Biofilm development on normal and modified surface in a hybrid SBR-based bioreactor

In this study, the performance of a sequencing batch reactor (SBR) by using rubber and metallic surfaces to grow fixed and dispersed particles-stabilized microbial biomass was investigated. The formation of biofilm on rubber, modified rubber by activated carbon, and metallic chip were studied. The biofilm developed on the surface that was modified by activated carbon through distributing method was more homogenous in comparison with other surfaces. Besides, the biofilm on this surface was less crashed during dehydration. It was found that the thickness of biofilm on this surface was more than the other ones. The effects of influent chemical oxygen demand (COD) and hydraulic retention time (HRT) on the reactor performance have been investigated. The maximum COD removal (%) was obtained for influent COD of 641 mg/L and aeration time of 4 h. The kinetic models for attached and suspended biofilm were assessed.