EFFICIENCY OF ACTIVATED CARBON REGENERATION AFTER THE LONG-TERM EXPLOITATION IN FILTERS FOR TAP WATER POST-TREATMENT

Abstract

Predominately mesoporous structured activated carbon is the best sorbent for the natural organic matter extraction from water. Mesoporous activated carbons KAU, KAU-TF and BAU were used in the adsorption filters for tap water post-treatment for a long time (more than three years). Structural-adsorptive characteristics of these carbons were estimated in the paper. The spontaneous bioregeneration takes place on the activated carbon surface. It is caused by the biofilm formation during water filtration in non-sterile conditions. As a result of this process active carbon adsorption parameters are restored, namely the part of the AC unoccupied total specific surface area is 61,1-82,9 % of the initial value, the part of the unoccupied total adsorption pore volume is 59,0-87,2 %, whereas the value of unoccupied effective supermicro- and mesopores surface can be up to 69,3-98,2%. Active carbon samples treatment with sodium hydroxide leads to a partial release of the micropores adsorption volume especially in the lower carbon bed layers by water passing. Spontaneous activated carbon bioregeneration under filtration of ozonated tap water runs more efficiently than bioregeneration after a non-ozonated water filtration under the same organic matter load on the AC. Efficiency improving of spontaneous bioregeneration after a pre-ozonated tap water filtration is caused by the transformation of organic substances molecules into a form that is more accessible to the functioning of native biofilm.