2/g. It exhibits amphoteric properties, and the parameter indicating the nature of the pH, namely a pH of zero charge, is 8.2. In the medium having a pH of less than 8.2 adsorbent material exhibits anion exchange properties, and at pH above 8.2 -cation exchange. For example, the mechanism of removal of arsenate ions from aqueous solutions of this adsorbent is close to the mechanism of removing arsenates in the slightly alkaline anion exchangers [Hering et al. 2004;Bratek et al. 2012]. Research Article ABSTRACT One of inorganic sorbents used in water treatment technology is activated alumina. It is recommended by the European Commission to remove inorganic impurities, such as arsenic, fluoride, selenium and silicates. The adsorbent is usually applied in a granular form, under flow conditions. It can become absorbent material, increasingly used due to the presence of arsenic beside iron and manganese in groundwater intakes. The aim of the study was to evaluate the effectiveness of groundwater treatment in the technological system containing adsorption on activated alumina. The experiment was performed on test model CE 581 manufactured by G.U.N.T. Hamburg, in which four treatment stages can be extracted. The first stage is used in a gravel filter of grain size 1-2 mm, in the second sand filter of grain size 0.4-0.8 mm. The third and fourth phase includes two adsorbers. The first adsorber comprises activated alumina (Al 2 O 3 ) and the other comprises a granular activated carbon. The study was conducted at different speeds of filtration: 5, 10 and 15 m/h. In the raw water samples and the purified water samples after each treatment step the following parameters were determined: pH, O 2 concentration, electrolytic conductivity, SO 4 2-, concentration, NO 3 -concentration, PO 4 3-concentration, Cl -concentration, color, turbidity, iron and manganese concentration, COD Mn , total hardness, calcium hardness, magnesium hardness, content of dissolved substances. The conducted research indicates that optimum filtration rate for most pollution is 15 m/h. Moreover, the presence of activated alumina has contributed to increasing the efficiency of nitrate (V) and phosphate (V) ions removal. STUDIES ON THE EFFICIENCY OF GRUNDWATER TREATMENT PROCESS

The emission of carbon compounds (in the form of soot) to the atmosphere has a significant impact on the environment and human health. Air pollution with combustion products, having a unique combination of physical and chemical properties, is an important component of very fine suspended dust, which is emitted from various sources related to combustion processes. The carbon compounds in aerosol form and deposited in the substrate are found all over the Earth. The paper presents results of comparative research on the content of 16 polycyclic aromatic hydrocarbons (PAH) in soot samples obtained as a result of combustion of solid fuels such as hard coal with granulation above 60 mm, coal with a grain size of 25–80 mm, coal with a grain size of 8–25 mm, pellets and dry wood. On the basis of the conducted tests, it was found that the soot obtained in the combustion of coal in different granulation contains more cytotoxic PAH in comparison to the combustion of wood pellets or dry firewood.

Biological membrane reactors or membrane bioreactors (MBRs) based on pressure separation techniques are placed among the latest and most modern methods of wastewater treatment. Currently, this method is becoming more and more popular and is being implemented in smaller and larger wastewater treatment plants (WWTPs). However, technologists, operators, and managers of small WWTPs often do not understand the MBR technology installed in their sites and need extensive professional and technological information. The aim of this study was to analyze the modernized WWTP in a small town of Wydminy, located in northeastern Poland in the Great Masurian Lakes region, where the traditional secondary settling tank was replaced by an MBR. The effectiveness of wastewater treatment before modernization and after installation of the membrane module was compared. On the basis of the conducted research, it was noted that the operation of the plant after modernization is more cost-intensive. There were additional electricity costs due to ensuring adequate pressure on the membrane. Nevertheless, the obtained results of the removal of contaminants place the plant in Wydminy in the group of the most effective Polish sewage treatment plants, as compared to the results obtained in other facilities. The MBR operation also places high demands on the exploiters, prompting them to observe even the smallest changes. The conducted research is a type of a case study, which could give the readers an understanding of the necessity of traditional WWTP modernization with MBR.

One of the most important technological processes of water treatment is the process of filtration. Scientists and producers keep on searching new filtration materials which allow for better water purification, are simple in exploitation and do not add chemical substances to the treated water. Therefore, the aim of the present study was to analyze physical and chemical parameters of two unknown porous masses X1 and X2. Such physical parameters as color, granulation, bulk density, the equivalent diameter, the coefficient of uniformity and the porosity of the material were measured and determined. Additionally, the possibility of water treatment was studied during the filtration process in the laboratory tests. Chemical parameters were examined in the water flowing through the mass, such as pH, conductivity and COD-Mn as a general indicator of the content of organic substances in the water. Both studied porous masses were characterized by uniform size of particles. But they were not efficient enough in satisfactory reduction of oxygen consumption. Mass X2 slightly better adsorbed organic substances. It was found that the tested unknown mass filter slightly increase the pH of the filtered water.

a b s t r a c tMagnetic field (MF), among others, influences more intense decomposition of many compounds, increases adsorption on the surface of the phase separation, as well as accelerates oxidation and reduction reactions. Therefore, they are used in the research as an aid for filtration process, which is one of the most popular stopping and separating processes for different components in different reservoirs. Beds usually function as an adsorbent, thus both filtration and adsorption processes are often. One of the inorganic sorbents that is used to remove metals and anions present in water is Al 2 O 3 . As part of this work, we investigated the use of a constant external MF as an elementary additional process to improve the filtration efficiency on activated alumina. The purpose of the study was to compare the effectiveness of the removal of elements (Fe, Mn, Cd, Cr, Cu, Pb, Zn, and Ni) from model aqueous solutions during the process of filtration assisted and not assisted by an MF on activated alumina. In addition, the purpose of the work was also to determine the influence of MF on the removal of these elements, as well as their affinity to physical properties of the adsorbate under the influence of MF. As a result of the experiment, it was proved that the MF support of the filtration on activated alumina for the removal of selected elements is more effective than the filtration without MF. Studies have shown that removal of individual metals occurs according to the following series of affinity toward alumina in magnetized samples: Pb > Mn > Ni > Zn > Cu > Fe > Cd > Cr.

The objective of this work was to verify the granular activated alumina (AA) sorption properties, during the process of removing copper, lead and cadmium from water, and to monitor the impact of magnetic field (MF) on the effectiveness of removing copper, lead and cadmium from water. Activated alumina adsorption is known to be an effective and inexpensive technology for the removal of selenium and arsenic from water, and was suggested by EPA as a BAT for point-of-use applications. The removal of copper, lead and cadmium from water using AA and impact of magnetic field was reported to a lesser extent. Pilot tests showed that the use of AA sorption materials with MF impact could possibly decrease the copper, lead and cadmium content in the model water. The MF also had a positive effect on the efficiency of removal copper, lead and cadmium on AA. Increasing the efficiency of heavy metals removal in the samples exposed to magnetic field varied from 1.9% to 8.2% compared to the control samples.

The production of thermal energy is one of the sources of environmental pollution, especially when it uses traditional fossil fuels (in particular hard and brown coal). Burning conventional fuels contributes to air pollution because of emitting gases and producing waste after the process of burning in the form of ash. The work below was aimed at determining the indirect emission of PAHs in the form of fly ash, depending on the type of fuel burned. The conducted research showed which solid fuel combustion content leaves the lowest content of PAH in the fly ash. This work contains the analysis and assessment of the content of 16 PAHs (polycyclic aromatic hydrocarbons) in fly ash from the combustion of five selected solid fuels in low-power boilers. The following fuels were chosen for the research: hard coal with granulation above 60 mm, coal with the grain size of 25–80 mm, coal with the grain size of 8–25 mm, pellets with the grain size of 6 mm, and mixed dry wood. The results of the research showed that the most frequent and most concentrated compounds were naphthalene and acenaphthylene from the PAH group. These hydrocarbons have the smallest number of rings in a molecule. It was also found that the content of the LMW (Low Molecular Weight Polycyclic Aromatic Hydrocarbons) fractions in the fly ash from the analyzed fuels in ∑PAHs exceeds 57% in the case of 6 mm pellets and in the case of the ash from wood and hard coal when the grain size >60 mm. The opposite dependence can be observed in the case of the HMW (High Molecular Weight Polycyclic Aromatic Hydrocarbons) fraction.

The aim of the study was assessment of groundwater stabilization. Corrosive water effects on metals include complex electrochemical and biochemical processes. None of the water components remain indifferent to the metal and can accelerate or delay its corrosion. On the basis of the conducted tests of water samples, the aggressiveness and corrosivity indicators were calculated. Conducted research included analyses of raw and treated water. Raw water was taken as groundwater. Then it was treated in individual and complex processes such as aeration, filtration and ion exchange. Water aggressiveness and corrosion level were introduced by the Langelier Saturation Index (LSI), the Ryznar Stability Index (RI), the Larsoni–Skold Index (LI) and the Singley Index (SI). Obtained results proved that used water treatment processes must be improved through additional aeration and filtration with a dolomite bed. A simple system typical for industrial water is not enough to reach stable water because of remaining aggressiveness and corrosion.