Jamestown Wastewater Treatment Facility - Executive Summary |
|
JAMESTOWN WASTEWATER TREATMENT FACILITY JAMESTOWN, NORTH DAKOTA EXECUTIVE SUMMARY A. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES The City of Jamestown has developed and implemented policies for safety with respect to the hazardous chemicals on the site. These policies include worker safety and emergency response protocols. Included in the facility is a chlorine scrubber, which, as an active mitigation device, will prevent release of chlorine to the atmosphere, should a release occur. Other active mitigation devices include chlorine leak detectors and a ventilation system that is activated when the cylinder room is occupied. Passive mitigation measures include the building which houses the chlorine cylinders. This building is constructed of prestressed concrete members. This type of construction offers resistance to disaster damage since it is non-combustible and, due to the weight and strength of the components, resistant to natural weather disasters. Ho wever, the presence of doors which are of lighter construction, the building envelope could be violated, thus opening the cylinder room to the atmosphere, i.e., the worst case scenario is not entirely mitigated by the building envelope. B. STATIONARY SOURCE The regulated substances handled include chlorine and sulfur dioxide, which are used in the disinfection process of wastewater from April 1 to October 31. Although the anaerobic lagoon generates biogas (methane), this gas is immediately burned either in the boilers or a flare. Should these ignition devices fail, the biogas is vented to the atmosphere through a passive ventilation system. The quantities of chlorine and sulfur dioxide on the site and connected to metering devices are subject to OSHA Process Safety Management Standard since the quantities exceed the threshold quantities in 29 CFR 1910.119. However, worksite safety in North Dakota falls under the jurisdiction of the North Dakota Workers Compensation Bureau, not OSHA. Because the quantities of chlorine and sulfur dioxide exceed the thresholds established by OSHA, the chlorine and sulfur dioxide processes are Program Level 3 processes. Due to the relatively low volume of methane stored under the cover of the Low Rate Anaerobic Treatment System, this process is not covered by 40 CFR Part 68, 20 CFR 1910.119 or 40 CFR Part 355. C. OFFSITE CONSEQUENCE ANALYSIS 1. Worst Case Release Scenario: The worst case scenario consists of a release of 2,000 pounds of chlorine (or sulfur dioxide) over a period of ten minutes. Since the chlorine (sulfur dioxide) is stored indoors, passive mitigation is provided by the building itself. The storage of chlorine outdoors is an administrative control which reduces the end point distances. The endpoint distance is 2.2 miles based on rural topography. The area within this distance includes the North Dakota State Hospital, the North Dakota State Penetentiary, the Northern Plains National Wildlife Resear ch Area, approximately 2,800 residents, the City's solid waste baling facility, and several commercial and industrial sites. 2. Alternate Release Scenario: The alternate release scenario consists of a release of 2,000 pounds of chlorine over a period of thirteen minutes. Although the passive mitigation provided by the building enclosure is taken into consideration, the active mitigation provided by the scrubber is neglected. If the mitigation provided by the scrubber was taken into account, there would be no offsite consequences for the chlorine leak. However, there is no scrubber present for the sulfur dioxide so the offsite consequences for both of the materials under this scenario are the same with the exception of minor differences in the end point distances. The end point distance for this scenario is 0.4 miles based on rural topography. The area within this distance includes the Northern Plains National Wildlife Research Area, approximately 50 residents and the City's s olid waste baling facility. D. GENERAL ACCIDENTAL RELEASE PREVENTION POLICY The general accidental release prevention policy includes training for employees, restrictions on hot work in the storage/feeder room. Inspection and testing of detectors, alarm systems and scrubbers is also performed on a regular basis to verify that measures are operable and available should the need arise. E. FIVE-YEAR ACCIDENT HISTORY There have been no accidents with respect to the chlorine or sulfur dioxide at this facility. F. EMERGENCY RESPONSE PROGRAM Whereas an emergency response program specifically for this facility has not been developed, the programs developed by the Stutsman County 911/Emergency Management office and programs developed for the water treatment plant cover the hazards that may exist at this facility if a release should occur. In general, the program discusses isolation of the leak (if possible, before additional emergency assistance arrives), contacting emergency respond ers including the fire department and law enforcement officials and maintaining operation of the chlorine scrubber, if required. G. PLANNED CHANGES TO IMPROVE SAFETY The facility has had no incidents which would indicate that safety programs for workers are inadequate and in need of change. Planned changes for safety programs include the development of a site specific emergency response plan, and increased involvement of employees in safety evaluations and programs. These programs will be developed and focus on employee safety and off-site consequences. |