Burning as a method of domestic waste disposal takes place in many countries. Combustible rubbish is added to heating and cooking fires inside the home. In homes with gardens, bulky garden refuse, paper and cardboard are quickly reduced to a small quantity of ash, which can then be scattered on the garden as fertilizer. The smell and smoke produced usually drifts into neighbours' garden, depositing smuts as it goes. Municipal incinerators achieve a similar, although usually more efficient, process of waste reduction so that the solid residues have about one eighth of the volume of the original waste. Combustion heat and gaseous products, some of which are acidic in nature, are released to the atmosphere, and incinerators, in common with coal-fired power stations, have been criticized for emitting pollutants which have been implicated in environmental damage. Some dustbin contents -- including food wastes and some plastics -- produce chlorinated hydrocarbons, such as dioxins, when they are improperly burned. Others -- such as batteries -- contain mercury and other poisonous heavy metals, which should be treated separately as hazardous waste.
Many of the 40 municipally-owned incinerators in the UK are of obsolete design, without energy recovery (36 of the 40) and producing more smoke and dust from their chimneys than incinerators built from the 1970s (which have moving grates which progressively dry, ignite and burn refuse more efficiently -- it being heterogeneous, only one fifth the density of coal but with a calorific value of nearly 40% that of coal). The operating cost of a modern, energy recovering plant of around 200,000 tonnes per year capacity is about £25-30 per tonne of rubbish. This cost may be either more of less than the cost of landfilling the untreated waste, depending on the nature of the site and the haulage involved. Denmark incinerates more than 60% of its municipal waste, France more than 40% and both the Netherlands and West Germany over 30%. In the EEC/EU as a whole, 80% of municipal solid waste incinerators have energy recovery facilities. Sweden incinerates about 80% of its municipal waste, and all its 25 incinerators are fitted with energy recovery facilities. In 1990, there were 135 mass burn plants in the USA, with another 53 under construction. Collectively they process 13% of the nation's municipal solid waste.