Water quality implications of the neutralization of acid mine drainage with coal fly ash from India and the United States

Weinberg, Rachel L.; Coyte, Rachel M.; Wang, Zhen; Das, Debabrata; Vengosh, Avner

doi:10.1016/j.fuel.2022.125675

Cited by 13 publications

(8 citation statements)

References 57 publications

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“…Notably, A2Q and AFQ achieved higher neutralization, yielding pH > 7.7, complying with South Africa Water Quality (SAWQ) guidelines within the pH 6.5 and 8.4 for agricultural use [ 39 ]. These findings are consistent with lime/limestone [ 9 , 11 ] and fly ash neutralization studies [ 13 , 15 ]. Further, quicklime and fly ash treatment also resulted to substantial reduction in EC reduction, SO 4 2− , NO 3 − and HM content (one way ANOVA, p < 0.05) ( Table 1 ) in bulk soils compared to untreated AMD water ( Table 1 ).…”

Section: Resultssupporting

confidence: 90%

“…Various alkaline materials, including NaOH, Ca(OH) 2 , MgCO 3 (cryptocrystalline magnesite), MgO, Na 2 CO 3 , Mg(OH) 2 , CaCO 3 and CaO, have also been found to be effective in neutralizing and removing contaminants from AMD [ 12 ]. In addition to lime, coal fly ash zeolites potential in the remediation of AMD treatment [ 13 , 14 ], and in reducing acid generation and controlling hydraulic conductivity of mine piles [ 15 ] have been demonstrated. These findings suggest that lime and fly ash zeolites are effective and promising methods for treating AMD and reducing its negative impact on the environment.…”

Section: Introductionmentioning

confidence: 99%

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Unlocking water potential in drylands: Quicklime and fly ash enhance soil microbiome structure, ecological networks and function in acid mine drainage water-irrigated agriculture

Munyai,

Ogola,

Wambui Kimani

et al. 2024

Heliyon

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Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Unlocking water potential in drylands: Quicklime and fly ash enhance soil microbiome structure, ecological networks and function in acid mine drainage water-irrigated agriculture

Munyai,

Ogola,

Wambui Kimani

et al. 2024

Heliyon

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“…Under alkaline (high‐pH) conditions, the magnitude of As mobilization would increase, leading to water contamination (Nordstorm, 2002; Plant et al., 2009; Smedley & Kinniburgh, 2002). The mobilization of As from coal ash under alkaline conditions is one of the key limiting factors for the ability to use fly ash as a medium for neutralization of acid mine drainage (Weinberg et al., 2022).…”

Section: Anthropogenic Mobilization Of Arsenicmentioning

confidence: 99%

The Global Biogeochemical Cycle of Arsenic

Schlesinger

Klein

Vengosh

2022

Global Biogeochemical Cycles

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Direct exploitation and use of arsenic resources has diminished in recent years, but inadvertent mobilizations of As from mineral extractions (metal ores, coal, and phosphate rock) are now as much as ten‐fold greater (1,500–5,600 × 109 g/yr) than the As released by the natural rate of rock weathering at the Earth's surface (60–544 × 109 g/yr). Although some As from mining activities enters global cycling through leaching and spills, the amount of dissolved As in rivers (23 × 109 g/yr) is similar to the theoretical mobilization of As from chemical weathering. Anthropogenic emissions to the atmosphere (17–38 × 109 g As/yr) are double the natural background sources (10–25 × 109 g As/yr), largely as a result of the smelting of Cu and other non‐ferrous ores. This results in increased atmospheric deposition near regions with high mining and industrial activities, with potential consequences to human health, natural ecosystems and agriculture. Using median values for As, the ratio of anthropogenic to natural emissions to the atmosphere (1.57) suggests a human impact on the global As cycle that rivals those for V, Hg and Pb.

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“…To summary, although the treatment cost of AMD using limestone or hydrated lime is cheap, the disposal cost of the sludge is relatively expensive [32]. In recent years, alkaline industrial by-products, such as concrete fines, lime kiln dust, coal ash, steel mill slag, red mud, and fly ash, have replaced traditional alkaline chemicals for treating AMD [33][34][35][36]. Using alkaline industrial by-products further reduces the treatment cost, but also makes it harder to reuse the sludge because industrial by-products introduce a variety of cations and anions into the sludge.…”

Section: Introductionmentioning

confidence: 99%

Alkaline Chemical Neutralization to Treat Acid Mine Drainage with High Concentrations of Iron and Manganese

Zhao,

Zhang,

2024

Water

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Due to its high acidity and toxic metal content, acid mine drainage (AMD) needs to be properly treated before being discharged into the environment. This study took the AMD collected from one specific mine in China as a sample and investigated the treatment methodology for AMD. The water quality of the AMD was measured, and the sample was treated with caustic soda (NaOH) and shell powder (one kind of conventional neutralizer, mainly composed of CaCO3) by the neutralization method. The results show that the AMD has a relatively low pH (2.16) and contains high concentrations of Fe (77.54 g/L), Mn (621.29 mg/L), Cu (6.54 mg/L), Ca (12.39 mg/L), and Mg (55.04 mg/L). NaOH was an effective neutralizer to treat the AMD and performed much better than shell powder. Various metals were precipitated, in the order of Fe(III), Cu, Fe(II), Mn, Ca, and Mg. The metal removal mechanisms included precipitation, adsorption, and co-precipitation. The optimal reaction conditions were the reaction duration was selected as 5 min and the mass ratio of NaOH to AMD was 0.16:1 (w:v). By this stage, the pH rapidly increased from 2.16 to 8.53 during AMD-NaOH interactions and various metals were efficiently removed (from 86.71% to 99.99%) by NaOH. The residual mass concentrations of Fe, Mn, Cu, Ca, and Mg after the treatment were 1.52, 1.77, 0.10, 1.65, and 2.17 mg/L, respectively. These data revealed that NaOH was a good treatment regent for this kind of AMD, based on the discharge criteria of China (GB28661 2012). Also, the shell powder was a helpful neutralizer for pH adjustment and copper removal. This neutralization method has the advantages of convenient operation, high speed, good effect, simple equipment, and low infrastructure cost. In addition, the resulting neutralized residue is a valuable and high-quality raw material, which can be used in metal smelting and separation.

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Water quality implications of the neutralization of acid mine drainage with coal fly ash from India and the United States

Cited by 13 publications

References 57 publications

Unlocking water potential in drylands: Quicklime and fly ash enhance soil microbiome structure, ecological networks and function in acid mine drainage water-irrigated agriculture

Unlocking water potential in drylands: Quicklime and fly ash enhance soil microbiome structure, ecological networks and function in acid mine drainage water-irrigated agriculture

The Global Biogeochemical Cycle of Arsenic

Alkaline Chemical Neutralization to Treat Acid Mine Drainage with High Concentrations of Iron and Manganese

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