Missouri River Wastewater Treatment Plant - Executive Summary |
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I. INTRODUCTION This document contains all the information that the MSD Missouri River Sanitary Sewage Treatment Facility needs in order to meet the requirements of 40 CFR 68 "Risk Management Program". This document consists of the executive summary and registration data elements (68.155 through 68.185). II. RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES The Missouri River plant generates methane (digester gas) from its wastewater treatment process. The Code of Federal Regulations (40 CFR 68), classifies methane (digester gas) as a flammable gas. The Missouri River plant adheres to all applicable Federal, state, and local rules and regulations to ensure a safe environment within the plant as well as for the surrounding community. Access to the digester gas system is restricted to certified operators, authorized contractors, and the Maryland Heights fire department (the primary responder in the event of an accidental release). The Missouri River plant is a manned facility. In the event of an accidental release, the methane alarm will sound alerting the appropriate MSD personnel. The primary emergency responder is the Maryland Heights fire department. Procedures are in place for notification of the Maryland Heights fire department, the LEPC, and the St. Louis County HAZMAT team. III. PROCESS DESCRIPTION AND REGULATED SUBSTANCES The Missouri River plant in Maryland Heights, Missouri is a sanitary sewage treatment plant. The plant has one regulated substance under 40 CFR 68: methane. Methane is a by-product of the treatment process and is used as a fuel for the plant's power generating system. The North American Industrial Classification System code (NAICS code) for the primary process at this facility is 22132. The methane system is comprised of four digesters, one gas storage sphere, and associated piping. Sludge collected in the wastewater process is stored in a digester. The sludge storage unit or digester generates gas from waste sludge und er controlled anaeribic conditions. The gas generated is called "digester gas" and has been analyzed to contain 65% methane and 35% carbon dioxide. Methane (digester gas) is a flammable gas under 40 CFR 68. The threshold for triggering applicability of 40 CFR 68 is 10,000 pounds. The maximum quantity of methane (digester gas) stored on-site at any one time is 13,297 pounds. Since this exceeds the threshold limit, the Missouri River plant is subject to 40 CFR 68 as a Program 2 facility. IV. WORST-CASE AND ALTERNATIVE RELEASE SCENARIOS IV.1 Worst-case Scenario For the Missouri River plant, the worst-case scenario is the loss of 10,2173 pounds of digester gas in ten minutes from the digester gas sphere located outside of the administration building. Since the digester gas is 65% by volume methane, the quantity of methane released is 4,033 pounds. The worst-case scenario does not affect any receptors. IV.2 Alternative Release Scenario The alternative release scenario ex amined involves the release of methane due to the waste gas burners not firing. The release rate for two gas burners is 17.8 lb/min. The alternative release scenario for methane does not impact any receptors. V. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS This facility complies with EPA's Accidental Release Prevention Rule and with all Federal, state and local codes and regulations. The plant continually conducts inspections to ensure the system is intact and operating correctly. These inspections ensure that the worst-case and alternative scenarios have a minimal chance of occurring. The plant has developed a prevention program for methane to meet the Program 2 requirements of the RMP rule. The prevention program was developed to comply with 40 CFR 68, to ensure the safety of the employees, and to ensure the safety of the surrounding community. The program covers a compilation of safety information, periodic conduct of hazard reviews , operating procedures, training, maintenance, compliance auditing and incident investigation. VI. FIVE-YEAR ACCIDENT HISTORY The review of this facility's accident history includes the following range of dates: June 22, 1994 - June 21, 1999. There have been no releases at this facility as defined by 40 CFR Part 68.42(a). VII. EMERGENCY RESPONSE PROGRAM As mentioned earlier, in Section 1.0, the Missouri River plant is not a primary emergency responder in the event of an accidental release but the plant will contact the Maryland Heights fire department, who are the primary responders. Procedures are in place for notification of the Maryland Heights fire department, the LEPC, and the St. Louis County HAZMAT team. The fire department is notified by dialing 911. VIII. PLANNED CHANGES TO IMPROVE SAFETY Based on the "what-if/checklist" Hazard Review completed for methane (digester gas), a list of action items was developed for implementation. The following examples briefly describe improvements occurring as a result of the Hazard Review. 1. The possibility of a methane release caused by untrained personnel operating the system is a major concern at the Missouri River plant. To address this concern the facility has initiated a training program for all personnel responsible for the operation of the methane system. Personnel who are not responsible for the operation of the system will not be allowed to perform any tasks related to the digester system. (5/99) 2. The Missouri River plant is installing identification tags on all valves associated with these systems (8/99) 3. The Missouri River plant reconditions each digester on a 5 to 10 year basis to ensure the digesters and associated valves are intact. (4/99) |