CCA*-treated wood has been replaced for most residential uses by alternative copper-based preserv... more CCA*-treated wood has been replaced for most residential uses by alternative copper-based preservative-treated wood such ACQ*-, CAand MCQ-treated wood. Treated wood wastes disposal is becoming a challenge because of increasing fees and stringent regulations regarding solid waste landfill. Technologies have been applied to CCA-treated wood wastes based on metals solubilization by leaching1-3. Previous studies identified an efficient chemical leaching process for CCA-, ACQ-, CAand MCQ-treated wood recycling4.
Solid waste management is the most important environmental challenge of mining operations worldwi... more Solid waste management is the most important environmental challenge of mining operations worldwide [...]
Various rare earth element (REE) deposits hosted by carbonatite complexes have been identified in... more Various rare earth element (REE) deposits hosted by carbonatite complexes have been identified in southern (Montviel, Niobec) and northern Quebec (Eldor deposit). During the winter in Quebec, the use of road salts to facilitate transportation on the mine site and/or avoid water freezing during mine operation may be necessary. The sources of salinity can be diverse on a mine site: process water, precipitation, alteration of minerals in the soil. Thus, tailings may come in contact with these salts and react. The purpose of the present study was to evaluate the impact of salinity on the behaviour of flotation tailings (Eldor deposit), i.e. the mobility of the elements contained in the tailings under these conditions and the environmental risks involved. For this purpose, leaching column tests were developed. The solutions were deionized water (CW column), NaCl (25 g/L; CS1 column) and CaCl2 (25 g/L; CS2 column). The leachate analysis revealed that the divalent cations (Ba, Cd, Mg, Mn, Sr, and Zn) are more mobile in the presence of CaCl2 (CaCl2 > NaCl > deionized water). The mobility of these elements appears to be governed by the competition with Ca2+ for tailings sorption sites. U and Sc are most mobile in the presence of salts regardless of the applied salt solution, i.e. CaCl2 = NaCl > deionized water. The formation of soluble chloride complexes with these elements could therefore be the cause of this phenomenon. For S, the leaching solution has no impact on its mobility. In conclusion, the presence of salts would tend to increase the mobility of divalent cations present in these residues and enhance their contamination potential. Modeling using PHREEQC software allowed comparison of these results with post-dismantling mineralogical characterization. Both methods showed: (i) total dissolution of fluorite [CaF2], galena [PbS], richterite [Na(CaNa(Mg,Fe2+)5[Si8O22](OH)] and Ba silicate; (ii) precipitation of iron oxides/hydroxides and silicate minerals. However, the modeling was unable to predict the behaviour of carbonate minerals. Further modeling tests involving kinetics should be considered in a future study.
Advanced Nano-Bio Technologies for Water and Soil Treatment, 2020
The definition and classification of contaminants of emerging concerns (CECs) in water and soils/... more The definition and classification of contaminants of emerging concerns (CECs) in water and soils/sediments have evolved over time. Stricter environmental regulations in many countries and consciousness for sustainable development have led to adapted solutions to reduce the footprint and potential impacts of anthropogenic activities. Characterization and treatment technologies for CECs have evolved consequently. Major actual challenges in CECs treatment include the lack of analytical methodologies for their adequate quantification in complex matrices, uncertainties on operational costs, limited creation of residual salinity, low volumes of stable sludge, and easy and safe management with limited potential impact of treated effluents on receiving natural waters. Other needs include the use of low toxicity, highly biodegradable, and green additives, reduction of emissions and energy requirements, and adequate management of the solids produced during the application of sorption and/or biotechnologies that contain CECs. Therefore, present gaps and research needs for the CECs include mainly analytical determination, toxicity evaluation of CECs and their degradation products, as well as the distribution, fate and degradation of CECs in the environment.
Responsible use and effective treatment of mine water are prerequisites of sustainable mining. Th... more Responsible use and effective treatment of mine water are prerequisites of sustainable mining. The behavior of contaminants in mine water evolves in relation to the metastable characteristics of some species, changes related to the mine life cycle, and mixing processes at various scales. In cold climates, water treatment requires adaptation to site-specific conditions, including high flow rates, salinity, low temperatures, remoteness, and sensitivity of receiving waterbodies. Contaminants of emerging concern (CECs) represent a newer issue in mine water treatment. This paper reviews recent research on the challenges and opportunities related to CECs in mine water treatment, with a focus on advanced oxidation and membrane-based processes on mine sites operating in cold climates. Finally, the paper identifies research needs in mine water treatment.
The contamination of soils by metals such as arsenic, chromium, copper and organic compounds such... more The contamination of soils by metals such as arsenic, chromium, copper and organic compounds such as pentachlorophenol (PCP) and dioxins and furans (PCDD/F) is a major problem in industrialized countries. Excavation followed by disposal in an appropriate landfilling is usually used site to manage these contaminated soils. Many researches have been conducted to develop physical, biological, thermal and chemical methods to allow the rehabilitation of contaminated sites. Thermal treatments including thermal desorption seemed to be the most appropriate methods, allowing the removal of more than 99.99% of organic contaminants but, they are ineffective for inorganic compounds. Biological treatments have been developed to remove inorganic and hydrophobic organic contaminants but their applications are limited to soils contaminated by easily biodegradable organic compounds. Among the physical technologies available, attrition is the most commonly used technique for the rehabilitation of soi...
Spent batteries contain hazardous materials, including numerous metals (cadmium, lead, nickel, zi... more Spent batteries contain hazardous materials, including numerous metals (cadmium, lead, nickel, zinc, etc.) that are present at high concentrations. Therefore, proper treatment of these wastes is necessary to prevent their harmful effects on human health and the environment. Current recycling processes are mainly applied to treat each type of spent battery separately. In this laboratory study, a hydrometallurgical process has been developed to simultaneously and efficiently solubilize metals from spent batteries. Among the various chemical leaching agents tested, sulfuric acid was found to be the most efficient and cheapest reagent. A Box-Behnken design was used to identify the influence of several parameters (acid concentration, solid/liquid ratio, retention time and number of leaching steps) on the removal of metals from spent batteries. According to the results, the solid/liquid ratio and acid concentration seemed to be the main parameters influencing the solubilization of zinc, manganese, nickel, cadmium and cobalt from spent batteries. According to the results, the highest metal leaching removals were obtained under the optimal leaching conditions (pulp density = 180 g/L (w/v), [H2SO4] = 1 M, number of leaching step = 3 and leaching time = 30 min). Under such optimum conditions, the removal yields obtained were estimated to be 65% for Mn, 99.9% for Cd, 100% for Zn, 74% for Co and 68% for Ni. Further studies will be performed to improve the solubilization of Mn and to selectively recover the metals.
In recent years, the development of appropriate wood waste disposal options has been encouraged b... more In recent years, the development of appropriate wood waste disposal options has been encouraged by severe regulations and expensive fees associated with wastes landfilling or burning. An efficient and economically attractive leaching process was developed at laboratory scale (200 mL) for CCA-, ACQ- and CA-treated wood wastes recycling. This leaching process consisted of three leaching steps of 2 hours each, at 75°C with a sulfuric acid concentration at 9.8 g/L followed by three water-rinsing steps. The objective of this study was to investigate a possible application of this process to various mixtures of copper-based preservatives-treated wood wastes at pilot scale (80 L). The mixture of copper-based preservative-treated wood wastes was defined in order to represent wood waste stream evolution in the next decades. At the end of the leaching process, more than 98% of arsenic, 89% of chromium and 99% of copper were removed from a mixture of treated wood. Metal concentrations of the e...
Remediation of copper-based alkaline copper quat (ACQ) and micronized copper quat (MCQ) wood-pres... more Remediation of copper-based alkaline copper quat (ACQ) and micronized copper quat (MCQ) wood-preservative-treated weathered southern pine mulch samples by monoethanolamine (Mea) extraction was studied. The potential reuse of Mea extract in ACQ wood preservative application was also evaluated. Continuous column extraction of copper-preservative-treated samples for 32 h, using 12 % Mea removed 66–86 % (between top and bottom of the column) and 65–80 % of Cu, respectively, from ACQ- and MCQ-treated wood. Mea extracts of treated wood could be reused in ACQ-treating solutions that met the American Wood Protection Association standard specifications for ACQ wood preservatives. This was achieved either by mixing the extract with industrial Cu–Mea solution at 1:4 ratio or by adding cupric acetate salt directly into the Mea extract. ACQ-treating solutions reformulated using Mea extracts of ACQ- and MCQ-treated wood performed similarly to wood treated with industrial ACQ solution and freshly prepared solution using cupric acetate. All treated wood had similar penetrations of Cu in wood during preservative treatment, Cu leaching from the treated wood in contact with water, corrosion of nails in contact with treated wood, and ability to protect wood from mold growth.
The disposal of metal-bearing treated wood wastes is becoming an environmental challenge. An effi... more The disposal of metal-bearing treated wood wastes is becoming an environmental challenge. An efficient recycling process based on sulfuric acid leaching has been developed to remove metals from copper-based treated wood chips (0<x<12 mm). The present study explored the performance and the robustness of this technology in removing metals from copper-based treated wood wastes at a pilot plant scale (130-L reactor tank). After 3 × 2 h leaching steps followed by 3 × 7 min rinsing steps, up to 97.5% of As, 87.9% of Cr, and 96.1% of Cu were removed from CCA-treated wood wastes with different initial metal loading (>7.3 kgm(-3)) and more than 94.5% of Cu was removed from ACQ-, CA- and MCQ-treated wood. The treatment of effluents by precipitation-coagulation was highly efficient; allowing removals more than 93% for the As, Cr, and Cu contained in the effluent. The economic analysis included operating costs, indirect costs and revenues related to remediated wood sales. The economic analysis concluded that CCA-treated wood wastes remediation can lead to a benefit of 53.7 US$t(-1) or a cost of 35.5 US$t(-1) and that ACQ-, CA- and MCQ-treated wood wastes recycling led to benefits ranging from 9.3 to 21.2 US$t(-1).
CCA*-treated wood has been replaced for most residential uses by alternative copper-based preserv... more CCA*-treated wood has been replaced for most residential uses by alternative copper-based preservative-treated wood such ACQ*-, CAand MCQ-treated wood. Treated wood wastes disposal is becoming a challenge because of increasing fees and stringent regulations regarding solid waste landfill. Technologies have been applied to CCA-treated wood wastes based on metals solubilization by leaching1-3. Previous studies identified an efficient chemical leaching process for CCA-, ACQ-, CAand MCQ-treated wood recycling4.
Solid waste management is the most important environmental challenge of mining operations worldwi... more Solid waste management is the most important environmental challenge of mining operations worldwide [...]
Various rare earth element (REE) deposits hosted by carbonatite complexes have been identified in... more Various rare earth element (REE) deposits hosted by carbonatite complexes have been identified in southern (Montviel, Niobec) and northern Quebec (Eldor deposit). During the winter in Quebec, the use of road salts to facilitate transportation on the mine site and/or avoid water freezing during mine operation may be necessary. The sources of salinity can be diverse on a mine site: process water, precipitation, alteration of minerals in the soil. Thus, tailings may come in contact with these salts and react. The purpose of the present study was to evaluate the impact of salinity on the behaviour of flotation tailings (Eldor deposit), i.e. the mobility of the elements contained in the tailings under these conditions and the environmental risks involved. For this purpose, leaching column tests were developed. The solutions were deionized water (CW column), NaCl (25 g/L; CS1 column) and CaCl2 (25 g/L; CS2 column). The leachate analysis revealed that the divalent cations (Ba, Cd, Mg, Mn, Sr, and Zn) are more mobile in the presence of CaCl2 (CaCl2 > NaCl > deionized water). The mobility of these elements appears to be governed by the competition with Ca2+ for tailings sorption sites. U and Sc are most mobile in the presence of salts regardless of the applied salt solution, i.e. CaCl2 = NaCl > deionized water. The formation of soluble chloride complexes with these elements could therefore be the cause of this phenomenon. For S, the leaching solution has no impact on its mobility. In conclusion, the presence of salts would tend to increase the mobility of divalent cations present in these residues and enhance their contamination potential. Modeling using PHREEQC software allowed comparison of these results with post-dismantling mineralogical characterization. Both methods showed: (i) total dissolution of fluorite [CaF2], galena [PbS], richterite [Na(CaNa(Mg,Fe2+)5[Si8O22](OH)] and Ba silicate; (ii) precipitation of iron oxides/hydroxides and silicate minerals. However, the modeling was unable to predict the behaviour of carbonate minerals. Further modeling tests involving kinetics should be considered in a future study.
Advanced Nano-Bio Technologies for Water and Soil Treatment, 2020
The definition and classification of contaminants of emerging concerns (CECs) in water and soils/... more The definition and classification of contaminants of emerging concerns (CECs) in water and soils/sediments have evolved over time. Stricter environmental regulations in many countries and consciousness for sustainable development have led to adapted solutions to reduce the footprint and potential impacts of anthropogenic activities. Characterization and treatment technologies for CECs have evolved consequently. Major actual challenges in CECs treatment include the lack of analytical methodologies for their adequate quantification in complex matrices, uncertainties on operational costs, limited creation of residual salinity, low volumes of stable sludge, and easy and safe management with limited potential impact of treated effluents on receiving natural waters. Other needs include the use of low toxicity, highly biodegradable, and green additives, reduction of emissions and energy requirements, and adequate management of the solids produced during the application of sorption and/or biotechnologies that contain CECs. Therefore, present gaps and research needs for the CECs include mainly analytical determination, toxicity evaluation of CECs and their degradation products, as well as the distribution, fate and degradation of CECs in the environment.
Responsible use and effective treatment of mine water are prerequisites of sustainable mining. Th... more Responsible use and effective treatment of mine water are prerequisites of sustainable mining. The behavior of contaminants in mine water evolves in relation to the metastable characteristics of some species, changes related to the mine life cycle, and mixing processes at various scales. In cold climates, water treatment requires adaptation to site-specific conditions, including high flow rates, salinity, low temperatures, remoteness, and sensitivity of receiving waterbodies. Contaminants of emerging concern (CECs) represent a newer issue in mine water treatment. This paper reviews recent research on the challenges and opportunities related to CECs in mine water treatment, with a focus on advanced oxidation and membrane-based processes on mine sites operating in cold climates. Finally, the paper identifies research needs in mine water treatment.
The contamination of soils by metals such as arsenic, chromium, copper and organic compounds such... more The contamination of soils by metals such as arsenic, chromium, copper and organic compounds such as pentachlorophenol (PCP) and dioxins and furans (PCDD/F) is a major problem in industrialized countries. Excavation followed by disposal in an appropriate landfilling is usually used site to manage these contaminated soils. Many researches have been conducted to develop physical, biological, thermal and chemical methods to allow the rehabilitation of contaminated sites. Thermal treatments including thermal desorption seemed to be the most appropriate methods, allowing the removal of more than 99.99% of organic contaminants but, they are ineffective for inorganic compounds. Biological treatments have been developed to remove inorganic and hydrophobic organic contaminants but their applications are limited to soils contaminated by easily biodegradable organic compounds. Among the physical technologies available, attrition is the most commonly used technique for the rehabilitation of soi...
Spent batteries contain hazardous materials, including numerous metals (cadmium, lead, nickel, zi... more Spent batteries contain hazardous materials, including numerous metals (cadmium, lead, nickel, zinc, etc.) that are present at high concentrations. Therefore, proper treatment of these wastes is necessary to prevent their harmful effects on human health and the environment. Current recycling processes are mainly applied to treat each type of spent battery separately. In this laboratory study, a hydrometallurgical process has been developed to simultaneously and efficiently solubilize metals from spent batteries. Among the various chemical leaching agents tested, sulfuric acid was found to be the most efficient and cheapest reagent. A Box-Behnken design was used to identify the influence of several parameters (acid concentration, solid/liquid ratio, retention time and number of leaching steps) on the removal of metals from spent batteries. According to the results, the solid/liquid ratio and acid concentration seemed to be the main parameters influencing the solubilization of zinc, manganese, nickel, cadmium and cobalt from spent batteries. According to the results, the highest metal leaching removals were obtained under the optimal leaching conditions (pulp density = 180 g/L (w/v), [H2SO4] = 1 M, number of leaching step = 3 and leaching time = 30 min). Under such optimum conditions, the removal yields obtained were estimated to be 65% for Mn, 99.9% for Cd, 100% for Zn, 74% for Co and 68% for Ni. Further studies will be performed to improve the solubilization of Mn and to selectively recover the metals.
In recent years, the development of appropriate wood waste disposal options has been encouraged b... more In recent years, the development of appropriate wood waste disposal options has been encouraged by severe regulations and expensive fees associated with wastes landfilling or burning. An efficient and economically attractive leaching process was developed at laboratory scale (200 mL) for CCA-, ACQ- and CA-treated wood wastes recycling. This leaching process consisted of three leaching steps of 2 hours each, at 75°C with a sulfuric acid concentration at 9.8 g/L followed by three water-rinsing steps. The objective of this study was to investigate a possible application of this process to various mixtures of copper-based preservatives-treated wood wastes at pilot scale (80 L). The mixture of copper-based preservative-treated wood wastes was defined in order to represent wood waste stream evolution in the next decades. At the end of the leaching process, more than 98% of arsenic, 89% of chromium and 99% of copper were removed from a mixture of treated wood. Metal concentrations of the e...
Remediation of copper-based alkaline copper quat (ACQ) and micronized copper quat (MCQ) wood-pres... more Remediation of copper-based alkaline copper quat (ACQ) and micronized copper quat (MCQ) wood-preservative-treated weathered southern pine mulch samples by monoethanolamine (Mea) extraction was studied. The potential reuse of Mea extract in ACQ wood preservative application was also evaluated. Continuous column extraction of copper-preservative-treated samples for 32 h, using 12 % Mea removed 66–86 % (between top and bottom of the column) and 65–80 % of Cu, respectively, from ACQ- and MCQ-treated wood. Mea extracts of treated wood could be reused in ACQ-treating solutions that met the American Wood Protection Association standard specifications for ACQ wood preservatives. This was achieved either by mixing the extract with industrial Cu–Mea solution at 1:4 ratio or by adding cupric acetate salt directly into the Mea extract. ACQ-treating solutions reformulated using Mea extracts of ACQ- and MCQ-treated wood performed similarly to wood treated with industrial ACQ solution and freshly prepared solution using cupric acetate. All treated wood had similar penetrations of Cu in wood during preservative treatment, Cu leaching from the treated wood in contact with water, corrosion of nails in contact with treated wood, and ability to protect wood from mold growth.
The disposal of metal-bearing treated wood wastes is becoming an environmental challenge. An effi... more The disposal of metal-bearing treated wood wastes is becoming an environmental challenge. An efficient recycling process based on sulfuric acid leaching has been developed to remove metals from copper-based treated wood chips (0<x<12 mm). The present study explored the performance and the robustness of this technology in removing metals from copper-based treated wood wastes at a pilot plant scale (130-L reactor tank). After 3 × 2 h leaching steps followed by 3 × 7 min rinsing steps, up to 97.5% of As, 87.9% of Cr, and 96.1% of Cu were removed from CCA-treated wood wastes with different initial metal loading (>7.3 kgm(-3)) and more than 94.5% of Cu was removed from ACQ-, CA- and MCQ-treated wood. The treatment of effluents by precipitation-coagulation was highly efficient; allowing removals more than 93% for the As, Cr, and Cu contained in the effluent. The economic analysis included operating costs, indirect costs and revenues related to remediated wood sales. The economic analysis concluded that CCA-treated wood wastes remediation can lead to a benefit of 53.7 US$t(-1) or a cost of 35.5 US$t(-1) and that ACQ-, CA- and MCQ-treated wood wastes recycling led to benefits ranging from 9.3 to 21.2 US$t(-1).
Uploads