Removal of nickel from neutral mine drainage using peat-calcite, compost, and wood ash in column reactors
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RESEARCH ARTICLE
Removal of nickel from neutral mine drainage using peat-calcite, compost, and wood ash in column reactors Dominique Richard 1 & Carmen Mihaela Neculita 2 & Gérald J. Zagury 1 Received: 29 June 2020 / Accepted: 9 November 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The effectiveness of compost, peat-calcite, and wood ash to remove Ni from a circum-neutral-contaminated mine water was tested in continuous flow experiments. Materials were compared in 4.8-L columns at hydraulic residence times (HRT) of ∼ 16.5 h over the course of 2.5–4 months. During this period, all columns successfully treated over 400 L of synthetic contaminated neutral drainage (4.05 mg/L Ni), mainly through sorption processes. Mid-column results (HRT ∼ 9 h) indicated that wood ash was the most effective material for Ni removal, and chemical extractions revealed that retained Ni was less mobile in this spent material. The pH-increasing properties of wood ash played a major role in this material’s performance, but a pH correction would be required in the initial stages of full-scale treatment to maintain the effluent within regulatory limits (6–9.5). Scaled to full-sized, mid-column results indicated that treatment cell sizes, designed for the 1-year treatment of a high discharge (10 m3/h)–contaminated effluent (4.05 mg/L Ni), would be the smallest with wood ash (< 500 m3), followed by compost (600 ± 140 m3) and peatcalcite (720 ± 50 m3). Keywords Neutral mine drainage . Columns . Ni . Sorption . Hydraulic retention time . Organic materials
Introduction Contaminated neutral drainage (CND) is a mine drainage characterized by pH values ranging between 6 and 9 and metal concentrations that exceed local regulatory discharge limit levels (Nordstrom et al. 2015). It can arise when the acidity resulting from the oxidation of sulfide minerals is buffered by the presence of carbonate or silicate minerals in the gangue rock, and the resulting composition varies depending on the mineralogy of each particular mine site. CNDs are typically characterized by high concentrations of major cations (Na+, K+, Ca2+, Mg2+) as well as distinct but relatively low concentrations of potentially toxic metals. Ni is often present in CND, and its ecotoxicity is mainly attributed to its free cation Ni2+ Responsible editor: Tito Roberto Cadaval Jr * Gérald J. Zagury [email protected] 1
Civil, Geological, and Mining Engineering Department, Research Institute on Mines and Environment (RIME), Polytechnique Montréal, Montreal, QC H3C 3A7, Canada
2
RIME, University of Quebec in Abitibi-Temiscamingue (UQAT), 445 Boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada
species which is predominant at circum-neutral pH (Stokes 1988). The main difficulties for CND treatment are the variable effluent compositions encountered, the remoteness of mining sites, and the specific particularities of each site (e.g., topography, temperature) (Calugaru et al. 2018). The implementation of gravity-fed passive reactors is considered a cost-e
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