BOROUGH OF PHOENIXVILLE WASTEWATER TREATMENT PLANT - Executive Summary |
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The Boro of Phoenixville owns and operates a 4.0-MGD wastewater treatment plant located on Second Avenue in Phoenixville, Chester County, PA. The wastewater collected within the Boro and some parts of Schuylkill Township is treated using the activated sludge process and the plant effluent is disinfected with chlorine gas prior to discharge in to the Schuylkill River. The plant is staffed with nine full time employees under the supervision of Mr. Scott Towler, Wastewater Plant Superintendent. Mr. Donald T. Edwards, P.E., Director of Public Works has overall responsibility for the wastewater system and the water system as well. Three one ton chlorine containers are on site at any given time. One container is in service with one 150 pound cylinder on stand by. An automatic switch over system transfers chlorine to the 150-pound chlorine cylinder. 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 release 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 di sinfection system at the facility including alternatives like sodium hypochlorite and UV disinfection. |