Treatment of Coal Mine Acid Water Using Nf270 Membrane as Environmentally Friendly Technology

Ex-mining pond water is widely used for the daily needs of the people these days, such as bathing, washing, and even drinking. Over time, it turns out that coal mine acid water has polluted the environment. The use of membrane technology to produce water that meets drinking water quality standards by the Minister of Health Regulation No. 492 of 2010 can be a solution to this problem. The NF270 membrane is a membrane process between reverse osmosis and ultrafiltration, which has a lower flux and operating pressure below 0.2-1.53 Mpa compared to reverse osmosis. Membrane NF270 is used for the reclamation of wastewater, water purification and softening, seawater desalination, and others. Its high rejection of organic molecules with a molecular weight of 200-2000 Da ions and multivalent can remove suspended solids, natural organic matter, bacteria, viruses, salts, and divalent ions contained in water, including coal mine acid water. The purpose of treating acid mine drainage with the NF270 membrane is to remove COD, TSS, TDS, and Fe metals. The NF270 membrane was used in this study to treat the coal mine acid water of PT. Bukit Asam. The performance of the NF270 process was assessed from the effect of pressure (4, 5, and 6 bar) on the flux and rejection rate of each parameter in a single solution, mixed and aqueous coal mine acid solution. The optimum pressure of the NF270 membrane for all parameters was 6 bar. This optimum pressure was then used to compare the phenomenon of flux that occurred and the level of rejection produced in the original sample of coal mine acid water. In the original coal mine acid water, there was a significant decrease in flux due to fouling deposition on the membrane surface. This phenomenon of decreasing flux was caused by fouling and polarization concentration. The rejection rates produced for the parameters of COD, TSS, TDS, and Fe with NF270 membranes were 56.4-93.1%; 78.5-100%; 43-69.3%; 67-100% respectively. Treated coal mine acid water using NF270 membrane technology can be used as drinking water that meets the standards of the Indonesian Ministry of Health Regulation. Thus, NF270 membrane technology can be used to process coal mine acid water into environmentally friendly drinking water.

Neutralization Acid Mine Drainage (AMD) using NaOH at PT. Jorong Barutama Grestone, Tanah Laut, South Borneo

Acid mine drainage (AMD) is mine water with a low pH derived from the oxidation of pyrite containing sulfide with water and air to produce sulfide acid (H2SO4) containing free sulfate. Acid mine drainage treatment carried out at PT Jorong Barutama Greystone Tanah Laut uses limestone at a cost of Rp.220. - per cubic meter of water. This study was conducted to determine the use of technical NaOH for changes in mine acid quality (pH. Fe and Mn). The method carried out by active handling is by adding technical NaOH into mine acid water. The results showed that neutralization of acid mine drainage using technical NaOH 10% to pH 8. was able to reduce Fe by 18.60 - 25.42% and Mn by 31.95 - 39.27%. at a cost of Rp.327. - per meter cubic of water

Potential of Acid Mine Formation in PIT 3000, Toraja Block, PT Trubaindo Coal Mining Based on Geochemical and Mineralogical Characteristics Study of Overburden and Underburden Rocks

Coal mining in Indonesia is mostly applied by an open pit system which causes the rocks in the mining location to be exposed to the surface, so that it will be easy to react with air and water directly. The high content of sulphide minerals such as pyrite and marcasite in coal mining site, has the potential to produce mine acid water. Mine acid water causes environmental pollution and a threat to aquatic and soil ecosystems by increasing the concentration of other heavy metal ions. This study aims to identify the mineral content of the overburden rock layers to determine the type of sulfide minerals forming acid mine and neutralizing minerals in rocks. The methods used in this study are field investigations, mineralogical content analysis, geochemical characteristics and measured stratigraphic to evaluate mineralogical content, geochemical characteristics and depositional environmental facies of overburden and underburden rocks from the Pit 3000 coal seam. The results showed that overburden rocks were composed by claystone with the thickness ranges 1.60 m – 5.15 m, whereas underburden rocks are characterized by diverse lithology such as claystone, siltstone and sandstone with the thickness ranges from 0.20 m – 4.50 m. Based on geochemical analysis on 18 overburden rock samples, it is known that overburden layers have characteristics that are dominated by Non Acid Forming (NAF) rocks with 83% NAF, 11% Potential Acid Forming (PAF) and 6% uncertain. The characteristics of the underburden layer are dominated by PAF rocks with 45% PAF, 19% NAF and 36% uncertain.

Identification of jarosite and other major mineral Fe phases in acidic environments affected by mining-metallurgy using X-ray Absorption Spectroscopy: With special emphasis on the August 2014 Cananea acid spill

The sulfuric acid spill into the Sonora river, enriched in iron and copper ions from the Buenavista del Cobre mine (Cananea), gave way to the formation of various solid iron (Fe) phases. In this study, the mineral phases were identified by X-ray Absorption Spectroscopy (XAS) and bulk powder X-Ray Diffraction (XRD), and chemically through acid digestions for multielemental quantification, as well as a 3-step selective sequential extraction (SSE) to quantify the types of Fe oxide phases and the contribution of the associated elements. Jarosite was the only Fe mineral identified by XRD, but XAS allowed identification of jarosite with potentially toxic elements (PTEs) incorporated in its structure, making these elements less prone to leaching. In addition, very poorly crystalline phases such as schwertmannite and ferrihydrite were identified in several samples through XAS, which was confirmed by SSE. These phases are probably associated with PTEs. Other possible adsorbent Fe(III) minerals were also identified by XAS, such as maghemite and goethite; as well as mixed Fe(II)-Fe(III) minerals, such as green rust. It was possible to infer the influence of the acid spill on the different sampled areas through various Fe phases identified and/or the presence of gypsum. The influence was detected to be lower where the mineralogy was not associated to low pH and high sulfate concentrations. All precipitated Fe(III) phases downriver from the acid spill are known for their high retention capacities of PTEs either from incorporation into their structures and/or from surface adsorption, thus, contributing to the immobilization of the initial metal(loid) pollution caused by the acid spill. In addition, several other samples of mining-metallurgical wastes were analyzed by the same three techniques, suggesting many of the findings from the secondary Fe mineralogy of the Buenavista del Cobre mine acid spill as common processes occurring in mining-affected environments.

Isolasi Mikroba Dari Air Asam Tambang Pada Area Pertambangan Tembaga Di Pulau Wetar, Provinsi Maluku

This research was conducted to find bacteria from the genus Acidithiobacillus ferrooxidans which isolated from mine acid water in the copper mining area on Wetar Island, Maluku Province. This bacterium will be utilized in the biohidrometallurgical process (bioleaching) for copper extraction in mining area. The results of this study indicate that bacteria can be isolated from mine acid water samples by enrichment method that was use liquid media from Leathen which is optimized using Trypton Soya Broth (TSB) and bacterial growth on solid media. The presence of Thiobacillussp bacteria was confirmed by the results of gene analysis using a 16S rRNA sequence showing the presence of mixed bacterial colonies but not a single colony.