Acid mine drainage (AMD) is widespread environmental problem associated with both working and abandoned mining operation, resulting from the microbial oxidation of pyrite in presence of water and air, to form an acidic solution containing metal ions. The present study aims to adjust low pH, remove iron, manganese and sulphate from AMD generated at open pit Jiří and depth Jiří, Sokolovská uhelná, Czech Republic. The local AMD is very problematic due to its composition and process taking place in the Water Preparing Plant Svatava (WPPS), where only pH value is adjusted and mainly high concentration of iron and suspended solids are removed.

In this work the effectiveness of the biotransformation of phosphogypsum in the cultures of sulphatereducing bacteria (SRB) was studied. SRB were isolated from soil contaminated with automobile fuel. The microorganisms were grown by two methods: the enrichment of the cultures and microcosms in: Postgate, minimal medium (with phenol, acetate or lactate) and Emerson medium. All media contained phosphogypsum as electron acceptors. The isolated microorganisms were passage in medium containing different carbon compounds: ethanol, lactate, phenol, acetate casein or lactose to test the effectiveness of biotransformation of phosphogypsum depending on the source of carbon used. In cultures in Postgate medium with lactate or casein there were found the maximal H2S concentration (654 and 540 mg HS-/dm3) and maximal decrease of phosphogypsum 84% and 64%, respectively. The isolated microorganisms utilised alcohol, sugar, protein and phenol.

Seasonal changes in the numbers of sulphate-reducing bacteria in water, soil, the surface of sedge (Carex acutiformis Ehrb.) immersed in waler and roots (dead and live) were studied. The study on one of larger wetland near Olsztyn (Masurian Lake District) was carried out in two annual cycles. Sulphate-reducing bacteria in the studied ecosystems occurred sporadically and generally in inappreciable count. Their count did not exceed 20 cells in I cm3 ofwaler; in the soil and in di ffercnt parts of sedge the number of bacteria ranged from several lo over dozen thousands cells in I g of dry weight. In the first year of studies these bacteria were the most numerous in June, July and during first days of December, bul in the second - in April (in soil and sedge immersed in water), in August (in soil and dead and live roots), in November (in waler, soil, sedge immersed in water and dead roots) and exceptionally in other months.

In this paper we studied the intensification of the water clarification process on contact clarifiers with quartz sand fil-tering bed, which was modified with a solution of aluminum sulphate coagulant. The modification of the quartz sand filter-ing bed was carried out by applying to the surface of grains of quartz sand solution of coagulant aluminum sulphate with different doses. Investigation of the electrokinetic potential of the filtering material (quartz sand) was carried out by the percolation potential method.

The influence of electrical properties (size and sign of the charge) of the filtering bed itself and suspended solids in the water on the filtration process was studied. The filter material – quartz sand used in contact clarifiers has a negative electric charge. When the electric charge of the particles decreases, that is, as the ζ-potential decreases, the repulsive forces de-crease and it the adhesion of particles becomes possible. This is the process of coagulation of the colloid. The forces of mu-tual gravity between the colloidal particles begin to predominate over the electric repulsive forces at the ζ-potential of thesystem less than 0.03 V.

Modification of quarts filtering bed with a solution of coagulant aluminum sulphate recommended for the purification of surface water allows: to intensify the process of water clarification, to reduce the consumption of reagents by 25–30%, with the obtaining purified water of the required quality, to reduce the production areas necessary for reagent management of treatment facilities, and to reduce the cost of water treatment by 20–25%.

Surfactants can interfere with the biological wastewater treatment processes. They contribute to the changes in activated sludge floes structure. In order to quantify the influence of surfactants on sludge floes morphology the series of experiments in the flow continuous system were conducted. Sodium dodccyl sulphate, which belongs to the most ubiquitous anionic surfactant in everyday use, was selected to be the object of investigations. The results of its biodegradation in continuous flow system at influent concentration of 250 mg -dm' are presented. It turned out that SDS diminished the mean projected area of floes from 50 OOO to 15 OOO μm' with the increase of dilution rate from 0.029 to 0.192 h·1• At the same time the obtained data confirmed that there was a correlation between the morphological parameters of floes and other biomass indicators. The linear relation between mean projected area of floes and volatile suspended solids was found.

The paper presents results of aluminium concentration determination in the samples of surface water and bottom sediments of the Mala Wełna River (West Poland). In the surface water the concentration of aluminium varies in the range from 4.14 to 25.9 ug/dm'. With use of the Mineql+ program the concentration of the aluminium sulphate complexes in the water samples studied has been determined in a model way. In the bottom sediments samples of the river aluminium has been determined in the granulometrie fractions of the grain sizes> 2.0; 2.0-1.0; 1.0-0.5; 0.5-0.25; 0.25-0.1; 0.1-0.063; < 0.063 mm, using the sequential extraction scheme proposed by Tessier el al. The lowest concentration of aluminium has been found in the granulometrie fraction 0.5-0.25 mm, while the highest in the fractions 0.1-0.063 and< 0.063 mm. An elevated concentration of aluminium has been also noted in the fraction> 2.0 mm. Taking into regard the chemical fractions the lowest concentration of aluminium has been found in the exchange fraction and the fraction bounded to carbonates (fractions I and li), whereas the highest concentration of aluminium has been determined in the lithogenic fraction (fraction V). The methods of sample preparation for analysis of aluminium in bottom sediments were compared. Il was observed that higher concentration of aluminium was present in grounded samples without its influence on grain size fractions. The concentration of aluminium in surface water samples has been determined by the GF-AAS, while in bottom sediments by F-AAS.

This study is the evaluation of the coagulation efficiency of the aluminum sulfate on the removal of catechol and pyrogallol. The study has focused on the impact of inorganic components of hardness Algerian waters. Jar-test trials were conducted on the two phenolic compounds dissolved in distilled water only, which was later enriched with minerals. Several reaction parameters varied, including the effect of pH and the influence of the salt content, and this approach yielded a better understanding of interaction between phenolic compounds and calcium/magnesium salts. The results indicate that the process efficiency depends on the number and position of OH in molecules. The main mechanisms would be either a physical adsorption, an exchange of ligand, or complexation on the floc surface of aluminum hydroxide. Moreover, the addition of inorganic salts appears to improve removal efficiency of tested phenolic compounds and have an effect on the optimal pH range for coagulation.

With the rapid development of industry, abundant industrial waste has resulted in escalating environmental issue. Steel slag is the by-product of steel-making and can be used as cementitious materials in construction. However, the low activity of steel slag limits its utilization. Much investigation has been conducted on steel slag, while only a fraction of the investigation focuses on the effect of steel slag particle size on the properties of mortar. The aim of this study is to investigate the effect of steel slag particle size as cement replacement on properties of steel slag mortar activated by sodium sulphate (Na2SO4º. In this study, two types of steel slag, classified as fine steel slag (FSS) with particle sizes of 0.075mm and coarse steel slag (CSS) with particle sizes of 0.150 mm, were used for making alkali activated steel slag (AASS) mortar. Flow table test, compressive strength test, flexural strength test and UPV test were carried out by designing and producing AASS mortar cubes of (50 x 50 x 50) mm at 0, 10%, 20% and 30% replacement ratio and at 0.85% addition of Na2SO4. The results show that the AASS mortar with FSS possess a relatively good strength in AASS mortar. AASS mortar with FSS which is relatively finer shows a higher compressive strength than CSS up to 38.0% with replacement ratio from 10% to 30%. This study provided the further investigation on the combined influence of replacement ratio and particle size of SS in the properties of fresh and hardened AASS.

Field surveys were undertaken in 1997–1999 across five ecological zones in Nigeria to collect isolates of Maize streak virus (MSV), genus Mastrevirus. Apart from maize (Zea mays L.), 15 other grass species were found with MSV symptoms in Nigeria. These hosts showed two types of symptoms viz: mild (with or without mottle) or severe (typical symptoms in maize). When Cicadulina storeyi China was used to attempt transmission of these isolates of MSV to seedlings a susceptible maize hybrid CML 254 X CML 247, six isolates were not transmissible to maize. Seven isolates that were transmissible to maize produced mild symptoms. The viral agents causing typical or severe streak symptoms in Axonopus compressus (Sw.) P. Beauv., Brachiaria distichophylla (Trn.) Stapf, Dactyloctenium aegyptium (Linn.) P. Beauv. and Setaria barbata (Lam.) Kunth produced symptoms that were typical of MSV in farmers fields, when transmitted to maize. Out of 33 plant species that seedlings were challenged with MSV, only eight proved susceptible. Four of them showed mild symptoms while the other four showed severe symptoms of MSV. Only three isolates collected during the surveys did not react with a MSV polyclonal antiserum produced in mice in Double Antibody Sandwich-Enzyme-Linked Immunosorbent Assay (DAS-ELISA). These isolates were found in Andropogon gayanus Kunth (from Kaduna), Thelepogon elegans Roth ex Toem & Schult (from Kadawa) and Rottboellia cochinchinensis (Lour.) Clayton (from Jos) exhibited mild streak/mottle symptoms. Specific monoclonal antibodies, raised against MSV, reacted with 12 out of 25 samples tested. The DAS-ELISA data also showed significant variation in concentration of the virus in the different plant hosts. The relationship dendogram through SDS-PAGE among eight purified virus isolates show 55–90% variation. At 0.55 coefficient of similarity, the dendogram divided the samples into two groups while at 0.9 coefficient of similarity, the 8 isolates were identified as distinct genetic entities.

The presence of natural organic matter (NOM) in water has a significant influence on water treatment processes. Water industries around the world consider coagulation/flocculation to be one of the main water treatment methods. The chief objective of conventional coagulation-based processes is to reduce the turbidity of the water and to remove natural organic matter (NOM) present in solutions. The aim of this paper is to present some developments in terms of improved coagulation for the drinking water of Sidi Yacoub treatment plant located in the Northwest of Algeria.
The experiments involved studying the effects of the application of two coagulants (ferric chloride and aluminium sulphate) on the removal of turbidity and natural organic matter from water by measuring the chemical oxygen demand ( COD) and the UV absorbance at 254 nm. The results showed that the rate of turbidity removal increased from 81.3% to 88% when ferric chloride was applied and from 89.91% to 94% when aluminium sulphate was applied. For NOM removal, the maximum removal rates of COD and UV254 were 48% and 52%, respectively, in the case of ferric chloride. These rates increased to 59% and 65% after optimised coagulation. When aluminium sulphate was used, the rate of removal in water increased from 43% to 55% for COD and from 47% to 59% for UV254 after optimised coagulation. The combination of the two coagulants at equal dosage shows a slight improvement in the values obtained after optimisation, both in terms of turbidity and the NOM.

The research paper presents the results of hydraulic conductivity, pore structure, phase composition and microstructural tests of hardening slurries prepared using Portland cement, bentonite, water and fluidized-bed ashes coming from hard coal and lignite combustion. The slurries were subjected to long-term (210 days) exposure to the filtering action of an environment strongly aggressive to a cement binder. A sulphate solution 2- with sodium content of SO4 2- = 6700 mg/l was applied, which modelled sulphate aggression. The comparative base were samples subjected to filtration in tap water (neutral environment).

The test covered dependencies between hydraulic conductivity k10 (filtration coefficient) and the parameters characterizing porous structure in the slurry, as well as the impact of an aggressive medium on slurry tightness (its porosity and hydraulic conductivity). Changes in the phase composition and slurry microstructure were analysed in terms of its corrosion resistance to the action of sulphate aggression.

Observations from other researchers have been confirmed that the use of fluidized fly-ash addition has a positive effect on increasing the resistance of cement matrix exposed to sulphate aggressiveness.

Pyrite framboids occur in loose blocks of plant−bearing clastic rocks related to volcano−sedimentary succession of the Mount Wawel Formation (Eocene) in the Dragon and Wanda glaciers area at Admiralty Bay, King George Island, West Antarctica. They were investigated by means of optical and scanning electron microscopy, energy−dispersive spectroscopy, X−ray diffraction, and isotopic analysis of pyritic sulphur. The results suggest that the pyrite formed as a result of production of hydrogen sulphide by sulphate reducing bacteria in near surface sedimentary environments. Strongly negative δ34SVCDT values of pyrite (−30 – −25 ‰) support its bacterial origin. Perfect shapes of framboids resulted from their growth in the open pore space of clastic sediments. The abundance of framboids at cer− tain sedimentary levels and the lack or negligible content of euhedral pyrite suggest pulses of high supersaturation with respect to iron monosulphides. The dominance of framboids of small sizes (8–16 μm) and their homogeneous distribution at these levels point to recurrent development of a laterally continuous anoxic sulphidic zone below the sediment surface. Sedimentary environments of the Mount Wawel Formation developed on islands of the young magmatic arc in the northern Antarctic Peninsula region. They embraced stagnant and flowing water masses and swamps located in valleys, depressions, and coastal areas that were covered by dense vegetation. Extensive deposition and diagenesis of plant detritus in these environments promoted anoxic conditions in the sediments, and a supply of marine and/or volcanogenic sulphate enabled its bacterial reduction, precipitation of iron mono− sulphides, and their transformation to pyrite framboids.

Crude oil and light or heavy oils as well as the detergent ABS in concentrations of 5 and 50 ppm partially inactivate arylsulphatases in Euphausia superba and E. crystallorophias. After one hour exposure to detergent solutions the arylsulphatase activity in experimental animals transitorily increased. The arylsulphatase activity proved to be affected also in krill homogenates. The change of temperature, of the krill incubation in solution of crude oil or detergent, from — 1°С to + 1°C did not influence the enzyme activity. The damage of lysosomal membranes, by oils and the detergent, has been confirmed by the fact of enhanced penetration of Trypan blue into krill tissues.

It has been acknowledged that two important rock aggregate properties are the Los Angeles abrasion value (LAAV) and magnesium sulphate soundness (M _wl). However, the determination of these properties is relatively challenging due to special sampling requirements and tedious testing procedures. In this study, detailed laboratory studies were carried out to predict the LAAV and M _wl for 25 different rock types located in NW Turkey. For this purpose, mineralogical, physical, mechanical, and aggregate properties were determined for each rock type. Strong predictive models were established based on gene expression programming (GEP) and artificial neural network (ANN) methodologies. The performance of the proposed models was evaluated using several statistical indicators, and the statistical analysis results demonstrated that the ANN-based proposed models with the correlation of determination (R2) value greater than 0.98 outperformed the other predictive models established in this study. Hence, the ANN-based predictive models can reliably be used to predict the LAAV and M _wl for the investigated rock types. In addition, the suitability of the investigated rock types for use in bituminous paving mixtures was also evaluated based on the ASTM D692/D692M standard. Accordingly, most of the investigated rock types can be used in bituminous paving mixtures. In conclusion, it can be claimed that the proposed predictive models with their explicit mathematical formulations are believed to save time and provide practical knowledge for evaluating the suitability of the rock aggregates in pavement engineering design studies in NW Turkey.