AWWA WQTC56948

The Greater Cincinnati Water Works (GCWW) is evaluating innovative technologies for use in meeting the long-term requirements of microbial inactivation/removal in drinking water. The three phases of this long-term evaluation entail: scenario assessments for long-term disinfection needs; bench-scale investigation of ultraviolet (UV) inactivation including disinfection byproducts, and assimilable organic carbon formations; and, pilot/demo-scale evaluation to address site-specific feasibility including hydraulic limitations. Scenario assessments indicated that GCWW would be able to meet Bin 1 or 2 of the upcoming LT2ESWTR with the existing conventional filtration and GAC filtration. The GCWW will need to add inactivation technologies (i.e. UV, UF, etc) only if the source water Cryptosporidium concentration falls into Bin 3 or higher. Bench-scale investigation of granular activated carbon (GAC) filtered water indicated that UV effectively inactivated all the organisms studied; however, no synergism was demonstrated when free chlorine addition following UV exposure was evaluated. Neither low pressure nor medium pressure UV light effected the concentrations of trihalomethanes, Haloacetic Acids, carboxylic acids, aldehydes, or total organic halogens (TOX). Additionally, there was no clear trend in AOC concentrations with respect to the quantity of UV energy applied to the water sample. The third phase of the evaluation is currently underway. Includes 8 references, figures.