Magdalena Balintova

Remediation of Acid Mine Drainage by Means of Biological and Chemical Methods

The formation and treatment of acid mine drainage is the biggest environmental problems relating to mining and processing activities in the worldwide. Various methods are used for the sulphates and heavy metals removal from acid mine drainage in the world, but any of them is universal. Main aim of the paper is the interpretation of chemical and biological-chemical methods for the metals and sulphates removal from acid mine drainage sample. The chemical method is based on the sulphates precipitation by the sodium aluminate in combination with the calcium hydrate. The biological-chemical method is based on the application of sulphate-reducing bacteria (SRB). A sample of acid mine drainage from the abandoned and flooded deposit of Smolník located in Slovak republic was used in this study.

Precipitation of heavy metals from acid mine drainage and their geochemical modeling

Abstract Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia) with the results obtained by geochemical modeling software Visual Minteq 3.0.

Material and Energy Interactions between Milling Bodies, Milled Particles, and Milling Environment

Changes in particle size, surface state, and composition brought about by planetary and vibration milling of silicon and quartz in various permittivity liquids were investigated. Using a variety of spectroscopic techniques (IRS, XPS, and Mössbauer spectroscopy) the changes in quality of the superficial layers of milled particles have been determined. During energy-intensive milling, the material being milled intensively interacts with the media and milling environment. The nature of the interaction and quality of the surface shell covering the milled particles depend on the reactivity and hardness of the interacting solids and of the milling environment. During planetary milling of silicon with tungsten carbide media, the superficial layers are formed by silicon suboxides and silicon oxide. The thickness of the superficial layer and the share of SiO2 increase with increasing permittivity of liquids. Milling with steel media results in a more complicated composition of the superficial layer. According to Mössbauer spectra, the iron is present in two main forms: as a magnetically ordered form identical with basic material of balls and in a paramagnetic form as a product of a mechanically stimulated surface reaction between Si and Fe. The presence of the superficial layers on the milled particles of silicon and quartz markedly influences the values of the specific surface area. This influence should be taken into consideration when calculating the specific contamination of the milled powder.

Metal Pollution Indices of Bottom Sediment and Surface Water Affected by Acid Mine Drainage

Sediments are normally the final pathway of both natural and anthropogenic components produced or derived from the environment. Sediment quality is a good indicator of pollution in the water column, where heavy metals and other organic pollutants tend to concentrate. Metals are introduced in aquatic systems as a result of the weathering of soils and rocks, from volcanic eruptions, and from a variety of human activities involving the mining, processing, or use of metals and/or substances that contain metal pollutants. Heavy metal concentration in the water column can be relatively low in some cases, but the concentrations in the sediment may be elevated. The presented work aimed to investigate the pollutant levels of some heavy metals (Fe, Mn, Al, Cu, Zn, As, Cd, Pb) in the water and sediments related to acid mine drainage (AMD) produced from an abandoned sulphide mine in Smolnik in Eastern Slovakia. A metal pollution index was used to compare the total content of metals at five sampling stations. The level of partitioning of the metals between the surface water and sediments in the area was calculated using Partition coefficients and the correlation coefficients between the metal pairs in both media were calculated by a Pearson coefficient.

Influence of Granularity of Sediment from a Water Reservoir on Phosphorus Sorption Processes

This research was designed to investigate the mechanism of phosphorus adsorption behaviour on the fine- (<0.063xa0mm) and coarse-grained (>0.063xa0mm) sediments of the Klusov water reservoir (Slovakia) due to the different particle cohesiveness. The study of the sediment physical parameters indicated that the clay/silt fraction dominates in fine-grained sediment sample and the silt/sand fraction in coarse-grained one. Based on the study of physico-chemical properties of sediments, it can be concluded that sediment particle size, specific surface area, organic content and aluminium content are the main sorption influencing factors. The Langmuir-Freundlich isotherm model was used to describe the phosphorus adsorption process of two different grain-size fractions of reservoir sediments. The R2 values of fitting (0.99 for fine- and 0.98 for coarse-grained sediments) revealed very well the description of the P sorption process by the Langmuir-Freundlich isotherm model. The results demonstrated a maximum phosphorus sorption capacity of 325xa0mg P/kg for fine-grained sediment and 207 mg P/kg for coarse-grained sediment. Reservoir sediments indicated maximum P sorption efficiency at low P content in solution and the release of phosphorus from sediment into water was observed without the addition of adsorbate. The results of this study indicate that the fine- and coarse-grained sediments of the Klusov water reservoir act as an efficient trap for phosphorus.

Bacterial Reduction Of Barium Sulphate By Sulphate-Reducing Bacteria

Abstract Acid mine drainage (AMD) is a worldwide problem leading to contamination of water sources. AMD are characterized by low pH and high content of heavy metals and sulphates. The barium salts application presents one of the methods for the sulphates removing from AMD. Barium chloride, barium hydroxide and barium sulphide are used for the sulphates precipitation in the form of barium sulphate. Because of high investment costs of barium salts, barium sulphide is recycled from barium sulphate precipitates. It can be recycled by thermic or bacterial reduction of barium sulphate. The aim of our study was to verify experimentally the possibility of the bacterial transformation of BaSO4 to BaS by sulphate-reducing bacteria. Applied BaSO4 came from experiments of sulphates removal from Smolnik AMD using BaCl2.

The Influence of Phosphogypsum Addition on Phosphorus Release in Biochemical Treatment of Sewage Sludge

The paper is focused on the research of biochemical treatment of sewage sludge and phosphogypsum under sulphate-reducing conditions with a phosphorus release process. The theoretical foundations of the work were based on the biochemical formalization using the principles of autocatalysis of natural systems. During the experimental research for the control of physicochemical parameters of the process spectroquantic, X-ray fluorescence analysis and other techniques were used. A schematic model of the dephosphatation process under anaerobic stabilization of sewage sludge and phosphogypsum was developed. The increase of phosphogypsum dosage had a close correlation with the release of phosphate ions. At the stimulating action of the phosphogypsum additive, a 2.5–5.0-fold increase in soluble phosphate concentration was observed. The rational dose of phosphogypsum was determined. Along with an increase the ratio of COD (Chemical Oxygen Demand)/phosphogypsum to 0.1, an increase in the phosphate ions in solution was observed. A further increase in the ratio of COD/phosphogypsum did not affect the concentration of phosphate ions in solution.

Utilization of poplar wood sawdust for heavy metals removal from model solutions

Abstract Some kinds of natural organic materials have a potential for removal of heavy metal ions from wastewater. It is well known that cellulosic waste materials or by-products can be used as cheap adsorbents in chemical treatment process. In this paper, poplar wood sawdust were used for removal of Cu(II), Zn(II) and Fe(II) ions from model solutions with using the static and dynamic adsorption experiments. Infrared spectrometry of poplar wood sawdust confirmed the presence of the functional groups which correspond with hemicelluloses, cellulose and lignin. At static adsorption was achieved approximately of 80 % efficiency for all treated model solutions. Similar efficiency of the adsorption processes was reached after 5 min at dynamic condition. The highest efficiency of Cu(II) removal (98 %) was observed after 30 min of dynamic adsorption. Changes of pH values confirmed a mechanism of ion exchange on the beginning of the adsorption process.

Study of Inorganic Pollutants Removal from Acid Mine Drainage by Hemp Hurds

Abstract Sulphates in wastewaters have an origin as the by-products of a variety of industrial operations. A specific and major producer of such effluents, which contained sulphates and heavy metals, is the mining industry. These contaminants should be removed from wastewater using an adequate process of treatment. The paper deals with selected heavy metals (iron, cooper, and manganese) and sulphate removal from acid mine drainage outflowing from an abandoned mine in Smolnik (Slovakia) using the modified biosorbent - Holland hemp hurds. Pre-treatment of acid mine drainage was based on oxidation of ferrous cations from acid mine drainage by hydrogen peroxide and subsequent precipitation. The precipitate were analysed by infrared spectrometry which found the precipitate containing hydroxide and sulphate functional groups. During this process the concentration of sulphate decreased by 43.8 %. Hemp hurds modified by NaOH decreased concentration of Cu2+ in solution by about 70 %