In current landfills breakdown of municipal solid waste (MSW) occurs slowly and the landfill leaves a legacy of care, management, monitoring and potential catastrophic failure over several generations. Social concern over these long term issues, with their legislative and economic implementation, increasingly favour practices which promote short stabilisation times and minimise environmental impact. This paper describes experiments carried out on mixed and unsorted municipal solid waste (MSW) in which 75% of the rapidly biodegradable fraction was degraded in about 2 months with an average yield of 0.18 m(3) CH4/kg volatile solids at sp. The experiments served to demonstrate that with proper leachate management very rapid decomposition of waste can be accomplished by taking the waste through a series of controlled degradation stages.