Characterization of Anaerobic Effluent: Seasonal Influence and Use of Anammox Process as Post-treatment

Abstract

This study aimed to verify if subtropical annual seasonality variation of organic matter and nitrogen ratio facilitates the use of anammox process as a post-treatment of anaerobic effluent. We characterized the anaerobic effluent from a wastewater treatment plant (WWTP) located in Campinas, SP, Brazil. The collected composed samples were from an UASB reactor in different days, hours, and months during 1 year. The mean temperature of all seasons was above 19 °C, which favors anammox activity, and seemed to influence much more than that of pluviosity on effluent composition. It may be explained by the separated sewage collection in Brazil, which is not constructed to receive and transport rainwater, although some not predicted connection may be added in. We also concluded that subtropical annual seasonality of COD/N ratio range (2.2 to 3.1) from anaerobic effluent indicates that the use of anammox process is suitable as post-treatment of anaerobic effluent in subtropical areas. However, as total COD degrades over time and as total nitrogen concentration is influenced by seasons, these factors need to be taken into account in the project and operation of the reactor over the year.Graphical abstract