PERFORMANCE EVALUATION OF THE PHOENIX® ODOR CONTROL SYSTEM

King County, Washington purchased two 8,000-cfm Phoenix odor control systems, developed by Calgon Carbon Corporation, to treat foul air at two major interceptors in the County's wastewater conveyance system. The systems, installed in 2003, replaced existing odor control equipment located at turbulent and odorous points in the conveyance system. The Phoenix system was installed as a single-stage treatment system at the Sweyolocken Force Main Discharge Structure and as the first stage of a two-stage system at the Lake City Regulator Station, with a deep bed carbon unit scrubber as the second stage.This paper discusses the Phoenix system's effectiveness at removing odorous gases when operated as a single-stage system and as part of a two-stage system. It includes an assessment of the system's overall performance in removing hydrogen sulfide and other odorous compounds from the air stream.A number of modifications were incorporated into the Phoenix system as a condition of purchase. These modifications were desired to make the system consistent with King County design standards, operation and maintenance practices, and industrial discharge permit conditions for the acidic wash water. The modifications included operating one of the units under negative pressure rather than the standard positive pressure, rerouting external piping to make canisters easier to remove, adding a neutralization system for the acidic wash water effluent, and enhancing the program logic controller (PLC). These modifications required significant redesign of the manufacturer's off-the-shelf model, which increased the cost of the units. This paper presents the results of a cost/benefit evaluation of these modifications and explores the value of the modifications based on actual operating conditions and reliability in the first year of operation.Operation and maintenance issues associated with Phoenix system are also presented in this paper. Significant operation and maintenance issues encountered include determining the optimal regenerating wash frequency, acidic mist carryover from the exhaust, leaks, accumulation of crystallized sulfate in the exhaust system, and operational complexity. The costs of operating the Phoenix system are also presented.