Using sewage sludge as a sealing layer to remediate sulphidic mine tailings: a pilot-scale experiment, northern SwedenReportar como inadecuado




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Environmental Earth Sciences

, Volume 70, Issue 7, pp 3093–3105

First Online: 12 March 2013Received: 01 November 2012Accepted: 28 February 2013

Abstract

At the Kristineberg mine, northern Sweden, sulphidic mine tailings were remediated in an 8-year pilot-scale experiment using sewage sludge to evaluate its applicability as a sealing layer in a composite dry cover. Sediment, leachate water, and pore gas geochemistry were collected in the aim of determining if the sludge was an effective barrier material to mitigate acid rock drainage ARD formation. The sludge was an effective barrier to oxygen influx as it formed both a physical obstruction and functioned as an organic reactive barrier to prevent oxygen to the underlying tailings. Sulphide oxidation and consequential ARD formation did not occur. Sludge-borne trace elements accumulated in a reductive, alkaline environment in the underlying tailings, resulting in an effluent drainage geochemistry of Cd, Cu, Pb and Zn below 10 μg-L, high alkalinity 810 mg-L and low sulphate 38 mg-L. In contrast, the uncovered reference tailings received a 0.35-m deep oxidation front and typical ARD, with dissolved concentrations of Cd, Zn and sulphate, 20.8 μg-L, 16,100 μg-L and 1,390 mg-L, respectively. Organic matter degradation in the sludge may be a limiting factor to the function of the sealing layer over time as 85 % loss of the organic fraction occurred over the 8-year experimental period due to aerobic and anaerobic degradation. Though the cover may function in the short to medium term 100 years, it is unlikely to meet the demands of a long-term remedial solution.

KeywordsGeochemistry Sewage sludge Sealing layer Remediation  Download fulltext PDF



Autor: Peter Nason - Lena Alakangas - Björn Öhlander

Fuente: https://link.springer.com/







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