GAC pore structure in Cincinnati during full‐scale treatment/reactivation

Abstract

Granular activated carbon (GAC) was evaluated during full‐scale treatment operation at the Richard Miller Water Treatment Plant, Cincinnati, Ohio. Starting with virgin GAC, GAC was monitored through six treatment cycles and subsequent onsite thermal reactivation. Pore structure was monitored at the beginning and end of each cycle. Influent and effluent total organic carbon was measured during each cycle. During the first cycle, adsorption caused a large decrease only in micropore volume. With each subsequent cycle, the pore size that exhibited a decreasing volume shifted into larger pores. By the fourth cycle, net pore volume losses occurred in all pore sizes, with the most extensive losses in 100–300 Å pores. Yet, all GACs were similarly effective during treatment. After each cycle, reactivation seemed to influence pores of progressively larger widths. The virgin GAC was highly microporous, whereas after six reactivation cycles, the GAC was very mesoporous.