Lawrence Water Filtration Plant - Executive Summary |
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Executive Summary The Lawrence Water Filtration Plant is located at 400 Water Street in Lawrence Massachusetts and began operation in 1938. The water filtration plant has a maximum rated capacity of approximately 15 million gallons per day. Raw water is drawn from the Merrimack River. The treatment process consists of screening, chemical addition, slow mixing, flocculation, clarification, filtration, adsorption and disinfection. The high lift pumping station, located across Water Street, pumps the treated water into the distribution system. Chlorine is used to provide pre-chlorination and post-chlorination of the drinking water supply. The addition of chlorine disinfects the drinking water and provides continued protection in the distribution system. The filtration plant building stores 6 one-ton containers, 2 are in active service and 4 are backup. The pump station stores 15 150-pound cylinders, 2 are in active service and 13 are backup. Hazard Analysis There were no re portable accidents related to the release of chlorine in the last 5 years. A vacuum system is used to introduce chlorine into the water supply. In addition, the chlorinator is mounted directly on the container, eliminating the need for any pressurized chlorine lines. This method reduces the potential for accidental releases in that any break in the chlorine line will cause the system to lose vacuum and prevent any additional chlorine from leaving the one-ton container. The 150-pound cylinders are operated in the same manner. The worst case and alternate case scenarios were modeled using the look-up tables contained in the EPA guidance document for wastewater treatment plants. The worst case scenario assumed a complete loss of chlorine contained in a one-ton container over a 10-minute period under atmospheric conditions that limited the amount of dispersion that would occur. The distance to the toxic endpoint was 1.2 miles and could potentially affect 13,000 people including res idences, schools, recreational areas, and businesses. The alternate case assumed that a one-ton container is dropped, breaking the valve on the container. The atmospheric conditions provided greater dispersion. The distance to the toxic endpoint for the alternate case was 0.2 miles and potentially affected 1,000 people. Prevention Program The facility is subject to the Prevention Program 2. The Massachusetts Division of Occupational Safety inspected the facility on May 6, 1999. Lawrence Fire Department performed a safety inspection on May 10, 1999. An inspection with regard to the Emergency Planning and Community Right-to-Know Act was conducted by an outside consultant on May 6, 1999. A hazard assessment was also conducted on June 15, 1999 in preparation of this Risk Management Plan to evaluate the potential for a chlorine release. The assessment consisted of a review of the process controls, monitoring systems, operating procedures, maintenance program and training program . Operation and maintenance manuals are kept for various pieces of equipment present at the facility. The City is working with an outside consultant to develop a detailed operating procedure for the chlorine system. Components of the chlorine system and monitoring devices are checked on a monthly basis. The City is working with an outside consultant to develop a detailed maintenance procedure for the chlorine system. Operators at the water filtration plant are licensed operators certified by the Commonwealth of Massachusetts. Continuing education courses are also provided. Emergency Response Program If an uncontrolled release of chlorine were to occur, the plant operators have been instructed to immediately call the Fire Department. If necessary, the Lawrence Fire Department will activate the HazMat Team. |