Biodegradation of xylene in a biofilter- effect of process variables, shock loads and kinetic modeling

The performance of a laboratory scale biofilter using date palm tree barks as packing material was studied to remove xylene. Experiments were performed by subjecting the biofilter to different xylene inlet loading rates(3.0-214.0 g/m³ h) and flow rates (0.06, 0.09 and 0.012 m³/h). Removal efficiencies greater than 90% were achieved in the inlet xylene concentration range of 0.1-3.2 g/m³. The elimination capacity was found to vary linearly with inlet loading rates. The concentration profiles were studied axially during the biofiltration experiments and the lower parts of the biofilter removed a significant part of inlet xylene. The temperature and pH variations were recorded during the entire biofiltration studies. The carbon dioxide production rate was related to elimination capacity by the equation CPR = 1.81 EC + 14.12. The Michaelis-Menten type model kinetic constants for the biofiltration of xylene were evaluated as maximum elimination capacity, EC_max = 178.57g/m³h and saturation constant K_s =1.232 g/m³. The stability of the biomass inside the biofilter was found to be good by subjecting the biofilter to shock load conditions.