Investigation of ammonium removal in batch system using biogenic manganese oxide

Ammonium is a pollutant frequently found in water bodies and has toxic effects on living things, making it necessary to eliminate ammonium from water before discharging it into surface water bodies. This study examines the ammonium nitrogen removal performance of anoxic nitrification-denitrification process based on biogenic manganese oxide (BMO) and immobilized biogenic manganese oxide (IBMO) beads. Biogenic manganese oxide was produced using Pseudomonas putida and alginate was used to prepare immobilized biogenic manganese oxide beads. Various analyses characterized BMO and IBMO and revealed that biogenic manganese oxide has an amorphous structure and exhibits dense mineral precipitation around bacterial cells and particles with irregular geometric shapes. The effects of C/NH4+-N ratio, pH, temperature, and stirring rate on anoxic nitrification-denitrification process were investigated and 92% and 89% ammonium nitrogen removal efficiencies were obtained for BMO and IBMO at C/NH4+-N ratio: 5, pH: 7.0, 20 oC and, a stirring rate of 150 rpm, respectively. Although BMO and IBMO effectively removed ammonium nitrogen in anoxic environments, the immobilization method can allow less sensitive environmental conditions for nitrification denitrification process, providing higher removal efficiency.