Humic substances (HS) cause problems in water purification because of disinfection by-product (DBP) formation during chlorination. The efficiency of activated carbon (AC) adsorption as a method in drinking water treatment has been investigated in removing HS at different pH values (pH = 5; 6; 7; 8) in static equilibrium experiments. The degradation of HS was studied with an EM (effective microorganisms) bacteria community, and solutions of fulvic acid, sodium humate furthermore extracts of sandy soil were investigated. EM products are widely used but their effect on HS has not been investigated before. The combination of EM and AC methods in the case of fulvic acid resulted in higher performance than any of these methods alone. Humic substances were analyzed using a UV–VIS spectrophotometer and by total organic carbon (TOC) measurements. The carbon/nitrogen ratio was also determined, which enabled conclusions to be made for the nutrient supply. According to these results the degradation was efficient, especially in fulvic acid solutions.
Keywords: adsorption, biological degradation, drinking water, GAC, humic substances