Since the late 1980s, finding alternatives to conventional landfill disposal has been a subject of intense interest in Kentucky. Centralisation of fewer but larger facilities that now average 500 tonnes/day MSW input
(the average amount produced by 200,000 residents) has increased waste transportation costs for some remote communities.
Steam classification was in a very early stage of development when individuals from Kentucky and
Indiana began work in 1991 to improve methods of processing MSW. Grant assistance offered by the Kentucky Division of Energy through the US Department of Energy's Southeast Regional Biomass Energy Program (SERBEP) encouraged WRT to
fabricate a system for testing at a landfill in Walton, Kentucky.
The primary objective was to model the process to project economic feasibility at 200 tonnes/day for recovery of waste metals, plastics and pasteurised
cellulose. A secondary objective was to test the combustion qualities of the separated cellulose. A prototype unit was installed in 1993 at a landfill which serves several Northern Kentucky client communities. Cinergy Corporation,
a regional coal-fired utility servicing Indiana, Ohio and Northern Kentucky, agreed to test-burn the extracted cellulose.
WRT views steam classification as an option to landfilling not a replacement for popular roadside
recycling programmes. However, some waste audits have shown that cellulose content does not differ significantly in refuse obtained from roadside recycling containers compared to raw MSW.
Representatives from WRT are
negotiating with various business interests to market the material as a pyrolysis feedstock for liquid fuel production or for gasification.
Other possibilities include pelletising the cellulose with a binder element or selling
it to utilities for coal co-firing using pneumatic feeding.