Tomáš Bakalár

Microfiltration of Concentrated Suspensions of a Microparticulate Ion‐Exchanger Through a Ceramic Membrane

Abstract Suspensions of a microparticulate Lewatit ion‐exchanger can be effectivelly concentrated by microfiltration (MF) to relatively high concentrations of about 25% of dry particles. This is important for formation of a hybrid process combining ion‐exchange and MF. A tubular ceramic membrane with the mean pore size of 0.1 µm and the ground ion‐exchanger Lewatit S100 with the mean particle size 5.25 µm have been used. Analysis of the flux decline revealed that the dominant membrane fouling mechanism is cake formation. With increasing suspension velocity the permeate flux significantly increases. The velocity of suspension above 2 m · s−1 should be used to achieve a reasonable flux. The limiting flux was reached at a pressure of about 100 kPa, but at higher suspension concentrations even at about 60 kPa. Surprisingly, the dependence of the permeate flux vs. suspension concentration goes through a flat maximum at the mass fraction of the dry resin of about 0.13. This can be interpreted as a result of inertial lift of larger particles in the suspension. At higher ion‐exchanger concentrations further accumulation of particles in the cake increases its resistance and decreases the flux. Even at concentrations as high as 37.5 mass% of wet (25% of dry) particles in the suspension the permeate flux of about 72 dm−3 · m−2 · h−1 can be achieved.

Increase of Alternative and Renewable Energy Sources Utilization in Slovakia by 2020 in Comparison to other Selected EU Countries

One way to save fuel is to use renewable energy, including solar, wind, hydro, geothermal and biomass. The use of renewable and alternative energy sources is contributing to environmental protection and nature conservation as a whole and provides a perspective of sustainable development. The aim of this paper is to compare the possibility of increasing the use of alternative and renewable energy sources in Slovakia with neighboring countries. It determines and also identifies the level of the Slovak Republic in the use of renewable energy sources because it is expected to increase by 2020 in each country. This paper is also devoted to the theoretical base of renewable and alternative forms of energy. One part of the paper deals with an analysis and comparison of the state of the use of renewable energy sources in Slovakia and in selected EU countries. Latest part deals with the overall national objectives set by the European Union for the proportion of energy from RES, which will be achieved by 2020. The paper is a partial result of the research project on RES realized at Technical University of Košice (Slovakia).

Development of Košice Region by Implementation of Environmental Projects in the Field of Water Management - Case Study

Abstract The development of the regions in Slovakia in recent years has significant disparities in both so-cio-economic as well as environmental issues, as evidenced by the eight environmentally polluted areas (these areas are highly urbanised with industrial agglomerations or intensive agricultural production). This article deals with a management system model of regional by implementation of projects in environmental field of water management with application-specific benefits and risks arising from the process of their implementation in relation to regional development. It analyses projects in the area of water management of one of the regions of Slovakia, KoŠice region in particular, in terms of connection to public water duct and sewer, identifes a strategy for development of the region and its socio-economic and environmental benefits based on the analysis of drinking water, the quan-tity and quality of treated wastewater through wastewater treatment plants (WTPs). It identifes the infuencing factors of benefits and risks and proposes procedure for solving at various stages.

Influence of Transmembrane Pressure on Microfiltration of Suspensions

The influence of transmembrane pressure on the permeate flux, and the critical and limiting fluxes in microfiltration of two sorbents Bentonite a natural sorbent, montmorillonite based clay and Lewatit S1468 a synthetic sorbent, styrene-divinylbenzene based copolymer were studied. An asymmetric single-channel inorganic ceramic membrane based on α-Al2O3 was used. The experimental data were obtained by continuous microfiltration equipment. According to the results the limiting flux ranged from 37 to 70 l.m-2.h-1 for Bentonite suspensions. It was not possible to estimate the limiting flux for Lewatit S1468 suspension.

Influence of Inner Configuration of Membrane on Microfiltration of Suspensions

The influence of membrane type on the permeate flux in microfiltration of two sorbents Bentonite a natural sorbent, montmorillonite based clay and Lewatit S1468 a synthetic sorbent, styrene-divinylbenzene based copolymer was studied. Two types of membranes, single-and multi-channel, both asymmetric inorganic ceramic membranes based on α-Al2O3, were used. The experimental data were obtained by continuous microfiltration equipment. According to the results use of multi-channel membrane has more advantages higher permeate flux, lower energy consumption, and lower flow rate than disadvantages longer time period to reach the steady state and higher pressure loss.

Impact of aeration rate and zeolite concentration on the microfiltration flux

Microfiltration is an efficient separation process in water purification. One of the drawbacks of this separation process is fouling. Several methods can be used for reduction of fouling. In this study the impact of aeration rate and the suspension concentration of two different zeolite fractions on the microfiltration flux was studied. Natural zeolite with main component of clinoptilolite with mean particle size of 20 and 50 μm and an asymmetrical inorganic membrane were used in the experiments. Microfiltration measurements were made to determine the enhancing effect of the aeration in the microfiltration system under various aeration rates and concentrations of the zeolite suspension. Higher permeate fluxes are reached at lower suspension concentrations of zeolite suspensions with mean particles of 20 μm irrespective of the applied air flow rate. At higher suspension concentrations the fluxes are similar for both the tested zeolite particle sizes. Regardless of the zeolite particle size used the applied air flow has a positive effect on the permeate flux due to the reduction of fouling of the membrane surface. The highest effect of the input air was at the flow rates of 1 and 1.5 m3·h–1 and at high suspension concentrations. In the microfiltration experiments with applied air flow a 20–70% enhancement of the permeate flux compared to the experiments without air flow was recorded.

Elimination of Heavy Metals from the Material of Sludge Bed Slovinky

Old environmental loads are priority environmental problems in Slovakia. An old environmental load is an anthropogenic constituent in landscape which has its origin in past works (for example mining and mineral processing) but in present time it can also pose risk for the environment. One of environmental loads in Slovakia is sludge bed in Slovinky. Village Slovinky is well-known for mining activities during several centuries. From the beginning copper ore was mined there, later on iron ore which was processed in the metallurgical factory in Krompachy. The mining activity in Slovinky was stopped in 1993. Flotation slurry from ore treatment plant was deposited on the sludge bed which was operated from 1968 to 1999. More than 4.8 million cubic meters of slurry is deposited there. Locality of Slovinky is included in State Remediation Program of Environmental Loads (2010-2015). The paper summarizes the actual state of knowledge about environmental impact of mineral processing and theoretical analysis of problem of environmental impact of environmental load – sludge bed in Slovinky. Experimental part of the paper is focused on study of possibilities of elimination of heavy metals in sludge bed material with the aim of improvement of the environmental quality of surveyed locality.

Hybrid Sorption and Microfiltration Characteristics of Zeolite

Industrial wastewater treatment and reuse is one of the principal tasks of present. For this purpose several physical, chemical and combined methods have been used. This paper deals with the study of sorption behaviour of natural zeolite with respect to Zn (II) and Cu (II) followed by cross-flow membrane microfiltration. The experiments realised were aimed at verification of effectiveness of ion exchange of selected metals from wastewater using zeolite – with main component clinoptilolite. The experimental data obtained were fitted using Langmuir and Freundlich isotherms. The sorption capacity was studied for zinc and copper uptake, followed by a study of microfiltration of zeolite suspension using a cross-flow microfiltration device with tubular ceramic membrane. According to experimental results the basic parameters of microfiltration process were evaluated. In comparison with other processes, the hybrid membrane microfiltration offers more effective way of water treatment.

The Use of Renewable Sources of Energy in the Development Process of a Slovak Municipality

The present article deals with the issue of renewable energy sources for the development needs of Čakanovce municipality in terms of solar, geothermal, and biomass energy which are available for this region. Using renewable energy is viewed not only in the context of environmental benefits, but also in the context of further socio-economic development of communities and an increase of its energy independence. The analysis of the solved problems was based on relevant data on the possibilities of using different types of renewable energy in relation to supporting the development of Olšava-Kecerovce region which also includes Čakanovce. Choice of the most appropriate types of renewable energies to promote further development of Čakanovce municipality was based on proportionately index method, according to pre-defined decision-making factors.

Brownfields as a Tool for Support of Regional Development of Slovakia

The paper deals with solutions of brownfields in Slovakia in the context of the regional development. It refers to the potential that brownfields have for the benefit of further development at not only local but also at regional level in order to create aesthetically and ecologically balanced environment and landscape. It also shows the interaction of revitalization and subsequent reuse of brownfields in order to minimize regional disparities in the territory of the Slovak Republic.