tank 11 for an initial gross separation of the solid liquid and vaporous constituents the gaseous portion of the digester charge is withdrawn from the top of the blow tank vessel through a large diameter pipe 12 and ducted into an accumulator vessel 13 for preservation of a major portion of the heat values present in the resulting condensate remaining vapors are drawn from the accumulator through pipe 14 and ducted to a condenser 15 for further heat removal and subsequently through pipe 16 to a scrubber 17 for reactive removal of remaining particulates and water soluble compounds the gaseous residue from the scrubber 17 drawn through pipe 18 by the draft induction of odor control fan 19 predominately comprises an odorous non condensible mixture of hydrogen sulfide methyl mercaptan methyl disulfide and turpentine gases which when combined with appropriate portions of oxygen are combustible damper regulated draft pipe 20 normally provides sufficient dilution air to exceed the combustible mixture range for the resulting gas air stream discharged from the odor control fan 19 through pipe 21 as auxiliary draft for a primary air supply fan 22 supporting a large heating appliance such as a lime kiln recovery furnace etc not shown within the firebox of such a large appliance the odorous gases are consumed harmlessly without consequence under unusual circumstances however such as when two or more digesters are blown simultaneously the quantity of such non condensible gas effluent increases sufficiently to.