Influence of eutrophication to the phytoplankton community were studied in the inner part of Boka Kotorska Bay (Kotor Bay and Risan Bay) from September 2003 to August 2004. Kotor Bay and Risan Bay is very interesting area because the influence of natural and anthropogenic eutrophication are mixed very often. Microphytoplankton density is high (greater than 10**6 cells/cubic dm) what is characteristic eutrophic area, to the highest eutrophic area (greater than 10**7 cells/cubic dm). These values we stated in the surface, because in this layer were the best conditions. In same time we stated very high values: SiO2, oxygen saturation and chlorophyll a. The conclusion is: Boka Kotorska Bay and especially Kotor Bay (as a part of Boka Kotorska) has to be protected of dangerous consequences such as blooming. It is needed to regulate wastewater, their purification and permanent control physico-chemical and biological parameters, and especially phytoplankton component.

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.

The puddles Novo Ilje 1 and Novo Ilje 2 are aquatic ecosystems periodically filled with moderate salt and alkaline water. In 2003 and 2004 quantitative analysis show the Euglenophyta domination. Trachelomonas taxa are the most common. The algae in planktonic communities are the most numerous in both puddles in researched years.

Ecological status of protected area of Ponjavica water body, evaluated using hydromorphological, basic physico-chemical and selected biological quality elements, can be indicated as very bad. The accerelated eutrophication process this water body (once running now stragnant water) undergoes, leads to hypereutrophic current condition, with clear trend towards dystrophy.

During the research of the flora of the river Moravica methodology of ass. Scirpo-Phragmitetum, Koch 1926, subass. typhetosum latifoliae, Pignotti 1953, with differential typa Typha latifolia with related marshy plants was applied. The community is developed as small units in the lower flow of the river Moravica (the part flowing through the town Aleksinac), where the anthropogenic influences are significant due to the empting of the sewage and industrial polluted waters of the town Aleksinac. Many diffuse forms of pollution are also present, particularly in the form of illegal dumps. Waste waters represent serious load on the recipient river and influence qualitative and quantitative content of the phytocenosis. Ecological index of the community shows change in water quality and presence of organic substances (above all nitrogen compounds) in the water and the riverbed ass. Scirpo-Phragmitetum, Koch 1926, subass. typhetosum latifoliae, Pignotti 1953, which indicates the riverbed loaded with organic substances (mezotrophic plants, N=3.50)

Composition of benthic macroinvertebrates and phytoplankton were examined during the period of July-November 2006, for purposes of freshwater quality assessment in protected area of Jegricka water body. Results of research show intensive sedimentation of organic matter in river bed, which is caused by eutrophication processes and small flow velocity in this canalized river of Vojvodina.

Scarce natural resources which are important for development of society or civilization itself are the issue of research for economists from the point of view of their efficient utilization. Theory of natural monopoly asserts that for society is better to treat scarce resources as monopoly than to put them on free market. The assertion is that it is better to invest in development of other markets than into free competition in sphere of some scarce resources. Main aim of this paper is to overview some elements of theory of natural monopoly.

Iron-related well-screen encrustation and aquifer biofouling has decreased the specific capacity of RB-7 well. This paper describes the role of iron-related bacteria in the encrustation process and relates their occurrence to chemical conditions in the well.

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.

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.