A novel bioelectrochemical system for chemical-free permanent treatment of acid mine drainage

作者：Pozo Guillermo; Pongy Sebastien; Keller Jurg; Ledezma Pablo; Freguia Stefano

来源：Water Research, 2017, 126: 411-420.

DOI：10.1016/j.watres.2017.09.058

• Bioelectrochemical system (BES)
• Acid mine drainage (AMD)
• Metal
• Sulfur
• Recovery

The mining sector is currently under unprecedented pressure due to stringent environmental regulations. As a consequence, a permanent acid mine drainage (AMD) treatment is increasingly being regarded as a desirable target with direct benefits for the environment and the operational and economic viability of the resources sector. In this study we demonstrate that a novel bioelectrochemical system (BES) can deliver permanent treatment of acid mine drainage without chemical dosing. The technology consists of a two-cell bioelectrochemical setup to enable the removal of sulfate from the ongoing reduction-oxidation sulfur cycle to less than 550 mg L-1 (85 +/- 2% removal from a real AMD of an abandoned silver mine), thereby also reducing salinity at an electrical energy requirement of 10 +/- 0.3 kWh kg(-1) of SO42--S removed. In addition, the BES operation drove the removal and recovery of the main cations Al, Fe, Mg, Zn at rates of 151 +/- 0 g Al m(-3) d(-1), 179 +/- 1 g Fe m(-3) d(-1), 172 +/- 1 g Mg m(-3) d(-1) and 46 +/- 0 g Zn m(-3) d(-1) into a concentrate stream containing 263 +/- 2 mg Al, 279 +/- 2 mg Fe, 152 +/- 0 mg Mg and 90 +/- 0 mg Zn per gram of solid precipitated after BES fed-rate control treatment. The solid metal-sludge was twice less voluminous and 9 times more readily settleable than metal-sludge precipitated using NaOH. The continuous BES treatment also demonstrated the concomitant precipitation of rare earth elements together with yttrium (REY), with up to 498 +/- 70 mu g Y, 166 +/- 27 mu g Nd, 155 +/- 14 mu g Gd per gram of solid, among other high-value metals. The high-REY precipitates could be used to offset the treatment costs.

• 出版日期2017-12-1