To fractionate municipal solid waste incineration bottom ash: Key for utilisation?

Abstract

For the past decade, the Finnish waste sector has increasingly moved from the landfilling of municipal solid waste towards waste incineration. New challenges are faced with the growing amounts of municipal solid waste incineration bottom ash, which are mainly landfilled at the moment. Since this is not a sustainable or a profitable solution, finding different utilisation applications for the municipal solid waste incineration bottom ash is crucial. This study reports a comprehensive analysis of bottom ash properties from one waste incineration plant in Finland, which was first treated with a Dutch bottom ash recovery technique called advanced dry recovery. This novel process separates non-ferrous and ferrous metals from bottom ash, generating mineral fractions of different grain sizes (0-2 mm, 2-5 mm, 5-12 mm and 12-50 mm). The main aim of the study was to assess, whether the advanced bottom ash treatment technique, producing mineral fractions of different grain sizes and therefore properties, facilitates the utilisation of municipal solid waste incineration bottom ash in Finland. The results were encouraging; the bottom ash mineral fractions have favourable behaviour against the frost action, which is especially useful in the Finnish conditions. In addition, the leaching of most hazardous substances did not restrict the utilisation of bottom ash, especially for the larger fractions (>5 mm). Overall, this study has shown that the advanced bottom ash recovering technique can be one solution to increase the utilisation of bottom ash and furthermore decrease its landfilling in Finland.

Bottom ash from municipal solid waste incineration. Basic parameters and ecotoxicological properties

“…Incineration reduces the weight and volume of municipal solid waste by up to 65-90%, provides usable energy and reduces the amount of landfilled waste. An incineration plant is used for the thermal treatment of wastes with or without recovery of the heat of combustion [5][6][7].…”

“…Sormunen and Rantsi [5] examined harmful substances leached from the bottom ashes produced from municipal solid waste incineration. The bottom ash was produced in a combustion grate at 1000 °C.…”

“…Currently, the bottom ash from the municipal solid waste incineration is landfilled. Some authors [2,5,6,8] demonstrated its potential use in construction, thereby reducing the number of primary resources used (aggregates, sand, cement). We focused on ecotoxicological properties and determination of heavy metals, which is essential information for utilization of this type of waste.…”

Characterisation of used traction sand for utilization aspects in earth construction based on the requirements of Finnish environmental legislation

“…To determine the water-soluble concentrations of metals/metalloids (Sb, As, Ba, Cd, Cr, Cu, Pb, Mo, Ni, Se, Zn, V, Hg), chloride, sulphate, fluoride and dissolved organic carbon (DOC) in the traction sand, European standard SFS-EN 12457-3 was used (Sormunen & Rantsi 2015). This procedure is a two-stage batch test at a liquid-to-solid ratio (L/S) of 2 L/kg and 8 L/kg, with an extractant containing ultrapure water.…”

Leaching behaviour of municipal solid waste incineration bottom ash: From granular material to monolithic concrete

“…The utilization and disposal of bottom ash may have negative impacts on water resources, human health and the environment due to the potential release of heavy metals and soluble salts. Thus, the environmental impact of bottom ash should be evaluated before its application (Sormunen and Rantsi, 2015; Tang et al, 2015).…”