Tull CAllen Waste Water Treatment Plant - Executive Summary |
|
Section 1 Executive Summary The Oxford Water & Sewer Board has developed a Risk Management Plan (RMP) for the Tull C. Allen Wastewater Treatment Plant in an effort to protect human health, to protect the environment and meet applicable federal regulations This plant is operated by the Oxford Water & Sewer Board and has a capacity to process 6 million gallons of domestic wastewater per day Currently, the plant is treating approximately 2 million gallons per day It is located in Section 4, Township 17 South, Range 7 East The plant is located at 2975 Silver Run Road, Oxford, Alabama In addition to the wastewater plant, the Oxford Water Board is developing two new public water supply wells referred to as the Eagle and Burrows wells Chlorine will be stored at these two facilities but at quantities less than the threshold quantity for RMP's; however, these two sites are included in this RMP This RMP has been developed to meet the standards published in the 40 Code of Federal Regist er (CFR) part 68 The EPA, in order to cover the accidental release prevention provision under the Clean Air Act ?112(r)(7) promulgated these regulations On June 31, 1994, The Federal Register, Vol 59, No 20, set forth a list of chemicals and threshold quantities On June 20, 1996, The Federal Register, Final Rule, was published (Vol 61, No. 120) This ruling requires facilities that exceed the cited threshold quantities for certain chemicals to develop a RMP The goal of a RMP is to focus on reducing the risk of accidental releases of certain chemicals; thereby, preventing harm to employees as well as potentially catastrophic impacts on the public. Over 60 accidental releases of regulated chemicals at water treatment plants (WTP's) and wastewater treatment facilities in the United States were reported between 1986 and 1995.1 Chlorine is currently used in the wastewater treatment process at this facility and the quantity stored on site exceeds the 2,500-pound threshold for coverage under the RMP Program. Currently, the maximum potential amount of chlorine to be present on site at any one time is 4,000 pounds Chlorine is stored and used at the site in one ton cylinders. All of the chlorine is stored within an enclosed building except during delivery. Sulfur dioxide is also used at the treatment plant. Currently, a maximum of 4,000 pounds of sulfur dioxide (SO2) is stored/used at the treatment plant. The threshold limit for sulfur dioxide is 5,000 pounds A single one-ton cylinder of chlorine will be used at each of the well sites. In addition to the one-ton cylinder, up to two 150 pound cylinders will also be stored at the facility A hazard analysis was conducted to determine the offsite consequences from a release at the wastewater plant of either chlorine or sulfur dioxide. Two analyses were performed on chlorine in order to estimate the offsite consequences. One analysis was performed for sulfur dioxide to estimate the offsite consequence from a likely release. The first release scenario is the case defined by the Environmental Protection Agency (EPA) as the "worst case" scenario. This scenario assumes that the largest vessel is full and it releases the entire contents of the containers during a ten-minute period. The second scenario (or alternative scenario) is based on a situation more likely to occur which will cause a release of chemicals at the facility. The radius of impact was determined based on the guidance provided in Chapter 4: "Offsite Consequence Analysis" of the General Guidance for Risk Management Programs dated October 27, 1998, the Compliance Guidance and Model Risk Management Program for Water Treatment Plants. The EPA defined "Worst Case" release analysis was performed by personnel with Industrial Chemical Company and the alternate analysis was performed by GM&CE. The distance to the end point concentration was determined with the aide of the Computer Programs Aerial Locations of Hazardous Atmosphere, version 5.2.1 (ALOHA), and the Environmental Protection Agency (EPA) RMP*Comp version 1.06 program. The alternate analysis was used to estimate the off-site consequences from a release of chlorine from the well sites. ALOHA was developed by the National Safety Council for emergency planners. ALOHA works in conjunction with the Computer-Aided Management of Emergency Operations (CAMEO) database and MARPLOT program In all release scenarios, the toxic end point concentration remained the same. The toxic end point for chlorine is three parts per million (ppm) or 0.0087 milligrams per liter (mg/l) and 0.0078 mg/l for sulfur dioxide, which is the endpoint concentration published in the 40 CFR Part 68. The American Industrial Hygiene Association (AIHA) has listed these concentrations as the "maximum airborne concentration", at which nearly all individuals could be exposed to for up to one hour without experiencing or developing life threatening health effects. This level is referred to as the Emergency Response Planning Guideline (ERPG-2) concentration. Results of the hazard analysis for the EPA "worst case" scenario led to an area defined by a 1.3-mile radius for chlorine. This 1.3-mile radius encompasses 5.3 square miles and includes a population of approximately 790 people (according to the U.S. Census Landview III Program with 1990 census data). The alternative off-site consequence analysis yields significantly smaller areas. The off-site analysis for chlorine indicates a 0.48-mile radius to the end point concentration. Based on the 1990 census data Landview III Program, the estimated population inside the area is 100. In addition to the off site consequence analysis for chlorine, an off site consequence analysis was performed for sulfur dioxide. The analysis indicated that concentrations of sulfur dioxide could exceed the ERPG-2 concentration up to 0.2 miles from the site. The ERPG-2 concentration for sulfur dioxide is 3 ppm. The key to a successful risk man agement program is to first define hazard risk and undertake a comprehensive approach to prevention. The Center for Chemical Process Safety has defined hazard as: A chemical or physical condition that has the potential for causing damage to people, property or the environment2 Once hazards are identified on the site, then, an evaluation of the risk involved will lead to a systematic identification, evaluation, and control of potential losses that may arise in operation from future events such as fires, explosions, or toxic chemical releases. Currently, the Tull C. Allen Wastewater Treatment Plant is operating in accordance with the procedures outlined in the plant's operation and maintenance manual. Throughout this RMP, the emergency readiness procedures and regular training schedules are emphasized. One of the goals of implementing these procedures and schedules is to minimize the chance of a release occurring. If the plant employees practice preventative maintenance and are we ll trained in emergency procedures, they will be successful in preventing and minimizing personnel injury if a release occurs. All employees of the Tull C. Allen Wastewater Treatment Plant are required to know the locations of the emergency telephone numbers and names of individuals to contact in case of a release. If an emergency occurs, each employee will have an assigned task. This risk management plan enhances the standard operating procedures because it provides a clear checklist that identifies predetermined individuals and agencies that require notification and coordination in case of an emergency. This RMP details which individuals will respond to the release in order to contain it. It also outlines the agencies that will be responsible for evacuating the appropriate areas, and for sounding the "all clear" once the leak is contained. In addition, the plan includes procedures for the periodic review of readiness. Since the Tull C. Allen Wastewater Treatment Plant has been operating, to date there has not been any major or minor reported releases from this facility. One of the goals of this RMP is to maintain the plant's current high level of safety and safety record. This plan includes the following sections: * Program requirements * Hazard Assessment * Emergency Response Plan * Prevention Plan * Audit Schedules Material Safety Data Sheets (MSDS), Tier 2 reports, employee training certificates and release confirmation and report forms will be maintained as part of this document. 1 EPA Accidental Release Information Program (ARIP) database 2 Center for Chemical Process Safety, 1989. Guidelines for Chemical Process Quantitative Risk Analysis. New York: AICHE. 2 1 |