City of Nacogdoches Southside WTP - Executive Summary
EXECUTIVE SUMMARY |
1.0 REGULATED SUBSTANCES
The City of Nacogdoches Southside Water Treatment Plant (WTP) uses one regulated chemical, chlorine, in the treatment of municipal water.
Chlorine is used in the disinfection of municipal water. Chlorine is stored prior to and during use in 1-ton containers on an unenclosed concrete pad. The chlorine is stored as a pressurized liquefied gas, and is released into water using a vacuum-regulated system. The maximum intended chlorine inventory at the facility is 8,000 pounds which exceeds the RMP threshold quantity of 2,500 pounds.
Chlorine is a toxic chemical and precautions must be taken in order to prevent unnecessary exposure to facility personnel and to reduce the threat of accidental release which might result in exposure to the surrounding community and to the environment. It is our policy to adhere to all applicable Federal, State, and industry rules, regulations, and guidelines. Chemical safety at the City of Nacogdoc
hes Southside WTP is dependent upon strict operating procedures, safe handling methods, and thorough training of employees. Chlorine safety devices are also inherent in the design of the facility and in the equipment used in the chlorine chemical process.
3.0 WORST CASE/ALTERNATIVE CASE SCENARIO ANALYSES INCLUDING ADMINISTRATIVE CONTROLS AND MITIGATION MEASURES TO LIMIT THE DISTANCES FOR EACH REPORTED SCENARIO
EPA defines the worst-case scenario as total failure of the largest vessel. The alternative-case scenario is defined as a release that is more likely to occur than the worst-case scenario. The alternative-case scenario should also reach an offsite endpoint, unless no such scenario exists.
At the City of Nacogdoches Southside WTP, the worst-case scenario for chlorine would result in a release of 2,000 pounds of chlorine gas. The impact radius would be 1.3 miles and affect 1,400 persons. Public receptors would include residences, public recreation areas or arenas, and major com
mercial or industrial areas. There were no environmental receptors within the impact radius.
The alternative-case scenario for chlorine would result in a release of 580 pounds of chlorine gas. The impact radius would be 0.1 mile and affect 10 persons. Public receptors would include residences. There were no environmental receptors within the impact radius.
4.0 PREVENTION PROGRAM AND CHEMICAL SPECIFIC PREVENTION STEPS
The City of Nacogdoches Southside WTP complies with the EPA's Accidental Release Prevention Rule and with all applicable State codes and regulations. Our facility has taken all the necessary steps to comply with the accidental release prevention requirements under 40 CFR Part 68. The following sections briefly describe the elements of the release prevention program that is in place at our facility.
The City of Nacogdoches Southside WTP maintains a detailed record of safety information that describes the chemical hazards, operating parameters, and e
quipment designs associated with the water disinfection process.
Our facility conducts detailed studies to ensure that the hazards associated with our chlorine process are identified and controlled efficiently. The studies are undertaken by a team of qualified personnel and are revalidated at least once every five years. Any findings related to the hazard review are addressed in a timely manner.
For the purposes of safely conducting activities within our chlorine process, the City of Nacogdoches Southside WTP maintains written operation procedures. These procedures address various modes of operation such as initial startup, normal operations, temporary operations, emergency shutdown, emergency operations, normal shutdown, and startup after a turnaround. The information is regularly reviewed and is readily accessible to operators involved in the process.
The City of Nacogdoches WTP has a comprehensive training program to ensure employe
es who are operating the chlorine process are competent in the operations procedures associated with the processes.
The City of Nacogdoches Southside WTP conducts regular maintenance checks on process equipment to ensure proper operations. Process equipment examined by these checks includes; pressure vessels, storage tanks, piping systems, relief and vent systems, emergency shutdown systems, controls, and pumps. Maintenance operations are carried out by qualified personnel with previous training in maintenance practices. Any equipment deficiencies identified by the maintenance checks are corrected in a safe and timely manner.
The City of Nacogdoches Southside WTP conducts audits on a regular basis to determine whether the provisions set out under the RMP rule are being implemented. These audits are carried out at least every three years and any corrective actions required as a result of the audits are undertaken in a safe and prompt manner.
The City of Nacogdoches Southside WTP promptly investigates any incident that results in, or could reasonably result in a catastrophic release of chlorine. These investigations are undertaken to identify the situation leading to the incident as well as any corrective actions to prevent the release from reoccurring. All investigation reports are retained for a minimum of five years.
5.0 FIVE YEAR ACCIDENT HISTORY
In the past five years, there have been no accidental releases of chlorine that resulted in deaths, injuries, or significant property damage onsite, or known offsite deaths, injuries, property damage, environmental damage, evacuations, or sheltering in place.
6.0 EMERGENCY RESPONSE PROGRAM
The City of Nacogdoches Southside WTP employees will not respond to a chemical emergency at the plant. As required by 40 CFR Part 68.90, the City of Nacogdoches is included in the community emergency response plan and appropriate mechanisms are in place to notify eme
rgency responders when there is a need for response.
7.0 PLANNED CHANGES TO IMPROVE SAFETY
The City of Nacogdoches Southside WTP has contracted with AVIA Environmental, LLC, to assist with developing chemical specific operating procedures, training procedures, and maintenance procedures. These procedures will then be implemented in order to attain compliance with RMP regulation requirements as well as to ensure the safe operation and mechanical integrity of the RMP regulated process.