City of Astoria Reservoir # 2 - Executive Summary

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CITY OF ASTORIA PUBLIC WORKS  
RISK MANAGEMENT PLAN 
EXECUTIVE SUMMARY 
 
   The safe storage, handling and use of chlorine are important to the operations of the City of Astoria Public Works Department.  Procedures and policies have been in place for many years in order to safely utilize chlorine at Public Works facilities.  Public Works uses chlorine gas to provide disinfection for the City's drinking water and wastewater treatment processes.  There are three water supply facilities and one wastewater facility that employ chlorine for this purpose. At the Headworks, Reservoir #3 and #2, chlorine is injected into water mains as it leaves the facilities.  This ensures that any pathogens and bacteria will be inactivated prior to the water arriving at the customer's tap.  For the City's wastewater treatment operations, chlorine is injected at the last stage of treatment just prior to discharge of the wastewater effluent to the Columbia River.   
 
   Under the Environmental Protection Agency's wo 
rst case release scenario, data was entered into a computer based release model (RMP comp version 1.6.)  This was done for each of the four facilities the Public Works Department operates.  This worst case release scenario as generated by the model, would have 2,000 pounds of chlorine released over a ten-minute period of time.  The estimated distance to the toxic endpoint is 0.9 miles.  Under this scenario there is the potential for major offsite impact to persons within this radius at Reservoir #2 and potential significant impact at the other three facilities. Given the intensive inspection of containers upon delivery and many other safety procedures and physical layout of our facilities, a release of this magnitude would be extremely unlikely.  The containers are inspected by the chlorine vendor to industry standards, after which Public Works goes further with an even higher set of standards that each container must meet or it is rejected.  In addition, we were in the process of chan 
ging our chlorinator system to vacuum feed which, in case of a piping leak, will automatically shut down the chlorine feed at the container.  These systems have been installed at two of the four facilities. Prior to the new regulations, Public Works had begun a program to install vacuum chlorinator systems at all facilities.  These chlorinators provide an added safety margin in the event of a leak.  This retrofit program was implemented at the Wastewater Treatment Facility and the City Watershed/Headworks.  Recent regulatory changes have postponed installation at the other two facilities until it is determined that chlorine gas will remain as the disinfection method of choice.   
 
 
   Under the Alternative Release Scenario, a more likely event was entered into the software model.  This event would simulate a leaking pipe connection from the container to the piping manifold.  This would have 0.5 pounds of chlorine leaking for one hour.  The estimated distance to the toxic endpoint is 0.1 m 
ile.  This would have no offsite impact to persons within this radius at each of our facilities with the exception of Reservoir #2. 
 
 
   The Astoria Public Works Department has several programs and policies that are designed to minimize the risk of a harmful accidental release.  One of the most important of these programs is the rigorous inspection, upon delivery, of the chlorine containers and cylinders.  Before they are unloaded from the delivery truck, each container is checked thoroughly for specific conformance with our standards.  We have regularly rejected shipments that were determined not to meet our standards for container integrity, valve cleanliness and function and tare weight labeling.  Another program that is extremely important is conducted annually on our chlorination equipment.  Critical parts are replaced, cleaned and /or calibrated to ensure proper feeding of the chlorine gas.  According to our records, over the past five years, there have been no accidental releases  
of measurable amounts of chlorine from Public Works facilities. 
 
   In the event of an emergency, personnel are trained to follow strict procedures that involve the participation of our local Fire Department.  We are fortunate to have within our Fire Department a Regional Hazardous Materials Response Team. They are well trained and equipped to respond to a variety of hazardous spill events including chlorine.  Astoria Public Works has two employees who are active members of this team to provide the firefighters with increased technical knowledge of our facilities and equipment.  The Public Works Department financially assists and supports these employees' participation on this team as a safety benefit to our department and the community at large.  Because of the concerns and regulations regarding chlorine gas, engineering studies are presently underway to review our future use of chorine gas in our system. 
 
   Once a final Engineering determination is made regarding the method of disinfect 
ion, our department will work toward the implementation of that system.  Balancing safety, effectiveness and suitability for our particular system needs will be the primary goal in the selection process. 
 
   
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