Rubbish facts

What happens to my rubbish?

All household waste either goes to one of our waste transfer stations or directly to the Cornwall Energy Recovery Centre (CERC). The rubbish that goes to the transfer station is loaded into larger Lorries and then taken to the CERC.

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At the CERC, the household waste is received within an enclosed building and tipped into a large bunker where the waste is mixed to ensure an even burn in the furnace. Induced draft fans are used to draw air from the tipping hall and bunker into the combustion process in order to reduce odours. The waste is loaded by a crane into a feed hopper and then it travels down a chute to the furnace.

Inside the furnace a series of rollers moves the waste through the furnace where it is dried and burned at temperatures of around 1,000 degrees centigrade.

Burning this waste creates hot flue gases which travel through a boiler transferring the heat of the gases to water that runs through boiler pipes. The heated water evaporates becoming steam. The steam drives the turbine which then generates electricity, which is exported to the National Grid. Some steam is also used to heat various parts of the site including the offices.

Bottom ash left over after burning the waste drops into a quench tank, then along a conveyor into the adjacent bottom ash treatment plant. Ferrous and non-Ferrous metals are separated and sent off for recycling. The remaining product (incinerator bottom ash aggregate) is also separated by size and can be used in the construction industry as a secondary aggregate.

The gases from the burned waste are thoroughly cleaned to neutralise acid gases and remove the dioxins and heavy metals. The gases are then passed through a fine fabric filter to capture particles before being released through a chimney. Prior to release, the cleaned gases are monitored using the continuous emissions monitoring system to ensure that the emissions are fully in line with the Environmental Permit.

Residues from the flue gas treatment process, called the Air Pollution Control Residues (APCR), are then loaded into lorries and sent to landfill. The APCR produced corresponds to a very small proportion of the waste treated at the CERC.