Desorption kinetics of chosen organochlorine compounds (pentachlorobenzene, lindane and pentachloroaniline) mediated by solid absorbent, XAD-4 macroporous ion-exchange resin, was studied for two different contact times of organic compounds and sediment (15 and 90 days) in order to determine the potentiality of using this sample and fast method for the assessment of (bio)availability of organic pollutants in sediment-water system.

In this paper aquatic macroinvertebrate community of the Peštan River was presented, including the characterisation of the species with regard to saprobic conditions and preference to the mineral substrate type. Sampling was carried out during 2011 at man stream and tributaries. A total of 52 taxa have been identified. According to the ecological classification of the taxa with regard to saprobic conditions for the main stream, the most species belong to the alpha-mesosaprobic group while majority of the species from the tributaries were characterised as beta-mesosaprobic species. The most of registered species preffered substrate type characteristic for lowland river. Results of saprobiological analysis indicate poorer status of the main stream in regard to tributaries.

In this work, the results of preliminary study of stomach content in brown trout (Salmo trutta L. 1758) of the Gradac in autumn are presented. The fishes were collected by the end of September of 2011 at three sampling sites along the course. A total of 12 fish specimens were examined. By examination of trout stomach content have been found members from macrozoobentho-groups – Trichoptera, Ephemeroptera, Diptera (fam. Ceratopogonidae), Oligochaeta, Coleoptera. At the same time, investigations of bottom fauna composition and structure have been done also. Our study showed that the diet of brown trout is dependent of bottom fauna availability and abundance.

The aim of this work is to present preliminary results of the Sava River investigation at five sites within the reach from Martinska Ves (Croatia) to Šabac (Serbia). A total of 70 macroinvertebrate taxa from 13 groups were recorded, with domination of molluscs and oligochaetes. Among them 7 alien species were registered. Invasive clam Corbicula fluminea was recorded at all five sites, while invasive amphipod Dikerogammarus haemobaphes was not recorded only at locality Šabac. It is expected that the taxa list of aquatic macroinvertebrates within investigated reach will contain more species, after the identification of the rest of biological material and more detail identification of certain taxonomic groups.

The Djerdap 1 Hydropower Plant (Djerdap 1 HPP) was joint projects of Yugoslavia and Romania, based upon the principles of equal benefits. The primary functions of the Djerdap 1 HPP are to effectively utilize the available hydropower potential of the Danube and to provide a full navigational capability under any hydrologic conditions. The utilization of the hydropower potential was conditional upon the provision of a Riparian Land Protection System for the Djerdap 1 reservoir, and the timely prevention of any adverse impacts due to the alternation of the natural regime as a result of backwater. ongoing enhancement of the Riparian Land Protection System and study of the various impacts have enabled a continual backwater increase and a resulting increase in the output of high quality power, with no significant risk of adverse impacts.

In the 21 century drinking water of acceptable quality should be available to every person. Numerous investigations are on-going worldwide around the world, to develop innovative and cost attractive approaches for production of high quality drinking water. To allow application of new treatment technology in practice, pilot testing under field conditions are required. Groundwater used for drinking water productions in the Subotica municipalities (Serbia) contains elevated concentrations of arsenic, iron and ammonia, and therefore provided a good basis for continuation of research of UNESCO-IHE, the Netherlands Institute for Water Education, that has been developing innovative water treatment technologies specifically in the field of groundwater treatment and specifically arsenic removal. Objective of this project presented in this paper were to test under field conditions IHE ADART, the innovative adsorptive arsenic removal technology. The pilot project has demonstrated that in addition to conventional approach based on coagulation and break-point chlorination, there is and alternative treatment approach based on biological ammonia removal and adsorptive removal of arsenic that could be economically and ecologically attractive.

The paper presents the results of laboratory research and application of continuous electro-coagulation and electro-flotation (ECEF) to remove natural organic matter (NOM) from groundwater in the treatment of drinking water. The highest NOM removal efficiency for current density of 5.78 mA/ cm square according to UV254 absorbance and dissolved organic matter (DOC) was 77% and 71% respectively. The specific energy and aluminum electrode consumption was 2.01 kWh/cubic m, 80 g Al/cubic m, respectively.

The aim of this paper is the investigation of natural materials that could be effectively used as a sorbent in the process of removing heavy metals from water. Interests are focused on the group to organic sorbents: natural wool fibres. The sorption experiments were conducted with lead, cadmium and zinc dissolved in distilled water, and then used as an example of heavy metal contaminated water and river water. Studies were performed in group sorption system. Possible use of natural fiber wool to remove heavy metals from water was determined by measurement of lead, cadmium and zinc before and after the sorption process. Analytical methods used for the determination of lead, cadmium and zinc in water by potentiometric stripping analysis. It was concluded that the sorption process mainly affect sorbent mass.

This study investigates the effect of low molecular weight carboxylic acid on degradation of textile dye C.I. Reactive Orange 16 (RO16), in function of initial pH, using Ultra Violet light and H2O2. Experiments were performed in photoreactor with UVC lamps in stationary conditions. Results shows that carboxylic acids have inhibitory effect on degradation process of dye. With increasing concentration of dye inhibitory effect grows. Inhibitory effect of acid are higher on pH values of solution higher than pKa acids, because than in solution acids appear almost entirely in the form of anion. The highest inhibitory effect shows formates, smaller propanoates, and the smallest acetates. UV/H2O2 process is very effective for removal of organic pollutants, but the efficiency of this process was significantly lower in the presence of lower carboxylic acids.

Microthrix parvicella is dilamentous bacterium common present in the activated sludge on the plants with biological nutrient removal. Microthrix parvicella is described as a bacterium which present in a large numbers, has an extremely negative impact on the sludge settling, and its considered as the primary cause of bulking sludge on the WWTP-s with biological nutrient removal. Also, this bacterium considered as the primary foam-forming microorganisms in activated sludge, because those hydrophobic cells stabilized air bubbles or affected by the oil droplets in foam. Although there are numerous data regarding the growth of certain filamentous bacteria, as well as their impact on the waste waters treatment and deposition of sludge, they are often vague, and not always in clear correlation, especially when comparing data from different plants. The aim of this paper was toexamine the growth and population size of Microthrix parvicella in correlation to water temperature (seasonal dynamics of growth), and a correlation between population size of filamentous bactereia (filamentous sludge index-FI), especially M. parvicella growth and the sludge settlement (Imhoff 30 '), or the ratio of FI and the volume of sludge (sludge volume index – SVI) on WWTP of Subotica during 2011.