Membrane technology applied to acid mine drainage from copper mining

Abstract

The objective of this study is to evaluate the treatment of high-strength acid mine drainage (AMD) from copper mining by nanofiltration (NF) and reverse osmosis (RO) at pilot scale. The performances of two commercial spiral-wound membranes - NF99 and RO98pHt, both from Alfa Laval - were compared. The effects of pressure and feed flow on ion rejection and permeate flux were evaluated. The results showed high ion removal under optimum pressure conditions, which reached 92% for the NF99 membrane and 98% for the RO98pHt membrane. Sulfate removal reached 97% and 99% for NF99 and RO98pHt, respectively. In the case of copper, aluminum, iron and manganese, the removal percentage surpassed 95% in both membranes. Although concentration polarization limited NF performance at higher pressures, permeate fluxes observed in NF were five times greater than those obtained by RO, with only slightly lower divalent ion rejection rates, making it a promising option for the treatment of AMD.

A Review of Acid Mine Drainage in a Water-Scarce Country: Case of South Africa

“…Membrane treatments can be classified as secondary processes for treatment of mine water (Ambiado et al, 2017). Membrane systems require pre-treatment of mine water to remove suspended solids to reduce fouling of membranes.…”

“…To avoid scaling of the membrane due to the presence of calcium and magnesium in mine waters, softening is implemented before microfiltration and/or ultrafiltration process steps. The polishing step to get high quality clean water is achieved through reverse osmosis which also a membrane based process (Ambiado et al, 2017) The treated water is free from colloids and microorganisms, but still contains solutes. Ultrafiltration and microfiltration can be used as pre-treatment options for nanofiltration and reverse osmosis (RO) treatment of mine water to produce drinking water (Kentish and Stevens, 2001).…”

“…Ultrafiltration and microfiltration can be used as pre-treatment options for nanofiltration and reverse osmosis (RO) treatment of mine water to produce drinking water (Kentish and Stevens, 2001). Membranes technology is very successful because of high removal efficiencies of heavy metals and others pollutants (Ambiado et al, 2017). There is a way to overcome this challenge should membrane cleaning process being achieved with water at high pressure toward the back of the membrane (Ambiado, et al, 2017).…”

“…Membranes technology is very successful because of high removal efficiencies of heavy metals and others pollutants (Ambiado et al, 2017). There is a way to overcome this challenge should membrane cleaning process being achieved with water at high pressure toward the back of the membrane (Ambiado, et al, 2017). Currently, many improvements have been recorded regarding the use membrane technologies, low pressure and anti-fouling membranes have been developed to overcome the challenges related to fouling and energy consumption.…”

Hydrochemical Characteristics of Open-Pit Groundwater from a Closed Metalliferous Mine in O'kiep, Namaqualand Region, South Africa

“…Sulphidic species are mobilised under oxidative conditions, whereas their derivitised oxides are solubilised in acidic solutions, with acidophilic bacteria, such as Thiobacillus ferrooxidans playing a crucial role in the ferrous-sulphate and sulphur oxidation processes, by modifying the surroundings to facilitate mineral leaching [12,13]. Such oxidation processes, are conducive to oxidation of metal sulphide in ores, such as pyrite and copper sulphides to produce sulphuric acid and the release of some heavy metals from the ore into the environment [14][15][16][17][18][19][20][21][22][23], further contributing to the pollution in the environment [24]. The key objective of this study was to characterise the hydrochemical composition of open-pit groundwater (OPGW) and its suitability for use for domestic and irrigation purposes.…”