PhD Mechanisms of surface-active chemical film formation and their mechanical properties Wageningen • Wageningen University & Research

Are you passionate about exploring how surface-active chemicals in the recycled cardboard industry interact with microbial biofilms? This PhD project delves into the intricacies of these chemical behaviors and their impact on process stability, guided by a multi-disciplinary team. Enjoy partially paid parental leave, a manageable work-life balance, and access to sports facilities on a vibrant, eco-friendly campus with a globally recognized reputation. Join us in advancing environmental technology! Read on to see how your skills fit into this role.

Your job

Are you interested in studying how commonly used surface-active chemicals in recycled cardboard industry behave at the solid-liquid interface of microbial biofilms, i.e., anaerobic granular sludge? Then this PhD vacancy might be something for you! At Wageningen University & Research we are looking for two candidates to join our team.

This project combines expertise and techniques from surface rheology and material science in food physics and from environmental process engineering at Wageningen University. We will investigate which ones of these chemicals are the problem source and redesign the biological process to avoid process instabilities. New insights into biodegradability and accumulation of surface-active chemicals on microbial biofilms and relations to mass transfer and process stability can be used to rationally design the water treatment in recycled cardboard making or to reassess the types of chemicals that the industry uses.

The aim of this PhD project is to illuminate the key mechanisms of how the surface-active chemical (SAC) films interact with the surface of microbial biofilms, to investigate rheological properties of these films and develop physical properties-composition relationships. Some work will also be devoted to study mass transfer of biogas through such films. To that end the PhD candidate will be developing methods like  surface rheology to study rheological properties of these films and colloidal probe atomic force microscopy (AFM) and super resolution microscopy to visualize the structure and quantify the location of selected compounds in these films. These approaches will be supported by state-of-the-art bulk rheological characterization of SAC films and microfluidics for assessing resistance to gas transfer.

The results of this PhD project will form a fundamental basis for the improved biological process design at the Environmental Technology group, wherein knowledge of the mechanical properties of the SAC films or film weakening components will be exploited.

This PhD project will deal with the following activities:

1. Preparation and rheological characterization of various SAC films on the biofilm surfaces;
2. development of surface rheology protocols and  colloidal probe AFM  method to investigate  the mechanical properties and structure of  SAC films;
3. study the structure-function  properties  of SAC films;
4. elucidate key mechanisms of SAC-biofilm interactions;
5. translate the insights into potential guidelines and protocols on weakening or avoiding SAC film formation.

The second PhD position is Sorption and biodegradation of surface-active chemicals in anaerobic granule-based bioreactors (at ETE – WUR). Both PhDs will be performed in close collaboration with Kemira, Paques B.V., DS Smith Kemsley and Smurfit Westrock Roermond. The project is funded by an NWO Open Technology Programme (OTP) grant. 

You will work here
The research is embedded within the chair of Physics and Physical Chemistry of Foods which is led by Prof. Erik van der Linden. You will be co-supervised by Dr. Dainis Sudmalis, Dr. Mehdi Habibi and dr. Leonard Sagis and will closely collaborate with a PhD working at Environmental Technology.
Your qualities

We are looking for highly motivated candidates holding an MSc. degree in physical chemistry, food physics, applied physics or mechanics, material science, chemical engineering, environmental engineering or biotechnology with a strong background in rheology, fluid dynamics or bioprocess engineering, and a strong desire for multi-disciplinary work. The candidates should be fluent in written and spoken English, enjoy working within the interface between curiosity-driven and application-inspired research. A key success factor of this project is intensive collaboration between the two PhD projects, which means that candidates should enjoy collaboration with other PhD-students and the experts from the industry involved in this project.

You also possess:

• An English proficiency certificate in case your MSc degree was not obtained in the Netherlands and/or English is not your mother tongue;
• Official, stamped MSc degree certificate;
• Good command of programming languages like Python will be considered as a plus;
• Experience with rheology will be considered as a plus;
• Experience with AFM (Atomic force microscopy) will be considered a plus.

For this position your command of the English language is expected to be at C1 level. Sometimes it is necessary to submit an internationally recognised Certificate of Proficiency in the English Language. More information can be found here.
We offer you

Wageningen University & Research offers excellent terms of employment. A few highlights from our Collective Labour Agreement include:

• Partially paid parental leave;
• working hours that can be discussed and arranged so that they allow for the best possible work-life balance;
• there is a strong focus on vitality and you can make use of the sports facilities available on campus for a small fee;
• a fixed year-end bonus of 8.3%;
• excellent pension scheme.

In addition to these first-rate employee benefits, you will receive a fully funded PhD position and you will be offered a course program tailored to your needs and the research team.

The gross salary for the first year is € 3.059,- per month rising to € 3.881,-  in the fourth year in according to the Collective Labour Agreements for Dutch Universities (CAO-NU) (scale P). This is based on a full-time working week of 38 hours. We offer a temporary contract for 18 months which will be extended for the duration of the project if you perform well.

Wageningen University & Research offers plenty of opportunities for growth and development, with a strong internal recruitment policy and excellent training programmes.

You will work on the greenest and most innovative campus in the Netherlands, in an international and open working environment. For 20 consecutive years, we have been voted the "best university" in the Netherlands! A place to be proud of.

Coming from abroad
Wageningen University & Research is the university and research centre for life sciences. The themes we deal with are relevant to everyone around the world and Wageningen, therefore, has a large international community and a lot to offer to international employees.

Because we expect you to work and live in the Netherlands our team of advisors on Dutch immigration procedures will help you with the visa application procedures for yourself and, if applicable, for your family.
Feeling welcome also has everything to do with being well informed. We can assist you with any additional advice and information about for example helping your partner to find a job, housing, or schooling. Finally, certain categories of international staff may be eligible for a tax exemption on a part of their salary during the first five years in the Netherlands.
Do you want more information?

For more information about this position, please contact Dr. Mehdi Habibi, associate professor of food physics (via de button "Solliciteer nu" op deze pagina.).

For more information about the procedure, please contact Evelien Janssen, corporate recruiter, by email: via de button "Solliciteer nu" op deze pagina..

Ready to apply?
You can apply directly using the apply button on the vacancy page on our website which will allow us to process your personal information with your approval. Only applications submitted through our website will be considered.

To apply, please send the following documents (max. 3 pages in total for both documents):

• Complete and up-to-date curriculum vitae;
• Motivation letter

The maximum length of the documents must not exceed 3 pages. If it exceeds, applications will not be considered. Additional files such as grades and transcripts are not required during this stage and will not be considered.

You can apply until Monday, November 25th, 2025. The first interviews are scheduled for Tuesday, December 2nd , 2025.

Additional information form
For this position, you must fill in a mandatory form which will allow us to have a comprehensive view of your qualifications and better assess your fit for it. You can access the form using the link below:

Your prompt response will ensure that your application continues to move forward in the evaluation process. We assure you that the information provided will be kept confidential and used solely for this application process.

Welcome, safe, and valued
Wageningen University & Research (WUR) highly values diversity and inclusion because we believe that different insights lead to innovative solutions. We create a work environment where everyone feels welcome, safe, and appreciated, regardless of background, identity, or experience. Together, we are building a culture where everyone's unique contribution adds to the success of our organization.
We are

The mission of Wageningen University & Research is ‘To explore the potential of nature to improve the quality of life’.

We pursue this mission through a synergistic approach between Wageningen University and Wageningen Research Foundation (applied research). Our research focuses on questions within the domains of food, living environment, and society. With approximately 30 locations, 7,700 staff members, 2,500 PhD candidates, and over 13,000 students, Wageningen University & Research is among the world’s leading knowledge institutions in its domain. The integral approach to challenges and the collaboration across various disciplines form the core of the unique Wageningen approach.

Read the 5 reasons why your future colleagues enjoy working at WUR.

We will recruit for the vacancy ourselves, so no employment agencies please. However, sharing in your network is appreciated.