The microbiological quality of the groundwater was monitored by determining relevant physiological groups of bacteria (organotrophic bacteria) which are indicators of water organic pollution. Standard high nutritive medium (Nutrient Agar) and low nutritive medium (R2A agar) were used. The enzymatic activity was also estimated based on IFA determination (index of phosphatase activity). According to the number of organotrophic bacteria and categorization by Kohl (Kohl, 1975) water is generally classified in category II. IFA showed variation of water quality, which varied from polluted to very pollute. The results showed organic pollution of groundwater and confirmed the sensitivity of enzymatic methods. In addition, cultivation methods confirmed superiority of low nutritive media.

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.