Encina Water Pollution Control Facility - Executive Summary
Pursuant to the Clean Air Act (CAA) Section 112(r)(1), this Risk Management Plan (RMP) Public Document is voluntarily submitted. This RMP Public Document reflects the efforts of the Encina Wastewater Authority (EWA) in the management and prevention of risks associated with the storage and processing of methane, a regulated substance (RS), at the Encina Water Pollution Control Facility (EWPCF). This RMP Public Document follows the San Diego County Department of Environmental Health (DEH) Hazardous Materials Division (HMD) California Accidental Release Prevention Program (CalARP) Guidelines dated 25 February 1999. |
The EWPCF has an excellent safety record and has been the recipient of numerous safety awards. No accidents involving the processes associated with methane have occurred within the last 19 years, the period of time for which safety records are available. The EWPCF has been recognized by the Association of Metropolitan Sewerage Agencies (AMSA), EPA, American Society of Civi
l Engineers (ASCE), and the Association of Electrical Engineers (AEE); the California Water Environment Association (CWEA) awarded EWPCF with the CWEA Safety Award in four out of the last six years.
Although the EWPCF currently processes and stores methane in quantities below the regulatory threshold quantity (TQ), the EWA is submitting this RMP voluntarily in anticipation of population growth in northern San Diego.
Accidental Release Prevention and Emergency Response Policies
The EWA has an Integrated Contingency Plan that is used to respond to emergency situations.
The Stationary Source and Regulated Substances Handled
The EWA's primary activity is the treatment of municipal wastewater. A byproduct of wastewater treatment is digester gas, which the EWA produces and uses; digester gas contains methane, a regulated substance. The processes that handle the digester gas include the digesters, gas management system, waste gas burners, and cogeneration and blower engines. The maximum
quantity of digester gas is 13,331 pounds, which represents the weight of digester gas, per EPA Guidance, and assumes three digesters are in operation. Under current conditions, only two digesters are in operation; the maximum quantity of two digesters is below the regulatory TQ.
Worst-case Release Scenario and Alternative Release Scenario
Both of the release scenarios follow EPA's RMP Guidance for Wastewater Treatment Plants (EPA, 1998). The worst-case release scenario involves the explosion of one of the digesters; this scenario results in a distance to endpoint of 0.099 miles. The alternative release scenario assumes that the entire contents of methane in one of the digesters are released over a ten-minute period (EPA, 1998), and that no passive and/or active mitigation was considered. The alternative release scenario results in a distance to endpoint of 0.024 miles.
General Accidental Release Prevention Program and Chemical-specific Prevention Steps
The EWA is dedicated to o
perating a safe facility and is in compliance with the Occupational Safety and Health Administration (OSHA) Process Safety Management (PSM) rule and the CalARP requirements.
Five-year Accident History
The EWA has an excellent safety record. No accidental releases from covered processes have occurred within the last five years that resulted in death, injury, or significant property damage on site, or known offsite death, injury, evacuation, sheltering in place, property damage, or environmental damage.
Planned Changes to Improve Safety
The EWA recognizes that an effective risk management program involves continuous improvement. After conducting the process hazard analysis (PHA) and seismic analysis, the EWA identified equipment, process, and management changes that will be implemented before January 2001. These improvements are summarized in our RMP Public Document.