Sault Ste. Marie Wastewater Treatment Facility - Executive Summary |
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The City of Sault Ste. Marie Wastewater Treatment Facility Risk Management Plan Executive Summary The following is the City of Sault Ste. Marie Wastewater Treatment Plant's Executive Summary of our Risk Management Plan. It is the highest priority of the City of Sault Ste. Marie Wastewater Treatment Plant to ensure that the quality of the St. Mary's River, our City's #1 natural resource, is not harmed in any fashion by the discharge from the plant or by it's operational techniques. The Wastewater Treatment Plant depends on the addition of chlorine to lower the final effluent's bacterial count to an acceptable level prior to it's entry into the St. Mary's. The citizens of Sault Ste. Marie depend on the St. Mary's River for their livelihoods and their recreation, so it is a goal of the Wastewater Treatment Plant to protect our neighbors from any accidental release of chlorine that is necessary to protect our river's high water quality. This Executive Summary is submitted in ei ght segments. It was created to both satisfy the Section 112r requirements and to assure our citizens of the great care taken in their protection from a release of the chlorine that is beneficial to the disinfection of their waste water. This Executive Summary was written by the management of the Wastewater Treatment Plant. It summarizes the overall safety programs that all Wastewater Treatment Plant staff created, maintain, update, and train for. In no way is it intended to provide all the safety measures and programs at the Wastewater Treatment Plant. It is an overview to provide our customers with the chlorine information and to satisfy the risk management plan requirements. The staff of the Wastewater Treatment Plant live in the City of Sault Ste. Marie. The citizens of Sault Ste. Marie are our family, friends, and neighbors. Their protection from an accidental release of chlorine has been, is, and shall remain to be of the utmost importance to us. I. The Wastewater Tre atment Facility The City of Sault Ste. Marie has approximately 15,000 residents who reside within it's 15 square miles. The City's boundaries are the St. Mary's River on the East, North, and West sides and 3 Mile Road as it's Southern border. The citizens of Sault Ste. Marie have been served by a municipally treated wastewater facility since 1959. Prior to this, the wastewater was diverted directly to the St. Mary's River. The original plant had primary treatment only, which provided only disinfection with chlorine and settling of solids materials. Ton containers of chlorine were utilized since the beginning of the City's wastewater treatment operations. In 1985, the City invested millions of dollars to upgrade the existing wastewater treatment plant provide complete treatment to our sewage. The current facility involves the following treatment methods: pre-aeration, bar screening, aerated grit-removal, primary sedimentation, secondary treatment with biological contactors, secondary sedimentation, and chlorination. The Wastewater Treatment Plant continues to use liquid chlorine for disinfection of it's final effluent. The City of Sault Ste. Marie has used liquid chlorine in ton containers for waste water disinfection for 40 years. The management and staff have a combined total of over one and a third century of liquid chlorine experience. We are very knowledgeable in it's use and extremely aware of the inherent dangers of it's presence. The Wastewater Treatment Plant is located at 1171 E. Portage Ave. The plant is situated on a large tract of land adjacent to the St. Mary's River. It's final effluent discharge line is 30" diameter pipe running out nearly 700 feet into the river. Approximately 76 miles of sanitary sewers empty into our Wastewater Treatment Plant. Our chlorination equipment was installed during the plant expansion in 1986. All chlorine equipment was manufactured by Wallace and Tiernan. All components in our chlorine system a re compatible with each other because they were designed as a package system by Wallace and Tiernan. Our chlorine is stored in ton containers. The active ton containers are stored in the Chlorine Room. The non-active ton containers are stored adjacent to the Chlorine Room on a rail mounted holding system designed specifically for ton containers. The Chlorine Room is kept locked at all times. Only authorized Wastewater Treatment Plant employees have access to the Chlorine Room. The Chlorine Room has a sensitive alarm system that activates in the event of the most minute chlorine leak. The maximum inventory capability is eight ton containers, although normal inventory levels are often less than half that amount. Our chlorination flow pattern begins at our ton containers. Container pressure pushes the chlorine gas (not liquid) to the chlorinator. The chlorinator meters, controls, and injects the chlorine gas into a water line forming a chlorine solution. The chlorine solut ion is piped to a jet disinfection pump, which in turn delivers the solution to a contact tank, where the disinfection process takes place. II. Regulated Substances Our chlorine supply is the only substance that falls under the Section 112r regulations. Our chlorine is also regulated under OSHA's Process Safety Management of Highly Hazardous Chemicals. Chlorine is considered a toxic substance and has a characteristic, penetrating, and irritating odor. The gas is greenish-yellow in color and the liquid is clear amber in color. Gaseous chlorine is heavier than air and will sink to lower levels in a release. It is non-flammable and alone it is stable, but it is a strong oxidizer and will and can react with a variety of hydrocarbons and metals. Chlorine gas is primarily a respiratory irritant. At chlorine concentrations above 5 parts per million, the gas is very irritating. At concentrations near the threshold of smell (well below 1 part per million for most people) chlorine gas will, after several hours of exposure, cause mild irritation of the eyes and the respiratory tract. In extreme cases of chlorine inhalation, difficulty in breathing can progress to the point of death through suffocation. Liquid chlorine in contact with eyes or skin will cause local irritation and /or burns. III. The Accidental Release Prevention and Emergency Policies at the Wastewater Treatment Plant. The Sault Ste. Marie Wastewater Treatment Plant takes a many-faceted approach to the safe handling of our chlorine and chlorination equipment. We follow OSHA's Process Safety Management of Highly Hazardous Chemicals rule to assist us in our use of chlorine. Our chlorine safety program begins with employee involvement. All Wastewater Treatment Plant employees have a hand in it's formation. We have bi-monthly safety meetings held on the first and third Wednesdays of each month. These meetings also cover topics related to chlorine safety, such as lock-out/tag-out, and per sonal protective equipment. Employees are encouraged to bring new safety issues to the meetings. It is a goal of the Wastewater Treatment Plant management and the City of Sault Ste. Marie to have a well trained workforce who can safely, correctly, and quickly respond to any situation by relying on their previous training and common sense to overcome any hazardous situation that may confront them. Training is the key to this goal, so all employees receive documented training on all our operating procedures. No employee can work a shift alone until they have become fully trained. Our operating procedures are annually reviewed by the staff to make sure they reflect any changes made to the operations or equipment. Our operating procedures are also checked to see if they could be made safer or more efficient. We have an extensive maintenance program at the Wastewater Treatment Plant. All chlorination equipment's maintenance requirements are documented and scheduled. Procedures, in accordance with the equipment's manufacturer, were written for all maintenance activities, and qualified personnel only work on our chlorination equipment. If an employee finds, or suspects a piece of equipment not to be performing up to specifications, it shall be removed from service and a work order made out to notify maintenance personnel of the problem. All work orders relating to our chlorination equipment receive the highest priority. The staff performed a Process Hazard Analysis on our chlorination system and all it's components and procedures. We used the "What If" method and wrote numerous "What If" scenarios. We answered the scenarios as a group and now include them in our operating procedures and our contingency plan. In short, Sault Ste. Marie Wastewater Treatment Plant employees are trained in Process Safety Management, Process Hazard Analysis, operating procedures, maintenance procedures, standard safety practices, and safe work practices on a continuing basis to guard against the possibility of a chlorine release. In the unlikely event of a chlorine release, the staff is trained in stopping and repairing the release and to know when to call in outside help if necessary. IV. Worst Case Scenario Our worst case scenario for chlorine release is the complete release of a full ton container in 10 minutes, which represents a release rate of 200 lbs of chlorine per minute. The model we used for our worst case is the "EPA's RMP Guidance for Wastewater Treatment Plants" reference tables and equations. The conditions in the worst case are a class F atmospheric stability, 50% relative humidity at 250 C with a wind speed of 1.5 meters per second. The height of the release is at ground level. Even though we have a relatively low population in the surrounding area of the Wastewater Treatment Plant, we selected the "urban" topography as directed in the RMP Submit instructions because of the surrounding buildings that represent obstructions. The endpoint for our worst case is 1.3 miles. Offsite consequences from the worst case include an effected population of 2500 people. Within the 1.3 mile radius is an school, residential housing, and numerous recreation areas owned by the City of Sault Ste. Marie. The worst case scenario is highly unlikely due to the fact that it requires liquid chlorine to escape from the container. We only use chlorine in the gaseous form. To get the volume of release calculated in the worst case scenario, a ton container would have to vent chlorine through and opening in the thick, steel container wall, which is very unlikely, or by breaking off the lower valve or fusible plug below the liquid line of the container. Due to the staff's extreme care and extensive training in the handling of the ton containers, this is also highly unlikely. V. Alternate Chlorine Release Scenario Our alternate release scenario is designed to represent the most likely type of chlorine release. It estimates t he loss of gaseous chlorine if a 1/4" line was broken and it released gaseous chlorine at a rate of 9# per minute for 10 minutes. It also represents weather conditions that are more frequent at the Wastewater Treatment Plant; a 3 meter per second wind speed with a class D atmospheric stability. We also chose a "rural" topography for our alternate release, because there are relatively few obstructions within the immediate surrounding area of the Wastewater Treatment Plant. All other data is the same as in the worst case scenario. The endpoint for our alternate release scenario is 0.2 miles. A 0.2 mile radius contains a population of 130 people. The alternate release scenario model is from the "EPA's RMP Guidance for Wastewater Treatment Plants. The chance of breakage on a 1/4" chlorine line is very remote. Strictly followed procedures, extensive training, and excellent preventive maintenance are just some of the tools our staff uses to prevent even the smallest of chlorine lea ks from occurring. VI. 5 Year Accident History The City of Sault Ste. Marie Wastewater Treatment Plant has never had a release of chlorine since the plant was commissioned in 1959. VII. Emergency Response Plan Our emergency response to a chlorine leak can be broken down into two parts: small releases that can be stopped and repaired in-house and larger leaks, where it is beyond the capabilities of the Wastewater Treatment Plant staff to deal with alone. Small releases are those that chlorine does not leave the Wastewater Treatment Plant's grounds. These type of releases are stopped and repaired by the Wastewater Treatment Plant staff by shutting down the chlorination system and repairing the defective component. The Wastewater Treatment Plant staff has an intimate knowledge of all aspects of our chlorination system and receive training in leak repair, chemical safety and Self Contained Breathing Apparatus (SCBA). For larger releases that endanger areas beyond the Wastewat er Treatment Plant's grounds, the staff shall immediately contact outside help to assist us in controlling the emergency situation. The outside help is the Chippewa County Office of Emergency Services. We shall invoke the Emergency Operations Plan for Chippewa County and notify and/or evacuate the effected public and prevent the release from becoming larger. Participants of the Chippewa County Emergency Operations Plant are: 1. Office of Emergency Services 2. City of Sault Ste. Marie Public Works Department 3. City of Sault Ste. Marie Police Department 4. City of Sault Ste. Marie Fire Department 5. Chippewa County Sheriff's Department 6. Michigan State Police 7. War Memorial Hospital 8. Sault Area Schools 9. United States Coast Guard 10. City of Sault Ste. Marie City Hall Personnel 11. Chippewa County Health Department The Chippewa County Emergency Operations Plan states duties for each of the above participants in the event of a toxic release, w ith the Police and Fire Departments performing the notification and/or evacuation if necessary. The Wastewater Treatment Plant's staff's primary duties during a large chlorine release is to immediately notify the Office of Emergency Services by calling 911. The 911 switchboard will activate Emergency Services. The Wastewater Treatment Plant staff shall provide all necessary information to prepare the responding agencies to take the proper actions. The Wastewater Treatment Plant staff shall make every effort to safely contain and stop the release using the proper techniques, personal protective equipment and our Chlorine Repair Kit "B" which has the capability to repair any type of release from a ton container. The Wastewater Treatment Plant staff are regularly training in the use or all emergency equipment. VIII. The Future of the Wastewater Treatment Plant's Chlorination & Operation of Chlorination Equipment. The City of Sault Ste. Marie Wastewater Treatment Plant has no cu rrent plans to replace our chlorine disinfection using ton containers. We could switch to 150 lbs cylinders and thus relieve us of these Risk Management requirements, but it is the opinion of the management and staff that the risk of a chlorine leak is greater with the smaller cylinders than our current practices, simply because we would have to change them more often, providing more opportunity for our alternate release scenario to occur. Our primary mission is to maintain and protect the integrity of the St. Mary's River for recreational and industrial use. We also strongly believe in protecting our downstream neighbors drinking water supplies. Our current chlorination equipment is the most economical and effective way of meeting these goals. Our broad and comprehensive approach to chemical safety and our well trained and conscientious employees compensate for any inherent dangers present from the chlorine that is beneficial to the health and welfare of our City and neighborin g communities. James Atkins Wastewater Treatment Plant Superintendent |