Assessment of the nitritation and anammox processes for mainstream wastewater treatment

Abstract

The implementation of autotrophic nitrogen removal processes such as the combined partial nitritation and anammox processes will contribute to maximise the wastewater energy recovery converting the wastewater treatment plants in net energy producers and enabling the wastewater reuse. Consequently, this thesis aims to assess the nitritation and anammox processes implementation at mainstream conditions characterised by its low temperature, low nitrogen concentration and high fluctuations of wastewater characteristics. Different reactor configurations, including one and two-stage systems, were employed. The treatment of different types of effluents, blackwater from a source-separation on-site system and municipal wastewater were studied, being specially focused on overcoming the nitrite oxidizing bacteria development that challenged the anammox based processes implementations. Special attention was paid to the production of effluents complying with the European discharge limits as well as the evaluation of the activities of the involved microbial populations.