Alma Wastewater Treatment Plant - Executive Summary

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The Alma Wastewater Treatment Plant, located at 1000 Washington, Alma, Michigan, 48801, treats all of the wastewater generated within the City of Alma plus wastewater from portions of two adjacent townships. Chlorine has been used at this facility for over 50 years. Current usage is about 40 tons per year. Because of the use of chlorine, we have developed this Risk Management Program in accordance with 40 CFR Part 68 and also a very similar State required Process Safety Management Program. 
There have been no accidental releases of chlorine in the past five years. We report this in accordance with Part 68.168. Actually, there have been no releases of chlorine in the history of the Treatment Plant which caused a threat to anyone outside of the immediate area of the Plant. 
Chlorine is delivered to the Wastewater Treatment Plant in one ton cylinders. There are normally seven cylinders on site containing between two and seven tons of chlorine. There are three rooms in the Main Control Bui 
lding at the Plant where a release of chlorine could take place. Outside of these three rooms, chlorine can only be found dissolved into liquid wastewater streams. Each of the three rooms are continuously monitored by a Fischer & Porter Chloralert chlorine detector. If chlorine is detected, operators are alerted immediately and the problem is corrected before there is any threat to anyone outside of the building. During off hours, on-call personnel are notified by means of a contracted alarm service. 
In the event of a chlorine leak severe enough to have possible off site consequences, Treatment Plant personnel will request assistance from the Alma Fire Department who will respond in accordance with their Emergency Response Program. 
Worst Case Scenario - It is conceivable that a full chlorine cylinder could rupture and release a ton of chlorine. This scenario is highly unlikly since all cylinders are hydrostatically tested every three years by the supplier to ensure that they are in s 
afe condition. But, if a cylinder were to rupture, 2000 pounds of chlorine could be released in ten minutes with a toxic end point of .9 miles. This determination was made utilizing the EPA software program "RMP*Comp".  
Alternate Release Scenario - It is somewhat more likely that a flexible connector could be broken releasing chlorine through a .25 inch diameter opening. This scenario would result in the release of 7.61 pounds of chlorine per minute until the cylinder valve could be closed. Assuming this release lasted for 15 minutes, this scenario would result in a toxic endpoint of .1 miles. This determination was also made utilizing RMP*Comp. 
A cloud of chlorine gas would have a tendency to remain in the immediate area of the Wastewater Plant because it is located in a low area and chlorine would have to rise in order to drift away from the plant. This fact was not considered in determining toxic end points however since it is dependent upon wind speed and direction. 
There are no 
foreseeable changes to our operation which would require any changes to be made to our Risk Management Program.
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