Culpeper Water Pollution Control Facility - Executive Summary |
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The Town of Culpeper operates a Water Pollution Control Facility (WPCF) for treatment of wastewater via chlorination followed by dechlorination (sulfonation) prior to discharge under an operations permit. The WPCF must comply with the Program 3 Risk Management Program (RMP), under Section 112[r] of the Clean Air Act. Chlorine and sulfur dioxide are managed in one-ton cylinders at the WPCF in total quantities which exceed threshold limits established under the RMP rule. The primary purpose of the RMP is to provide operators, emergency response personnel and the public with information concerning the potential offsite consequences of an accidental release. Offsite consequence analyses were performed for two release scenarios of toxic gases (e.g., chlorine, sulfur dioxide) identified as 1) a worst case release, and 2) an alternative release scenario. The worst case scenario is defined by EPA as the release of the entire contents of chlorine or sulfur dioxide gas in a one-ton cylinder in 10 minutes, use of the one-hour average ERPG-2 as the toxic endpoint, and consideration of the population residing within a full circle with radius corresponding to the toxic endpoint distance. An alternative release scenario was selected by reviewing the process and determining the activity that poses the greatest risk for causing an accidental release. Damage to piping or a valve during connection of a chlorine or sulfur dioxide one-ton cylinder to the process was chosen as the alternative release scenario. The EPA's RMP-Comp. model (v. 1.06) was used for evaluating off-site consequences. The primary component of the RMP is a detailed Program 3 Prevention Plan, which is derived from the Operations and Maintenance Manual (O&M), inclusive of Standard Operating Procedures (SOP). The Prevention Plan was designed to limit to the extent possible the potential for an accidental release based upon the following key elements: 7 Employment of experienced and highly trained personne l 7 Continued training of personnel 7 Use of state-of-the-art process and safety equipment 7 Use of accurate and effective operating procedures, written with the participation of the operators 7 Performance of a hazard review of equipment and procedures 7 Preventative maintenance program 7 Implementation of an auditing and inspection program. Furthermore, the Town of Culpeper involved the local emergency response council in the preparation of the RMP in order to optimize response to potential major releases, and optimize release prevention by the facility operators. No accidental releases of chlorine or sulfur dioxide have occurred at the facility within the last five years. |