44th Street Water Treatment Plant - Executive Summary
Risk Management Plan |
A. Accidental Release Prevention Policy
The Town of Ocean City Division of Public Works accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices. All applicable procedures of the US EPA Prevention Program are adhered to. The Division of Public Works continues to evaluate and improve its procedures and practices with regards to its accidental release prevention policy.
The Division of Public Works response policy involves the preparation of response plans which are tailored to each facility and to the emergency response services available in the community, and is in compliance with the EPA Emergency Response Program requirements.
B. System Description and Regulated Substance Handled
The 44th Street Water Treatment Plant provides the Town of Ocean City with potable (drinking) water. The 44th Street Water Treatment Plant (WTP) is located on 44th Street in Ocean Cit
y, Maryland. Disinfection of water is part of the water treatment process required by the Safe Drinking Water Act and the State of Maryland. At the 44th Street Water Treatment Plant (WTP), disinfection is accomplished with chlorine treatment.
Chlorine liquid is stored and handled at the 44th Street WTP for the disinfection process. The water treatment plant chlorination system has a chlorine storage room and a chlorination room. Equipment at the facility includes liquid chlorine containers, chlorine gas manifolds, a vacuum feed system, chlorinators, safety equipment, and chlorine leak detectors.
Typically, twenty (20) 150 lb cylinders of chlorine are on site. Six of the twenty cylinders are on-line. The water treatment plant is normally unmanned. Water treatment plant operators visit the facility daily, and respond to any trouble alarms which may occur.
C. Offsite Consequence Analysis
The Offsite Consequence Analysis includes the consideration of two chlorine release scena
rios identified as "Worst-Case Release" and "Alternative Scenario". The first scenario is defined by EPA, stating that, "the owner or operator shall assume that the...maximum quantity in the largest vessel...is released as a gas over 10 minutes" due to an unspecified failure. The Alternative Scenario is defined as "more likely to occur than the Worst-Case Release Scenario." The Offsite Consequence Analysis for the 44th Street WTP was conducted with the use of the EPA Risk Management Program Guidance for Wastewater Treatment Plants.
1. Based on the tables and information provided for a worst-case chlorine release, the following was determined:
a. The "Worst-Case Release Scenario," as defined by EPA, would be for three 150 lb cylinders of chlorine to release, as a gas, in a ten minute period.
b. The toxic endpoint for Cl2 gas is 3 ppm.
c. Passive mitigation can be expected from the building housing the chlorine and this will reduce the release rate by 45%.
d. The distance fr
om the release site to the toxic endpoint is 0.45 miles.
It should be noted that the design of the chlorine feed system and the chlorine leak detection system make the possibility of the EPA described "worst-case" scenario practically impossible.
2. The "Alternative (Release ) Scenario" was evaluated with the use of the EPA Risk Management Program Guidance for Wastewater Treatment Plants. For the 44th Street WTP a possible alternative release scenario would be a release through a 1/8 inch i.d. Cl2 gas stainless steel flexible connector. Such a leak would not have an impact outside the facility boundaries. The reason for this is because of the passive and active mitigation measures that are in place. These are:
a. Building enclosure providing 45% reduction of release rate
b. Chlorine leak detection and alarm system.
D. The general 44th Street WTP accidental release prevention program and chemical-specific prevention steps are based on the Town of Ocean City's program and consi
sts of the following key elements:
1. Highly skilled and trained operators (State licensed)
2. Preventive Maintenance Program
3. Use of state-of-the-art process and safety equipment.
4. Performance of a Process Hazard Analysis of equipment and procedures
5. Implementation of an auditing and inspection program
6. Availability of SCBA to the emergency responders
7. Awareness of the toxic properties and hazards of chlorine
8. The presence of chlorine leak detectors.
E. Five-Year Accident History
No accidental release of chlorine has occurred at this facility in the past five years.
F. Emergency Response Program
The 44th Street WTP has an emergency response program that is coordinated with Town of Ocean City Volunteer Fire Department and the Ocean City Special Hazardous Intervention Team (HAZMAT). The program includes an organizational structure of emergency responders and their responsibilities. Emergency response to a leak at the 44th Street WTP would include selected person
nel of the Town of Ocean City Division of Public Works, who have specific knowledge and training for chlorine-leak response. Emergency-response drills and emergency-procedure evaluations are conducted regularly.
G.. Planned Changes to Improve Safety
Planned changes to improve safety of chlorine-handling at the facility have been approved and are expected to be implemented within the next year and include:
1. Installation of an emergency scrubber system that is sized to handle the simultaneous release of all, on-line, chlorine gas.
2. New leak detectors in the chlorinators that alarm to the Town of Ocean City Communications Center, as well as provide locally audible and visible alarms.