The release of As, Cr and Cu from contaminated soil stabilized with APC residues under landfill conditions

Abstract

The aim of this study was to investigate the stability of As, Cr and Cu in contaminated soil treated with air pollution control residues under landfill conditions. The influence of landfill gas and temperature on the release of trace elements from stabilized soil was simulated using a diffusion test. The air pollution control residues immobilized As through the precipitation of Ca-As minerals (calcium arsenate (Ca5H2(AsO4)3 × 5H2O), weilite (CaAsO4) and johnbaumite (Ca5(AsO4)3(OH)), incorporation of As into ettringite (Ca6Al2(SO4)3(OH)12 × 26H2O) and adsorption by calcite (CaCO3). The air pollution control residues generally showed a high resistance to pH reduction, indicating high buffer capacity and stability of immobilized As in a landfill over time. Generation of heat in a landfill might increase the release of trace elements. The release of As from stabilized soil was diffusion-controlled at 60 °C, while surface wash-off, dissolution, and depletion prevailed at 20 °C. The air pollution control residues from the incineration of municipal solid waste immobilized Cr, indicating its stability in a landfill. The treatment of soil with air pollution control residues was not effective in immobilization of Cu. Contaminated soils treated with air pollution control residues will probably have a low impact on overall leachate quality from a landfill.

Characteristics of fine and ultrafine aerosols in the London underground

“…The sample was scanned for 16 h with a step size of 0.0334 0 from 0 to 100 0 at room temperature. Spectra collected by Ferreira, Travar, Hamdan and Alawadhi (Ferreira et al, 2006;Travar et al, 2015;Hamdan and Alawadhi, 2020) were used as a reference.…”

Leaching of metal(loid)s from ashes of spent sorbent and stabilisation effect of calcium-rich additives

“…Immobilisation is one of the conventional methods used to treat metal(loid)-contaminated soils, and among other immobilising agents such as P compounds and Fe or Mn oxides, materials rich in Ca are also being used (Bolan et al 2014 ). As reported by Travar et al ( 2015 ), the formation of poorly soluble Ca-As minerals such as calcium arsenate, weilite and jahnbaumite were responsible for the immobilisation of As in the contaminated soil, where a Ca-rich waste product derived from the air pollution controller in an incinerator was added. In the same study, it was reported that the addition of Ca had a slight mobilising effect on Cr and Cu.…”

Copper Recovery from Polluted Soils Using Acidic Washing and Bioelectrochemical Systems

“…There is thorough lab-scale research on chemical soil washing using a variety of leaching agents, including inorganic acids, bio surfactants and complexing agents such as EDTA or its derivates [2][3][4][5][6][7][8]. Apart from cases where water was used as the leaching agent, not many pilot scale experiments have been conducted [9]. A reason might be that when virgin chemicals are used, recirculation or reuse of the leaching agents is essential in order to ensure an efficient and economically viable process.…”