West Bank Wastewater Treatment Plant - Executive Summary |
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4688 LDEQ Facility ID Number Accidental Release Prevention and Emergency Response Policies Accidental Release Prevention: Both the Sewerage & Water Board (S&WB) and its contractor Professional Services Group, Inc. (PSG) are committed to the safe operation of the West Bank WWTP. Continuous review of standard operating procedures (SOPs) and mechanical integrity programs help to ensure that the chlorine system is operated and maintained in a safe manner. PSG provides formal training for all operators and maintenance personnel focusing on chlorine safety. The Hazardous Material (HAZMAT) Team of the New Orleans Fire Department (NOFD) is scheduled to conduct an annual site visit of the plant to familiarize themselves with the chlorine system. Emergency Response Policies: Operators at the West Bank WWTP will not respond to leaks beyond their ability to control through the use of valves. In the event of such a release, plant personnel will evacuate with the exception of the plant super visor or chief operator who will remain on site to activate the City's emergency system. It is anticipated that the first responders will be the NOFD. They will establish a safe perimeter and begin public notification until the HAZMAT Team of the NOFD arrives to contain the release. This facility is included in the Local Emergency Planning Committee's community emergency response plan. The West Bank Wastewater Treatment Plant The West Bank Wastewater Treatment Plant (WWTP) is a 10 million gallons per day trickling filter plant and serves the entire West Bank of Orleans Parish. Treated effluent from the plant is discharge to the Mississippi River. Disinfection of the effluent is accomplished by injecting chlorine into the effluent box. Chlorine is stored in a maximum of nine-one ton cylinders. The plant is owned by the S&WB but is operated and maintained by a private contractor, PSG. Located on the West Bank of the Mississippi River in Orleans Parish, the facility is close to th e Plaquemines Parish to the South and near the English Turn community to the East. Worst Case Release The worst case release at the West Bank WWTP, as defined by 40 CFR 68.25, involves the release of the entire contents of a full one-ton cylinder over a ten minute period equating to an 200 lb/min release rate. Under F Class atmospheric stability (very stable atmosphere), 25 0C (77 0F), 1.5 m/s wind speed (3.4 mph), in an urban environment, it is expected that the toxic endpoint, 0.0087 mg/L (3 ppm), of the chlorine plume will be reached 1.3 miles downwind from the point of release. This value was determined by using the computer model produced by the Environmental Protection Agency (EPA), RMP*Comp(TM). Alternate Release Scenario The scenario modeled under the alternate release scenario was a leak from a whip connecting the cylinder to a distribution header. Chlorine is expected to leak through a hole of approximately 0.1 square inches in area and continue for 37 minutes until t he cylinder is empty. Using RMP*Comp(TM), this scenario produced an endpoint of 0.3 miles downwind from the point of release. No active or passive mitigation measures were assumed to mitigate the release. The General Accidental Release Prevention Program and Chlorine Release Prevention The West Bank WWTP is subject to the OSHA Process Safety Management (PSM) rule. The PSM incorporates several elements that aid in operating a safe plant and in reducing the possibility for off-site releases. Among the critical elements that have been recently reviewed and updated are the Standard Operating Procedures (SOPs), Mechanical Integrity Program, and Training Program. These three programs have a significant impact in the continued safe operation of the chlorine system. The Five-Year Accident History There have been no accidents, as defined in 40 CFR 68.42, at the West Bank WWTP in the last five (5) years. The Emergency Response Program As described above, personnel at the West Bank WWT P will not act as responders to uncontrollable releases of chlorine. Rather, the Emergency Action Plan will be implemented which notifies the City's HAZMAT Team who will contain chlorine releases beyond the ability of plant personnel. The West Bank WWTP is included in the community emergency response plan for the City of New Orleans. Planned Changes to Improve Safety The S&WB and PSG plan to take the following action at the West Bank WWTP to mitigate the consequences of an uncontrolled release of chlorine: 7 Construct a physical enclosure to house the chlorine cylinders 7 Install a chemical scrubber to treat a chlorine release 7 Install additional process area alarms 7 Install indicators of chlorine release in the operator control room The S&WB expects that the use of these active and passive controls will eliminate any chlorine release from the chlorine storage area. The S&WB has set forth the following schedule to implement physical improvements to the current distribution sy stem: 1) Install all specified additional alarms and controls by October 1999. 2) Complete preliminary engineering design for additional controls, e.g. enclosures, chemical scrubbers, etc., by November 1999. 3) Complete engineering designs by March 2000. 4)Complete construction and equipment installation by July 2001. |