Eureka Wastewater Treatment Plant - Executive Summary

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I.     Introduction and Executive Summary 
 
A. Background 
 
The storage, use and handling of hazardous materials by businesses, agencies and households has grown exponentially since the development of the petrochemical industry and allied chemical manufacturing industries.  This expansion has been one link in a chain of developments that has supported an increase in the general lifestyle of western culture.  While many of the advancements and applications of newly developed chemical products have had direct positive effects on public health, other situations, e.g., contamination of drinking water sources, have had both real and at times perceived negative effects.  Accidental releases of acutely hazardous chemicals from industrial sites has been one type of incident that has had negative consequences and catalyzed public awareness.   
 
During a ten year period from 1974 to 1984 at least four major accidents, most notably Bhopal, India, occurred which had catastrophic effects on surroundi 
ng populations.  Although the accident at Three Mile Island during this same period was a radioactive versus chemical release, it further sensitized the public, and governmental agencies, to the potential hazards and risks posed by the use of acutely hazardous materials in relatively close proximity to populations.   
 
The regulatory agencies responded by adopting legislatively mandated requirements which focused on the prevention of such accidental releases of acutely hazardous materials.  First, the Federal Occupational Safety & Health Administration enacted the Process Safety Management standard that requires affected facilities to identify and analyze the potential causes which could lead to releases and then implement mitigation and prevention steps, including additional employee safety training.  The U.S. Environmental Protection Agency then followed with amendments to the Clean Air Act (section 112(r); 40 CFR 68) which focuses on prevention of releases which could have potential  
offsite consequences to either the public and/or environmental receptors.  This latter requirement is titled Risk Management Programs for Chemical Accidental Release Prevention or more generically referred to as the Risk Management or RMP program.   
 
The Elk River Wastewater Treatment Plant must comply with both the OSHA Process Safety Management standard and EPA RMP regulation by virtue of the volume of chlorine and sulfur dioxide (PSM only) that is present on site at any one time.  The Eureka water treatment facility will have to comply with California's version of the RMP regulation at some point in the next year due to the volume of chlorine stored and used at that location.  The content of the PSM plan  constitutes a substantial portion of the RMP plan and, consequently, there is some economy of effort when complying with both and the integration helps facilitate a consistent approach with regard to multiple agency enforcement.   
 
A. Executive Summary 
 
The City of Eureka and the m 
anagement of the Elk River Wastewater Treatment Plant are committed to providing a safe and healthful workplace free from recognized hazards as well as minimizing to the greatest extent practicable the risks to the public and visitors.  This commitment is embodied in this Risk Management Program plan for the prevention of accidental releases of acutely hazardous materials and in particular chlorine gas.  Risks shall be reduced by ensuring that recognized industry standards of process engineering and hazard mitigation engineering are employed along with effective administrative procedures including emergency response and employee training.   
 
This RMP focuses on the prevention of release of chlorine gas from the wastewater disinfection process.  This process involves the extraction of gaseous chlorine from 1 ton compressed gas cylinders and subsequent injection of that chlorine into solution in the wastewater effluent.  The phase during which the chlorine is extracted and delivered to t 
he injectors via piping is the period during which an accidental release could potentially have offsite consequence depending upon the extent of the release.   
 
The RMP regulation mandates that facilities assess at least two scenarios of potential releases, one a default worst-case release and an alternate scenario.  The parameters effecting the dispersion of an airborne release for any given situation, e.g., release rate, ambient temperature, wind speed, etc., are mandated as default values by EPA for the worst-case release scenario.  Under these set conditions the release rate is defined as the loss of the entire contents of the largest container, in this case 1 ton, in ten minutes.  EPA acknowledges that such a scenario may well be, as it is in this case, so improbable as to be a near impossibility.  Likewise, the physical properties of chlorine are such that 1 ton of it could not be released and dissipate as a gas in ten minutes.  This scenario depicts a catastrophic breach of the  
1 ton cylinder and under these circumstances there are no mitigation measures in place to effectively address such a release.  This type of catastrophic cylinder breach could only be brought about by perhaps a roof collapse or an airplane striking the cylinder.  Under these highly improbable scenarios any engineered mitigation measures would likewise be destroyed and, thus, rendered ineffective.   
 
The parameters characterizing both the cause and dispersion factors for the alternate release scenario are to be selected by the operator of the facility taking into account accidental release history, process design and operating procedures, and location-specific climatic and topographic data.  EPA does dictate, however, that the alternate release must reach an endpoint offsite regardless of how unlikely it is to occur just as long it exists as a potential.  The alternate release scenario selected involves the release of chlorine gas through a 5/16" diameter hole in the tank valve for a per 
iod of 90 minutes.  The primary mitigation measures to address this would be to apply a fine water spray to the release point until the Humboldt/Del Norte Hazardous Materials Response Team, stationed at Eureka Fire Department, responds and stops the release.   
 
The wastewater treatment plant's Process Safety Management and Injury & Illness Prevention plans, as well as standard operating procedures and preventative maintenance form the core of the accidental release prevention strategy.  These programs ensure that regular facility & equipment inspections, preventative servicing and repairs are made in a timely manner and, consequently, reduce the risk of equipment failure that could interrupt the disinfection process and/or potentially lead to a release of chlorine.  On-going employee training prepares employees to respond effectively and rapidly to releases or threatened releases of chlorine.  Additional steps implemented to reduce the risk of an accidental release includes cylinder in 
spection procedures prior to acceptance during delivery by the vendor and third-party observations and assessments of operating and response procedures.   
 
The wastewater treatment industry has overall an excellent safety record for the storage and use of chlorine.  Likewise, the Elk River plant has never had any release that presented a serious health risk to individuals offsite nor any minor release in the last five years which resulted in injury or illness [This wording needs to be checked by Clay & company.] In 1997 there was a minor sulfur dioxide release resulting from a break in the sulfur dioxide injector feed line to the outfall pipe.  In 1998, a faulty valve on a tank created a leak when connected to the pigtail tubing; the tank was taken out of service.   
 
The emergency response program for the wastewater treatment plant emphasizes a rapid defensive response to maintain employee safety and, if necessary, quickly activate a response by the hazardous materials response team.   
The level of response by treatment plant personnel is limited to that which is possible with use of air-purifying respiratory protection.  This will include most minor leaks.  Any major leak necessitating the use of supplied air respirators such as self-contained breathing apparatus will require the response of the Eureka haz-mat team.  The response procedures also include making the proper notifications to Humboldt County Environmental Health Division and other agencies.   
 
During development of the Process Safety Management plan and recent review of operating procedures, some changes have already been implemented as means to reduce the risk of an accidental release.  The use of a cylinder receiving checklist now provides a procedure whereby full cylinders being delivered by the vendor can be checked to make sure that they are in compliance with federal hydrostatic testing requirements.  These periodic testing requirements are directly related to the structural integrity and strength  
of the cylinders.  Any cylinders which are either overdue for testing or could become overdue for testing while onsite are not accepted for delivery.  A spare regulator is now going to be kept onsite as an emergency replacement unit should a regulator that is in use develop a leak.
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