This study was performed to investigate the influence of the ozonation process on natural organic matter (NOM) and trihalomethane, haloacetonitrile and chloropicrin precursors in groundwater. The largest reduction in dissolved organic carbon, DOC (up to 25%) and UV 254 values (up to 69%) was achieved using 3 mg O3/mg DOC. Reducing the total organic matter resulted in a reduction of trihalomethanes precursors to 194 micro g/L. On the other hand, when it comes to the precursors of the high priority nitrogenous disinfection by-products, the oxidation of NOM by ozone and the resulting increase in organic matter with a low molecular lead to an increase in the haloacetonitrile precursors compared to the raw water and the formation of chloropicrin precursors.

A contemporary biostability assessment of raw and treated water requires determination of biodegradable organic matter fraction responsible for bacterial growth. BDOC test allows monitoring of bacterial growth by assaying chemical changes in the test-water and thereby determine the content of biodegradable dissolved organic carbon (BDOC). The aim of this study was to optimize the required period for performance of BDOC tests, and to examine the use effectiveness of different biofilm carrier. The results indicate that the BDOC test with sand-inoculation is more effective compared to the anthracite, and recommendations for monitoring of biodegradation process are a period of 3-5 days.

The content of aluminum, boron, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, cadmium, barium and lead was analyzed in raw water and drinking water that is used by the Belgrade Water Supply and Sewage Company. Total of 14 samples were examined from all water treatment plants that are part of the Belgrade Water Supply and Sewage. The measurements were conducted using the inductively coupled plasma-mass spectrometry (ICP-MS) technique. The aim of this research was to examine the effectiveness of the process of drinking water preparation in the existing plants. In all drinking water samples concentrations of the elements were bellow the maximum allowed levels according to the Serbian regulations. Correlation coefficients for the elements, which were analyzed in this paper, show that three groups of elements can be distinguished. Boron, manganese, arsenic and barium are related to each other and probably originate from the same source; copper, nickel and zinc have lower mutual correlation coefficients, indicating a potential common origin; finally, lead, aluminum and cadmium are not in correlation with any tested element.

The Rapid Small Scale Column Test (RSSCT) was developed to predict the adsorbtion of organic compounds in activated carbon adsorbers. In the RSSCT, a small column, which is loaded with an adsorbent ground to small practicle sizes, is used to simulate the performance of a pilot or full scale system. Due to the similarity of mass transfer processes and hydrodynamic characteristics between the small, pilot and full-scale columns, the breakthrough curves are expected to be similar. Due to its small size, the RSSCT requires a fraction of the time and water volume compared to pilot column testing. Recently the RSSCT has been used successfully in simulating the performance of metal-oxide based arsenic adsorbers. The adsorptive-filtration column was scaled down to mimic the performance of continuous flow, full and pilot scale arsenic treatment systems using the RSSCT approach. This paper investigates the application of the RSSCT method for assessing arsenic removal by unconventional adsorptive media such as waste materials.

This paper examines the impact of ozonation (0.4 to 3.0 mg O3/mg DOC) and the Peroxone process – O3:H2O2 (0.4 to 3.0 mg O3/mg DOC; O3:H2O2 = 1:1) on the content of natural organic matter (NOM) in water. It was found that the Peroxone process results in a greater degree of total organic matter content removal (up to 81% UV254), but also oxidises a greater amount of hydrophobic NOM compared to ozonation. Ozonation was more effective for the removal of the specific haloacetic acid (HAA) precursors (29-50% HAAFP), whereas the Peroxone process was more effective in the removal of haloacetonitrile (HAN) precursors (19-43% HANFP).

The paper presents the results of laboratory research and application of continuous electro-coagulation and electro-flotation (ECEF) to remove natural organic matter (NOM) from groundwater in the treatment of drinking water. The highest NOM removal efficiency for current density of 5.78 mA/ cm square according to UV254 absorbance and dissolved organic matter (DOC) was 77% and 71% respectively. The specific energy and aluminum electrode consumption was 2.01 kWh/cubic m, 80 g Al/cubic m, respectively.

In the 21 century drinking water of acceptable quality should be available to every person. Numerous investigations are on-going worldwide around the world, to develop innovative and cost attractive approaches for production of high quality drinking water. To allow application of new treatment technology in practice, pilot testing under field conditions are required. Groundwater used for drinking water productions in the Subotica municipalities (Serbia) contains elevated concentrations of arsenic, iron and ammonia, and therefore provided a good basis for continuation of research of UNESCO-IHE, the Netherlands Institute for Water Education, that has been developing innovative water treatment technologies specifically in the field of groundwater treatment and specifically arsenic removal. Objective of this project presented in this paper were to test under field conditions IHE ADART, the innovative adsorptive arsenic removal technology. The pilot project has demonstrated that in addition to conventional approach based on coagulation and break-point chlorination, there is and alternative treatment approach based on biological ammonia removal and adsorptive removal of arsenic that could be economically and ecologically attractive.