Modeling biological denitrification in the presence of metal ions and elevated chloride content: Insights into abiotic and biotic mechanisms regulating metal bioprecipitation

Abstract

Biological denitrification is a critical process in which microorganisms convert nitrate to nitrogen gas. Metal ions, such as those found in industrial wastewater, can be toxic to microorganisms and impede denitrification. It is critical to identify the mechanisms that allow microorganisms to tolerate metal ions and understand how these mechanisms can be utilized to improve denitrification efficiency by modeling the process. This study presents a mathematical model of biological denitrification in the presence of metal ions. The model includes key biotic and abiotic mechanisms and is based on pilot scale results. The model predicts the bioprecipitation of metal ions due to pH shift and alkalinity production during the metabolic activity of microorganisms. The model parameters are estimated to fit the experimental results and the mechanisms regulating metal detoxification via biological metal precipitation are presented. The model provides a valuable tool for understanding the behavior of denitrification systems in the presence of metal ions and can be used to optimize these systems for more efficient and effective treatment of industrial wastewater.