Diffusion of phenol through a biofilm grown on activated carbon particles in a draft‐tube three‐phase fluidized‐bed bioreactor

Abstract Diffusion of phenol through a biofilm attached to activated carbon particles was investigated. The biofilm was grown on activated carbon particles in a draft‐tube three‐phase fluidized‐bed bioreactor operating in a fed‐batch mode. It was found that phenol did not adsorb on the biofilm and that the diffusion coefficient of phenol within the biofilm varied from 13 to 39% of its corresponding value in water. The diffusion coefficient of phenol within the biofilm was reduced by increasing the biofilm density. An extensive literature review of diffusion of substrates through biofilms indicated that this conclusion could be extended to biofilms grown on flat surfaces, rotating cylinders, and even bioflocs.