The Yosemite Rim Fire, named for its starting location along the Tuolumne River, goes on record as the third largest wildfire in California's history burning from August 17 � October 24, 2013. Perimeter of the Rim Fire encompasses the outskirts and northeast corner of Yosemite National Park, making up nearly half of the watershed area for the Don Pedro Reservoir. Source waters from Don Pedro are carried west along the Tuolumne River into the Modesto Reservoir, which are then treated by the Modesto Irrigation District (MID) Wastewater Treatment Plant. Treated water from MID is used primarily for surrounding industrial and agricultural water supplies but provides for 50% of the domestic water supply for the city of Modesto. It has been determined through previous studies following forest fires that the levels of peak flow, ash, and debris tend to rise in receiving waters, returning to normal background levels within several years time � increases in these levels raises concern of: turbidity, DOC, TOC, temperature, and pH. Samples of water taken from Wards Ferry Bridge, prior to entrance in the Don Pedro Reservoir, have revealed roughly 4,000 times more turbidity, 50 times more TOC, and eight times more DOC than the average after the most recent rainfall. This study examines the severity of these changes and determines appropriate treatment methods for resolution. Standard disinfection is conducted through the use of ozone and dependent on CT values to achieve desired disinfection and TOC reduction. Bench-scale monitoring of ozonation will be performed using a Nano ozone generator (Absolute Ozone �) with variations of pH, CT, and DOC. Further testing will be conducted with a pilot-scale of MID's treatment process at the MID treatment facility for verification of results.

Disinfection by ozone of a surface water reservoir affected by wildfire runoff

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.