Draper Water Treatment Plant - Executive Summary |
|
The Draper Water Treatment Plant (DWTP) has adopted this Program 3 Risk Management Plan (RMP) in order to comply with federal requirements in 40 C.F.R. 68 regulating risk management of highly hazardous chemicals. This plan will help prevent the occurrence of, or minimize the consequences of, catastrophic releases by stating policies and procedures for the management of process hazards in start-up, operation, inspection, maintenance, and the other matters addressed in the federal standard. The DWTP plan calls for employee participation and includes all the elements of the employee participation provisions of the standard. At a minimum, DWTP employees will: (1) participate in the development and implementation of the site specific Process Safety Management (PSM) and RMP programs; (2) participate in conducting the chlorine and ammonia process hazard analysis; (3) be trained annually on the PSM and RMP programs and be made aware of any interim changes to the program or process systems; (4) work with management to develop additional programs or procedures relative to chlorine and ammonia process safety; and, (5) participate in periodic audits of the chemical processes and the PSM Program. Accidental Release Prevention and Emergency Response Policies Preventative maintenance is the key to minimizing the potential for accidental releases. Standard Operating Procedures (SOPs) are reviewed and revised, as necessary, to enable the employees to perform their work in a safe and efficient manner. The DWTP has chosen to be a non-responding facility in the event of an emergency. Responsibility for emergency response to an accidental release has been given to the Oklahoma City Police and Fire Departments and the State and Local Emergency Planning Committees. Stationary Sources and Regulated Substances. The DWTP utilizes chlorine and ammonia for disinfection of treated water. The maximum inventory and threshold quantities for these chemicals are shown below. Chemical Maximum Inventory (lb.) Threshold Quantity (lb.) Chlorine 80,000 2,500 Ammonia 45,920 10,000 Worst-Case and Alternative Release Scenarios The Offsite Consequence Analysis (OCA) evaluated a worst-case release and alternative release scenarios. A dense gas dispersion model (RMP*COMP) was used to determine endpoint distances for both scenarios. The model input parameters and assumptions fulfilled 40 CFR Part 68 requirements and are summarized in the following table RMP*COMP Input Parameters Parameter Worst-Case Scenario (CL2) Alternative Scenario (CL2) Alternative Scenario (NH3) End Point Concentration (mg/l) 0.0087 0.0087 0.140 Windspeed (m/s) 1.5 3 3 Atmospheric Stability Class F D D Temperature (0 F) 77 77 77 Terrain Rural Rural Rural Release Rate (lbs/min) 200 90 228 Duration (min) 10 10 10 The results of the air dispersion model are summarized in the table along with estimated populations within the impact areas. The population data was estimated using the Land-view block uniform density group method. RMP*COMP Output Results Parameter Worst-Case Scenario (CL2) Alternative Scenario (CL2) Alternative Scenario (NH3) Im pact Radius (miles) 3.0 2.0 1.2 Estimated Pop. in Impact Area 2,240 1,054 359 The DWTP is located in a predominantly rural area south of Stanley Draper Lake. Stanley Draper Lake is a sporting and recreational area. The properties surrounding the DWTP include sensitive environmental receptors such as wilderness and wetland areas. General Accidental Release Prevention Program The DWTP has acquired knowledge regarding process safety and hazard assessment. Under Program 3, DWTP has used this information to implement policies and procedures related to operations, training, mechanical integrity, incident investigations, compliance audits, management of change, pre-start review, contractors, employee participation, and hot work permits in order to create a safe workplace. Chemical - Specific Prevention Steps The complet ion of the Hazard Assessment resulted in the recognition of preventive steps in order to eliminate or minimize the possibility for accidental releases and employee exposure to chemical risk. Process Safety Management Program DWTP has compiled a Process Safety Management program to minimize releases. This Program includes safety information related to the covered chemicals, hazard review, operating and maintenance schedules, training, compliance audits, incident investigations, and emergency response procedures. Five-year Accident History In the past five years there have been two accidental releases reported at the DWTP. The first release occurred on June 27, 1994 at 12:30 A.M. Approximately five pounds of chlorine was released and one emloyee was treated for chlorine inhalation. This incident did not result in an offsite impact and no offsite responders were called. The second release occurred on September 22, 1994 at 03:55. Approximately 2,000 pounds of chlorine was release d and offsite emergency assistance was provided by the Oklahoma City Fire Department Hazmat Response Team. One DWTP employee was medically evaluated for chlorine exposure. Property damage was confined to metal surfaces within the Chlorine building. No offsite impact was reported. |