Description du poste

The anaerobic ammonium oxidation (anammox) is a new and effective treatment for the removal of nitrogen from wastewaters containing high ammonium and low biodegradable organic carbon (e.g., biogas digester supernatants). However, anammox bacteria have a low growth rate. Although these organisms can form part of the microbial community in natural and man-made ecosystems, before operation of an anammox bioreactor it is necessary to enrich sludge in these bacteria. Use of nitrite in anammox

Description of the project
The aim of this PhD is to develop and characterize the performance of ANR systems implemented at lab-scale for the treatment of biogas digester supernatants.
- It is planned to use specific molecular typing tools targeting anammox bacteria:
1) to conduct an environmental screening in order to identify locations positive in anammox bacteria,
2) to define a procedure for the enhanced start-up of anammox reactors including biomass enrichment.
- In addition, two different ANR units will be run for several months using enriched anammox biomass and targeting stable process performances. The main tasks planned at this point are the comparison between:
1) reactor configurations (i.e., double- vs. single-stage design),
2) supernatant sources (i.e., sewage sludge vs. animal manure).
This research will be conducted in collaboration with the US Department of Agriculture - Agricultural Research Service, which will provide the enriched anammox sludge. It will be considered positively the candidate’s experience in process engineering and molecular biology. reaction as electron acceptor also makes necessary a previous partial oxidation of ammonium to nitrite under aerobic conditions by ammonium-oxidizing organisms. The coupling of both processes (i.e., partial nitritation and anammox) results in totally autotrophic nitrogen removal (ANR). Hence, the ANR could be a key technology for the development of more economical and energy-efficient ammonium treatments. The ANR systems can be engineered under different reactor configurations, and considering double- and single-stage designs.