Performance and modeling of a moving bed biofilm process: nickel and chromium heavy metal removal from industrial wastewater

Abstract

The process of a lab-scale moving bed biofilm reactor (MBBR) using simulated sugar-manufacturing wastewater as feed was investigated. The concentration of the metals used in the present study were 10, 30, 50 and 100 milligrams per liter with a chemical oxygen demand (COD) of 800 mg L⁻¹. After activation of the reactor at adapted circumstances of microorganism, chromium and nickel as heavy metals were added to the system during a specified time interval with concentrations of 10 to 100 milligrams per liter. The results showed that the COD removal efficiency of the system was 1.87% at the time of the microorganisms' adaptation. The maximum removal of chromium at the concentration of 50 mg L⁻¹ and time of 20 h was 93.52% and this percentage was 82.41% for nickel at the concentration of 30 mg L⁻¹ and time of 20 h. Then, for the biological modeling process, three models including first-order, second-order (Grau) and Stover–Kincannon model were used. Finally, according to the kinetic analysis of chromium and nickel removal, the Stover–Kincannon model was selected as the appropriate model for modeling the MBBR process.