City of Ukiah Water Treatment Plant - Executive Summary

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    1.   Accidental release prevention and emergency response policies 
         The City of Ukiah uses chlorine gas to disinfect the potable water it produces for the 
    protection of this community and to meet state health codes and EPA guidelines for the 
    protection of the distribution system.  
         Being aware of this, the city has prepared an extensive training program, in both safety 
    and first aid, for those employees that have to manage and handle chlorine.   They also 
    demanded certain safety equipment to be considered and implemented in the construction 
    of the water treatment plant. 
         They have educated the police and fire departments  about emergency procedures in case 
    of an accidental release.  These procedures further protect the community which we serve 
    and in which we live. 
    2.   The stationary source and regulated substances handled 
         The primary purpose of the City of Ukiah, Public Utilities Department's, Water  
    is to provide to the community an adequate, safe, and healthy supply of water.  The 
    primary source of water to the community comes from the water treatment located 
         behind the men's softball fields east of highway 101.  The treatment plant receives chlorine 
    in one ton containers that are approved for use by the Chlorine Institute.  These 
    containers have been inspected and hydrostatically tested before shipment and visually 
    inspected again upon receipt at the plant.  These cylinders contain liquid chlorine under 
         The properties of chlorine that make it an effective disinfectant against the microbes that 
    are present in our source water also makes it dangerous to humans in higher 
    concentrations.  Chlorine is a greenish-yellow gas that is two an one-half times heavier 
    than air, has a pungent odor, and is toxic to humans above 10 ppm (parts per million).  It 
    will increase in volume from liquid to gas app 
roximately 460 times.  When it combines 
    with moisture it creates both hydrochloric acid, HCl, and hypochlorous acid, HOCl, both 
    of these chemicals are corrosive and can cause severe respiratory and ocular damage. 
         The chlorine storage area is a secure area within the plant grounds and the total maximum 
    amount at the plant is 4000 pounds. 
    3.   The worst case scenario and alternative release scenario 
         The worst case scenario that has been developed for the City of Ukiah water treatment 
    plant uses the premise that there are no safety factors involved.  It is assumed that the 
    wind is blowing at 4.5 mph and that the temperature is 77E.  The scenario further states 
    that all 2000 pounds of one container would convert from liquid to gas and disperse within 
    ten minutes from within an enclosed room.  The results of this model determine that the 
    chlorine gas would have to travel 1.3 miles in the direction of the wind in order to be 
    reduced to 3 ppm.  Depending on the wind direction this would affect all of Ukiah proper 
    going as far south as Talmage Rd. and as far north as Ackerman Cr.  The cemetery to the west       and to the east dispersion would be limited by the foothills.  This, again depending on the 
    direction of the wind, would involve all of the schools, all hospitals, juvenile hall, all 
     commercial and industrial sites, all parks, all day care centers, and all residences down 
    wind from the treatment plant. 
         The alternative release scenario takes into account that there are safety features designed 
    into the plant and the fact that the most likely leak that may occur would release less than 
    twenty-one ponds per minute for less than fifteen minutes. 
         The system in use at the treatment plant is a pressure/vacuum system and the pressure 
    portion involves the cylinder, valve, and less than four inches from the chlorine cylinder to 
    a vacuum regulato 
r.  The vacuum side is approximately seven feet and is controlled by the 
    vacuum regulator.  This means that if a vacuum is not being applied the vacuum regulator 
    is closed and there is no gas flow.  If the vacuum regulator were to fail the vacuum side of 
    the system would then be pressurized and the flow would be equivalent to the degree of 
    failure.  The plant has installed, two chlorine gas detectors that have battery backup.  
    These detectors are set to alarm at 1-3 ppm.  When they alarm several items automatically 
    come into play.  The first is the chlorine scrubber which is a chemical neutralization 
    process specifically for chlorine.  This draws the heavy gas into a tank engineered to mix 
    the chlorine gas with the contents.  Thus no gas will escape to the atmosphere.  The 
    second item that happens simultaneously with the first is an audible and visual alarm 
    indication and the water supply to the injectors is closed.  The third item is t 
hat after one 
    minute our phone system automatically calls the City of Ukiah dispatch center and they in 
    turn dispatch first the fire department and then the necessary plant personnel to investigate 
    the cause of the alarm.  The fourth item is the computer at the plant will shut down the 
    plant and eliminate any further draw of chlorine other than the leak.   
         With all of these factors involved during a minute leak, the incident and any effect will be 
    isolated to the enclosed space and there will be no off site impact. 
At well 5 there aren=t any safety factors currently in place except for the fact it is in an        enclosed room.  With a twenty-one pound per minute release the duration with a 150 pound           cylinder would be just over seven minutes long.  With no alarms the entire contents would be           lost. The release would be minimal and would cover approximately one-tenth of a mile, and           would not affect any residences, recreatio 
n areas, commercial or industrial sites, schools,               hospitals, or day care centers. 
At well 2, like well 5, there are no safety factors on site and with the same release scenario         there would be approximately twenty-four people involved because of the proximity of the         softball fields.  
    4.   The general accidental release prevention program and the specific prevention steps 
         The City of Ukiah water treatment plant is actively involved in several regulatory 
    mandates when it comes to handling and using chlorine gas.  These are OSHA Reg 29 
    2735, and the STATE EPCRA. 
         The OSHA Reg CFR 1910.38 Emergency Action Plan sets specific guidelines on training 
    in safety and maintenance prior to an emergency and if an emergency might occur. 
    The OSHA PSM (process safety management) covers nearly identical features. 
     The State Health and Safety Code 2735 
covers air quality. 
         The State EPCRA is the Emergency Planning Community Right-to-know Act and sets 
    guidelines for the notification of the community in the event of a release above a pre- 
    determined amount. 
    The EPA CFR 40 is the Federal Clean Air Act.  
         The city is acutely aware of the importance of safety meetings, safety training, 
    maintenance training for its employees, and the community's right to know about the 
    situations which could cause impairment or death.  As such we at the treatment plant are 
    even more aware because the water which we deliver to the community has to be healthy 
    and the products we use to achieve this can also cause illness if not handled carefully and 
    if the safety parameters are not kept under close scrutiny.  As water treatment specialist 
    we receive many technical publications and journals that outline changes in procedure and 
    new products on the market for enhancing our water or for monito 
ring the process.  We 
    also occasionally receive product updates on the equipment already installed and material 
    used in our process.  Safety and technology are a part of our day-to-day operation. 
         We also use the manufacture's Operation and Maintenance manuals as a reference as to 
    the regularity of maintenance of the equipment we use. This equipment is also installed 
    using the Chlorine Institute as an authority for material and products. 
         Part of our maintenance on the scrubber includes running the system weekly and checking 
    the pressure readings and daily checking the seal pressure and noting the liquid level in 
    the tank. 
         Part of our maintenance on the chlorine system is to daily inspect the system and when 
    there is no demand, to check the pressure and vacuum sides for leaks.  
         Personal safety items that we have on hand and maintain include chemical exposure suits, 
    hard hats with face shields, safety showers, 
self contained breathing apparatus, and a 
    Chlorine Institute type "B" chlorine repair kit. 
    Our training is usually conducted by a certified instructor. 
    5.   The five-year accident history 
         Because of the knowledge, training, and  responsible attitude of the employees and the 
    commitment of the management to be accident free when it comes to chlorine, there have 
    been no releases, accidental or otherwise, for greater than five years. 
    6.   The emergency response program 
         See EAP.TXT attachment. 
    7.   Planned changes to improve safety 
         The treatment plant personnel, after reviewing our recent process hazard analysis, have 
    determined that the following items should be changed: 
         A windsock should be installed to assist emergency personnel in determining the direction 
    of the most  severely affected areas in case of an accidental release. 
         Indicator lights should be installed on the alarm panel t 
o further designate which part of 
    the process, pressure or vacuum is in alarm. 
     Move a gas vent closer to within the proximity of the gas detector. 
         Install a tie down system for the cylinder in storage.  The cylinder in use is already in the 
    tie down status. 
    Possibly install automatic louvers in the scrubber line to prevent back draft.
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