Stamford WPCF - Executive Summary

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Description:  The Stamford water pollution control facility is a 20 million gallon per day advance wastewater treatment facility.  It treats wastewater from the City of Stamford and Town of Darien.  Chlorine is used to disinfect the wastewater prior to discharge to the East Branch of Stamford Harbor. 
 
Worst-Case:  The worst case scenario would be a failure of a valve on one of the one-ton cylinders while placing it in service.  This probably would result in the release of the entire contents of the cylinder.  Using the EPA model, this release would impact an area with a radius of 2.2 miles.  Although there are usually eight cylinbders on site.  Only one is used at any time. 
 
Alternative Release:  The alternative release is a failur of the whip (transfer hose).  This would be most likely what would occur and would effect an area with a radius of about 0.1 miles. 
 
There are alarms in the chlorine storage and process buildings.  These alarms are tested weekly and are set at a very sensiti 
ve level.  The tanks are stored in an enclosed building which helps to mitigate any releases. 
 
The staff is trained on the dangers of chlorine and safe handling procedures.  The procedures are reviewed periodically with the operators.  All connections are checked with ammonia solution to insure there are no leaks.  The amount of chlorine on-site (about 8 one-ton cylinders) is the minimum amount to insure continuous disinfection between deliveries.  This has been reduced from 12 cylinders in the past.  Most important is that the the chlorine disinfection process will be replaced by ultraviolet disinfection.  The process is currently under design adn should be on-line in 2001. 
 
There has been one reportable accident in the past five years which was a problem with the transfer hose and was caused by human error.  Procedures have been put in place to prevent this.  This accident occured almost two years ago and there have been no problems since. 
 
The staff have trained the Stamford Fire De 
partment in the use of the "B" repair kit for one-ton chlorine cylinders and have explained the problems and properties of chlorine to them.  Periodically, we sponsor a chlorine safety day on which the chlorine distributor gives a safety presentation to both teh fire department and plant staff.  The fire department is the first responder in case of an emergency.  The plant staff begins assessment and correction of the problem after the fire department is notified. 
 
The most import aspect is to insure that the operators are well trained and recognize the danger involved with chlorine and the threat to the health and welfare of the public.  Furthermore, they inspect all cylinders during delivery to insyre that no damage has ocurred in transite.  The most import safety improvement is that within about 18 to 24 months, chlorine will no longer be used at this site.
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