Waynesboro Wastewater Treatment Plant - Executive Summary
The City of Waynesboro Wastewater Treatment Plant owns a wastewater treatment plant which treats approximately 4.0 million gallons per day of industrial, commercial, and municipal wastewater generated throughout the City. The operation of this pant is administrated by Earth Tech, Inc. Once the wastewater has received both primary and secondary treatment, there still remain bacteria in the wastewater which may be harmful to both humans and the environmnet. In order to kill these bacteria, chlorine in added at an average fee rate of 90 - 150 lbs-per-day to the wastewater via the tertiary sand filter. After the appropiate amount of contact and mixing time, the bacteria are reduced in numbers to those approved by the state. Following the chlorination process, a dechlorination agent, sulfur dioxide, is then added at an average feed rate of 75 - 100 lbs-per-day for the purpose of chemically removing the chlorine prior to final effluent discharge into the South River. |
The chlorination r
oom is located at the side of the plant with two standard 1-ton containers connected to an automatic switchover system. When one container becomes empty, the second automatically begins feeding. Standard procedure dictates the need to then order a new 1-ton container for delivery.
Along with the chlorine containers in the chlorine room are the gas feed controls. The chlorinator room is provided with a shatter resistant, hermetically sealed imspection window in an interior wall so that the equipment, ton cylinders and instrument readings are observable. The room has two doors to the building exterior --weather-stripped, panic bars and self closing device. There are no door openings to the building interior. Floor drains terminate outside the building in a safe area for venting (gravity sewer). All oher openings in the room are sealed; the room is above grade and the inside temperature of the room is maintained at 60 degrees F at a minimum. The ton cylinders are restrained in a p
osition stored separately from any organic materials, solvent or ammmonia
Chlorine is received at the plant and offloaded from the supplier with the use of an overhead hoist. The maximum amout located on site at any given time is 4,000 lbs. New containers exchanged for empty containers with the new ones being placed on scales where daily weight measurements are taken.
The chlorine room is equipped with a chlorine sensing and alarm device to measure low concentrations of chlorine gas in the room. The alarm is set to go off at 3 mg/l concentration. An exhaust fan operates automatically when the lights are turned on and remain on until the lights are turned off. The complete details for entry during alarm or emergency operations are detailed in the facility emergency action plan.
The offsite consequence analysis includes consideration of two chlorine release scenarios, identified as "worst case release" and "alternatice scenario". This was accomplished utilizing the RMP-Comp prog
ram. The worst case release has a radius of 1.30 miles and the area includes several businesses, residents, parts of the South River, several industries, a cummunity recreation park and schools. The alternate release has a radius of 0.2 miles. All of the entities in both areas are located on the maps included.
The general accidential release prevention program is based on the following key elements: (1) Preventive maintenance program, (2) State of the art process and safety equipment, (3) auditing and inspection program, (4) training of operators and (5) review of O & M manuals, PSM (June 1999 latest review) and forms.
Chemical-specific prevention steps include availability of self-contained breathing apparatus (SCBA) and awareness of the hazardous and toxic propertied of chlorine, and presence of chlorine detectors. A training seminar with demonstration specifically on chlorine was held for all plant employees by the chlorine vendor in late 1998. A SCBA training is set f
or June 22, 1999 for all plant employees.
No accidential releases of chlorine hace occurred at this facility in the past five years.
The facility emergency program is handled by the plant manager or operator on duty if the release is small in nature. The local Waynesboro Fire Department, specifically the HAZMAT team, is the local responder in case of emergency toxic release conditions. Furthermore, the LEPC is notified in a toxic release.
The What-If scenario was used to review the PSM and several areas of concern are being address to improve the quality of training and operation of the plant.