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.
Toward full Total Nitrogen (TN) removal in Aerobic Granular Sludge (AGS) systems operated in continuous-flow mode?
Topic A large fraction of Swiss wastewater treatment plants (WWTP) is reaching their maximum treatment/clarification capacities, resulting in operational problems such as incomplete nitrification. It is therefore crucial to develop new technologies to upgrade existing WWTP and intensify their treatment capacities. Aerobic granular sludge (AGS) represents a key advance for wastewater treatment processes (van Loosdrecht and Brdjanovic, 2014), and is presented as the main alternative to conventional activated sludge systems. AGS systems are usually operated as sequencing batch reactors (SBR), where both microbial and physical selection mechanisms take place, leading to granulation. But most of the existing WWTP are operated in continuous-flow (CF) mode, while the conversion of CF systems into SBR is very challenging. A main challenge is therefore to develop aerobic granules in systems operated in CF mode, where conditions in terms of microbial and hydraulic selection are not favourable.
Also, mass-transfer in AGS systems is limited by diffusion, resulting in the formation of concentration gradients within the granules. During the aerated phase, an oxygen gradient thus develops within the granules, whereby the outer layer is aerobic and the inner core is anoxic or anaerobic (de Kreuk et al., 2007). The formation of different redox conditions within the granules allow nitrification and denitrification to occur simultaneously (Winkler et al., 2013). But practical experience however indicates that SND is limited during the treatment of municipal WW with AGS systems (Layer et al., 2020). In theory, aeration could be fine-tuned to control the flow of organic substrates towards denitrification in order to maximize TN removal. However, it is not clear how the aeration influences the fate of organic substrates (hydrolysis, fermentation, storage), their utilization by the different microbial communities and the denitrification and total nitrogen (TN) removal. Another challenge is therefore to better understand how to control aeration in order to increase SND and TN removal, without increasing green-house gas emissions such as N2O.This project is a collaboration between two engineering firms (Hunziker Betatech AG and ARA Consult) and two WWTP (WWTP of Gossau and Laufäcker).
We are looking for a master student with interests (1) advanced technologies for biological wastewater treatment, and (2) microbial processes applied to wastewater treatment. Previous knowledge in the characterisation of municipal wastewater is required. The candidate should be able to communicate in both German and English. Preferred starting date: September/October 2022.
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
Applications can be submitted until the position is fulfilled, and will therefore be evaluated on a rolling basis. Applications should include a short application letter describing your interests and their relevance to this position, a CV and list of lectures/grades.
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.
Applications from employment agencies/personnel consultants are not welcome and will not be considered.