Utilisation of chemically stabilized arsenic-contaminated soil in a landfill cover

Abstract

The aim of the study was to determine if an As-contaminated soil, stabilized using zerovalent iron (Fe0) and its combination with gypsum waste, coal fly ash, peat, or sewage sludge, could be used as a construction material at the top layer of the landfill cover. A reproduction of 2 m thick protection/vegetation layer of a landfill cover using a column setup was used to determine the ability of the amendments to reduce As solubility and stimulate soil functionality along the soil profile. Soil amendment with Fe0 was highly efficient in reducing As in soil porewater reaching 99 % reduction, but only at the soil surface. In the deeper soil layers (below 0.5 m), the Fe treatment had a reverse effect, As solubility increased dramatically exceeding that of the untreated soil or any other treatment by one to two orders of magnitude. A slight bioluminescence inhibition of Vibrio fischeri was detected in the Fe0 treatment. Soil amendment with iron and peat showed no toxicity to bacteria and was the most efficient in reducing dissolved As in soil porewater throughout the 2 m soil profile followed by iron and gypsum treatment, most likely resulting from a low soil density and a good air diffusion to the soil. The least suitable combination of soil amendments for As immobilization was a mixture of iron with coal fly ash. An increase in all measured enzyme activities was observed in all treatments, particularly those receiving organic matter. For As to be stable in soil, a combination of amendments that can keep the soil porous and ensure the air diffusion through the entire soil layer of the landfill cover is required.

Assessment of bauxite refining residue (red mud) as a liner for waste disposal facilities

“…Main chemical constituents (Table 1) were Fe, Ti and Al oxides, which together accounted for 70% of the total constituents of the RM. The main mineral phases, determined by X-ray powder diffraction, in this RM were haematite (αÀFe 2 …”

“…Moreover, a large number of old EU landfills should be appropriately closed within the next few years as a consequence of the requirements established by the EU Directive on the Landfill of Waste 99/31/EG [1]. To meet these requirements, more than a billion tonnes of construction materials are needed [2]. Thus, the development of technologies for pollution avoidance and confinement remains a very important social and industrial target for Europe [3].…”

Arsenic mobility and speciation in contaminated kitchen garden and lawn soils: an evaluation of water for assessment of As phytoavailability

“…Indeed, significant correlations have been found between dissolved Fe and As confirming that Fe oxides/hydroxides represent one of the major sorbing agents for As in soils (Masscheleyn et al 1991;Marin et al 1993;Kumpiene et al 2013;Molinari et al 2013). On the other hand, it was found that the speciation of As in the water extracting solution depended on the soil uses.…”

Evaluation of Arsenic Leaching Potential in Gold Mine Tailings Amended with Peat and Mine Drainage Treatment Sludge

“…Peat also has high CEC (94 cmol[+] kg −1 ) and allows efficient immobilization of metal cations from pore water. Peat mixed or modified with Fe‐based materials was effectively used for efficient removal of metalloids (Ansone et al, 2013; Kumpiene et al, 2013). In the present study, the amendment of peat mixed with Fe‐rich sludge decreased up to 85% the total As concentrations in tailings.…”

“…Finally, peat mixed or modified with Fe‐based materials was found to be efficient in removing metalloids. The better As removal was explained by the existence of As‐O‐Fe bonds in Fe‐peat amendment (Ansone et al, 2013; Kumpiene et al, 2013; Zhang et al, 2018). It is worth noting that Fe‐based materials were reported to have a high metalloids scavenging capacity (Bolan et al, 2014).…”