A mass burn facility is a type of municipal solid waste (MSW) incineration, or waste-to-energy (WTE), facility in which MSW is burned with only minor presorting to remove oversized and noncombustible items, and hazardous or explosive materials. After pretreatment, the MSW is fed into an incinerator, where it is supported on a grate or hearth. Air is fed above or below the grate to promote combustion. Mass burn plants range from small modular plants with capacities as low as 25 tons (22,700 kilograms) per day to facilities with capacities of 3,000 tons (2.7 million kilograms) of MSW per day or more. In addition to receiving and handling, and combustion and steam generation, the other major components of a mass burn facility include flue gas cleaning, power generation (optional), condenser cooling water, residue ash hauling, and landfilling.

Mass burn technologies represent over 75% of all the WTE facilities constructed in the United States to date. The other common form of incineration or WTE technology involves refuse-derived fuel.