The following are, in the most part, terms that are used in the waste management sector which may not be familiar to process engineers.

Animal By-Products (ABP) Regulation: Legislation governing the processing of wastes derived from animal sources.

Biogas: Gas resulting from the fermentation of waste in the absence of air (methane/carbon dioxide).

Biodegradable Municipal Waste (BMW): The component of Municipal Solid Waste capable of being degraded by plants and animals. Biodegradable Municipal Waste includes paper and card, food and garden waste, and a proportion of other wastes, such as textiles.

Green Waste: Vegetation and plant matter from household gardens, local authority parks and gardens and commercial landscaped gardens.

In-vessel Composting: The aerobic decomposition of shredded and mixed organic waste within and enclosed container, where the control systems for material degradation are fully automated. Moisture, temperature, and odour can be regulated, and stable compost can be produced much more quickly than outdoor windrow composting.

Mechanical Biological Treatment (MBT): A generic term for mechanical sorting/separation technologies used in conjunction with biological treatment processes, such as composting.

Municipal Solid Waste (MSW): Household waste and any other wastes collected by the Waste Collection Authority, or its agents, such as municipal parks and gardens waste, beach cleansing waste, commercial or industrial waste, and waste resulting from the clearance of fly-tipped materials.

Process Gas: Useful gas produced during the gasification and hydrolysis process, and which can be used either as a combustion energy source, or cleaned and processed further as used as a chemical feedstock.

Refuse Derived Fuel (RDF): A fuel produced from combustible waste that can be stored and transported, or used directly on site to produce heat and/or power.

Renewables Obligation: Introduced in 2002 by the Department of Trade and Industry, this system creates a market in tradable renewable energy certificates (ROCs), for which each supplier of electricity must demonstrate compliance with increasing Government targets for renewable energy generation.

Source-segregated/Source separated: Usually applies to household waste collection systems where recyclable and/or organic fractions of the waste stream are separated by the householder and are often collected separately.