In the mid 1970s, Andco Incorporated developed and commercialized a slag­ging process called the Andco-Torrax System for converting MSW to low — energy gas and an inert glassy aggregate (Davidson and Lucas, 1978; Mark, 1980). Plants ranging in size from 2.4 to 7.5 t/h were installed in Europe, Japan, and the United States. Refuse is charged into the top of the gasifier without prior preparation except to shear or crush bulky items to about one meter or less in the longest dimension. As the refuse descends within the gasifier, it is dried and then pyrolyzed by the hot, oxygen-deficient gases produced in the hearth area. Char from the pyrolysis process and the noncom­bustible materials continue to descend. Primary combustion air at temperatures of about 1000°C is admitted to the gasifier immediately above the hearth to oxidize the char at temperatures sufficient to slag the inerts. The slag is continuously drained from the gasifier. The low-energy gas, the heating value of which is about 4.7 to 5.9 MJ/m3 (n), from the top of the gasifier is burned in a secondary combustion chamber at slagging temperatures. The slag is collected from this unit also. The heat from the secondary combustion chamber is used for hot water, steam, and power production. It is believed that this process can be used for waste disposal and energy recovery with combined feeds of MSW and tires, sludge, or waste plastics, and for the manufacture of cement. The first Andco-Torrax plant in the United States was built at Disney World in Orlando, Florida. This plant was used for waste paper from restaurants in the theme park. The performance of the gasifier in this plant was felt to be unsatisfactory because “arching” of the feedstock frequently occurred in the upper zone of the gasifier and resulted in feed stoppage. This problem could probably have been eliminated without design changes by densifying the very light waste paper feed.