Abstract: Earth solids which have been contaminated by volatile organic contaminants can be treated by a method and in an apparatus of this invention. The apparatus includes a rotary kiln, a baghouse filter, a high temperature incinerator and a recycle conduit to recycle a major portion by volume of the hot exit gases from the rotary kiln back to the gas inlet end of the rotary kiln. The remainder of the rotary kiln exit gases is delivered through a baghouse filter to remove gas-borne particulates and the substantially particulate-free kiln exit gas is discharged through a high temperature incinerator which converts unburned volatile organic contaminants to innocuous products of combustion. Recycling the kiln exit gas to the gas inlet end of the kiln permits use of a larger kiln with accompanying increased solids throughput by permitting use of smaller baghouse filters and a smaller incinerator. In the preferred embodiment the entire system preferably is mounted on a frame suitable for highway mobility.