Abstract: A compact thermal oxidizer is disclosed, comprising a combustion chamber and a series of ducts including a first duct, a second duct, a third duct, and a fourth duct. The combustion chamber is connected to the first duct, which in turn directs fluid flow into the second duct in an antiparallel direction to the combustion chamber. The second duct is linked to the third duct, which guides the fluid flow into the fourth duct, in aa direction antiparallel to the flow in the second duct and parallel to the flow in the combustion chamber. A refractory lining is disposed on the interior surfaces of the combustion chamber, first duct, and second duct.