Simultaneous biodegradation of methane and styrene in biofilters packed with inorganic supports: Experimental and macrokinetic study.

Four upflow 0.018 m biofilters (3 beds), B-ME, B-200, B-500 and B-700, all packed with inorganic materials, were operated at a constant air flow rate of 0.18 m h to eliminate methane (CH), a harmful greenhouse gas (GHG), and styrene (CH), a carcinogenic volatile organic compound (VOC). The biofilters were irrigated with 0.001 m of recycled nutrient solution (NS) every day (flow rate of 60 × 10 m h). Styrene inlet load (IL) was kept constant in each biofilter. Different CH-ILs varying in the range of 7-60 gCH m h were examined in B-ME (IL of 0 gCH m h), B-200 (IL of 9 gCH m h), B-500 (IL of 22 gCH m h) and B-700 (IL of 32 gCH m h). Finally, the effect of CH on the macrokinetic parameters of CH biofiltration was studied based on the Michaelis-Menten model. Average CH removal efficiencies (RE) varying between 64 and 100% were obtained at CH-ILs increasing from 7 to 60 gCH m h and for CH-ILs range of 0-32 gCH m h. More than 90% of CH was removed in the bottom and middle beds of the biofilters. By increasing CH-IL from 0 to 32 gCH m h, maximal EC in Michaelis-Menten model and macrokinetic saturation constant declined from 311 to 39 g m h and from 19 to 2.3 g m, respectively, which confirmed that an uncompetitive inhibition occurred during CH biofiltration in the presence of CH.