Eawag, the Swiss Federal Institute of Aquatic Science and Technology, is an internationally networked aquatic research institute within the ETH Domain (Swiss Federal Institutes of Technology). Eawag conducts research, education and expert consulting to achieve the dual goals of meeting direct human needs for water and maintaining the function and integrity of aquatic ecosystems.
The Department of Process Engineering has a vacancy for a
Master student working on the production of bioplastics (polyhydroxyalkanoates) from municipal wastewater
Topic: The wastewater treatment plants (WWTP) of the future is a net source of energy and valuable products, i.e., a water resource recovery facilities (WRRF). While conventional WWTPs only focus on the removal of organic substrates and nutrients, WRRFs will also aim at converting pollutants into valuable end-products. The current project aims at evaluating the conversion of organic carbon from municipal wastewater (WW) into bioplastics, i.e., polyhydroxalkanoates (PHA). PHAs are biodegradable intracellular polymers produced by storing-microorganisms as carbon and energy sources. PHAs represent, to a certain extent, a relevant alternative to plastics produced by oil industry. The production of PHA from municipal WW is usually performed in a 2-steps approach (Valentino et al., 2015). In step #1 PHA-storing micro-organisms are selected in sequencing-batch reactors, i.e., by imposing a feast-famine regime. In step #2 the accumulation of PHA by these specialized micro-organisms is maximized in a separate fed-batch reactor. Such 2-steps approach has strong limitations (different influent compositions are required for the enrichment and accumuation steps, complex operation, etc.). Recent research efforts thus aimed at evaluating to what extent PHA can be produced from municipal WW using a single reactor operated in continuous mode (Brison et al., 2022; Brison et al., 2023).This research highlighted that nutrient limitations, e.g., phosphorus, can be modulated to trigger the production of PHA and that storing-microorganisms with a high PHA content (> 70% w/w) can be cultivated on real fermented municipal WW. However, the exact nutrient limitation responsible for the PHA storage response during treatment of fermented municipal wastewaters, as well as the microbial mechanisms associated to this nutrient limitation, was not identified.
The main goal of the proposed master thesis is to gain fundamental understanding of how environmental growth conditions (nature and extent of the nutrient-limitation, composition of the carbon sources) influence the selection of storing micro-organisms during treatment of real fermented municipal WW and ultimately their storage response (substrate to PHA conversion yield and type of monomers produced). The proposed master thesis project will especially aim at:
• characterizing the detailed composition of fermented municipal WW in terms
of nutrients (nitrogen, phosphorus, iron, sulphur, etc.) in order to anticipate the
nutrient limitations responsible for the storage-response
• Assessing that PHA production during treatment of fermented WW is triggered
by the identified nutrient, via:
– long-term PHA production experiments using the same fermentate
(mass balanced on nutrients)
-short-term PHA accumulation using synthetic or real fermented WW doped
with selected nutrients
We are looking for a master student with interests in advanced technologies for biological wastewater treatment and biotechnologies applied to resource recovery. The candidate should be able to communicate in English.
Eawag is a modern employer and offers an excellent working environment where staff can contribute their strengths, experience and ways of thinking. We promote gender equality and are committed to staff diversity and inclusion. The compatibility of career and family is of central importance to us. For more information about Eawag and our work conditions please consult www.eawag.ch and www.eawag.ch/en/aboutus/working/employment.
Preferred starting date: February 2024 for a period of 6 months.
Applications can be submitted until the position is fulfilled, and will therefore be evaluated on a rolling basis. Applications should include a description of your interests, a CV and the list of lectures/grades.
For further information, please contact Dr Nicolas Derlon.
We look forward to receiving your application. Please send it through this webpage, any other way of applying will not be considered. A click on the button below will take you directly to the application form.
