Glossary

GLOSSARY

 

APC residues: Air Pollution Control residues comprise

(i)                            Dry and semi-dry scrubber systems involving the injection of an alkaline powder or slurry to remove acid gases and particulates and flue gas condensation/reaction products (scrubber residue);

(ii)                           Fabric filters in bag houses may be used downstream of the scrubber systems to remove the fine particulates (bag house filter dust) and (iii) the solid phase generated by wet scrubber systems (scrubber sludge). APC residues are often combined with fly ash.

 

Bottom Ash: Comprises heterogeneous material discharged from the burning grate of the incinerator (grate ash) and material that falls through the burning grate to be collected in hoppers below the furnace (grate riddlings).

 

Circulating Fluidised Bed Combustion (CFBC): Is a combustion system in which the fuel (usually processed waste fuels such as coarse refuse-derived fuel) are burnt in a fine inert material fluidised by a high velocity air stream. The off-gas and entrained solids are separated in a high efficiency cyclone and the solids are returned to the bed.

 

Co-disposal: Is the practice of mixing wastes from different origins in the same landfill.

 

Energy from Waste EFW, also known as Waste to Energy (WTE): Is the conversion of waste into a useable form of energy, e.g. heat or electricity. A common conversion process is waste combustion.

 

Fluidised Bed Combustion (FBC): Is a combustion system in which a fine inert material, such as sand, is maintained in a fluid condition by air blowing upwards through it. This system is used in combination with processed waste fuels, such as coarse refuse-derived fuel.

 

Fly Ash: Is finely divided particles of ash which are normally entrained in the combustion gases. Fly ash is recovered from the gas stream by a combination of precipitators and cyclones.

 

Mass-Burn Incineration: The incineration of waste in a grate combustion system.

 

Monofill: Is the landfill site practice whereby only one type of waste material (e.g. MSW bottom ash) is placed in landfill.

 

Municipal Solid Waste (MSW): Is waste which is collected for treatment and disposal by a local authority. MSW generally comprise waste from households, civic amenity sites, street sweepings, local authority collected commercial waste, and some non-hazardous industrial waste.

Pozzolan: Is a silica-rich or silica and alumina-rich material which in itself possesses little or no cementious value, but which will, in finely divided form and in the presence of moisture, react chemically with calcium hydroxide to form compounds possessing cementious properties.

 

Refuse Derived Fuel (RDF): Is a fuel product recovered from the combustible fraction of household waste.