Simultaneous partial Nitritation, Anammox and Denitrification (SNAD) process for treating ammonium-rich wastewaters

Biological nitrogen removal from strong ammonium wastewaters received a great deal of attention during the last years. Since the discovery of anammox bacteria the traditional theory of biological nitrogen removal has been extended to new nitrogen metabolic pathways. This thesis deals with the study of Simultaneous partial Nitritation, Anammox and Denitrification (SNAD) process in a Sequencing Batch Reactor (SBR) to treat wastewaters with a high ammonium load and low biodegradable organic matter, such as anaerobic digester effluent and old landfill leachate. The bacterial diversity in the reactor was investigated by analysis of specific gene clone libraries, Polymerase Chain Reaction (PCR) and fluorescence in situ hybridization (FISH). SNAD process is a complex biological process where different populations with opposed environmental requirements coexist, thus, experiments have been performed with a lab – scale reactor, focusing on the assessment of the feasibility of SBR configuration for achieving a simultaneous carbon and nitrogen removal. In addition, proper operational conditions, control strategies and a suitable loads were investigated.