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 m 2 m −3 . 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 (10.7-21.3 hr), aeration time (from 2 to 8 hr), and initial phenol concentration up to 600 mg L −1 . It was found that the upgraded SBR increased the removal efficiencies of biological oxygen demand (BOD 5 ), 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%. © 2021 Water Environment Federation • Practitioner points• Upgrading conventional SBR by adding biofilm carriers is necessary for wastewater treatment with high strength wastewater. • The upgraded SBR has a higher resistance toward phenol compound due to the presence of the attached biofilm. • The upgraded SBR enhances sludge settling properties, decreases the amount of excess sludge, and also reduces the start-up period. • The number of cycles per day by upgraded SBR was more than the conventional SBR by 15%. • The upgraded SBR is an effective system and has good operational stability.