Arsenic is a highly toxic, easily transportable and widespread contaminant in groundwater throughout the world. Arsenic causes acute toxicity by disrupting biological functions. In groundwater arsenic concentrations can reach up to a few milligrams per liter. Current regulations on arsenic content in drinking water are becoming more stringent and require the standard to be reduced to a few parts per billion. Arsenic exists as oxyanions in aqueous solution in either trivalent or pentavalent oxidation states depending on the oxidation-reduction potential and pH of the medium. Several treatment methods are available for removing arsenic from water. However, cost, operational complexity of the technology, skill required to operate the technology and disposal of arsenic bearing residual are factors that should be considered before the selection of any treatment method. Most of these techniques are also effective only in removing As(V) and not As(III). N,N’-bis(2-mercaptoethyl)isophthalamide), abbreviated BDTH2, is known to effectively precipitate soft heavy metals from water. A solid-supported reagent with the metal capture ability of BDTH2 would be ideal to use as a filtration column packing material for removal of aqueous As(III). In order to attain this objective, a new dithiol compound, 2,2'-(isophthaloylbis(azanediyl))bis(3-mercaptopropanoic acid) (abbreviated ABDTH2) has been synthesized and immobilized on silica beads. Silica-supported reagent ABDTH2 (SiABDTH2) thus prepared, completely removed As(III) from water by forming As-S bonds. In batch study, SiABDTH2 reduced the concentration of As(III) in aqueous solutions from 200 ppb to below 5 ppb at pH 5, 7 and 9. XAFS study of ABDT-As(III) and SiABDT-As(III) indicated that arsenic was present in +3 oxidation state as well as As(III) was only bonded to sulfur atom of ABDT unit. When SiABDTH2 was used as filtration column material, only 3% of ABDTH2 was leached out from the column. However, 100% As(III) was removed from 20 L of 200 ppb As(III) aqueous solution at a flow rate of 20 mL/min.

Constructed wetlands and the soil filters are water treatment devices using the filter material that in most cases consists of natural river gravel, coarse sand or crushed stone. Master´s thesis deals with the research of cleaning effect of unconventional filtration materials, or more precisely with examination to load real waste water in a filtration column, to prove their ability to be used as an alternative medium that can ensure better cleaning effect. For the research work following metallurgical industry materials were used: fine slag and coarse slag 8-16 mm, materials from the natural character: zeolite, keramzit, a plastic material: PUR-foam. Also the traditional materials of fine gravel and coarse gravel were tested to compare the cleaning efficiency. Both the hydraulic and the cleaning efficiency of all above mentioned materials were tested. The examined hydraulic parameters are particularly porosity, hydraulic conductivity and suspended solids, turbidity and oxidation-reduction potential of both the inflow and outflow of the filter columns were determined. Accredited laboratory set the inflow and outflow of the filter columns BOD5, CODCr, total phosphorus, total nitrogen, nitrite, nitrate, ammonia and dissolved oxygen. By evaluating the results of the measurements it is determined which materials are suitable to be applied in the constructed wetlands and the soil filters. This filtration column was modeled by program HYDRUS and the result was compared with real results.