Tyrone Wastewater Treatment Plant - Executive Summary
Borough of Tyrone
Wastewater Treatment Plant
Route 453 One Mile South of Tyrone
Tyrone, PA 16686
The Borough of Tyrone takes pride in observing the required safety precautions in preventing hazards in the workplace, and has an emergency response plan in effect in the event of accidental releases of regulated substances. The emergency response plan is tailored for the wastewater treatment facility owned and operated by Tyrone. Tyrone employs the latest technology in process controls and monitoring detection systems. Active and passive mitigation systems are designed to minimize the impacts of any accidental releases of regulated substances.
The Tyrone Wastewater Treatment Plant (WWTP) provides sewer service to residential, commercial and industrial users in the Boroughs of Tyrone and Bellwood, and in portions of Antis and Snyder Townships, Blair County. The WWTP utilizes one (1) chemical onsite which is subject to the Chemical Accident Prevention provisions found at 40 CFR Part 68.
This toxic substance is Chlorine. Chlorine is used for disinfection of the treated wastewater prior to its discharge to the Little Juniata River.
Typically, there are three (3) one-ton containers of chlorine present onsite at any given time. These containers are located in a chemical storage building. The room containing the containers vents to the outside. The chlorination feed system has a manual shutoff for emergency situations. A remote alarm system is employed to notify employees of any releases of chlorine gas. Safety equipment is located nearby. The facility is manned 16 hours per day, five days per week, plus 2 hours each weekend day. Gates to the facility are locked when personnel are not on duty, therefore, the chlorination building is not accessible to the public.
The offsite consequence analysis conducted for Tyrones WWTP consisted of two scenarios, worst-case release and alternative release. The parameters for the worst-case release scenario are established by EPA. Th
ese parameters assume the maximum quantity in the largest vessel is released over a 10-minute period with default wind speed, temperature and humidity conditions. The only passive mitigation present at the Tyrone WWTP is that the chlorine containers are stored in a building which vents to the outside air. Using EPAs RMP*Comp model, the estimated distance to the toxic endpoint for a worst-case release is 0.9 miles. The estimated residential population within the 0.9 mile radius of the facility is 150 persons based on 1990 U.S. census data. The public receptors include residential, commercial and industrial users.
The proposed alternative release scenario assumes a release will occur due to equipment failure. The assumed parameters used in the RMP*Comp model are based on an actual incident that occurred at a similar WWTP, in which a screw on the yoke assembly of the vacuum regulator could not be tightened and a small amount of chlorine was released. It is estimated that the duration of
the release was less than one minute and that no more than one pound of chlorine was actually released into the room atmosphere. The estimated distance to the toxic endpoint for the alternative release is less than 0.1 mile. The estimated residential population within the 0.1 mile radius of the facility is 1 person based on 1990 U.S. census data.
A prevention program policy document was developed for Tyrones WWTP in accordance with regulations found at 40 CFR ''68.48-68.60. The facility is classified as a Program 2 facility. Tyrones Program 2 Prevention Program summarizes the pertinent safety information, hazard review procedures, operating procedures, training requirements, maintenance procedures, compliance audits and incident investigation policies.
The facility has standard operating procedures (SOPs) in effect for operation and maintenance of the chlorination system. These SOPs are readily accessible to the chlorine building. Safety precautions include, checking the chlorin
e detector before entering the chlorine storage room, use of a face mask and other appropriate personal protective equipment, and testing for leaks with ammonia solution. A chlorine emergency kit "B" for 1-ton containers is available to contain small leaks and for minor repairs. Appropriate training on the use of the chlorine kit is provided to all employees. Other training plant employees are offered include: confined space entry, excavation and trenching, lockout/tagout procedures and first aid. Documentation of the training events for each employee is maintained in the employees personnel file.
Tyrone has an Off-Site Emergency Response Plan in effect which has been coordinated through the Blair County LEPC. The Plan provides notification procedures, emergency response procedures, reporting requirements, and coordination efforts of all involved parties. The plan is reviewed and revised periodically to ensure contact names and telephone numbers are correct.
It is important to note
that the Tyrone WWTP will begin an upgrade project in 1999. During calendar year 2000, a UV disinfection system will be added to replace the existing chlorination system. Within six (6) months following the completion of this new disinfection installation, Tyrone will notify EPA and request to be de-registered from the requirements of the RMP rule.