The City of Appleton, Wisconsin operates an 800 l/s Drinking Water Treatment Plant (WTP). Lake Winnebago serves as the source water which experiences algae blooms that are typically accompanied by severe taste and odor (T&O) episodes. Historically, raw water quality in the summer months prevents the full capacity from being achieved despite the use of potassium permanganate, powdered activated carbon (PAC) and granular activated carbon (GAC) filters. Thus, the City proceeded with a study of various treatment processes to mitigate the T&O problems experienced during the summer months. The relatively short duration of T&O episodes and extensive experimental plan necessitated a bench-scale testing for rapid evaluation of various oxidation and adsorptive processes.
This paper presents a review of the effect of carbon type, dosage, contact time, and application point on the performance of PAC in controlling odors. In addition, the effect of GAC type and empty bed contact time (EBCT) on removal of T&O compounds were evaluated using a rapid small scale column test (RSSCT).