UN(K)NOWN Project: Development of Anammox microbial inocula to improve nitrogen removal efficiency in wastewater treatment

The discovery of anaerobic ammonium oxidation (anammox) revealed the existence of a shortcut in the classic nitrogen cycle where ammonium is converted directly to dinitrogen gas. Anammox process can be used to develop more cost and energy-efficient sustainable nitrogen removal systems comparing to those existing today. However, large-scale applications are limited by the slow growth rate of anammox bacteria described so far. This project proposes to explore the presence of these bacteria in different ecological niches, and select the appropriate seeding sludge starter as the inoculum for reactors. Anammox biomass is enriched in batch experiments as well as in laboratory scale bioreactor systems, such as Up-flow Biofilter and Anaerobic Baffled Reactor. Afterwards, microbial community composition, optimum growth conditions, and nitrogen removal efficiency are studied. The ongoing project aims to investigate new anammox bacteria and the relation between community structure and process activity. Ultimately, it is planned to develop microbial inocula to be used as seeding sources for anammox reactors, and to contribute to a wider application of the anammox process in wastewater treatment. Acknowledgments: Project UNNOWN (PTDC/BTA-BTA/31098/2017), co-financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF, and by FCT through national funds.