The recycling of bottom ash generated from the operations of the facility helps to conserve natural resources and promotes the circular economy
The waste-to-energy plant at Westenergy produces bottom ash, consisting of materials such as ash, glass, metals, ceramics, and stone. Larger metal objects are separated from the bottom ash at Westenergy’s plant and sent for recycling into new metal products. After the metal screening process, the remaining bottom ash is delivered for further processing to our partner, Suomen Erityisjäte Oy.
During the further processing of bottom ash, a sand- and gravel-like material known as the mineral fraction is separated. This mineral fraction is suitable for use as construction material and can be utilised, for example, in the production of concrete products and as a base material in infrastructure construction. In addition to the mineral faction, the processing also enables the recovery of smaller residual metal fragments, which are separated and directed to recycling.
Last year, approximately 12,250 tonnes of mineral fraction separated from the bottom ash supplied by Westenergy were used as construction material.
Recycling bottom ash and utilising the recovered mineral fraction helps conserve natural resources, as it replaces virgin materials such as natural sand and gravel. Replacing virgin materials with recycled minerals also supports the European Union’s sustainable development goals and promotes the circular economy. Last year, approximately 12,250 tonnes of mineral fraction separated from the bottom ash supplied by Westenergy were used as construction material.
Recycling metals significantly reduces, among other things, carbon dioxide emissions, especially when compared to the production of primary metals, which requires the extraction and processing of natural raw materials such as ore – a process that consumes a large amount of energy and causes considerable emissions. This highlights the importance of recovering valuable metals from bottom ash.
Metal recovery from bottom ash is important. Last year, 2,999 tonnes of metal fragments separated from Westenergy’s bottom ash were recycled into new metal products.
Recovered metals can be recycled into new materials such as steel, aluminium, copper, and zinc. Last year, larger metal objects separated directly at Westenergy’s plant alone were recycled into new products totalling 399 tonnes. In total, 2,999 tonnes of metal pieces separated from Westenergy’s bottom ash were recycled into new metal products.
The bottom ash is processed in accordance with environmental permit requirements, and its recycling into secondary materials helps to conserve natural resources. In addition, the reuse of bottom ash is continuously being developed to support the circular economy.
Other residual materials from plant operations
In addition to bottom ash, Westenergy’s plant operations generate boiler ash and flue gas treatment residues, commonly referred to as APC (Air Pollution Control) waste. APC waste consists of cleaning chemicals and the impurities they capture, while boiler ash originates from ash particles that detach from the boiler’s heat transfer surfaces. The further treatment of these residues is carried out in collaboration with NG Nordic Finland Ltd.
Last year, a total of 4,197 tonnes of APC waste and 1,627 tonnes of boiler ash were delivered for further processing.
Last year, a total of 4,197 tonnes of APC waste and 1,627 tonnes of boiler ash were delivered for further processing. Like bottom ash, these residues are handled in accordance with environmental permit requirements. Part of the ash is treated at an ash refinery, where the associated carbon dioxide emissions are reduced, which decreases the need for final disposal. In addition, some of the material is stabilised with cement prior to disposal. Alongside bottom ash, Westenergy is actively working to promote the reuse of these residual materials.
