ALARM MANAGEMENT AT THE SRCSD: BOON OR BANE TO OPERATIONS?

The Sacramento Regional Wastewater Treatment Plant (SRWTP) blends well with the natural environment. Through coordinated wetland and wildlife conservation efforts, this habitat supports hundreds of wildlife species, including owls, cranes, and wild flowers. The plant employs reliable treatment processes that mirror nature's handling of wastewater, with one important advantage: what nature takes months to complete, the plant can accomplish in about eight hours.SRWTP is one of the few wastewater treatment plants designed during the 1970s that incorporated fully automatic control. The 400 MGD peak capacity facility treats an average of 165 MGD. The Process Computer Control System (PCCS) has more than 37,000 database points. In June 2001, the Sacramento Regional County Sanitation District (SRCSD) completed installation of an Emerson Ovation PCCS that provides extensive alarm capabilities and enables operators to monitor and view nearly every aspect of plant, process, and equipment performance and condition. All alarms from plant processes and the computer system are displayed on operator alarm screens.This new alarm capability quickly overran the alarm screen. An April 2003 alarm system audit showed more than 700 active alarms, most of the nuisance variety. An analysis of this audit revealed that redundant and inhibit alarms comprised 64 percent of nuisance alarms; 10 percent were caused by alarm limits set too close to acceptable operating limits or calibration tolerances; and 13 percent were considered as lower priority than assigned. SRCSD and its consultant, EMA, applied an approach of Assess, Design, Implement, and Optimize to resolve these alarm management issues. This paper will explore how that was done.