Upgrading sequencing batch reactor using attached biofilm.

Abstract

A conventional sequencing batch reactor (SBR) was upgraded using fixed biofilm carriers with a specific surface area around 18 m2 /m3 . The upgraded SBR was investigated to remove phenol from high strength wastewater operated under various operational conditions. The operational conditions used were variable volume exchange ratio (VER) up to 75%, hydraulic retention time (HRT) from (10.7 to 21.3 h), aeration time (from 2 to 8 h), and initial phenol concentration up to 600 mg/L. It was found that the upgraded SBR increased the removal efficiencies of biological oxygen demand (BOD5 ), chemical oxygen demand (COD), and total suspended solids (TSS) by about 10% using high strength wastewater without phenol compared to SBR. Furthermore, the removal rate of phenol for the upgraded SBR was higher than conventional SBR by about 18% at 600 mg/L of initial phenol concentration under the same operational conditions. Compared to the conventional SBR, the upgraded version reduced the aeration step by 25% and achieved higher removal efficiency of phenol. Moreover, it reduced the excess sludge by about 23 % and enhanced its properties by lowering the sludge volume index (SVI) by about 33%.