Mohammad Reza Afshoon; Nasser Mehrdadi
Abstract
Introduction: In copper industries, mining has great importance from the environmental point of view, as many by-products are generated during this process. Most of the mining tailings are sulfide minerals that are oxidized after they are extracted and exposed to oxygen and water, which consequently ...
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Introduction: In copper industries, mining has great importance from the environmental point of view, as many by-products are generated during this process. Most of the mining tailings are sulfide minerals that are oxidized after they are extracted and exposed to oxygen and water, which consequently leads to the production of acid mine drainage (AMD). Water management strategies are conducted to control AMD. Generally, one of the most important methods to refine AMD and release it into the environment is treatment technology. AMD treatment methods are classified as active and passive systems. In the present study, the need for the treatment methods was investigated and then the optimum system was specified.Material and methods: Sungun copper mine is located in northwestern Iran, 130 km north of Tabriz and 30 km north of Varzeqan. The production rate of tailings in this mine is roughly 11.2 million tons per year, which has over 3 km2 area in Pakhir Valley. Samples of acidic drainage from Pakhir Chay River were collected 7 times and transferred to the laboratory of Omran Zist Azma Company. Bottles of polypropylene (200 ml) were used to gather samples for analyzing acidity, sulfate, and TDS, and HDPE bottles (250 ml) were used to gather samples for analyzing heavy metals (copper, iron, and manganese) parameters. Moreover, concentrated nitric acid was used for stabilizing the samples. The flow rate of the river was measured by Mouline (flow meter and flow cross-section method), which was on average 32 liters per second.Results and discussion: Analyzing the results of 7 sampling periods, it was found that the average value of pH, sulfate, copper, iron, and manganese parameters were 3.94, 2601.4, 276.78, 0.193, and 46.04 mg /l, respectively. According to the standard limits of the Environmental Protection Organization for discharging wastewater into surface water, all parameters except iron had exceeded the permissible limits, so a treatment system will be required before releasing AMD into the environment.Conclusion: Based on the quantitative and qualitative characteristics of the acid mine drainage in the present study and various acidic effluent treatment methods, it can be concluded that the active treatment method is a promising option to eliminate contaminants from the acidic effluent. Moreover, among the active purification methods, the DAOS method will have better efficiency so that it leads to higher efficiency of system’s operation, and the best quality output will be discharged into the environment.
