Papers by Keyword: Acid Mine Drainage

Abstract: Most of the coal mining in Indonesia that uses the open pit mining method faces serious problems, namely the treatment of acid mine drainage. This constitutes a relatively large volume of wastewater, especially in areas that have rainfall in the range of 2000–4000 mm yearly. Acid mine drainage as acidic wastewater formed during excavation cannot be avoided due to the oxidation process during overburden removal. The acidic wastewater that has formed must be managed strictly and appropriately prior to being released into public waters. There are two methods of treating acid mine wastewater, namely active and passive treatments. Active treatment is generally used more frequently during operations, considering the time, effort, and costs; however, when entering the mine closure period, natural processes must be used at lower costs. Undertaking passive treatment in this area has shown a reduction in the chemical materials used and has enabled a greater amount of wastewater to be managed. The purpose of this research is to describe the active and passive treatment processes in the management of acid mine drainage and to analyze the results of passive treatment in preparation for the mine closure stage. Development of passive treatment by swampy forest system can reduce cost of treatment, naturally process and more environment friendlier by reducing the quicklime materials.

Abstract: Acid mine drainage (AMD) is one of the major environmental problems the mining and mineral processing industries face. Treatment of AMD involves active and passive treatment. In the long term, passive treatment is the most effective way to treat acid mine drainage, but it can be expensive. if handled properly. Therefore, the study of flow rate in a passive treatment system is one of the important ways to identify optimum hydraulic retention time to ensure the maximum percentage of heavy metal removal can be achieved while keeping the cost to a minimum level. This study focused on developing and comparing the Response Surface Methodology (RSM) model and Artificial Neural Fuzzy Inference System (ANFIS) model to predict the outlet flow rate of the passive treatment system column based on three parameters inlet flow time, thickness of peat soil bed, and inlet flow rate. The RSM model was created by Design-Expert software whereas MATLAB created the ANFIS model with 80% of data used for the model training and 20% of the data for model testing. The models' performances were compared in terms of statistical errors (AAPE, RMSE, R², STD, minimum error, and maximum error). It was found the ANFIS model has performed better in predicting the outlet flowrate with R² value of 0.99 RSM model with the value of 0.97. The inlet flow rate was an insignificant parameter affecting the outlet flow rate of the passive treatment column. From the 3-D surface response plot, the highest outlet flow rate is predicted to be 524 mL/min.

Abstract: The cobalt content in LIB (Lithium-ion Battery) can be recycled using green technology through a bioleaching process with the help of microorganisms to have high efficiency, low cost, easy method, and environmentally friendly. The bacterial strain of A. ferrooxidans in the bioleaching process isolated from acid mine water was capable to extracting cobalt in LIB to obtain pure metal ions. The aim of this research is to isolate bacteria A. ferrooxidans from acid mine water in order to extract the element cobalt from a LIB. This study has recovery with culture time of 0-14 days, aerobic systems, inoculum concentrations of 5%, 10%, and 20%. The optimization of bacterial growth was done by aerating the culture. The recovered cobalt were analyzed from the filtrate after the bioleaching process using ICP analysis. LIB and sediment of the bioleaching process were analyzed by XRD, SEM and EDX. The conclusion of this study showed that the recovery of cobalt metal (Co) using the bacterial strain of A. ferrooxidans was obtained at 73.95% for 14 days with the addition of a battery cathode of 1 gram/100 ml at the optimum conditions obtained when the addition of 20% inoculum, pH: 2-4, temperature: 30°C, and the aeration system uses an aerator. Bacterial strains isolated from acid mine drainage have the potential as oxidizing agents for lithium and cobalt metals in bioleaching processes.

Abstract: The environmental problem that often occurs in coal mining is acid mine drainage which can pose a serious threat to human health, animals and ecological systems. Acid mine drainage contains heavy metal contaminants such as iron and manganese. The purpose of this study was to determine the adsorption equilibrium carried out using natural zeolite adsorbents type mordenite from Klaten, Central Java. The application of natural zeolite with a volume of 100 mL synthetic acid mine drainage with concentrations of Fe 41.97 mg/L, Mn 21.75 mg/L and variations in dose of natural zeolite (2, 4, 6, 8, and 10 grams). The highest percent removal was at a dose of 10 grams of zeolite resulted in % removal of 97.94 % for Fe and 67.81 % for Mn. The results obtained using Langmuir and Freundlich adsorption isotherms. The results followed the Freundlich isotherm model with an adsorption parameters K_f = 0.427 mg/g, R² = 0.991, n = 1.610 Fe metal and Mn metal adsorption parameters are K_f = 0.006 mg/g, R² = 0.9971, and n = 0.578

Abstract: Acid mine drainage is characterized by low pH value, many types of heavy metals, high concentration of heavy metals and great environmental damage. Copper precipitation by sulfate reducing bacteria is a common method. In this experiment, the AMD after iron removal was treated by an upflow anaerobic bioreactor. The effects of HRT, carbon source type, carbon source dosage and reactor temperature on the operation of the reactor were studied. The optimum process parameters were determined: HRT was 12h, formic acid was used as carbon source and the dosage was 0.5g/L, and the temperature was 30 °C. Under the process conditions, the Cu concentration in the reactor effluent decreased to 0.043mg/L, and the recovery rate of Cu metal was 99.9%. The mechanism of copper deposition in the reactor was studied by characterization of the structure and morphology of the precipitated product and the analysis of the microbial community structure in the effluent of the reactor.

Abstract: Acid Mine Drainage (AMD) is one of the consequences of environmental impact due to surface coal mining and has big challenge how to treat the AMD both active and passive treatment efficient and effectively. The most expensive method to actively raise the pH and concentration heavy metal reduction of this wastewater is the use of chemical additives. We present the development of passive treatment with Swampy Forest (SF) system as a new natural and sustainable method with lower costs, and greater environmental sustainability. The SF system consists of selecting organic matter and combining it with the planting of selected grass and tree species in the form of a forest constructed wetland. As a preliminary to the construction of the SF, a batch reactor system was used to carry out experiments to find the best individual grass species for SF as the development of AMD passive treatment. The four grass species selected were shown to reduce the concentration of Fe and Mn, which generally has out of threshold value, thus achieving the threshold parameter to comply with applicable regulations for managing mine wastewater.

Abstract: Acid mine drainage is detrimental to the environment, which is rich of a variety of heavy metals, and has a low pH value and high acidity. The purpose of this paper is to study the bio-oxidation of ferrous iron and the selective precipitation of ferric iron, to gain a long-term effective solution to the environmental problem. The maximum ferrous iron bio-oxidation rate (76.19mg/L·h) was obtained at a low pH value of 3.0 and culture temperature of 30°C. In addition, we found a relatively higher ferric iron removal rate (99.18%) and the lowest copper loss rate (4.59%) at a pH value of 3.2 and reaction temperature of 30°C and stirring time of 4h.

Abstract: In this study, the adsorption efficiency of Philippine natural zeolite for treating acid mine drainage is investigated. The metal ions considered were Cu²⁺, Ni²⁺, and Pb²⁺ ions. The natural zeolite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDX). The XRD result revealed that the natural zeolite is mainly composed of heulandite (Ca,Na)₂-₃Al₃(Al,Si)₂Si₁₃O₃₆ • 12H₂O. Plate-like structures having rough surface and micro-pores were observed. The natural zeolite exhibited adsorption efficiencies of 99.03%, 35.88% and 35.36% for Pb²⁺, Cu²⁺, and Ni²⁺ ions, respectively, which are higher than those of alumina adsorbent for the same ions. Based on these results, the Philippine natural zeolite has a great potential for removing cationic heavy metal species from acid mine drainage (AMD).

Abstract: In some mines where sulfide minerals can occur in form of pyrite acid mine drainage (AMD) may occur, and it constitutes one of the main environmental impact. In order to prevent that AMD compromises aquifers layers and reaches mine surroundings, a treatment that consists in its neutralization with the use of a hydrated lime suspension is usually conducted. Contaminants that are soluble in AMD are precipitated, remaining in the solid phase. The work here presented aims recover uranium and rare earths found in one of these precipitates, which consists of calcium diuranate and metal hydroxides in a calcium sulfate matrix. This material contains approximately 0.25% of triuranium octoxide (U₃O₈) and 2.5% of rare earth oxides (TR₂O₃). The recovery of uranium and rare earths contained in the precipitate was performed through a hydrometallurgical process. The test resulted in a leaching with sulfuric acid presented solubilization of 96% for uranium and 90% for rare earths. A percentage yield of 99.7% and 99.9% was obtained in the steps of uranium extraction and re-extraction from the leachate, respectively.

Abstract: Río Tinto (Iberian Pyrite Belt, SW Spain) is a natural extreme acidic environmentwith a constant acidic pH and high concentration of toxic heavy metals. The characterization of the Tinto basin performed by our group during more than thirty years has provided evidences on the importance of the iron and sulfur cycles in generating the extreme conditions of theriver and maintaining the high level of prokaryotic and eukaryotic diversity detected on it.It has also proven that the extreme conditions of the Tinto basin are not generated by the long record of mining activities in the area, but the consequence of an underground bioreactor sustained by the massive sulfidic minerals existing in the Iberian Pyrite Belt. To test this hypothesis two drilling projects, MARTE (NASA Ames and Centro de Astrobiología, 2003-2006) and IPBSL (Centro de Astrobiología, 2011-2015) have beenperformed to provide evidences ofchemolithotrophicmicrobial activities operating in thisunderground bioreactor.Considering all the information collected from this natural ARD and AMD model system, its biohydrometallurgical interest is discussed