Waste recovery is a broad term used to describe the process by which energy stored in waste is extracted in the form of fuel, heat or power. There are several ways of recovering the energy from waste:
- Waste incineration with energy recovery also known as Energy from Waste (EfW)
- Conversion of waste using Mechanical Biological Treatment (MBT)
- Use of Landfill gas
- Controlled anaerobic digestion
Energy from Waste
Waste is combusted under strictly controlled conditions, reducing the volume and hazardousness of waste material. This process produces energy in the form of heat and electricity.
Mechanical Biological Treatment
MBT plants take bulk waste and remove recyclable or non-combustible materials, the remainder of the waste can then be processed. There are three types of MBT process:
- Production of both a refuse derived fuel (RDF) product and a compost product
- Production of a RDF product
- Production of a compost product
Landfill gas
The methane generated as a by-product of biodegradation in a landfill site must be controlled in order to minimise its effect on the environment. Collecting it and using it as a fuel has two benefits - avoiding pollution and generating energy. However, the energy recovery from landfill is considerably less efficient per tonne of waste than EfW.
Anaerobic Digestion
Biodegradable material is processed in an enclosed vessel under controlled conditions. The material breaks down in the absence of air and produces a gas, liquid fraction and compost-like material. The gas produced can be used to generate electricity, which can then be sold to the national grid. |