As indicated earlier, liquids and solids produced from waste conversion can be used either as fuel for power generation or they can be upgraded by numerous conventional and novel technologies such as hydroprocessing, catalytic cracking, product blending, aqueous phase reforming, tri-reform­ing, and gas to liquid conversion (Fischer-Tropsch and related syntheses) among others, to make useful transportation fuels, chemicals, and materials. These technologies are extensively discussed in the literature [29, 84, 145], and they can be applied to waste conversion products.

The effectiveness of a particular type of upgrading technology to waste conversion products depends on the quality of the products which in turn depends on the nature of the waste. For example, pyrolysis of rubber tires can generate gases that contain significant amounts of ethylene and pro­pylene which are the basic building blocks of polymers. Landfill gas that predominantly contains methane and carbon dioxide can be upgraded by dry reforming to make syngas, which is the basic building block for Fischer- Tropsch synthesis. Aqueous phase reforming of lignocellulosic waste can produce a variety of useful chemicals. The upgrading technologies are now increasingly being applied as more efforts are being made to convert waste into useful products.