Novi Sad is one of the major consumers of water in the Republic of Serbia. This is why the presence of safe and abundant sources of raw dringing water has been of utmost importance for this city which is expanding urbanistically and demografically. This paper presents major data related, above all, to the capacity of the present water sources in Novi Sad, as well as the results of the analyses considering the possibilities for the expansion of source capacity. Furthermore, the text considers the problem of numerous pollutants which have been polluting water sources and offers possible measures for their efficient protection.

The possibility of applying the process solidification/stabilization for treatment of arsenic containing sludge, obtained after coagulation and flocculation treatment in the preparation of raw drinking water, using lime, cement and lime and cement in the mixture as stabilization agents was examined. Test results showed a high content of arsenic in the initial sample of sludge, above the allowable 41 mg As/kg by the USEPA prescribed for disposal of waste sludge. Performance of S/S process was investigated by two leaching tests, PCLP and DIN 38414-S4 test, which showed the highest efficiency of lime and cement mixture in the removal of arsenic by this procedure.

This paper presents the data of sediment quality in the zone of three sources for water supply in Novi Sad, Serbia. The data indicate that the sediment in the area of these sources contain petroleum products (mineral oils) above the permissible concentrations. Only in one sample of sediment was detected DDT / DDD / DDE in the location of the source against the Strand wells RB-1 in a concentration which can specify as the maximum risk. The data indicate a significant anthropogenic influence of refinery waste water and urban waste water, motor boats in the marine (source Strand) and anchor of ships (source Petrovaradinska Ada) on the quality of sediment in these sources.

Quality of groundwater from aquifers used for water supply in the town of Zrenjanin, does not meet the drinking water quality requirements. Among the basic problems are the high content of natural organic matter and arsenic, but also sodium and boron. This paper presents one of possible alternative of technological solutions for drinking water preparation in Zrenjanin. Research has lasted three years. The paper presents a only an outline of the drinking water preparation processes.

The city of Novi Sad uses groundwater as drinking water source. For this purpose only water from Danube alluvium is used, and the water is abstracted at three sites. The Danube water and sediment quality in the zone of the drinking water sources is of great importance, as the river Danube recharge alluvial aquifer. The microbiological quality of these environments was monitored, in order to determine their influence on drinking water quality. The water characterization was carried out using sanitary and ecological microbiological parameters of Danube water and sediment.

This study was performed to investigate the efficiency of Fenton's process (FP) for removing natural organic matter, in particular the main disinfection by-products precursors. In order to determine the optimal reaction conditions of the process, the influence of pH, mixing speed and reaction time were investigated, as well as the influence of initial concentration and the molar ratio of Fe2+ and H2O2. The best results in terms of reducing the DOC content (by 82%) were achieved under pH 5, 30 rpm, reaction time of 15 min, Fe2+ concentration of 0.25 mM and a molar ratio of 1:10, and in terms of reducing trihalomethane and haloacetic acid precursors (by 98-99%) under a Fe2+ and H2O2 molar ratio of 1:20.