Town of Garner WWTP Facility - Executive Summary |
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The Town of Garner is committed to chemical safety for both employees and the general public. The Town of Garner is currently subject to OSHA's Process Safety Management Standard. The Town of Garner has a cooperative agreement with Wake County Public Safety to respond to any accidents or emergencies that may result from chlorine releases. Wake County Public Safety is trained to respond to situations involving chlorine. The chlorine supplier acts as an alternate response team in case of accidents or emergencies. The Town of Garner processes wastewater through primary and some secondary treatment procedures, then applies this wastewater by surface irrigation to property owned by the Town of Garner. The water and nutrients are utilized by producing various crops (hay, trees,..). Prior to disposal to the land surface, the wastewater is disinfected with chlorine gas to kill dangerous pathogenic bacteria. During irrigation events, chlorine gas is withdrawn from two pressurized cylinders at various rates depending on the irrigation flow rate. Vacuumed controlled chlorinators are used in order to minimze potential accidents. The system will shut down if leaks exist in the chlorination system thus preventing the release of chlorine gas directly to the air. The chlorine gas is mixed with the effluent through a venturi system. The solution is directed to the head of the chlorine contact chamber for mixing with the irrigated wastewater resulting in disinfection. The Town of Garner's policy involving accidents and emergencies is not to act as a response team, rather coordinate efforts to communicate to the public and employees any accidents, offer assistance to reach safe areas, contact emergency response teams, and assist in mitigation efforts. The Town of Garner has utilized th Offsite Cosequence Analysis Guide developed by EPA to determine the worst-case and alternative release scenarios. The worst case scenario identifies a 1.3 mile radius from the tank location as the a rea of impact. This would include a complete rupture of a one ton container of chlorine gas for ten minutes at a rate of 200 lbs/min. Note that this area is contained within the boundaries shown on the attached map and includes 205 residences. The alternate release scenario could be characterized as the breakage of a 3/8" supply line, and a malfunction of the vacuum chlorine regulator. The EPA model (2000 lbs. @ 60 minutes=33.33 lbs./min) was used to determine a .1 mile radius as the area of impact. In both scenarios, a chlorine alarm will sound, wind speed and direction would be observed, notification to employees would be may by radio and by indicators (red flares released in the sky). Employees would then call 911 and Garner Police, identify to the dispatcher the problem, communicate to any persons that may be at the end of Wrenn Road (one farm and one unmanned cellular tower), proceed to the intersection of New Bethel and Wrenn Roads (primary command post), and communicate to ne ighbors down wind from the chlorine gas, and meet the emergency response team at the primary command post. There have been no accidents to report in the past five years and ongoing inspections, reviews, and audits play inertgal roles in quality assurance for this safety program. |