Refuse-derived fuel is available at almost all levels of waste generation -- the household, industry and municipality -- and could be used provided there is an appropriate match of fuel and technology that can burn efficiently without producing pollution. For example, mechanical shredding and sorting of municipal waste can separate out the combustible portion. Either a loose fuel, known as fluff, floc or coarse refuse-derived fuel (c-RDF), can be produced and burned in appropriate furnaces, or a densified pellet or briquette (d-RDF) can be produced which has a bulk density and calorific value around half that of coal and higher than peat. One alternative waste disposal option for larger urban areas is "waste-to-energy", or mass incineration where, apart from removal of bulky items, such as refrigerators or car engines, the whole of the waste stream is incinerated as delivered. This reduces waste volumes by 80 to 90%, and the resulting energy recovery brings financial rewards. However the capital costs for waste-to-energy can be high, especially for cleaning equipment necessary to ensure compliance with emissions limits. Solid organic wastes (eg garden refuse) or liquid organic waste (eg animal slurry) can be separated out and digested anaerobically to produce biogas. This is possible also at landfill sites. Many industries, or their near neighbours, have both furnaces and combustible wastes. It is possible that some of their energy needs can be met by waste incineration, either to produce low-grade heat (for hot water or space heating), high-temperature steam or straight substitution for some of their conventional furnace fuel.