Presentation is dealing with data on raw and drinking water quality of water supply sources and water supply systems in Podgorica, Montenegro (Serbia&Montenegro). Special attention was paid to organic matter content, concentration of disinfectants and disinfection by-products. Average values of all parameters examined are below maximum permissible levels defined by regulations. That means that physical-chemical quality of water is excellent.

Slow sand filtration is an effective water treatment process. However, the performance of slow sand filters is influenced by the raw water turbidity. Filtration on pebble-matrix and roughing filters is introduced as a process effective in reduction of raw water turbidity. Efficiencies of these pretreatments documented on the raw water sources world-wide are presented in this paper as well as the investigation results from the similar raw water source in Serbia (Serbia&Montenegro).

The results of a study on the water of the Sumanka river during several years point out the decrease in its quality. The results of the present study show that the technological actions, as well as the some technical changes, carried out in the Lebane's plant in Grgurovci gave the satisfactory effects. Turbidity, colour, KMnO4 demand and ammonia are efficiently reduced, along with low concentrations of Fe, Mn, and residual Al, ensure completely the water standard quality in accordance with the Protocol.

According to existing national Standard for drinking water quality NO3 sup(-) ion is limited to 50 mg/l. Removal of NO3 sup(-) concentration greater than this limit is necessary. One of the possible methods is biological denitrification with CH3OH. Principals of this method are described in this paper with recommendation for construction of pilot plan on the specific groundwater source.

The process of removal of natural organic matter from groundwater by adsorption on powdered activated carbon, coagulation and flocculation was investigated. It was found that the combination of these processes yielded a decrease of KMnO4 values, which allowed the reduction of the coagulant concentration, needed to achieve the necessary quality of drinking water, up to 50%. Also, it was established that the sequence of adding powdered activated carbon and coagulant is one of the essential factors determining the efficiency of NOM removal from water, and which is primarily conditioned by the nature of the organic matter present in the investigated water.

The paper deals with pilot-scale investigations of the effect of preozonation on NOM removal from groundwater by coagulation and flocculation processes. It was found that the preozonation increased the efficiency of organic matter removal by coagulation and flocculation from 23.6 to 47.2% as judged on the basis of KMnO4 values. From the aspect of the change of content of trihalomethanes precursors preozonation exhibits both the positive and negative effects if their content in the water after coagulation is considered in dependence of the applied ozone dose. The obtained values siggest the necessity of careful optimization of the processes of preozonation, coagulation, and flocculation, especially from the aspect of the change in content of the precursors of disinfection byproducts.

Membrane processes is gaining broad application in potable water treatment. Experience in application of membrane system for treatment of potable water so far showed that these systems have wide range of advantages versus conventional treatment: lower capital costs, lower operation costs, use of chemicals is minimal; space for installation is much smaller, usage of chlorine for disinfection is minimal due to significant reduction of microorganisms; sludge production during the process is smaller due to smaller usage of chemicals, construction period is shorter due to smaller scope of works and relatively simply installation of membrane batteries.

The area of Zidine is located southwest of Belgrade, Serbia&Montenegro, in the sanitary protection zone of the existing Belgrade water source. This potential water source is capable of yielding water of better quality than that of the existing raw groundwater, for final treatment plants at Bezanija and Banovo Brdo. In view of available capacities of these plants and the raw water system, the water disposal issue is practically resolved and the water source is also highly advantageous in economic terms. Two options of preliminary treatment after settling were considered: sand filters and microfilters.