Topic background

Micropollutants have been identified as contaminants of concern present in municipal wastewater treatment plant (WWTP) effluent. They are not effectively removed in conventional municipal WWTPs because the WWTPs were not originally designed to remove these contaminants. The Dutch water partners are currently researching innovative technologies to remove these micropollutants through an extensive Innovation Program initiated by the Dutch Ministry of Infrastructure and Water Management and the Dutch water authorities and managed by STOWA. Wetsus and partners have been investigating an optimized Biological Activated Carbon (BAC) treatment line as a promising tertiary treatment technology to improve micropollutants removal at WWTPs, both at lab- and pilot-scale. However, the influence of parameters such as reactor design, oxygen levels, backwashing regime and pre-treatment of the influent waters needs to be further investigated, especially in a real-world setting, i.e., using real wastewater effluent.

Research challenge
The BAC filters investigated in our work combine adsorption, oxidation, biodegradation, and precipitation processes. The research challenge of this new project is to quantify and understand these interdependent removal processes, to translating this knowledge into a filter design and operation optimised specifically for micropollutant removal.An example of a parameter that needs to be optimised is biofilm thickness. In BAC filters, the surface of the granules is covered with a biofilm. This biofilm is essential for micropollutants degradation, as the biofilm matrix binds the micropollutants which are then degraded via the action of bacterial exoenzymes. However, uncontrolled biofilm growth results in clogging and mass transfer limitations. Excessive biofilm accumulation can be controlled by backwashing and by controlling the dissolved oxygen levels. Another design consideration is how to minimise detrimental effects of the bulk particulate and dissolved organics also present in the water, e.g., by applying pre-treatment of the influent water which can remove recalcitrant organics.

Your assignment
The main objective of the project is to try to predict the effect of key design and operational parameters on the micropollutant removal events in BAC filters, by studying the underlying mechanisms. To achieve this goal, your will work with both lab and pilot scale BAC filters, using different matrices and model compounds. In addition, the work will comprise physico-chemical and microbiological characterization of carbon granules and the attached biofilms.

Supervisory Team: TBD.

Project partners: Advanced Water Treatment

Your profile
We are looking for a highly motivated and enthusiastic candidate with an MSc degree in Environmental Engineering, Chemical Engineering or equivalent. Additional knowledge of municipal wastewater, adsorption technology bioprocess engineering and/or biofilms (microbiology) is desirable. You are able to work in a multidisciplinary, international team. You are fluent in written and spoken English.

Keywords: Biodegradation, biofilms, granular activated carbon (GAC), adsorption, oxidation

Salary and working conditions are according to the collective labour agreement of the Cooperative Association of Dutch Universities (VSNU) for PhD students.

Wetsus, European centre of excellence for sustainable water technology is a facilitating intermediary for trendsetting know-how development. Wetsus creates a unique environment and strategic cooperation for development of profitable and sustainable state of the art water treatment technology.

The inspiring and multidisciplinary collaboration between companies and research institutes from all over Europe in Wetsus results in innovations that contribute significantly to the solution of the global water problems. Wetsus’ scientific research program is defined by the private and public water sector.

Read more about our current PhD program. All info about the research at Wetsus can be found here.