In this paper two different combinations for wastewater treatment are proposed for specific problems that Vojvodina (Serbia) has with arsenic. Both proposed technologies take into account treatment of water and treatment of waste. In this paper the concrete solution for water treatment is proposed for water that contains arsenic (the concentration is around 100 microgram/L) in Obrovac and Palic. With these water treatment plants the removal of ammonia (measured concentration was above the maximum allowed value, from 1.35-2.5 mg/L) is also included in case of Obrovac wastewater plant, and for Palic the proposed treatment plant the removal of iron (measured concentration was above the maximum allowed value, from 1.35-2.5 mg/L) is also included. With both treatment plants and with both proposed technologies the overall treatment of water is planned.

The paper analyses application of different methods for removal of the high content of ammonia from groundwater sources of the Grocka municipality neighborhoods Umcari and Pudarci. According to the relevant data from this field method, biochemical oxidation with the Nitrosomonas and Nitrobacter bacteria was used. Parameters of biological processes of the ammonia oxidation were defined on the pilot model located at the groundwater source. On the pilot model, consisting of a trickling filter and a fast gravel filter, quantitative oxidation NH4 to NO3 was done. Purification plant was designed with parameters of the pilot model, with minimal investment and exploitation expenses, without undesired side products and ecological risks characteristic for procedure of chemical oxidation of ammonia, which recommends this procedure as the optimal solution.

Determination of total arsenic and As(III) was performed in untreated and treated water samples collected in some small water supply systems in Northern Backa district (Serbia). Concentration of total arsenic in treated water was between 71 and 115% of total arsenic in untreated water (0.001-0.168 mg As/cubic dm). In untreated water concentration of As(III) was between is less than 0.001 and 0.078 mg As/cubic dm. However, during the water treatment (chlorination process) As (III) concentration decreased significantly to the level of 1 to 2% of start concentration in untreated water. Influence of conservation water sample with HCl increased with consumption of KMnO4 on determination of As(III).

In this paper the results of the application of WQI method on Vojvodina main rivers and canals are shown. There were investigated 41 localities, from April 2002 to May 2003. There was observed high degree of correlation between the WQI values and the qualitative composition of the desmid community. Exceptions to that rule were noticed, since that WQI is not sufficient parameter of the water quality.

During 2005 the referent monitoring of the chemical quality of surface waters and sediments in Vojvodina was conducted as a supplement to the regular monitoring program in Vojvodina. It is concluded that the water quality mainly satisfies the criteria of the 1st/2nd class acccording to our legislation, but regarding the more stringent Canadian and Dutch water quality standards content of some micropollutants may be considered as potentially problematic. Sediment quality is mainly satisfying, with the exceptions of the DTD canal Vrbas-Bezdan monitoring station after Srbobran, which showed a slight contamination with PAHs, and the Sava-Sabac monitoring station, as the target values according to Dutch legislation were exceeded for DDT and its metabolites.

During the spring of 2005, the chemical quality of surface waters and sediments in selected protected areas of Vojvodina (Serbia) was monitored, as a part of the Referent monitoring of the chemical quality of surface waters in Vojvodina during 2005 project. This work presents the results of the referent monitoring and establishes the chemical quality of the surface waters and sediments, and identifies particularly polluted and threatened areas. It is shown that in terms of organic micropollutants content, the chemical quality of the water in the protected areas is in most cases satisfactory, except in the protected areas of Carska Bara, at the Stari Begej Wharf site, and Lake Ludos, where higher mineral oils concentrations were detected. Furthermore, the toluene concentration in Lake Ludos exceeded Canadian guidelines.

In the course of implementation of project Ecological Significance Evaluation of River Moravica Basin with Pollutants Identification, supported by REC and DRP, chemical and physical water analysis were done, as well as slime analysis. Heavy metals presence in water, herb Mentha aquatica and slime was analysed at six relevant locations downstream river Moravica. Heavy metals test results in slime and herb Mentha aquatica points out the presence of Zn, Cu, Fe, Mn, with heavy metals concentration rise from spring to mouth of river Moravica to river Juzna Morava. Chemical and physical analysis of water content, and detection of heavy metals presence in herb Mentha aquatica - as bioindicator and in slime, shows on water contamination with heavy metals as the inflow result of waste waters from numerous polluters.

The paper deals with quality of water and deposits in the Nadela stream (in Banat, Serbia). This stream is outline of regional multipurpose hydrosystem within the same name. Analyses are carried out according to water usability for irrigation and properties of settled sediments from stream bottom. Their potential influence, and effect of their application to surrounding arable soil were investigated.

In the frame of the project Water Supplying of the Cities and Protection of the Groundwater Quality in the Velika Morava Valley, was obtained the analysis of potential polluters of groundwater sources of town Velika Plana - Livade. This paper presents results of water physical, chemical and microbiological characteristics of soil. According to the results of research and way of usage of the soil, it was concluded that agricultural production does not have negative influence on quality of the groundwater source.

The EU Water Framework Directive imposes special requirements for transboudary groundwater bodies, and thereby emphasizes their significance. The management of a common resource calls for an integrated approach to monitoring and status assessment, as well as implementation of improvement measures. Serbia, Hungary and Romania share a water body in the Pannonian Basin, for which cooperation has already been established within the framework of the ICPDR and at the bilateral level.