A BETTER BEACH WITH OZONE DISINFECTION

Salt Creek and South Monarch Beaches are two popular beaches in South Orange County, California. Yet, in recent years, the beaches have been subject to public health postings due to bacteria levels exceeding state standards. The source of the bacteria is Salt Creek, an urban creek located in the City of Dana Point (City), that discharges at these beaches.An innovative ozone treatment facility under construction at the Salt Creek outlet will treat the dry weather urban runoff, a typical source of pollution in coastal California. The design of this facility came about following a careful evaluation of disinfection technologies including chlorination/dechlorination, UV light, and ozone. Ozone disinfection was selected because it could most reliably and cost-effectively achieve the City's disinfection goals given the creek's relatively high levels of turbidity, total suspended solids (TSS), iron, and manganese.This paper will present steps taken to evaluate disinfection options and to design a dry weather urban runoff treatment facility for the City. Design parameters, process design, site selection, permitting requirements, and steps taken to minimize aesthetic impacts of the facility in its coastal setting are included.Disinfecting urban runoff is still relatively uncommon but is gaining interest as municipalities nationwide seek means to meet increasingly stringent urban runoff regulatory requirements. The evaluation and design process used for this project could be applied effectively to urban runoff and stormwater concerns throughout the United States.