Day Street Pump Station - Executive Summary
Policy Statement |
It is the policy of the Day Street Pump Station (PS) and of the Montgomery Water Works and Sanitary Sewer Board (MWWSSB) to operate the pump safely, reducing to the greatest extent possible any hazards associated with the processes and reducing any subsequent risk to the surrounding community, personnel, and environment. The policy includes working with the surrounding community and local emergency response agencies to promote a spirit of cooperation and teamwork and to orchestrate an effective contingency plan in the unlikely event that a process incident occurs at Day Street PS.
Stationary Sources and Regulated Substance Handled
Primary Activities: Drinking water treatment is the primary activity.
Use of Regulated Substances: Chlorine is used primarily as a disinfectant.
Quantities of Chlorine Handled or Stored
Amount Handled: 1 one-ton container, equivalent to 2,300 pounds
Amount Stored: 4 one-ton containers, equivalent to 9,200 pounds
Chlorine Worst-case Rel
Failure of one liquid chlorine cylinder resulting in a release of 2,300 pounds of chlorine in 10 minutes. There are no administrative controls in place. The 4 containers are stored in an enclosed building with a concrete roof. The building is 17 feet long and 12 feet wide. The actual release rate is 55 percent of the total chlorine released in the enclosed building because of passive mitigation. The actual release rate of 0.96 kg/s is modeled using DEGADIS 2.1.
Distance to Endpoint: Under the worst-case weather conditions prescribed by the RMP rule, the distance to a toxic endpoint of 3 ppm is 2.02 miles, beyond which there will be enough dispersion to no longer pose a hazard to the public.
Chlorine Alternative Release Scenarios
Release of chlorine from a pipe of 3/8-inch in diameter connecting the chlorine container to the evaporator. For a release duration of 15 minutes, the release rate is 0.10 kg/s. A chlorine scrubber and accessory equipment will be in
stalled and be operational by January 1, 1998. Once installed, the chlorine sensors at Day Street PS can detect concentrations of chlorine greater than 5 ppm and activate the chlorine scrubber. The chlorine scrubber will be designed to remove chlorine with an efficiency of 99 percent. The release rate from the scrubber will be 0.001 kg/s, which is modeled using DEGADIS 2.1.
Distance to Endpoint: Under realistic weather conditions of 3.0 m/s wind speed and a wind stability class of "D," chlorine could travel 0.07 miles or 0.11 kilometers before dispersing enough to no longer pose a hazard to the public.
Accidental Release Prevention Program and Chemical-specific Prevention Steps
Day Street Pump Station is in compliance with the RMP Rule, 40 CFR 68. The facility has conducted a comprehensive review of all systems, as well as administrative, technical, operating, and maintenance procedures, in addition to the other required program elements of the RMP rule. A hazard review was
conducted at this facility using a checklist extracted from the Guidelines for Hazard Evaluation Procedures.
Five-year Accident History
Day Street PS has never had a release of chlorine, as defined by the RMP Rule.
Emergency Response Program
The MWWSSB has an Emergency Response Program that applies to the Day Street PS, which coordinates response efforts with the local fire department's HAZMAT team, the police department, and the hospital. Response activities also have been discussed with the Alabama Emergency Management Office.
Planned Changes to Improve Safety
The changes to improve process safety identified during the Hazard Review of Day Street Pump Station and those identified in the report, Vulnerability Analysis of the Water and Wastewater Systems, are given below. The installation of chlorine scrubber and associated equipment is underway, as follows:
1. Install smoke detectors and natural gas leak detection equipment.
2. Relocate low-lying electrical lines that i
nterfere with chemical deliveries.
3. Increase security by modifying the main entrance gate to prevent unauthorized personnel from accessing the site without the proper security code.
The following modifications have been completed in response to the hazard review:
1. Installed chlorine scrubber for mitigation of chlorine gas releases.
2. Provided alternative power source for emergency operations.
3. Provided adequate fire extinguishers throughout the facility.