John M. Asplund Wastewater Treatment Facility - Executive Summary
Facility personnel as well as upper management have a strong commitment to safety at all of the Anchorage Water and Wastewater Utility (AWWU) facilities. Specifically, at the John M. Asplund Wastewater Treatment Facility, monthly safety meetings are held to discuss predetermined issues such as ladder safety, forklift safety, and chlorine safety. In addition, weekly operations meetings are held and safety issues are discussed as they come up. New personnel are trained prior to starting work at the facility. Dangerous or hazardous equipment and/or chemicals are well labeled, MSDS sheets on all compounds used at the facility are readily available, and new personnel are always accompanied by experienced personnel when handling compounds such as chlorine. |
The John M. Asplund Wastewater Treatment Facility is subject to RMP since it stores gaseous chlorine in quantities greater than the threshold for the program. The facility treats municipal wastewater. Gaseous chlorine is injected int
o the treated wastewater for disinfection as the last process prior to release into Cook Inlet. Eight to twenty one 1-ton containers of chlorine are stored at the facility at any one time.
A worst-case release scenario was modeled to determine potential offsite impacts. The worst case scenario involves release of the largest vessel (1-ton) in 10 minutes as described in the guidance for the RMP program. Since the chlorine is stored in a building, a passive mitigation factor of 55% of the unmitigated release rate was used. This modeling resulted in a toxic endpoint of 3 PPM out for a radius of 1.34 miles. Within this radius there are no schools, residents, hospitals, or prisons/correctional facilities. There are recreation areas, commercial areas, and an officially designated wildlife refuge within this radius.
An alternative release scenario was also modeled to determine potential offsite impacts. This scenario involves a manifold rupture that would release 10 pounds of chlorine in
1 minute. This scenario was selected as the worst of the more likely scenarios. Passive or active mitigation was not assumed for this scenario. This modeling resulted in a toxic endpoint of 3 PPM out for a radius of 0.31 miles. Within this radius there are no schools, residents, hospitals, prisons/correctional facilities, or commercial areas. There is a recreation area and an officially designated wildlife refuge within this radius.
The facility is also in compliance with the Process Safety Management (PSM) program and the SARA Title III program. Several ongoing steps are taken to prevent accidental releases. They include continuous evaluation and updating of the system such installing additional shut-off valves, making maintenance procedural improvements as they are recognized, and implementing on-site training on a regular basis.
The facility has had three minor accidents in the last five years. In each case less than one pound of chlorine was released and no off-site consequence
s were experienced. One accident involved a minor release of chlorine which remained as residual in the pipes after the system was emptied. Review of this accident resulted in a procedure of wearing respirators when working with or changing chlorine containers. The other two accidents involved an improperly seated connection which released a small amount of chlorine when the valve was briefly opened and immediately shut off when the sound of the leak was heard. Each of the three accidents resulted in taking one person to a hospital for observation.
No other impacts occurred.
The emergency response program for the facility primarily involves response by the Anchorage Fire Department (AFD). The AFD has well trained and equipped Hazmat teams who will respond in the even of an uncontrolled leak. AFD and AWWU personnel have participated together in emergency response drills. As part of the Comprehensive Emergency Management Plan for the Municipality of Anchorage, the facility is on
e of the listed dispatch centers which are in contact with the Emergency Operations Center during an emergency.
Recently it was determined that certain types of releases such as slow leaks could be minimized by installing vessel shut-off valves that are actuated through the leak detection system. The valves are presently on order and will be installed upon receipt. Modeling of the alternative release scenario assumed these valves are in place.