Effect of the continuous addition of ozone on biomass clogging control in a biofilter treating ethyl acetate vapors.

Biofiltration systems have been recognized as a cost-effective and environmentally friendly control technique for volatile organic compounds (VOC) removal. However, the long-term operation of biofilters causes biomass accumulation, and thus the occurrence of bed clogging, leading to a major decrease in biofilter performance. Control methods have been carried out in order to solve clogging problems, including backwashing, bed stirring, modification of flow patterns, predation, starvation and others. Ozone (O3 ) has been used in biofiltration systems at low concentrations to control the excess of biomass. It is worth mentioning that all these biofiltration studies involving O3 treated recalcitrant pollutants such as chlorobenzene, formaldehyde and toluene, which do not produce enough biomass to effectively prove clogging prevention. Thus, this study evaluated the effect of the continuous addition of O3 as a chemical oxidant at a very low concentration (90ppbv ) as a practical solution to overcoming clogging in a process of biofiltration of ethyl acetate (EA), a readily degradable molecule. The maximum elimination capacities achieved ranged from 200 to 120gm-3 h-1 , with and without O3 , respectively. The biomass concentrations in these systems ranged from 23.3-180.1 to 43.31-288.46mgbiomass gperlite -1 with and without O3 addition, respectively. Based on the results, it was concluded that the continuous addition of O3 could be an attractive solution to improving biofilter performance and extending the lifetime of the filter bed.