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This paper investigates the occurrence of natural attenuation in sediments from a water reservoir impacted by metals and radionuclides resulting from acid mine drainage. The chemical and radiochemical characterization indicated the enrichment of radionuclides (238U and 226Ra) and metals (Zn) in the sediments. The isotopic deviation δ34S (− 1.3 to − 17.4‰) and high contents of Acid Volatile Sulfide (2.34 to 5.71 g kg−1) indicated the occurrence of natural attenuation all through the reservoir, which contributes to the chemical stabilization of the contaminants. [ABSTRACT FROM AUTHOR]

The pulp industry is a high natural resources consumer and has a large polluting potential. The pulping sector with the most effluent generation is the bleaching plant. Based on the need of water consumption reduction, this research aimed to evaluate the treatment of the alkaline effluent from an EP-stage bleaching plant and the white water from drying machine using ultrafiltration membranes in order to enable the reuse of the permeate in the process. An ultrafiltration pilot plant was used. Laboratory analyses were performed for the feed, permeate and retentate. Flux and transmembrane pressure (TMP) data were obtained from the pilot plant database. There were an average color and COD removals of 38 % and 39 %, respectively, for the EP-effluent and 58 % and 67 %, respectively for the white water; and a high turbidity and TSS removal (above 98 %) for both effluents. Substantial metals removal such as sodium, potassium, calcium, iron, magnesium and manganese was achieved. Some possibilities to reuse were considered: return to the water treatment plant, cooling of the digester bottom, equipment cooling, reuse in evaporation surface condensers. The use of ultrafiltration for the treatment of the alkaline effluent from the bleaching EP-stage and white water can be an interesting option. [ABSTRACT FROM AUTHOR]

Pyritic coal wastes produced by a coal beneficiation plant in the State of Santa Catarina in southern Brazil are acid generating. In this paper, we report the results from the first phase of a study evaluating the performance of dry covers for minimizing generation of acid mine drainage and its release to the environment. The first phase includes our investigation of locally available materials for dry covers. Numerical modeling led to four configurations being selected for testing: a dry cover using a double capillary barrier with bottom ash, a dry cover with a single layer of clay, a dry cover with mixed waste, and waste with no cover. Modeling also showed that the best position for the lysimeter was at the bottom of the excavation, where it would not interfere with the water flux in the waste. A subsequent paper will describe the construction of the experimental unit and the results of the geotechnical and geochemical studies. [ABSTRACT FROM AUTHOR]

Fuzzy logic was applied to model acid mine drainage (AMD) and to obtain a classification index of the environmental impact in a contaminated riverine system. The data set used to develop this fuzzy model (a fuzzy classifier) concerns an abandoned mine in Northern Portugal—Valdarcas mining site. Here, distinctive drainage environments (spatial patterns) can be observed based on the AMD formed in the sulphide-rich waste-dumps. Such environments were established, as the effluent flows through the mining area, using several kinds of indicators. These are physical–chemical, ecological and mineralogical parameters, being expressed in a quantitative or qualitative basis. The fuzzy classifier proposed in this paper is a min–max fuzzy inference system, representing the spatial behaviour of those indicators, using the AMD environments as patterns. As they represent different levels (classes) of contamination, the fuzzy classifier can be used as a tool, allowing a more reasonable approach, compared with classical models, to characterize the environmental impact caused by AMD. In a general way it can be applied to other sites where sulphide-rich waste-dumps are promoting the pollution of superficial water through the generation of AMD. [ABSTRACT FROM AUTHOR]

Copyright of Mine Water & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mine Water & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In Ouro Preto/MG, pyrite was exploited at an old mine from 1930 through 1967. Considered as one of the best resources of pyrite in Brazil, this mine was exploited in order to supply sulfuric acid for explosives manufacturing, at the President Vargas Plant in Piquete/SP. The mine site is abandoned and has slope instability and acid leakage generation as the main environmental liabilities. Lately, the site has been used for illegal deposition of all sorts of urban waste. The Ouro Preto Administration, on its turn, has the intention of using part of the mine site for the disposal of solid residues of civil construction. This paper presents the results of kinetic tests carried out, in leaching columns, to assess the acid mine drainage potential in samples collected from the mine site and to evaluate the possibility of controlling and minimizing acid generation by using solid residues as a covering system. Laboratory results show that cover with solid residues of civil construction was effective in the reducing the acidity, concentration of metals and sulfate. [ABSTRACT FROM AUTHOR]

This paper summarises environmental applications of conventional and unconventional flotation to remove pollutants from waters. Emphasis is given to the design features of innovative inline reactors, namely the Flocs Generator Reactor and Flocculation-Flotation, and their applications for the flocculation and flotation in solid-liquid separations involving water (and wastewater) treatment and reuse. Applications are shown in potable water clarification, treatment and water reuse from car washing units and in the treatment of acid mine drainage. Results show that these inline flocculation (or flotation) separators have a great potential for water/wastewater treatment and reuse, especially in applications requiring high rate solid-liquid separations. [ABSTRACT FROM AUTHOR]

Copyright of Mine Water & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A mine in an area of naturally occurring radioactive materials (NORM), characterized by acid mine drainage, generates effluents with natural radionuclide concentrations, usually above the limits authorized by the regulator. The plant exploiting NORM controls the water quality and discharges it into the aquatic environment after meeting technical requirements. Downstream, water usage is unrestricted. In order to reach activity concentrations in the released effluents below the authorized values, the facility applies a chemical treatment to the effluent. Then, to ensure the effectiveness of the treatment, the facility performs sampling of treated effluent and determines the activity concentration of natural radionuclides (Unat, 226Ra, and 210Pb from the uranium series and 232Th and 228Ra from the thorium series). In the current study, the proportion and distribution of these radionuclides between the soluble and particulate fractions were determined. The measured activity concentrations were compared with the values proposed by the World Health Organization and Brazilian legislation, as well as other authorities, as regards the potable use from the radioprotection point of view. It was observed that the radionuclides are not in secular equilibrium. The fractions contribute differently to the total release of radionuclide, and there is no linear relationship between the fractions. The average activity concentrations did not result in radiological restrictions to water use, and the committed effective dose due to ingestion was estimated at 0.06 mSv y−1. Therefore, there is no radiological restriction to water use, since the dose which was found was below the constraint value for the public. [ABSTRACT FROM AUTHOR]

Introduction: Flowing of the acid mine drainage may contaminate the adjacent water bodies causing substantial changes in the aquatic ecosystem. This aspect is the most relevant problem in the southern of Santa Catarina once the contaminated areas are inserted in the watershed of the Araranguá, Urussanga, and Tubarão rivers, increasing the need for recovery studies. These areas are between Criciúma, Içara, Urussanga, Siderópolis, Lauro Müller, Orleans, and Alfredo Wagner towns where a conservation unit exist called the Environmental Preservation Area of Baleia Franca. Aiming to compare the kinetics of the ash derived from burning coal and to neutralize acid mine drainage, different neutralizer, limestone, fly, and bottom ash, was mounted on a pilot scale experiment. Discussion: The transport parameters showed the same order of infiltration and dispersion: fly ash < bottom ash < limestone. The order of measured alkalinity was: limestone < fly ash < bottom ash, with pH values of 9.34, 12.07, and 12.25, respectively. The limestone kinetics of acidic drainage neutralization was first order with reaction rate constant k = 0.0963 min, bottom ash was 3/4 with k = 0.0723 mol L min, and the fly ash had higher order kinetics, 4/3, with reaction rate constant k = 27.122 L mol min. However, by mathematical modeling, it was found that due to a combination of transport and kinetics, only limestone treatment reached a pH above 6 within 5 years, corresponding to the ideal as planned. [ABSTRACT FROM AUTHOR]

Copyright of Mine Water & the Environment is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)