Microbiological monitoring of river water quality is obligatory for use-related aspects such as drinking water production, irrigation and recreation. Assessment of the microbiological quality of water and sediment at the Velika Morava River was performed at five sites, during 2010 and 2011. By applying standard procedures for sanitary correctness and organic load assessment, total of 16 parameters were analyzed. Results of analysis indicated that microbiological water quality of the Velika Morava River is unsatisfactory.

Physico-chemical and microbiological analysis of Brvenica River water was conducted in period 2006-2010 and showed seasonal variations of water quality. The results of correspondence analysis indicated that the year 2006 regarding the physical and chemical characteristics of water, was different from the rest of the examined period. This year was characterized by the absence of ammonia, low contents of nitrite, iron and chlorine, and increased concentrations of KMnO4 consumption. In 2007 and 2008 presence of manganese in water, low concentration of KMnO4 consumption was detected as well increased turbidity and electrical conductivity. And the third distinguish period are years 2009 and 2010 when water was characterized by low concentration of NO3, and the presence of ammonia, NO2, and iron in the water, while turbidity was low and conductivity was average. In Brvenica River water Escherichia coli, Citrobacter sp., Enterococcus sp., Klebsiella sp. are detected. In year 2006 number of aerobic bacteria and total coliforms were rather low, while their number in 2008 is relatively high. Over the whole period, only in 2008 fecal streptococci were not detected. Other years are characterized by growth of aerobic bacteria and total coliforms and the occasional presence of fecal streptococci. Throughout the whole examination period fecal coliform bacteria were present in the water.

The paper presents results of microbiological quality of three drinking water sources – Ratno ostrvo, Petrovaradinska ada and Strand. The following analyses were carried out in 2010: total count of aerobic mesophilic bacteria at 37 deg C, count of organotrophs (categorization according to Kohl), aerobic facultative organotrophs, lipolytic and hydrocarbon oxidizing bacteria. Organotrophic count was determined on low nutritive R2A medium. Enzymatic activity of water was also determined and water was categorized according to index of phosphatase activity (IFA).

Creation of scientific basis for rational use of water resources is impossible without studying viability of the microorganisms, their influence on the formation of chemical properties of natural waters and an explanation of the principles of biochemical processes such as transformation of elements in the aquatic environment. The survey of microbial (bacterial) characteristics of watercourses in the Republic of Srpska was conducted on a total of 64 streams within Operational, International and National surveillance monitoring. Sampling and analysis of samples was performed during the period from May to October. The study included ecological and sanitary aspects of river quality.

The results of microbiological analyses of raw water of two water supplies of city of Novi Sad (Ratno Ostrvo and Petrovaradinska Ada) are presented. The sampling was performed monthly during 2008 and 2009. The following parameters were monitored: aerobic mesophilic bacteria count at 37 deg C, organotroph count (water categorization according to Kohl), facultative oligotrophs, lipolitic and hydrocarbon-oxidizing bacteria count. The count of organotrophic bacteria was determined using low nutritive R2A medium. In addition, water was classified according to enzymatic activity of water, expressed as index of phosphatase activity (IFA).

The Bovan reservoir is built on the river Moravica, near Aleksinac (Serbia), primarily for the purpose of water supply. Investigations were carried out during the period of June 2005 to December 2006, with the aim to determine the quality of water, the composition, spatial and time dynamics of communities of microorganisms. The results showed that according to the total number of bacteria in the water reservoir Bovan fall into the category of clean water by Amrazena (1976). By Kohl (1975), water reservoir Bovan belongs to class 2. Summer-time give maximum water characteristics the 2nd-3rd class. Index T/H varies from category to category moderately contaminated clean water. Values heterotrophs percentage representation in the total number of bacteria indicating the great burden of water organic matter.

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.

Water wells are among the oldest hydraulic engineering structures in the world. Today, hundreds of water wells service water supply systems in Serbia, and groundwaters are widely used for public water supply. Extensive practical engineering experience in water well operation has identified a number of problems which affect well service life and capacity (i.e. reduce specific yield). Some of the encountered problems are, also, a result of microbial activity in groundwater. Products of life processes of groundwater specific microbial community cause biocorrosion, blockage, closure, plugging, deposition, and biofouling of well screens and collectors. We applied BART biodetectors as a reliable tool in monitoring well rehabilitation effectiveness. This paper presents several process assessments based on BART biodetector tests conducted at Belgrade groundwater source.

In this paper the results of preliminary microbiological investigations of the canal Nadela water quality, done in order to determine level of pollution, are presented. Bacteriological analysis included the monitoring of quantitative composition of the organotrophs, presence of some physiological groups of bacteria and total number and fecal coliforms. Beside of that, level of water phosphatase activity and chlorophyll a concentration as important parameters of waterstate, were determined. Obtained results indicated low quality of the canal Nadela water and overload by organic matter, that cleary reflected negative influence of pollutants presents in that area.

Microbiological and saprobiological characteristics of river Moraca and Skadar lake for period of 2004/2005 are done at localities: Pernica, Moraca estuary and Vranjina (Skadar Lake). The objective of the research is to establish quality of water of these aquatic ecosystems based on microbiological and saprobiological analyses, as well as, to show need for protection of these water ecosystems from permanent contaminations, mainly by sewage should be pointed out. Saprobiological index is determined based on Gulyas Pal, and Pantle Buck is used to determine saprobiological level.