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.

Conventionally treatment method in potable water preparing, such as coagulation/flocculation, sedimentation and filtration has been shown reduction in efficiency of the contents of natural organic matter. There has been developed many alternative NOM removal technologies, in recent years. It has been made significant research effort in finding optimal drinking water treatment for NOM range reduction prior disinfection, that can minimise the formation of disinfection by-products and reduce the residual required to control bacterial regrowth in the distribution system, which is a consequence of coagulant with humic matter settling. Conventionally treatment modified by MIEX resin appliance meet the current water quality standards, with significant reduction of the coagulant quantity.

A great floristic variety has been noted according to qualitative analysis of phytoplankton. The presence of 187 taxa from 7 divisions of algae has been noted. The results of quantitative analysis show the dominance of centric diatoms. The high values of biomass that point out on the trophicity increase are noted on the strech from Nestin to Zemun (Serbia) with the maximum at Centa (Serbia) with 15,885 mg/cubic dm. Downstream Zemun, it has been noted gradual decrease of biomass up to Pancevo (Serbia), and afterwards downstream the considerable reduction all the way up to Brnjica (Serbia), where the value of algal biomass was 1,697 mg/cubic dm.

This paper presents the results of the examinations of phytoplankton community of the Tamis river from March 2003 till December 2004. During the investigation it was determined 136 algal taxa from 6 divisions: Cyanophyta (10 taxa), Chrysophyta (1 taxa), Bacillariophyta (66 taxa), Pyrhophyta (4 taxa), Euglenophyta (14 taxa) and Chlorophyta (41 taxa). The contents and the structure analysis of phytoplankton as well as saprobiological valorization of water quality, has been carried out in the Republic Hydrometeorological Service of Serbia. Results of quality and quantitative analysis point to domination of Bacillariophyta and Chlorophyta. The index of saprobity given on the basis of Pantle-Buck method indicated that the quality of water of Tamis river on Jasa Tomic border locality belonged to beta and beta-alfa mesosaprobic category.

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.

Recent surveys of river Tisza (Serbia) have shown that class Oligochaeta is commonly present as dominant member of benthic macroinvertebrate community. Knowing the fact that this class is very good indicator of organic upload in aquatic ecosystem, in this paper it is used for saprobiological water quality assessment of middle and lower stream of river Tisza in summer of 2002, 2004 and 2005. Results presented as saprobiological indices, showed that water quality of river Tisza (Serbia) was alfa-mesosaprobioc (the third class) during research period.

The puddles Slatina and Pecena Slatina are the old meanders of the river Tamis. These ecosystems are periodicity fill with moderate salt and high alkaline water. The paper gives a review of qualitative and quantitative analysis of the algal compositions. Cyanoprokaryota and Euglenophyta are more common. All investigated parameters like compositions of lagal communities, their abundace, biomass and chlorphyll-a showed a high level of nature eutriphication in these ecosystems.

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.