West District Wastewater Treatment Plant - Executive Summary
The City of Baytown has incorporated a low risk approach to chemical safety. We have implemented safety procedures over the past years to reduce the possibilities of chemical releases. We also have a commitment to review our policies and procedures periodically to improve our safety program. |
The City's wastewater treatment facilities use the chemicals Chlorine and Sulfur Dioxide as part of its process for disinfection of treated wastewater and for removal of residual chlorine (chlorine that is left over in the wastewater after the disinfection process is complete) before it discharges to the bay or river. The wastewater facilities do not manufacture the Chlorine or Sulfur Dioxide. The chemicals are ordered from an outside company and brought by truck to the facilities in 2000 pound steel containers designed specifically for these chemicals. Each site ususally stores one to three containers of each chemical.
The Worst Case and Alternate scenarios in the City's pro
gram were developed using the Environmental Protection Agencies Risk Management Program Guidance for Wastewater Treatment Plants (40 CFR Part 68). A Worst Case scenario would be a catastrophic failure of all safety systems and no response from trained emergency responders. This scenario consists of a 2000 pound container releasing its entire chemical within a ten minute period. This scenario would have a chemical plume that could reach up to 1.3 miles and possibly have an offsite impact. The Worst Case scenario is unlikely to happen because of several safety systems in place.
First, the chemical containers are inspected by the company that supplies the chemicals to assure they meet safety specifications designed for those containers.
Second, the systems used to draw the chemicals out of the containers are a total vacuum system. The systems have a vacuum regulator valve attached to the container that is designed to shut off automatically in the event there is a brea
k in the system stopping any release of the chemical.
Third, the vacuum system is formally inspected by trained operators once every three months, and visually inspected every time an empty container is changed to a full one.
Fourth, in the event a leak occurs due to a failure of all safety systems, we have operators on call that are trained in the first response to stop or minimize the leak. These operators also have links to off-site responders such as the Hazardous Material Team from the company that supplies the chemicals and the local Fire Department.
The Alternate scenario would consist of a leak of chlorine gas due to a tubing failure or failure of a connection or valve. The total release of this scenario would be 111 pounds in a three minute period. The distance the gas would travel is 0.1 mile under normal wind conditions and could have an off-site impact. This scenario is also unlikely to happen because of the same safety systems in place as listed in
the Worst Case scenario.
Another Alternate Scenario would consist of a leak of Sulfur Dioxide due to tubing failure or failure of a connection or valve. The total release of this scenario would be 54 pounds in a three minute period. The distance the gas would travel is 0.1 mile under normal wind conditions and could have an off-site impact. Because the Sulfur Dixoide systems are identical to the Chlorine system, this scenerio is unlikely to happen because of the same safety systems in place as both chlorine senerios.
Through careful handling pratices and safe procedures using these gases, the City has never had an accident. The City has a training program in place for the operators at all of its wastewater treatment plants. The operators have hands-on training exercises every three months using the leak repair equipment, and personal protective equipment. The operators also have communications links with the Fire Department, which has access to the emergency siren
alert system. The alert system is a set of sirens stationed in various areas around town that are used by the City and Industry to alert citizens in the event of a chemical release. When the sirens are sounded, residents can be informed of the event through a local emergency radio station.
The City's Wastewater Treatment Division reviews its safety procedures at its quarterly safety meetings and takes consideration of new ideas that may improve safety practices. The City will continue to monitor its practices to provide a safe environment for the public as well as our personnel.