A method for breaking down a pallet of plastic, paper, cardboard, and organic material to produce bio-gas, fertilizer, and water includes a step of maintaining a negative pressure during the steps of removing, separating, recycling, feeding, and converting to clean odorous air. The step of maintaining the negative pressure is further defined as removing the odorous air generated during the steps of separating, recycling, feeding, and converting. The chamber of the biofilter is maintained at a predetermined humidity of at least 80% and a predetermined temperature of between 70° F. and 80° F. A biofilter for removing odorous air includes a filter media having a mixture of woodchips having hardwood chips being present between 30 wt. % and 50 wt. %, softwood chips being present between 50 wt. % and 70 wt. %, and microorganisms disposed therein.