Ahmadreza Yazdanbakhsh - Workplace Health Promotion Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran- Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohsen Sadani - Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohammad Golaki - Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran

The removal of formaldehyde as a toxic substance from aqueous solutions is of particular importance. In this research, a sequencing batch rotating-bed bioreactor (SBRB) was used on a laboratory scale for biodegradation of formaldehyde from synthetic wastewater. The reactor was made of plexiglas with a cylindrical shape. Kaldnes media were placed in a rotating cylindrical basket in the reactor. The effects of formaldehyde concentration (۵۰۰–۱۵۰۰ mg/L), hydraulic retention time (HRT) (۸, ۱۵, ۲۴ hours), and injection of hydrogen peroxide (۰.۱-۰.۵ mM) on the performance of the reactor were investigated. The results showed that in the SBRB, at an HRT of ۲۴ hours and an inlet formaldehyde concentration of ۱۰۰۰ mg/L, the removal efficiencies of formaldehyde and chemical oxygen demand (COD) were ۹۹.۲% and ۹۲%, respectively, while without rotating the bed, the removal efficiency of formaldehyde and COD was found to be ۹۵% and ۸۳%, respectively. By adding hydrogen peroxide at a concentration of ۰.۳ mM and operation of the SBRB with an HRT of ۸ hours and an inlet formaldehyde concentration of ۱۰۰۰ mg/L, an improvement in the removal efficiency of formaldehyde and COD (۴% and ۲۲%, respectively) was observed. Accordingly, SBRB stimulation with hydrogen peroxide could be considered as a highperformance process for the removal of formaldehyde and corresponding COD at a short HRT.

Formaldehyde, Rotating bed, Bioreactor, Wastewater, Peroxidase