Abstract: Apparatus for treatment of material containing biodegradable volatile organic compounds in solid or liquid state, comprises a first chamber having a gas inlet and a gas outlet, the gas inlet being below the gas outlet. Material to be treated is supported in the first chamber between the gas inlet and the gas outlet. The material to be treated is warmed and an upward flow of air is established in the first chamber whereby biodegradable volatile organic compounds in the material are volatilized and become entrained in the upward flow of air. A second chamber has a gas inlet and a gas outlet, the gas inlet of the second chamber being below the gas outlet thereof. A duct delivers gas from the gas outlet of the first chamber to the gas inlet of the second chamber. A biologically active matrix including at least one organism that biologically converts the organic compounds to a non-toxic form is supported in the second chamber between the gas inlet and the gas outlet thereof.