Abstract: A method and apparatus for treating sludge from a paint spray booth operation. The sludge from the spray booth is deposited onto a porous belt of a conveyor system to allow the water to pass through the belt where it is collected for discharge from the apparatus. The remaining residue is passed over a vacuum device positioned beneath the belt and is then carried by the belt through an oven comprising a series of infrared thermal reactors arranged in serial fashion over the belt. The sludge is passed continuously beneath the infrared reactors and is dried thereby so that the sludge leaving the apparatus is in a dried particulate form which may be readily disposed of and/or solid. Convection air is recirculated through the apparatus to preheat the incoming sludge, remove smoke and other contaminants from the oven, and provide the desired pressure condition within the oven to optimize the efficiency of the thermal reactors.