Wpływ mineralizacji wody na współczynnik filtracji piasków

Abstract

INFLUENCE OF WATER MINERALIZATION UPON FILTRATION COEFFICIENT OF SANDSSummaryThe paper presents the results obtained from laboratory examinations of the influence of (artificial) water mineralization upon the change in filtration coefficient of sands. The work was made at the Hydrogeological Department of the Geological Institute.   Examinations embraced Quaternary dune sands, Tertiary glauconite and brown-coal sands from the region of Warsaw, and Lower Cretaceous glass sands from Biała Góra, near Tomaszów Mazowiecki. Sand samples were placed in an apparatus for filtration researches (type of Kamieński's tube) and then solutions of rock salt and of Ciechocinek salt in various conventrations were let through the samples. The examinations of 192 samples have been made by means of 1152 determinations of filtration coefficient. They have demonstrated that the increase in water mineralization up to 200 g/l NaCl causes a decrease in filtration coefficient within the following boundaries: dune sands from 2.14 x 10-2 to 1.9 x 10-2, i.e. 22 per cent.; Oligocene sands from 2.3 x 10-2 to 2.1 x 10-2, i.e. 11 per cent.; Lower Cretaceous sands from 6.6 x 10-3 to 5.0 x 10-3 cm/sec, i.e. 24 per cent. Initial results have been obtained using distilled water let through the sands examined. Moreover, the examinations have shown that high concentrations of the Ciechocinek salt also causes a decrease in filtration coefficient of sands. A considerably drop of filtration ability of sands can be obtained by means of water that contains a greater amount of iron compounds (1,5–50,0 mg/l Fe), which precipitate under conditions of air acces. The results of the examinations discussed in the present paper allow to draw conclusions that when determining the filtration coefficient of sands for the waters characterized by a mineralization amounting to about 10g/l, we may disregard the influence of mineralization, since it falls within the boundaries of accuracy of the method commonly to determine the coefficient under consideration