Management and Utilization of Municipal Solid Waste Incineration Ash

Incineration of municipal solid waste yields substantial quantities of ash residues, principally fly ash and bottom ash, which pose environmental and health risks due to their content of heavy metals, chlorides and dioxins. Effective management encompasses characterisation, pretreatment and stabilisation to mitigate leaching and facilitate safe disposal or reuse. Common pretreatment methods include water washing to remove soluble salts, thermal and chemical treatments to volatilise or immobilise toxic elements, and mechanical activation such as ball milling to alter particle size and surface reactivity. Stabilisation and solidification techniques embed ash in cementitious or geopolymeric matrices, reducing mobility of contaminants and enabling incorporation into construction materials. Resource recovery strategies target extraction of valuable metals through acid or alkaline leaching and thermal processes. Emerging applications exploit ash as raw material for low-temperature geopolymers, cement replacement in concrete or pavement aggregates, mineral carbonation for CO₂ sequestration, and ceramics or bricks. Lifecycle assessments emphasise circular economy principles, balancing energy use, greenhouse-gas emissions and economic feasibility. Globally, advances in ash utilisation can reduce landfill dependence, recover resources and contribute to sustainable urban waste management.

Research from Nature Portfolio

Foundational work has demonstrated the efficacy of thermal chlorination for heavy-metal removal from mixed sludge and municipal solid waste fly ash. Controlled heating between 900 °C and 1 000 °C in the presence of inherent or added chloride agents promotes volatilisation of lead, cadmium, zinc and copper, achieving removal efficiencies of up to 89 % for lead and over 50 % for cadmium and zinc. The choice and dose of chlorinating agent markedly affect volatility, with magnesium and calcium chlorides outperforming sodium chloride in resource recovery and decontamination. This seminal study underpins current efforts to integrate thermal-chemical decontamination into industrial ash treatment processes.

Management and Utilization of Municipal Solid Waste Incineration Ash publication trend

The graph below shows the total number of articles in management and utilization of municipal solid waste incineration ash across all publications each year (not limited to Nature Index journals).

Technical terms

Fly ash: Fine particulate residue from combustion flue gases, containing high concentrations of soluble salts and heavy metals.

Bottom ash: Coarser, non-combustible fraction collected at the grate, comprising glass, ceramics and unburnt organic matter.

Stabilisation/solidification: Processes that immobilise contaminants by embedding ash in cementitious or geopolymeric matrices to reduce leaching.

Leaching: Mobilisation of hazardous elements from ash into aqueous solution under specified environmental or test conditions.

Geopolymer: Inorganic polymer formed by alkaline activation of aluminosilicate precursors, used to encapsulate waste ash and immobilise pollutants.

Thermal chlorination: Treatment combining heat and chlorine-bearing agents to volatilise and recover heavy metals from ash.

References

1. Recycling of Pre-Washed Municipal Solid Waste Incinerator Fly Ash in the Manufacturing of Low Temperature Setting Geopolymer Materials. Materials (2013).
2. Review on Cement Stabilization/Solidification of Municipal Solid Waste Incineration Fly Ash. Advances in Materials Science and Engineering (2018).
3. Changes in composition and lead speciation due to water washing of air pollution control residue from municipal waste incineration. Journal of Hazardous Materials (2018).
4. Increased Sustainability of Carbon Dioxide Mineral Sequestration by a Technology Involving Fly Ash Stabilization. Materials (2019).
5. Physical and Chemical Properties, Pretreatment, and Recycling of Municipal Solid Waste Incineration Fly Ash and Bottom Ash for Highway Engineering: A Literature Review. Advances in Civil Engineering (2020).
6. Suppressing Heavy Metal Leaching through Ball Milling of Fly Ash. Energies (2016).
7. Heavy metal removal from MSS fly ash by thermal and chlorination treatments. Scientific Reports (2015).
8. Microstructure and Strength of Alkali-Activated Bricks Containing Municipal Solid Waste Incineration (MSWI) Fly Ash Developed as Construction Materials. Sustainability (2019).
9. Heavy metals removal/stabilization from municipal solid waste incineration fly ash: a review and recent trends. Journal of Material Cycles and Waste Management (2022).