Energy recovery. Recovery of energy from waste incineration or the combustion of landfill gas. Many wastes, including municipal solid waste, sewage sludge and scrap tyres, contain an organic fraction which can be burnt in an incinerator. The energy is recovered via a boiler to provide hot water for district heating of buildings or high- temperature steam for electricity generation. The incinerator installation represents a high initial capital cost and sophisticated emissions control measures are required to clean-up the flue gases. Producing energy by combined heat and power (CHP) enables the maximum recovery of energy from waste by producing both electricity and district heating. The waste is again incinerated, but CHP systems would use a different type of steam turbine which would generate a lower amount of electricity, then the steam effluent from the turbine would be at a higher temperature, enabling district heating also to be incorporated. The production of landfill gas from the biodegradation of the organic fraction of wastes such as domestic waste and sewage sludge in a landfill site, produces a gas consisting mainly of methane which can be collected in a controlled, engineered way and burnt. Again the derived energy is used for either district heating or power generation. Additionally, there are newer technologies such as pyrolysis and gasification which can recover energy in the form of gas or liquid fuels. These can then be exported to power stations or used to generate energy on site