The Hazardous Status of High Density Sludge from Acid Mine Drainage Neutralization

Bonokwakhe Hezekiel Sukati, Pieter Christiaan De Jager, John George Annandale and Philip Dale Tanner
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Bonokwakhe Hezekiel Sukati: Department of Plant and Soil Sciences, University of Pretoria, X20, Hatfield 0028, South Africa
Pieter Christiaan De Jager: Department of Plant and Soil Sciences, University of Pretoria, X20, Hatfield 0028, South Africa
John George Annandale: Department of Plant and Soil Sciences, University of Pretoria, X20, Hatfield 0028, South Africa
Philip Dale Tanner: Department of Plant and Soil Sciences, University of Pretoria, X20, Hatfield 0028, South Africa

Sustainability, 2018, vol. 10, issue 11, 1-18

Abstract: Classification of waste is an essential part of waste management to limit potential environmental pollution; however, global systems vary. The objective was to understand the waste classification of high density sludge (HDS) from acid mine drainage (AMD) treatment, according to selected global systems. Three sludges from two limestone treatment plants, and three others from a limestone and lime treatment plant from the Mpumalanga coalfields of the Republic of South Africa (RSA) were evaluated. Systems for the RSA, Australia, Canada, China, and the United States Environmental Protection Agency (USEPA) were considered. The USEPA system rated all six sludges non-hazardous, Canadian and Chinese systems allocated a hazardous status to one sludge from the limestone treatment plants based on Ni solubility. The RSA system considered two of the sludges from limestone treatment plants to be higher risk materials than did the other countries. This was due mainly to the RSA system’s inclusion of Mn and use of appreciably lower minimum soluble levels for As, Cd, Pb, Hg, and Se. None’s use of lime resulted in higher soluble Mn. Minimum leachable concentration thresholds for Cd, Hg, Pb, As, and Se in the RSA system were below method detection limits for Toxicity Characteristic Leaching Procedure (TCLP) extracts, making the guidelines impractical, and revision is advised. Considering all the systems, the probability that the HDS from the coalfields of Mpumalanga, South Africa will be classified as hazardous waste increases if the material is only subjected to limestone treatment because of Ni solubility.

Keywords: waste; classification; AMD; HDS; TCLP (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2018
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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