Lake Stevens Sewer District Treatment Plant - Executive Summary |
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The Lake Stevens Sewer District(LSSD) is committed to providing a safe enviornment for its employees, neighbors, customers and the surrounding community by preventing and/or controlling the accidental release of any hazardous chemicals. The LSSD Wastewater Treatment Plant, located at 500 N. Sunnyside Blvd. in rural Snohomish county, Washington, recveives wastewater from the greater Lake Stevens drainage basin and processes and disinfects the wastewater before releasing it to Ebey Slough, part of the Snohomish river esutary system. The wastewater is disinfected by introducing chlorine to the wastewater to kill harmful bacteria. Chlorine is the only toxic chemical regulated by the Risk Management Program that is present at the LSSD Wastewater Treatment Plant. The amount of chlorine on site at any given time does not exceed 6000 lbs., stored in one-ton cylinders in an enclosed building. The worst case release senario at the LSSD Wastewater Treatment Plant involves the catistrophic failu re and release of the entire contents of an entire one-ton liquid chlorine cylinder. Using EPA's dispersion modeling program, RMP Offsite Consequence Analysis Guidence table 14, the maximum distance downwind from the storage tank to an endpoint concentration of .0087ppm is 2.15 miles. An Alternative release senario was also developed based on a one-ton cylinder being dropped while unloading, causing a 1/4 inch puncture through which all of the contents of the container are released. Using the same modeling program, it is calculated the chlorine concentration from this release could reach .0087ppm up to .68 miles downwind. The toxicity of chlorine at high concentrations make it necessary for the LSSD Wastewater Treatment Plant to observe certain safety precautions to prevent unnecessary human exposure, and to reduce the threat to the personal health of employees as well as nearby members of the community. It is our policy to adhere to all appicable federal and state rules and regulati ons. Safety depends upon the manner in which we handle toxic chemicals, including equipment design, operator training and safe operating procedures. The chlorine storage and handling equipment meets or exceeds design codes and standards as well as incorporating good engineering practices recommended by by industry groups, such as the Chlorine Institute. As a result the equipment incorporates inherently safe designs. Written operating procedures are prepared and reviewed annually for accuracy and safety. Operation and maintenance personnel are thoroughly trained on proper procedures and safety hazards, and are provided with regular refresher training. Equipment and procedures are frequently evaluated and updated with the goal of continuous improvement in both operation and training. During the 5 year period between May 1994 and June 1999, the Lake Stevens Sewer District Wastewater Treatment Plant has had no reportable release of chlorine. The Lake Stevens Sewer District's Emergency Re sponse Program integrates OSHA's ans EPA's preparedness planning response and training requirements. In the event of an accidental chlorine release, the emergency response plan includes notifying local responders. Plant personnel receive classroom training in implementation of the response plan in addition to participating in training exercises. Plans to improve safety at the LSSD Wastewater Treatment Plant include the conversion to ultaviolet disinfection in the year 2001, thus eliminating the need to keep large quantities of chlorine on hand. Until that time the process will be regularly evaluated to assure the safety of employees and neighbors. |