Turning Trash into Treasure

This article describes various aspects of advanced waste-to-energy (WTE) technologies for converting trash into a clean and valuable resource. Renewed interest in WTE is largely driven by new technologies, improved economic models, energy trends, and policy changes. Gasification of municipal solid waste is gaining attention as new technological advances make this process more affordable. Gasification is the partial oxidation of the organic content in the municipal solid waste (MSW) feedstock to produce a synthesis gas, or syngas, rich in hydrogen and carbon monoxide. Covanta Energy, a major player in the waste-to-energy field, has developed and commercialized a gasification process for unprocessed, post-recycled MSW, in an air-based process requiring no other reactants or energy inputs. Another WTE approach is converting waste into solid recovered fuels—blends of non-recycled waste that are engineered into a fuel-pellet feedstock. This technology is especially suitable for plastics such as disposable diapers that are difficult to recycle, or those that decompose slowly in landfills.