الفهرس 
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Abstract
A conventional sequencing batch reactor (SBR) has been upgraded using fixed biofilm carriers of fiberglass material with a specific surface area around 18 m2/m3 which is designed for supporting the biofilm formation and increasing the system efficiency. First, the conventional and upgraded SBRs were operated for the treatment of municipal wastewater under various organic loading rates (281, 375, 469, and 563) g COD/m3/d that corresponding to various volume exchange ratios (37.5, 50, 62.5, and 75%), respectively. The effect of aeration time was studied applying a volume exchange ratio (VER) equal to 50% under various aeration times ranging from 2 h to 8 h. Second, the two reactors were operated under various concentrations of initial phenol ranging from 50 to 600 mg/L were mixed with municipal wastewater to study the influence of phenol in terms of phenol and COD removal efficiencies at a VER of 50%. The operating conditions were similar for the two reactors including influent wastewater characterization, temperature, Dissolved Oxygen (DO), mixed liquor suspended solids (MLSS), and cycle time. It was found that the effluent of biological oxygen demand (BOD5), chemical oxygen demand (COD), and total suspended solids (TSS) of the upgraded SBR under the highest VER of 75% with a cycle time of 8 h was 20, 32 and 27 mg /L, respectively, while for SBR was 34, 58 and 45 mg /L, respectively. The results indicated that the SBR required a longer aeration time than the upgraded SBR to achieve the same performance. The maximum removal rate of phenol was 660 g/m3/d at 400 mg/L of initial phenol concentration in the upgraded SBR, while the maximum phenol removal rate in the SBR was 556.5 g/m3/d at an initial phenol concentration of 350 mg/L under the same operational conditions. Compared to the conventional SBR, the upgraded version has increased the removal efficiencies of BOD5, COD, and TSS by about 10% using high strength wastewater without phenol, reduced the aeration step by 25%, and 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. Moreover, it has reduced the excess sludge by about 23 % and enhanced its properties by lowering the sludge volume index (SVI) by about 33%. The upgraded SBR can be considered an effective system for municipal and industrial wastewater treatment.