Effect of Cobalt, Cadmium and Manganese on Nitrogen Removal Capacity of Arthrobacter arilaitensis Y-10

Abstract

The aim of this study was to investigate the possibility of a simultaneous nitrification–denitrification hypothermic bacterium for applying in Cd(II), Co(II), and Mn(II)-contaminated wastewater. The influence of Cd(II), Co(II), and Mn(II) on the inorganic nitrogen removal capacity of the hypothermia bacterium Arthrobacter arilaitensis Y-10 was determined. The experimental results demonstrated that low concentration of Cd(II) (2.5 mg/L) exhibited no significant impact on bioremediation of ammonium. The nitrate and nitrite removal activities of strain Y-10 were enhanced by 0.1 and 0.25 mg/L of Cd(II), but hindered by more than 0.25 and 0.5 mg/L of Cd(II), respectively. However, the cell growth and denitrification activity ceased immediately once Co(II) was supplemented. In terms of Mn(II), no conspicuous inhibitory impact on ammonium bioremediation was observed even if Mn(II) concentration reached as high as 30 mg/L. The bioremediation of nitrates and nitrites was significantly improved by 0.5 mg/L of Mn(II), and then dropped sharply along with the increase of Mn(II). The order of the degree of inhibitory influence of the three heavy metal ions on the nitrogen bioremediation ability of strain Y-10 was Co(II) > Cd(II) > Mn(II). All the results highlighted that the heterotrophic nitrification was less sensitive to the inhibitory effects of Cd(II), Co(II), and Mn(II) relative to aerobic denitrification.