Regional Wast Water Treatment Plant - Executive Summary
Executive Summary - Risk Management Plan |
The City of Johnson City Water and Sewer Services Department operates three (3) wastewater treatment plants (Knobcreek, Brushcreek and Regional) and two (2) water filtration plants (Unicoi and Watauga) which all use chlorine in the disinfection process. The City of Johnson City Water and Sewer Services Department takes a very serious approach in providing safe drinking water to our customers, treating the wastewater as well as protection of the environment. As a result, the City also take a very serious approach in the way chlorine is handled, stored and used at each of our facilities. All water and wastewater treatment plants use chlorine stored in 1-ton cylinders and each facility has chlorination rooms that contain the cylinders in use as well as additional storage for cylinders not on-line. The Brushcreek and Regional WWTPs also use sulfur dioxide as a dechlorinator. The chlorination and dechlorination rooms have monitoring alarms to alert
the operators should a leak occur. Private chemical companies transport the cylinders to each facility and are off-loaded by a monorail system to the storage area. The operators at each facility have received training in the safe handling of the cylinders, proper use of personal protective equipment and self-contained breathing apparatus (SCBA) use.
This Risk Management Plan (RMP) submission was a cooperative effort between the water treatment, wastewater treatment, engineering and administration divisions of the Water and Sewer Services Department as well as the Johnson City Fire Department and the Washington County Emergency Management Agency. This plan will become part of the Local Emergency Response Plan for the Johnson City and Washington County area.
This Risk Management Plan, as submitted, followed the criteria as set forth by the Environmental Protection Agency Chemical Emergency Preparedness and Prevention Office (EPA/CEPPO) and followed the American Water Works Association
Research Foundation (AWWARF) guide, "Compliance Guidance and Model Risk Management Program for Water Treatment Plants" as a tool for development of our plan. Each facility location was mapped to determine wind speed, direction and plume modeling, using real wind speed and direction data obtained at each facility.
Regional Wastewater Treatment Plant
The Regional Wastewater Treatment Plant is located on Highway 75 in Washington County, Tennessee. The Regional WWTP is owned and operated by the City of Johnson City Water and Sewer Services Department and treats wastewater from residential, commercial and industrial users. The Regional WWTP uses liquid chlorine in 1-ton cylinders and sulfur dioxide in 150-pound cylinders. The liquid chlorine is converted to a gas, which is then injected into the treated wastewater for disinfection purposes. After the disinfection process is complete, the wastewater is then injected with sulfur dioxide prior to the treated water bein
g discharged into the South Holston River.
Accidental Release Policies and Emergency Response Policies
Should an accidental release of chlorine or sulfur dioxide at this plant occur, the plant operator is alerted to the release by alarms and the operator will follow the Emergency Response Plan (ERP) Procedures, which are defined in the department's Process Safety Management (PSM) manual. The operator will also notify the Chief Operator at this plant as well as the Superintendent of Water & Wastewater Treatment and will notify 9-1-1 of the release in which case the Johnson City Fire Department, the Johnson City/Washington County Hazardous Materials Team, and the Johnson City/Washington County Emergency Management Agency will respond to the plant site for proper mitigation of the release.
"Worst-Case" and "Alternate Release" Scenarios
The "worst-case" scenario for the Regional WWTP is based upon chlorine with a total-release of 2,000 pounds, at a rate of 200 -lbs./minute for a 10-mi
nute duration in an urban setting. This scenario is based upon Table A5-1 of the American Water Works Association Research Foundation (AWWARF) guide, "Compliance Guidance and Model Risk Management Program for Water Treatment Plants" (CLW-2).
The "alternate release" scenario for this plant was also based on chlorine, using Table A5-1 of the AWWARF guidebook, but with a different quantity released. The "alternate release" scenario is based upon a total release of 317 pounds, at a rate of 10.5 lbs./minute over a 60-minute duration in an urban setting.
The Regional WWTP also uses sulfur dioxide as a dechlorination chemical. Sulfur dioxide is shipped, stored and used in 150-pound cylinders. Therefore, "worst-case" and "alternate release" scenarios are provided although the scenarios for chlorine are the true worst case scenarios.
Wind speed and direction were obtained from actual site conditions over a 60-day time period and these were factored into the plume modeling for both the "wors
t-case" and "alternate release" scenarios. The plume models were generated using the Aloha and Cameo programs as developed by the Environmental Protection Agency (EPA).
5-Year Accident History
The City of Johnson City Water and Sewer Services Department is proud of our safety record in handling chlorine and sulfur dioxide. We have not had any accidents using chlorine or sulfur dioxide in our wastewater treatment process at this plant. This accident-free record is due mainly to the emphasis placed on safe handling of chlorine and sulfur dioxide by both management and operators.
The Regional WWTP's Prevention Program is classified as a Program 3 and also falls under the OSHA Process Safety Management Rule. One of the most important aspects of prevention is the training received by the operators and maintenance provided to this plant by our Facility Maintenance Division. Routine maintenance is performed on the chlorine and sulfur dioxide alarms as well as the ch
lorinators and cylinder regulators.
Emergency Response Program
Should an accidental release of chlorine or sulfur dioxide occur at this plant, the Johnson City Fire Department, Johnson City/Washington County Hazardous Materials Team and the Johnson City/Washington County Emergency Management Agency will respond to the plant and the LEPC Plan for Washington County will be placed into operation. The LEPC details the chain of command, public notification and if necessary evacuation procedures.
Planned Safety Improvements
At the time that this Risk Management Plan was developed, there are no planned safety improvements for the Regional WWTP but plant expansion plans may be designed in the near future. During the design process, the City will evaluate the need to upgrade any safety improvements necessary and will include these improvements in the final design. After expansion is completed, the RMP will be revised and resubmitted.