Performance of passive systems for mine drainage treatment at low temperature and high salinity: A review. (April 2019)

• Record Type: Journal Article
• Authors: Ben Ali, Houssem E.; Neculita, Carmen M.; Molson, John W.; Maqsoud, Abdelkabir; Zagury, Gérald J.
• Is Part Of: Minerals engineering. Volume 134(2019)
• Page Start: 325
• Page End: 344
• Publication Date: 2019-04
• Subjects: Acid mine drainage -- Neutral mine drainage -- Passive biochemical reactor -- Reactive transport modelling -- Cold climates -- Salinity -- Temperature; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2019.02.010
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: Low temperature and high salinity characterize mine drainage in northern climate. Passive (bio)-chemical treatment of mine drainage is challenging in northern climate. Low temperature and high salinity deteriorate treatment efficiency in cold climate. Treatment efficiency decreased by over 50% when temperature dropped from 22 °C to 2 °C. Reactive transport models are used to predict long-term passive treatment efficiency. Abstract: Passive systems are an effective and promising technology for treatment of moderately-contaminated mine drainage (MD) under temperate and/or semi-arid climates. However, ensuring performance of passive treatment is challenging in northern climates, which are characterized by low temperatures (<5 °C) and often high salinities (up to 20 g/L), in addition to the highly variable MD quality. This paper reviews the principal parameters and processes that influence the quality of MD and the performance of passive treatment of MD in cold climates. A literature review shows that metal removal mechanisms depend strongly on the MD quality and on the chosen passive treatment system. For acid mine drainage (AMD) treatment, metals can be removed mainly by precipitation as oxy-hydroxides, carbonates or sulfides, and by co-precipitation, primarily with iron oxy-hydroxides. For treatment of neutral mine drainage (NMD), sorption is the main mechanism on which most passive systems rely. For both AMD and NMD, sulfates can be removed by precipitation, biologic reduction using sulfate reducing conditions or sorption. Major factors such as low temperature, contamination level and salinity that affect treatment performance of passive systems, especially passive biochemical reactors (PBRs), are highlighted. Low temperatures generally decrease metal and sulfate removal efficiency, with efficiency decreasing by over 50% when the temperature drops from 22 °C to 2 °C. This review also discusses the effect of MD contamination level on PBR efficiency. The effect of high salinity, with its potential to increase or decrease metal and sulfate removal depending on the major ions present, is then discussed. Reactive transport models used to predict long-term MD treatment efficiency are also considered. Low temperature and high salinity seem to be important parameters that jointly affect MD treatment performance in cold climates but unfortunately have usually been studied separately. Further studies are needed to evaluate the simultaneous combined effect of these parameters on the performance of PBRs.