23rd. Ave. Treated Water Storage Facility - Executive Summary |
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40 CFR 68.155 Executive Summary a. The City of Greeley 23rd Ave. Treated Water Storage Facility accidental release prevention policy involves a unified approach that integrates advanced technologies, procedures, and management practices. The Greeley 23rd Ave. Treated Water Storage Facility Emergency Response Policy involves utilization of, and coordination with, offsite responders to address potential chlorine-related incidents. b. The 23rd Ave. Treated Water Storage Facility serves the customers in Greeley, Colorado. The facility stores 67 million gallons of treated water that is delivered to the facility from our two water treatment plants.The facility adds chlorine to the treated water that it stores to maintain adequate residual disinfection action as the water is distributed to the customer. The distribution/disinfection building consists of three rooms. One room contains two vacuum type chlorinators and vacuum piping that extend into a second room which contains two one- ton chlorine containers, scales, hoists, and tools required for the process. The third room contains the electrical panels, flow recorders, chlorine alarm and various safety equipment. The chlorine container room and chlorinator room have piping which connects to a chlorine scrubber. The facility is normally staffed from 7:30-4:30 Monday thru Friday. Operators who have been trained and certified in the operation and maintenance of the chlorination equipment are on call 24 hours a day, seven days a week, and will respond to any alarms which may occur. The alarm system activates an alarm on the system computer that is operated by a Win-911 system which notifies pertinent personnel, and also the City Police and Fire Dispatch Office. Only incidental (known and immediately controllable) events are handled by facility staff. All other emergency events are responded to by the city's Hazmat Team. c. The offsite consequence analyses includes the consideration of two chlor ine release scenarios, identified as the "worst-case release" and " alternate release" scenarios. The first scenario is defined by the United States Enviornmental Protection Agency ("EPA") which states that "the owner or operator shall assume that the . . . maximum quantity in the largest vessel . . . is released as a gas over 10 minutes," due to an unspecified failure. The alternate scenario is defined as "more likely to occur than the worst-case release scenario." The worst-case scenario must assume the catastrophic release over ten minutes of the entire contents of a full one-ton container of chlorine, certain specified atmospheric conditions and the failure of all active mitigation systems. As permitted by the guidance, the facility assumed that the chlorination building would provide a degree of passive mitigation by slowing the release of chlorine gas to the atmosphere. Applying the guidance, and assuming an obstructed urban landscape, the facility determined tha t the defined worst-case release scenario would have an off-site toxic endpoint of .9 miles. (The toxic endpoint is identified as the maxium airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action.) A number of potential alternate release scenarios were considered, and determined to have no reasonable potential to result in an off-site toxic endpoint. The scenario considered most relevant was the rupture of the flexible connection (pigtail) to a one-ton container. In this case, the rupture of the 5/16 inch connector tubing would result in a chlorine release of 15 lbs. per minute. The one-ton chlorine containers are stored in a cinder block and brick building. The building is equipped with a chlorine detector that will trigger an alarm at concentrations greater than one part per million. This alarm will notify the operators and dispatch personnel through the phone system. The building is also equipped with a chlorine scrubber which is automatically started when the chlorine detector is activated. The mitigation and safety measures that are in place should neutralize any chlorine release in case of a pigtail rupture. There has been no accidental releases at the City of Greeley 23rd Ave. Treated Water Storage Facility in the past five years. d. The City of Greeley 23rd Ave. Treated Water Storage Facility accident release prevention program is based on the following key elements: High level of training of the facility operators and maintenance personnel; Preventative maintenance program; Use of state-of-the-art process and safety equipment; Use of accurate and effective standard operating procedures, written with the participation of the operators; Performance of a hazard review of equipment and procedures; and Implementation of an auditing and inspection program. Chemical-specific prevention steps include the availability of self-contained breathing apparatus (SCBA) worn by the operators during the connection/disconnection of chorine supply, awareness of the hazardous and toxic properties of chlorine, and the presence of a reliable and accurate chlorine detection system. A "B" kit for one-ton containers is also maintained and kept on the plant site for use only by the off-site emergency response team, if it is ever needed. e.No accidental releases of chlorine have occured in this facility in the past five years. f.The City of Greeley 23rd Ave. Treated Water Storage Facility utilizes local hazard reponse personnel to respond to emergencies at the facility. The program has also been reviewed by the Weld County Office of Emergency Management and coordinated with the Union Colony Fire Authority. All personnel will review these procedures on an annual basis. g.Planned chang es to improve safety include utilizing STOP (Safety Training Observation Program) to enhance employee awareness by promoting the concept that in terms of importance, safety is equal to productivity. Other changes include posting of more signs, additional lighting in the chlorine container room, better documentation of practices and procedures, color coded piping, installation of a sprinkler system for fire suppression. |