Waste from electronic and electrical equipment or “WEEE” constitutes around 4% of municipal waste and is forecast to grow by 3-5% per year. Electronic and electrical equipment is one of the largest known sources of heavy metals (lead, mercury, nickel, cadmium) and organic pollutants in the waste stream. When this and other household waste in landfill sites is acted on by rainwater, the organic and inorganic constituents are dissolved, and a highly toxic leachate results, collecting at the base of the landfill. This is normally high in heavy metals, ammonia, toxic organic compounds and pathogens. Meanwhile, at the top of the landfill, gas is produced by the fermentation of organic material. Approximately equal quantities of carbon dioxide (CO 2 ) and methane (CH 4 ) are released. Both are greenhouse gases, but methane is 26 times more effective than carbon dioxide in this respect. In addition to leachate and biogas problems, landfill sites are very unpopular with local residents: traffic, smell, noise, vermin, seagulls, blown litter, and disease can all spoil the neighbourhood and lower property prices.