Biofilm naturally occurs in many water distributive systems. The aim of the paper is to determine biofilm forming potential of bacteria isolated from tap water from Novi Sad. A colometric crystal violet microtitre plate test was used to determine bacterial potential to form biofilm. The results show that some isolates have a great potential to form biofilm, especially when grow on higher temperature and in the reach nutritive media.

Coagulation and flocculation can be efficiency applied in drinkling water treatment, in order to remove natural organic matter (NOM). However, in the experiments presented in this paper, the water used is very rich in NOM, and required investigations of additional processes. In order to increase the efficiency of coagulation and flocculation processes in removing NOM from groundwater, the following processes were investigated: adsorption on powdered activated carbon (5-30 mg PAC/l) and preozonation with applied ozone doses of 1.1-6.3 mg O3/l. The parameters used to evaluated the changes in NOM content during the experiment were: KMnO4 consumption, UV absorbance at 254 nm, pH and turbidity.

In this study possibilities for application of natural aluminosilicates, zeolites in the wastewater treatement has been investigated. Under the laboratory conditions the pilot experimental a column filled with aluminosilicates was established. Technological characteristics of the system were estimated by wastewater flow monitoring and calculation of Darcy filtration coefficient.

One of the last stages in purification of waste water is by aquaculture pond using macro biological cells - fishes. In such outdoor ponds, oxygen depletion events can occur at anytime, but most likely to cause fish kills during summer hot weather. Aquaculture pond model can predict dissolved oxygen using small number of measurements and very simple numerical model. Alarm system can be activated urgently when the oxygen level drops below a certain concentration, depending on fish species. Such a model is realized for WWTP at Citluk coal mine, close to Sokobanja in Serbia, and explained in this paper.

The red algae Womersleyella setacea is Indo-Pacific species but introduced to Mediterranean Sea were is now relatively widely distributed. During research of benthic communities in Ponta Veslo locality (Lusnica peninsula, Montenegrian coast, Adriatic sea) in summer 2007 dense assemblages on rocky substratum and on sea grass Posidonia oceanica (L.) Del. rhizomes were discovered. The impact on biocenosis structure is discussed.

During the first five months of 2007 at one station in front of the entrace the Bay of Boka Kotorska, it was collected mesozooplankton using Nansen net, mesh netting of 200 microns. 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 zooplankton groups.

In Boka Kotorska Bay there are two recorded species of Copepoda from family Temoridae: Temora stylifera and Temora longicomis. This paper presents the data on horizontal distribution and abundance of these species during 2007. Temora stylifera has a wide horizontal distribution in coastal and open waters of Adriatic sea, while Temora longicomis is a typical representative of estuary-neritic waters of northern Adriatic, Kvarner area and the Italian coats at the west. Their abundance was particularly high in spring and summer.

Lake ecosystems determined by trophic conditions, accurately defined Ecological status of protected area. Trophic condition of water of Lake Skadar and two rivers, the inflow Moraca and the outflow Bojana was described via plankton data considering abundance of phytoplankton, seasonal dynamics of organotrophs, cyanobacteria, total coliforms, plankton biodegrading potential and nitrogen fixing bacterioplankton. The trophic potential for phytoplankton growth has been detected in late autumn throughout September-November 2004, contrary to early summer June-July 2005, and adverse growth of bacterioplankton in May, June and September 2005, respectively. The results of quantitative analysis of coliforms showed good relation of Lake Skadar and Ada Bojana, contrary to similarities between Moraca River and Ada Bojana estimates in accordance with the Pantle-Buck index. Nevertheless, investigation pointed out Lake Skadar beta-mesosaprobic level and moderate self-purification rate. In evaluating trophic conditions the good ecological potential of protected area has been proposed.

Explorations were done at the location Ilje, near Melenci. Novo Ilje 1 is a canal used for regulation of irrigation at the local fields. Novo Ilje 2 is a bog that dries out during the periods of low precipitation. Quantitative phytoplankton analysis of Novo Ilje 1 sample from 2003 determined that total amount of cells was 1.5 x 10**5 cell per liter. Total amount of cells in 2004 sample was 1.8 x 10**5 cell per liter. Quantitative phytoplankton analysis of Novo Ilje 2 sample from 2003 determined that total amount of cells was 1.7 x 10**5 cell per liter. Total amount of cells in 2004 sample was 3.1 x 10**5 cell per liter. Phytoplankton biomass in Novo Ilje 1 sample from 2003 was 2.6 x 10**8 cubic micrometer/l, and in 2004 sample was 1.09 x 10**8 cubic micrometer/l. Phytoplankton biomass in Novo Ilje 2 sample in 2003 was 3.06 x 10**8 cubic micrometer/l, and in 2004 sample was 1.62 x 10**8 cubic micrometer/l.