Biological phenol removal using suspended growth and packed bed reactors

Phenol removal was studied using batch cultures of free suspended cells and attached growth processes. Indigenous bacteria from olive pulp were enriched and used as inoculum for the filter and a suspended-growth flask reactor. A pilot-scale packed bed reactor was constructed and operated for biological phenol removal from industrial wastewater. The packed bed reactor was found to be more resistant to high phenol concentrations and led to significantly higher removal rates than the suspended-growth reactor. Two different operating modes were used to investigate the optimal performance of the filter, i.e., continuous and draw-fill. The latter was found to achieve removal rates up to 12.65 g phenol/(l d), while the continuous operating mode achieved removal rates only up to 0.082 g phenol/(l d).The low operating cost combined with the high phenol removal rates indicates that the above technology may offer a feasible solution to a serious environmental problem.