Conversion of Chlorine Gas Wastewater Disinfection to UV Disinfection - A National Park Perspective

This paper describes the process of evaluating disinfection alternatives to replace the chlorine gas disinfection system at the El Portal Wastewater Treatment Facility (WWTF) that serves Yosemite National Park, using the Value Analysis process. The disinfection alternatives considered included ozonation, sodium hypochlorite, and UV disinfection.Disinfection options were evaluated using the Value Analysis approach. The goals of the VA process were to satisfy all of the objectives of the project, add value to the project, and to reduce costs where possible within the project goals. The options were evaluated based on ability to minimize disinfection by-products, protection of the environment and public, improved safety for Park staff, and the cost of the system.The paper also highlights some of the major design issues applied to achieve the required effluent criteria and to minimize impact on existing plant operation during construction of new facilities.