Reuse potential of municipal solid waste incinerator bottom ash as secondary aggregate: Material characteristics, persistent organic pollutant content and effects of pH and selected environmental lixiviants on leaching behaviour

DOI: 10.1016/j.wasman.2024.07.026

Authors: Felipe E. Sepulveda Olea (University of Leeds) , Ian T. Burke (University of Leeds) , Arif Mohammad (Cardiff University) , Douglas I. Stewart (University of Leeds)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Waste Management , VOL 187 , PAGES 262 - 274

State: Published (Approved)
Published: October 2024
Diamond Proposal Number(s): 33049

Abstract: Increasing municipal solid waste (MSW) production poses challenges for sustainable urban development. Modern energy-from-waste (EfW) facilities incinerate MSW, reducing mass and recovering energy. In the UK, MSW incineration bottom ash (MSW IBA) is primarily reused in civil engineering applications. This study characterizes UK-produced MSW IBA, examining its pH-dependent leaching behaviour and response to environmental lixiviants. Results show predominant components include a melt phase, primary glass and fine ash aggregations, and a chemical composition dominated by SiO2 (30–50 %), CaO (∼15 %), Fe2O3 (∼10 %), and Al2O3 (∼8%). X-ray absorption near edge structure (XANES) analysis shows that Zn and Cu are most likely oxygen-bound (adsorbed to oxy-hydroxides and as oxides) with some sulphur bound. Polychlorinated biphenyls (PCBs) and polychlorinated dibenzodioxins/furans (PCDD/Fs) are well below regulatory limits, and polycyclic aromatic hydrocarbons (PAHs) were undetectable. Leaching tests indicate trace elements mobilize at pHs ≤ 6. With a natural pH of 11.3 and high buffering capacity, significant acid inputs to the MSW IBA are required to reach this pH, which are improbable in the environment. Wood chip additions increase leachate’s dissolved organic carbon (DOC) and reduce pH, but had minimal impact on metal-leaching behaviour. Synthetic plant exudate solutions minimally affect metal leaching at realistic concentrations, only enhancing leaching at ≥ 1500 mg l−1 DOC. This work supports MSW IBA’s low-risk in specified civil engineering applications.

Diamond Keywords: MSW IBA; Metal leaching; Persistent organic pollutants; Circular economy; Environmental lixiviants

Subject Areas: Environment, Chemistry, Materials


Instruments: I18-Microfocus Spectroscopy

Added On: 31/07/2024 09:22

Documents:
1-s2.0-S0956053X24004161-main.pdf

Discipline Tags:

Desertification & Pollution Earth Sciences & Environment Chemistry Materials Science

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Absorption Near Edge Structure (XANES)