East Bank Wastewater Treatment Plant - Executive Summary |
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17689 LDEQ Facility Number Accidental Release Prevention and Emergency Response Policies Accidental Release Prevention: Both the Sewerage and Water Board (S&WB) and its contractor Professional Services Group, Inc. (PSG) are committed to the safe operation of the East Bank WWTP. To facilitate protection of its employees and the public, there are several chlorine sensor alarms that will alert operators of a leak. Also, 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. Also, the HAZMAT Team intends to conduct workshops for nearby schools on how to react to notification o f a chlorine release. Emergency Response Policies: Operators at the East 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 manager 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. Built into the emergency action plan for the plant are mechanisms to notify the St. Bernard Parish Fire Department and schools located within the radius defined under the alternate release scenario. This facility is included in the Local Emergency Planning Committee's community emergency response plan. The East Bank Wastewater Treatment Plant The East Bank Wastewater Treatment Plant (WWTP) is a 122 million gallons per day activated sludge plant and serves the entire East 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 channel. Chlorine is stored in two 55-ton rail cars, each supplying approximately a 3 month supply of chlorine. The plant is owned by the S&WB but is operated and maintained by a private contractor PSG. Located on the East Bank of the Mississippi River in Orleans Parish, the facility is close to the St. Bernard Parish line to the East and surrounded by Bayou Bienvenue on the North, East, and West sides of the plant. To minimize the threat of flooding from storm surges, the entire plant is protected by a levee over 8 feet high. The only entrance road into the plant is from the South, however emergency exits leading through the levees exist at each of the cardinal compass points. The WWTP produces its own oxygen on site and uses it, rather than air, in the treatment of w astewater to increase microbial degradation of organic waste. Also the WWTP incinerates its sludge on site prior to land disposal at an off-site landfill. A Title V permit for this facility has not yet been issued by the state. Worst Case Release The worst case release at the East Bank WWTP, as defined by 40 CFR 68.25, involves the release of the entire contents of a full 55-ton rail car over a ten minute period equating to an 11,000 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 9.9 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 manual shutoff valve on the liquid side of the chlorine distribution line between the rail car and the evaporator. Chlorine is expected to leak through a hole of approximately 0.8 square inches in area and continue for 30 minutes until isolated. Using RMP*Comp(TM), this scenario produced an endpoint of 0.8 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 East 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 Hi story There have been no accidents, as defined in 40 CFR 68.42, at the East Bank WWTP in the last five (5) years. The Emergency Response Program As described above, personnel at the East Bank WWTP 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 East Bank WWTP is included in the community emergency response plan for the City of New Orleans. Planned Changes to Improve Safety Many changes, such as the revision of operating procedures and the installation of additional alarms have already taken place. However, the S&WB plans to take the following additional action at the East Bank WWTP to mitigate the consequences of an uncontrolled release of chlorine: 7 Construct a physical enclosure to house the 55-ton rail cars. The S&WB may install a spray system and/or ventilation controls depending on th e results of an engineering feasibility study. The S&WB expects that the use of an enclosure for chlorine storage at the East Bank WWTP will reduce the actual release rate by 55 percent. Therefore, this could reduce the toxic endpoint of the alternate release scenario from 0.8 miles to 0.6 miles and reduce the population within the impact radius from 13,600 to 10,200. Additional measures, such as spray systems may reduce the impact even further. The S&WB has set forth the following schedule to implement physical improvements to the current distribution system: 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. |