Recycling at the Facility
The combustion of 190,000 tonnes of waste will give rise to approximately 40,000 tonnes of Incinerator Bottom Ash (IBA), comprising mainly clinker, brick rubble and soils, glass, ceramics, and metals. This material will be cooled in a quench bath and conveyed to a storage/process hall in the main building of the facility. The material will be processed with an array of crushers, screens, magnets, and eddy current separators to recover ferrous and non-ferrous metals, and grade the material for use as an aggregate-replacement raw material in construction and civil engineering.
The flue gases from the combustion process will be ‘scrubbed’ with a mixture of hydrated lime and activated carbon, in order to neutralise the acid gases and capture potentially harmful elements such as dioxins and heavy metals. Combined with fine particulate matter entrapped by bag filters, some 7,000 to 8,000 tonnes of Air Pollution Control residues (APCr) will need to be managed. This material is classified as Hazardous Waste (largely by reason of its alkalinity), and has been traditionally managed by mixing with water (into a cake-like form) prior to disposal at permitted hazardous waste landfill.
There will be a capability at the facility to capture and harvest rainwater from the main buildings, which may be used in the process and administration block (for toilet flushing etc.) thereby reducing the demand for mains fresh water. In addition, further savings on mains water demand will be made through using ‘dirty’ water from sources such as yard/hard-standing areas to quench the hot ashes from combustion.