A series of measurements has been conducted with various combinations of ejector dimensions. Variables were diameter of the nozzle and the distance between the end of the nozzle and the beginning of the pipe. Vacuum head in function of water flow was measured when there was no air flow, and when there was air flow (from a reservoir with constant volume). The results are presented in this paper.

This study investigates the effect of pH, temperature, contact time and initial metal concentration on Cu++ ions removal from water solutions, using biomass of Lagenaria vulgaris skin (LV). With higher pH, the efficiency of copper sorption increases and reaches its maximum at pH 7.0. Temperature has negative effect on sorption process due to its exothermic properties. Biosorption efficiency increases with time and reaches equilibium after 40 min. Increasing initial copper concentration gives an increase in biosorbent sorption capacity, and a proportional decrease in treatment efficiency. Obtained results have shown that LV based biosorbent is an efficient and available mean for toxic metal removal from natural and waste waters.

Anionic clays (layered double hydroxides) comprise positively charged layers with at least two different metal cations, octahedrally coordinated by hydroxyl groups. The positive charges of layered double hydroxides are counterbalanced by interlayer anions. The interlayer anions and water, which fill the interlayer space, are often labile. Therefore, anionic clays exhibit anion exchange capacity (AEC). Anionic clays which have a high surface area and a high anion exchange capacity, are potential adsorbents for anionic contanimants, such as the oxyanion of chrome. The adsorption study of chromium (VI) from aqueous solutions by natural cationic clay mineral (kaolinite, montmorillonite, etc.) was not given much attention, perhaps due to the fact cationic clays have negatively charged layers and clay mineral surface shows no affinity for oxyanion of chrome.

Arsenic speciation can be very important in analysis of water, foodstuffs, and environmental samples, besides of total arsenic analysis. Hydride generation atomic absorption spectrometry can be used for speciation analysis based on different hydride generation condition. In our work, we studied effect of L-ascorbic acid like the reaction medium and the prereducing agent.

The stable isotope content of hydrogen (2H/1H), carbon (13C/12C), nitrogen (15N/14N), and oxygen (18O/16O) in surface water (the Sava river and channels) and groundwater (Ranney wells) were determined in Belgrade (Serbia) during July 2008. Detailed evaporation calculation has estimated that fraction of water loss to be between 10 and 20% in the channels using the local meteoric water line and the local evaporation line. Carbon-13 content in dissolved inorganic carbon is distinguished between surface water and groundwater indicating different evolution pathways of carbon. Based on carbon and nitrogen isotopic composition and C/N ratios, sources of inorganic carbon and of organic matter in analyzed waters are discussed.

The weekly measurement of physico-chemical and biological parameters was done during the spring of 2008 in order to assess the level of eutrophication in the Kotor Bay. Chlorophyll a was used as trophic level indicator and its values varied from minimal 1.00 mg/cubic meter in June on the depth of 10 m to maximal 3.71 mg/cubic meter on the sea surface in May. According to Nixon criteria during investigation period it can be concluded that the area in question is oligotrophic. On the other hand, according to UNEP criteria which are somewhat stricter when the concentration of chlorophyll a is in question, Kotor Bay was mesoeutrophic area.

Zooplankton community analysis was conducted for spring (April - 07) and summer (August - 07) in Boka Kotorska Bay. Analyses included determination of biomass and qualitative composition. Data are given on the number of specimens per cubic meter as well as on the volume organisms. Qualitative composition showed domination Copepoda of zooplanktons groups.

Due to drainage as a significant measure of land reclamation, large part of Vojvodina Province (Serbia) affected by excessive water could become an agricultural land. The stability of ecosystems could be decreased by degrading the biodiversity. Additionally, Vojvodina has cca 6% of sylvan landscape but according to documents of spatial arrangement planning that area should be 14%. In order to solve this problem the implementation of biological measure could increase drainage efficiency by improving biodiversity and increasing the area covered by sylvan landscape, which is likely to do using biological measures of drainage on low productivity areas and buffer strips along canal network.

During field research of phytocenic characteristics of the river Moravica flow and the influence of anthropogenic pollution, the presence of the following hydro-phytic biocenoses has been established: Floating macrophytes ass. Lemnetum minoris Oberd. 1960 and submersed macrophytes Myriophyllo-Potametum Soo 1934. Based on physicochemical water analyses and ecological indexes, these biocenoses belong to transitional group of mesotrophic and eutrophic biocenoses which develop in water highly saturated with mineral substances (highly polluted waters). Biocenosis Lemnetum minoris with differentiating species Lemna minor matches - meso - saprogenic waters. These biocenoses grow in both mid and upper river flow.