Due to very high concentration of organic matter there is a great need for alternative solutions for drinking water disinfection in the world. Chlorine dioxide has been successfully used for almost 50 years for disinfection and later for taste removal, odor control, color reduction and oxidation of inorganic compounds such as iron and manganese. An advantage of using chlorine dioxide instead of chlorine is that it does not directly react with organic matter and form halogenated byproducts when it is used for disinfection. THMs, such as CHBr3, ChCl3 etc, are considered as most dangerous for people health. In this article we are to represent the results got from raw water disinfection treatment with chlorine dioxide.

The paper deals with the essential of economic insurance within the whole economy procedure in the water management companies. As it is well known, the fundament of insurance is risk itself. The risk, by its appearance, power and intensity, has its impacts on processes, objects and activities in the water management. That is why is very important to know and apply knowledge, awareness and comprehension about risk management in the field of water management. Any sort of risks must be analyzed, planned, controlled, organized, prevented, repressed, averted and fixed in order to decrease detriments and disadvantages. The best way to preclude all predicted and unpredicted tribulations and costs is to go all-out for the rules of covenanted and unsolicited types of insurance. The paper also gives a brand - new approach to bypassing risks within management by the system of covenanted and unsolicited insurances.

Biofilm is a complex aggregation of microorganisms, principally bacteria, associated with their extracellular polymers, and surface attached. Many bacteria, mainly saprophytes, but also some oportunistic human pathogens, live in a water sypplying system. Depending on water quality and other factors, these bacteria are able to form biofilms. The formed biofilm is usually resistant to traditional supply system treating methods, including disinfection. The aim of this study is to make a contribution to the knowledge about bacteria Pseudomonas aeroginosa in biofilm structure. By understanding biofilms, wrong interpretation of microbiological results in water supply system samples analyses could be avoided.

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.

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 groundwater quality on the National Park Kopaonik is determined by the chemical and radioactive structure of water, formed through the processes that due to the contact of minerals from the water - bearing rocks and groundwater. Atmosphere precipitation are the main source of the entire resources of the ground water in the national park, and the aggressive components that are carried into the underground are the main catalyst in the process of leaching of the predominant minerals from the water-bearing rocks. In the national park, crystalline and marble limestones have the greatest water potential in the sense of the quantity and quality, and the granite massif dispose with the ground water, with the most complex radioactive structure.