Browsing by Subject "pääionit"

Artificial groundwater is produced in Jäniksenlinna water treatment facility in Tuusula by infiltrating surface water from the lake Päijänne to the Jäniksenlinna aquifer. The geochemical properties of the artificial groundwater vary and challenge the water purification process in the Jäniksenlinna facility. The objective of the study was to solve the geochemical quality of the water in different locations inside the aquifer area and in the different steps of the water purification process and to solve the changes in the geochemistry of the water caused by the seasonal changes. The study was put into effect by collecting 20 water samples, 16 of which were from different locations inside the aquifer area and 4 of which were from the different steps of the water purification process in the water plant. The samples were collected during the spring 2018 and repeated during the summer 2018. Each water sample was analyzed for major ions by ion chromatography, trace elements by ICP-MS method and stable isotopes of hydrogen and oxygen with the help of Picarro device. Additionally, each sample was analyzed in the field for electric conductivity, pH and temperature and in laboratory for alkalinity, pH and electric conductivity. The results from the spring and from the summer were handled separately since they differed with statistically significant levels from each other. The results were treated with statistical methods and visualized with tables, graphs, photos from the sampling points and maps. The results show that season changed the proportion of the natural and the artificial groundwater in the sampling points. However the season had no effect on the existence of the artificial groundwater in the sampling points. The proportion of the artificial groundwater was highest while the groundwater level was low, that is during the summer. The sampling points were selected with different distances to the infiltration area. However, the amount of infiltrated water did not decrease with the growing distance to the infiltration area, since the geological structures of the aquifer define the water flow inside the aquifer. The amount of artificial groundwater was lower in one sampling point closer to the infiltration area than in two sampling points further away the infiltration area. The water purification process removes the excess iron and manganese from the artificial groundwater and produces water which fulfills the standards set for the drinking water. The amount of iron and manganese in the drinking water might get even lower by conducting the water from the well 12 to the iron and manganese removal. The study covered the spring and the summer seasons, but in order to study the whole annual picture, the sampling should cover the autumn and the winter seasons as well. Flow modelling could give better picture of the formation of the artificial groundwater in Jäniksenlinna.