Short-Term and Long-Term Inhibitory Effects of Copper on Anammox Process

Abstract

The main goal of this study is to evaluate the short-term and long-term inhibitory effects of Cu (II) on Anammox process. To investigate the short-term inhibition level, four different concentrations (1, 2.5, 5 and 10 mg L−1 as Cu2+) were tested in batch reactors. IC50 levels for short-term exposure deduced as 4.57mg L−1 (R2: 0.97) from the modified non-competitive inhibition model. Lab-scale continuous flow up-flow fixed bed reactor with Kaldness biofilm carriers was operated 240 days with gradually increased Cu concentrations (from 0.2 to 8 mg L−1). To identify the IC50 levels in case of prolonged exposure of Cu(II), experimental data were fitted with a modified non-competitive inhibition model, and calculated as 6.77 mg L−1 (R2: 0.95). The results show that the IC50 level for copper in long-term exposure was higher than in short-term exposure and the possible reason for that is the self-adaptation of Anammox bacteria.

Keywords

• anammox
• copper
• inhibition
• nitrogen removal
• heavy metal