Vol 41, No 3 (2019)

Based on isotope-geochemical study of mineral-forming fluid of the gold and uranium deposits of two megablocks of the Ukrainian shield, a significant difference between the hydrothermal systems of the Archean and Proterozoic (3042—1750 million years) has been established. The study included the experimental determination of the hydrogen, oxygen and carbon isotopic composition, and the ratio of water and carbon dioxide of fluids of gas—liquid inclusions in quartz, pyrite and feldspars.

the analysis of scientific publications and normative documents concerning properties, fields of using and methods of producing ultrapure water was made. Features of determination of electrical conductivity (resistivity) of ultrapure water as the method of the primary control of its quality were considered. The most effective and spread methods of producing ultrapure water on an industrial basis were described as well requirements to the process of its distribution, storage and use, whose fulfillment rules out degradation of water quality.

The efficiency and peculiarities of 2-nitropenol (NP) desorption from activated carbons under the action of biotic and abiotic factors have been studied. The biotic NP desorption during one month reached 25–30% of the initial saturation of sorbent. The rational duration of bioregeneration was found to be equal to 14 days. The rate of biotic desorption is shown to be limited by the rate of internal diffusion. The intensity of self-bioregeneration of biological activated carbon is by an order of magnitude less that the NP destruction rate in the solution volume and to a greater degree corresponds to the intensity of abiotic desorption.

The extraction conditions of the Cu(II) complex with 6,7-dihydroxy-4-methyl-2-phenylben-zopyrylium chloride having component ratio 1 : 2 and formed in the solution at pH 4.5 have been optimized. Isoamyl alcohol was shown to be the most effective extractant. It was established that the extraction equilibrium was achieved during one minute, while the optimal ratio of organic and aqueous phases was equal to 1 : 5. The values determined of distribution coefficient (D) and complex recovery ratio (R) amounted to 61 and 92%, respectively. A high sensitivity extraction-spectrophotometric technique for determining Cu(II) by using 6,7-dihydroxy-4-methyl-2-phenylbenzopyrylium chloride was developed. This technique is relatively simple and features the detection limit of 0.007 μg/cm³. The calibration graph is linear in the range 0.02–0.96 μg/cm³. This technique was approbated in the process of analyzing different categories of water.

The elimination of Salmonella and Shigella from drinking water by electrolysis methods is the purpose of this study. The removal efficiency of bacteria was evaluated in different situations of pH (6–8), time (10; 20; 40 min) and voltages (10; 20; 30; 40 V) and the optimum conditions were found. Tests were also performed in optimum conditions on the influent sewage of chlorination pool. Data analysis was done by using SPSS software and Pearson correlation coefficient. The optimum conditions for elimination 10⁵Salmonella and 10²Shigella per milliliter were obtained at pH 7, the voltage of 20 V, and electrolysis time 20 min. In optimal conditions, the maximum removal efficiency of Salmonella and Shigella in both two synthetic and real samples were 100 and 99.9%, respectively. Due to the high efficiency of electrolysis method to eliminate Salmonella and Shigella, and also advantages such as relatively low-cost, non-production the disinfection byproducts and high efficiency is an effective method to remove fecal coliforms from drinking water.

The layout of the system comprised 3 experimental units with 3 replicates. Each unit consists of one level of water depth with four levels of Pistia stratiotes coverage (50; 70; 90 and 0% (control)) under the outdoor condition. The results indicated that P. stratiotes can be successfully used for wastewater treatment since it had the ability to achieve the goal of proposed design; where the highest removal percentages of BOD₅; NH₃; TN; TP were 83.5; 97.53; 90.3; 87% after 5; 3; 5; 4 days, respectively in the case of 25 cm of water depth with plant coverage of (90; 70; 50 and 70%, respectively). As compared with K—C* and P—K—C* models, this system achieved high removal efficiencies of water measurements and heavy metals (Fe, Cu, Ni and Pb). The results showed that this aquatic plant P. stratiotes can be successfully used for waste water treatment and therefore can be used for large-scale.