Analysis of the impact of changes in surface water quality on the dynamics of treatment processes in drinking water treatment technological systems

The study presents the results of the analyses of changes in the physicochemical and bacteriological condition of the Dunajec River waters in the years 2012-2021. The physicochemical condition was characterized based on the tests of 16 parameters: pH, specific electrolytic conductivity ( SEC), total suspended solids, turbidity, color, dissolved oxygen, five-day biochemical oxygen demand, ammonium ion, nitrates, nitrites, phosphates, sulfates, chlorides, total iron, manganese, phenolic index. The bacteriological condition was assessed by analyzing the indices of coliform bacteria and Enterococcus faecalis. The analysis of the physicochemical state of the Dunajec River waters was carried out against the background of changes in water-sewage management, industry, land use, hydrological and meteorological conditions. The average values of physicochemical and bacteriological indicators of the Dunajec River waters tested over the years 2012-2021 were within the A1 and A2 categories of surface water quality. The results of the maximum tests in the year for such parameters as: total suspended solids, color, total iron, pH, ammonium ion, phenolic index, coliform bacteria and E. faecalis were in the A3 category of surface water quality. The analyses carried out showed that in the study period a decrease in nitrates, nitrites, sulphates, coliform bacteria and E. faecalis was observed as well as the rise of total suspended solids and pH of water. The technology used in the water treatment plant in Stary Sacz allows for an effective removal of physicochemical and bacteriological impurities from the surface water taken for the needs of the plant. The concentrations (annual average and maximum values in the year) of individual quality indicators of the treated water tested over the years 2012-2021 did not show any exceedance of permissible standards.