaf prize

Former ETE PhD researcher Arnoud de Wilt receives the 2019 Jaap van der Graaf prize for his article on removing pharmaceutical residues from wastewater. The prize is awarded to a student or researcher who wrote the best English-language article on the urban water cycle in the previous year.The award was set by consultancy firm Witteveen + Bos to further raise the profile of Dutch expertise in the field of water technology in this
field.

Important criteria

The winning paper of De Wilt and his colleagues, ‘Enhanced pharmaceutical removal from water in a three-step bio-ozone-bio process’, was published in Water Research in 2018 and based on his PhD research at ETE. Around 60 papers competed, all had ‘a very high scientific level’. But de Wilt’s research met all the important criteria the best: social relevance, practical approach and applicability. According to the jury, de Wilt’s research offers a pragmatic and well-developed solution to the ever-growing concentration of medicine residues in waste and surface water: one of the biggest challenges facing the water boards at the moment.

Three-step treatment

To remove medicine residues from wastewater, de Wilt focused on using ozone in combination with bacteria. Just ozone treatment to degrade pharmaceutical residues is not cost-effective, among others due to high amounts of background organic matter in wastewater: a lot of ozone is consumed by degrading this fraction. ‘In my research, conducted at ETE, we used wastewater from a nearby plant, so a very practical and realistic approach’, says de Wilt. ‘We removed pharmaceutical residues in a three-step follow-up treatment: bacteria, ozone and again bacteria.’ The first bacterial step removed organic matter. As a result, less ozone was required during the second step, where this gas effectively degrades pharmaceuticals. Due to the first bacterial treatment, ozone demand dropped by more than a third. After the ozone step, a final bacterial step removed the remaining ozone products. This 3-step method targets different pharmaceuticals, and results in a cost-effective pharmaceutical removal of more than 85 %, while the average treatment costs increase by no more than five to ten euros per person per year.

Full scale implementation

De Wilt’s current employer, Royal HaskoningDHV, is involved in the follow-up study. ‘We examine what needs to be done to bring this three-step wastewater treatment method from the lab to practice’, says the Wilt. ‘Then we aim to start a pilot in 2019, together with a water board. When this pilot is successful, full-scale implementation is the next step.

Selected publication

de Wilt, A., van Gijn K., Verhoek T., Vergnes A., Hoek M., Rijnaarts H.m, & Langenhoff A. 2018. Enhanced pharmaceutical removal from water in a three-step bio-ozone-bio process. Water Res. 138, 97-105.