Combined nitrogen and aniline removal from hyper-saline industrial wastewater

Abstract

In the treatment of industrial wastewater, the biological removal of aniline & nitrogen often occurs simultaneously within the hyper-saline water matrix. This study focuses on pioneering the research
on combined aniline-nitrogen removal in a hyper-saline environment. The experimental approach assessed the cause of nitrite accumulation phenomena in this specific case study as well as the influence
of oxygen concentration and aniline as a carbon source on nitrification. The hypothesis of increasing aniline biodegradability by making it chemically react with nitrite was experimentally tested. In addition, data analysis of the full scale of this study was performed in order to create analytical models to represent its biological processes. It was found that the correlation between oxygen concentrations and nitrification was non-linear and differs from what is observed in the literature due to the significant influence of different boundary conditions. The unavailability of carbon sources during the nitratation process was the cause of nitrite accumulation, which crucially affects nitrification. The chemical reaction between aniline and nitrite (most likely polymerization) resulted in a compound that did not limit nitrification and had more biodegradable potential. Furthermore, an aerobic model was developed but the promising results were most likely caused by the mathematical optimization, which was done in order to bypass the lack of data. Nevertheless, respirometry was used to build an empirical model to detect nitrite accumulation in the effluent of the full scale, which showed promising results. This study can potentially pave the way for the application of Anammox technology in the combined treatment of aniline & nitrogen, which is discussed in the hypothetical design implementations.