There was carried out microbiological analysis of five bottled water of manufacturers from Serbia. Bacteriological quality was estimated using important parameter-aerobic mesophylic bacteria. Two nutrient media were used: standard (PCA) and low nutrient R2A. Plates were incubated at two temperatures (37 deg C and 22 deg C) during 24 hours, 48 hours, 3 days and 5 days. Results show that this group of bacteria is very abudant in bottled waters and their number depends on water types and manufacturers. Moreover, water from different bottles of the same manufacturer has different microbiological quality. Used media, temperatures and period of incubation also have influence on results and R2A medium gives higher values of aerobic mesophylic bacteria.

Removal of colour by coagulation in the drinking water treatment is described. Optimal results are obtained by pH correction. Buffer capacity of raw water is dominant on efficiency and rentability of the process.

This work considers the possibility of enhancing the iron (III) chloride coagulation process in natural organic matter removal by flocculation sludge recirculation. The results show that flocculation sludge has the potential to coagulate organic matter, and shows a dependence on the depth in the precipitator (0, 30 or 70 cm). Recirculation of flocculation sludge at a dose of 1.6 g/l (from a depth of 30 cm), results in a reduction of required coagulant by 25%.

Stable complexes formation caused by usage of complexing agents as additive in plating solutions, made waste water treatment aggravated and expensive. The investigation results of samples that contain some cations expected in waste waters from this type of facilities, are presented in this paper. The precipitation of disolved heavy metals by neutralization, in the presence of strong chelators, do not give requested results. The dithiocarbamates are effective in complexing heavy metal ions forming insoluble compounds, with solubility far below that of the corresponding hydroxides. Inductively Coupled Plasma Optical Emission Spectroscopy is used for wastewater samples analysis. After the reduction of Cr6+ into Cr3+ ions and homogenization, dithiocarbamate is added. Modified neutralization process with unchanged retention time and pH 9.0 +/- 0.2 results the Law permitted wastewater quality.

During technological process of coal treatment and coal improvement in RB Kolubara waste water is produced in the waste water cleansing installation and waste mud is separated. The examination have been executed concerning agrochemical and mechanical properties of this material as well as the presence of heavy metals and phenol. Based on the results which appeard during examination, this materail can be included in the biological reclamation process as bonifactor and deposol fertilizer. Inserting such organic materials, the requared organogenic features are increased and the physical and mechanical characteristics of deposol substrate are improved. The economical effects are important for RB Kolubara as well as for Kolubara-Prerada. The most important contribution is to environmental protection and fulfilling the legal regulations for bringing back of degraded soil to the primary purpose.

Filamentous bacteria are commonly found in activated sludge. If numerous, they can cause bulking problems. In order to control their number in a system detailed identification of filaments is necessary. In Subotica Wastewater Treatment Plant (WWTP) daily analyses of filamentous bacteria were performed from January 2006 till March 2007. The dominant and constantly abundant was Thiothrix sp. The filaments of Haliscomenobacter hydrosis and Type 1863 were also common (moderately numerous with periods when develop massively). Nostocoida limicola was frequent, but not numerous. Sphaerotilus natans was numerous in some periods when even dominant. Type 1701, Beggiatoa sp. and nocardioform actinomycetes were rarely found and were not abundant.

In Serbia, in the most cases, drinking water supply is based on alluvial sources. The appearance of nitrate in some important alluvium aquifer has been observed and an increasing of this problem can be expected with a currently tendency for intensifying the agricultural production. Therefore, the used techniques which are able to identify the source of nitrate in groundwaters and existing processes of its reduction will be more and more requested. Simultaneously determination of both nitrogen and oxygen isotopic fingerprints allows us to make a difference between nitrate from artificial fertilizer and manure or animal waste as well as nitrate formed from nitrification of organic material and consequently the dominant source of the nitrate to be indicated. Once the origin of nitrate in drinking water sources is understood, corrective measures may be taken to prevent or minimize further contamination.

Water quality in drainage canals system is under big influence of activities on surrounding agricultural land. In order to decrease transport and deposition part of plant protection chemicals and mineral fertilizers, vegetation belts with different shapes, characteristics and rules are possible to use. Besides the main purpose, this kind of belts are corridors for moving, but also place for living of wild plants and animals, what is increasing biodiversity. In that way, favourable conditions for organic agriculture in land reclamation area are possible to create.

Aquatic macrophytes are exceptional accumulations of heavy metals and they are very important in phytoremediation of the pollutants. The aim of the survey was to show according to content of heavy metals in aquatic macrophytes DTD (Danube-Tisza-Danube) canal complex, at localities under great human influence indicate the situation of chemical contamination these localities and to define test species, actually the ones that have the greatest accumulation. Plant material was prepared according to the Standard Methods for Examination of Water and Wastewater of the American Health Association. Analysis of heavy metals in the plant tissue samples was done by standard methods using atomic absorption spectrophotometry. The best accumulator of majority of heavy metals is Ceratophyllum demersum. The results show that mentioned species can be used for removal of heavy metals from water, what means that it has the ability of phytoremediation of pollutants.

Seasonal dynamics of plankton in DTD hydrosystem in Backa region (Serbia) was estimated during the period June 2002-March 2003. More irregular cycles of the phosphorus level and plankton activities in DTD canal network gradually downstream (Northern Western - Southern Eastern channel direction) was observed. The plankton group of total coliforms was developing in early spring in the period of beginning of vegetation season and in summer, when the phosphatases of pH 5 and pH 9 have the highest activities, in all DTD sectors. In the assessment of trophic condition of DTD canal network, sectors of canals were corresponded with bacteriological analyses and level of phosphatase enzyme activities.