What is MBT?
Mechanical Biological Treatment (MBT) is a term used to describe a group of technologies that deal with residual municipal waste. When waste goes to an MBT facility, recyclable or re-usable material will be extracted from it by a mechanical process, with the waste then subjected to further treatment to produce a more biologically stable material. MBTs operate as part of a wider integrated approach involving additional treatment stages, such as Energy Recovery.
What is Energy Recovery?
There are a number of energy recovery technologies, including incineration, gasification, pyrolysis and use of cement kilns.
The North West Joint Committee has decided that incineration is not an acceptable technology in the North West Region.
Gasification is one of the main forms of advanced thermal treatment of waste. It is used to recover energy from residual waste. Gasification uses small amounts of oxygen to dispose of waste in such a way that useful energy is produced, in the form of electricity and heat. Gasification involves the partial oxidation of a substance. This means that oxygen is added but the amounts are not sufficient to allow complete oxidisation or full combustion to occur. The temperatures employed are typically above 650 degrees Celsius and the main product is a syngas, which is used to drive turbines or gas engines to produce electricity. The other main product is a solid residue of non-combustible materials (ash) which contains relatively little carbon.
Pyrolysis is a similar process to gasification but uses no oxygen rather than restricted oxygen, as in gasification. In the cement kiln process, the use of fossil fuels is displaced and that energy saved.
For more detailed information on MBT and energy recovery plants, see the Frequently Asked Questions section.