| Accident History | Chemicals | Emergency Response | Registration | Source | Executive Summary |

The Boro of Phoenixville owns and operates a 5.0-MGD water treatment plant located on Water Street and Cromby Road in Phoenixville, Chester County, PA.  Raw water from the Schuylkill River is clarified, filtered and disinfected with chlorine gas prior to distribution.  The plant is staffed with nine full time employees under the supervision of Mr.  Andrew Fabian, Water Plant Superintendent.  Mr. Donald Edwards, P.E., Director of Public Works has overall responsibility for the water system and the wastewater system as well. 
Chlorine gas is primarily used for pre treatment of the raw water to hasten the oxidation of organic matter and improve settling.  The chemical is also used for post settling and final disinfection after filtration. A maximum of twelve one ton chlorine containers are on site.  Two containers are in service with two on standby.  An automatic switch over system transfers chlorine feed should the other container become empty.    A 150-pound chlorine cylinder is also us 
ed at the Lane Avenue water tank site in the southern part of the Boro to improve chlorine residuals in the system.  
The worst case release of chlorine gas at the facility consists of a catastrophic release of 2000 pounds of the gas from a ton container over a 10-minute period at a rate of 200 lbs/min.  The container is located inside the chlorine room at the facility.  No credit has been taken for any mitigating factors in calculating the extent of the release.  The estimated distance to the toxic end point of 0.087 mg/l is 1.3 miles, and an estimated residential population of 5000 would be affected.  The toxic end point was calculated using EPA Document No. 550-B-98-010 dated October 1998 entitled, " Risk Management Program Guidance For Wastewater Treatment Plants (40 CFR Part 68).   The population figures were estimated.   
The alternative release scenario for chlorine gas consists of a leak created by a faulty valve mounted on the cylinder.  Although unlikely to occur, this releas 
e scenario is more likely to occur than the worst case scenario described above.  The maximum distance to toxic end point is estimated at 0.3 miles.  The toxic end point was obtained from the same EPA Document described in the previous paragraph.   
The staff at the facility follows procedures that include daily inspections of the chlorine system, periodic safety training programs and quarterly inspection and repair/replacement program of the chlorination equipment by an outside agency.  The staff also takes advantage of the Operator Outreach Program of the Pennsylvania Department of Environmental Protection to continually update their skills in maintaining and safely operating the system.  One such training program including a safety audit is being scheduled presently.  A safety review of the facility is also conducted by the Boro's insurance carrier on an annual basis.  The most recent review was held on November 8, 1998.   
The facility has had no accidental release of chlorine gas  
in the past five years. 
A written emergency response plan approved by the Local Emergency Planning Committee of the County of Chester is updated on an annual basis. 
The Boro is actively engaged in planning for future improvements and upgrades to the disinfection system at the facility.
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