Abstract: A waste treatment system is provided, including a waste melter system and an air pollution control system. Hazardous and/or radioactive waste in drums is conducted through a waste feed system into a plasma chamber where the waste is exposed to heat from a plasma torch. A part of the waste volatilizes and leaves the plasma chamber for a secondary reaction chamber, in which the waste is combusted to form a waste gas stream. The air pollution control system treats the waste gas stream through quenching, filtering and scrubbing, to produce a clean gas stream suitable for release to the atmosphere. Offgas may be recirculated through the waste treatment system as desired. The waste remaining inside the plasma chamber melts and drops onto sloped processing surfaces inside a hearth located below the plasma torch. The hearth includes ground electrodes configured for electrical contact with waste held in the hearth so that the melted waste in the hearth may be further heated by the plasma torch.