Water Reclamation Facility - Executive Summary |
|
EXECUTIVE SUMMARY Accidental release prevention and emergency response program and policies The Padre Dam Municipal Water District, Water Recycling Facility (WRF) , has an effective and well implemented emergency response plan in effect. The plan, included within Padre Dam Municipal Water District's Risk Management Plan, has been developed and designed with the following in consideration: The WRF's plan is designed to provide the following: 1. To protect the lives of the Water Reclamation Facility staff, support activities related to release prevention and mitigation, and to protect ANY public receptors within the toxic endpoints of an accidental release. 2. For the purpose of mitigating all potential releases from the Facility and to prevent injuries. 3. To minimize damage to property and to the surrounding environment Padre Dam Municipal Water District has taken on an aggressive hazardous materials emergency response training program to prevent any potential rele ases from the Water Reclamation Facility. This activity has included the purchase and outfitting of a 16' Hazmat emergency response trailer which contains all the tools and communication equipment necessary for an effective response a chemical release, a quarterly training program on emergency responses to hazardous material releases, and a quarterly hazardous materials emergency response drill coordinated with the Santee Fire Department, the City of San Diego Hazmat Unit and the County of San Diego Hazmat Unit. All personnel actively participate with the safety training and planning for the facility. The Water Reclamation's Hazardous Materials Business Plan as well as the safety plan provides the personnel organization and notification needed to effectively attend to Chlorine and Sulfur Dioxide chemical release issues. The Emergency Response Plan identifies health hazards and mitigation procedures which will be implemented to respond effectively should an emergency situation ar ise. The plan is an active part of the operation of the Water Reclamation Facility and as such is it updated on a regular basis and not less than once per year. All effort are made to ensure that the Plan meets compliance with the PSM, RMP, and CalARP regulations. Padre Dam Municipal Water District also maintains a safety committee that performs safety and hazardous materials audits its facilities on a regular basis including the Water Reclamation Facility. The safety committee reviews documents related to the operation of the WRF facility including the Hazardous Materials Business Plan. Stationary Source and Regulated Substances Padre Dam Municipal Water District, Water Reclamation Facility began operation in 1967. The address of the Facility is 12001 North Fanita Parkway, Santee, CA 92071. The Facility used Chlorine injection until 1975, when it was discontinued due to a change in processes. Chlorine and Sulfur Dioxide were re-introduced to the facility in 1996/97 as a result of an upgrade and expansion of the Facility to a 2 MGD Wastewater treatment facility. The Facility treats wastewater to Title 22 reclaimed water standards for distribution into a reclaimed water system within the Santee region. Chlorine and Sulfur Dioxide are fed through a system consisting of one-ton containers which are the storage vessels for chlorine and Sulfur Dioxide. Chlorine and Sulfur Dioxide gas are drawn from a maximum of one tank at a time through a vacuum regulator to the Chlorinators and Sulfur Dioxide injectors. Still under vacuum from the Chlorinators and the Sulfur Dioxide injectors, the gas is drawn to injection pumps and mixed with water for distribution through-out the wastewater treatment plant. Maximum chlorine stored at facility is 5 one-ton cylinders for a total of 10,000 pounds. Maximum Sulfur Dioxide stored at the Facility is 4 one-ton cylinders for a total of 8,000 pounds. Hazardous Assessment Summary Worst Case Release Result Summary Scena rio Description: Release of the maximum quantity of chlorine that can be stored in a vessel - 2,000 pounds. Two cylinders are hooked at a time and both are separated by vacuum breaker assemblies that shut down should either cylinder fail. 2,000 pounds released at 200 pound per minute in 10 minutes. The tanks are stored enclosed in a building, therefore, passive mitigation measures were used. Additionally, the storage building is connected to an air scrubber that can neutralize the effects of a release of a one ton cylinder. The most pessimistic meteorological conditions were used: 1.5 meters per second wind speed, and F stability. Reference tables from the EPA's RMP Offsite Consequence Analysis Guidance, and EPA's RMP Guidance for Wastewater Treatment Plants, along with the SLAB modeling program were used. Distance to Toxic End Point: 1.2 miles, based on EPA's RMP Guidance for Wastewater Treatment Plants. Scenario Description: Release of the maximum quantity of Sulfur Dioxide th at can be stored in a vessel - 2,000 pounds. Two cylinders are hooked at a time and both are separated by vacuum breaker assemblies that shut down should either cylinder fail. 2,000 pounds released at 200 pound per minute in 10 minutes. The tanks are stored enclosed in a building, therefore, passive mitigation measures were used. Additionally, the storage building is integrated with a fine mist overhead sprinkler system for active mitigation of an sulfur dioxide release. The most pessimistic meteorological conditions were used: 1.5 meters per second wind speed, and F stability. Reference tables from the EPA's RMP Offsite Consequence Analysis Guidance, and EPA's RMP Guidance for Wastewater Treatment Plants, along with the SLAB modeling program were used. Distance to Toxic End Point: 1.2 miles, based on EPA's RMP Guidance for Wastewater Treatment Plants. Alternative Release(s) Result Summary Scenario Description: A release of chlorine gas from a 1/4 inch diameter leak. The relea se rate of chlorine due to the pressure of the tank is 10.1 pounds per minute. However active and passive mitigation measures were utilized since the building is enclosed and has a scrubber system designed to remove contained chlorine gas from the room to be neutralized and vent the neutralized gas into the atmosphere. Consequently, the release rate after these measures was calculated to be 3.2 pounds per minute. The meteorological conditions used were 3 meters per second wind speed, and D stability. References tables were from EPA Guidance Documents as well as the SLAB modeling program were used. Distance to Toxic Endpoint: 0:1 miles, based upon EPA's RMP Guidance for Wastewater Treatment Plants. Scenario Description: Because chlorine gas and sulfur dioxide gas share nearly identical physical properties and are stored, injected and are mechanically connected the same at the Water Reclamation Facility, a similar scenario was used: A release of sulfur dioxide gas from a 1/4 inch diameter leak. The release rate of sulfur dioxide gas due to the pressure of the tank is 10.1 pounds per minute. However active and passive mitigation measures were utilized since the building is enclosed, has an air venting scrubber system designed to remove contained sulfur dioxide gas from the room and has a active mist sprinkler system to knock down sulfur dioxide within the room. Consequently, the release rate after these measures was calculated to be 3.2 pounds per minute. The meteorological conditions used were 3 meters per second wind speed, and D stability. References tables were from EPA Guidance Documents as well as the SLAB modeling program were used. Distance to Toxic Endpoint: 0:1 miles, based upon EPA's RMP Guidance for Wastewater Treatment Plants. Accidental Release Prevention Program and Chemical Specific Prevention Steps The Padre Dam Municipal Water District has an aggressive and active safety program in place to manage the handling of chlorine and sulfur dioxide gas. Practices and procedures proper chlorine handling were obtained from the Chlorine Institute Manual for the Safe Handling of Chlorine. Because sulfur dioxide gas is nearly identical in physical properties to chlorine and is stored and feed in identical cylinders as Chlorine, same safety practices are used for sulfur dioxide. In addition to plant safety program for the handling of chlorine and sulfur dioxide, there are chlorine gas detectors in the chlorine storage and feeding rooms that detect chlorine at the level of 1 ppm and will activate a visual/audible alarm and scrubber system. In the sulfur dioxide storage room, there are sulfur dioxide gas detectors as well as in the feeding rooms that detect sulfur dioxide at the level of 1 ppm and will activate a visual/audible alarm, scrubber system and water mist sprinkler knockdown system. The entire chemical feed system at the facility is tied into a Factory Link - NT computer system(s) that monitors and operate s the facility. In the event of an accidental release, detected by either activation of a scrubber or a sensor within the storage buildings, WRF personnel are notified by auto-dial pager systems. The system operates 24hrs a day and is tested on a daily basis. The auto-dialer system also notifies other District personnel in addition to respond as backups or first entry individuals to mitigate the leak. Five Year Accident History There have been no release(s) of either chlorine or sulfur dioxide at this facility in the past 5 years. Emergency Response Program The Padre Dam Municipal Water District, Water Recycling Facility (WRF) , has an effective and well implemented emergency response plan in effect. The plan, included within Padre Dam Municipal Water District's Risk Management Plan, has been developed and designed with the following in consideration: The WRF's plan is designed to provide the following: 1. To protect the lives of the Water Reclamation Facility staff , support activities related to release prevention and mitigation, and to protect ANY public receptors within the toxic endpoints of an accidental release. 2. For the purpose of mitigating all potential releases from the Facility and to prevent injuries. 3. To minimize damage to property and to the surrounding environment. Padre Dam Municipal Water District has taken on an aggressive hazardous materials emergency response training program to prevent any potential releases from the Water Reclamation Facility. This activity has included the purchase and outfitting of a 16' Hazmat emergency response trailer which contains all the tools and communication equipment necessary for an effective response a chemical release, a quarterly training program on emergency responses to hazardous material releases, and a quarterly hazardous materials emergency response drill coordinated with the Santee Fire Department, the City of San Diego Hazmat Unit and the County of San Diego Hazmat Unit. All personnel actively participate with the safety training and planning for the facility. The Water Reclamation's Hazardous Materials Business Plan as well as the WRF safety plan provides the personnel with notification needed to effectively attend to potential Chlorine and Sulfur Dioxide chemical release issues. The Emergency Response Plan identifies health hazards and mitigation procedures which will be implemented to respond effectively should an emergency situation arise. The plan is an active part of the operation of the Water Reclamation Facility and as such is it updated on a regular basis and not less than once per year. All effort are made to ensure that the Plan meets compliance with the PSM, RMP, and CalARP regulations. Padre Dam Municipal Water District also maintains a safety committee that performs safety and hazardous materials audits its facilities on a regular basis including the Water Reclamation Facility. The safety committee reviews documents related to t he operation of the WRF facility including the Hazardous Materials Business Plan and produces formal audits as well as recommendations for process improvement. PROCESS CHANGES TO IMPROVE SAFETY The Process Hazard Analysis (PHA) has provided the mitigation measures outlined below to improve safety at the Padre Dam Municipal Water Reclamation Facility. The PHA consisted of a day long review that included a HAZOP study, a Facility walkthrough, and a "what-if" review as well as a check list function. Items that were identified were placed upon a priority correction list with a completion by 12 - 31-99. Items that were identified were: R01 - Place two additional windsocks at each end of the facility to augment the current five for visibility when coming on site. R02 - Purchase and install communication devices within the level A suits used for responses to chemical releases R03 - Expand future chemical response drills to include adjoining city fire departments. R04 - Staff to have extended training on Incident Command System R05 - Purchase 1 ton scrubber for SO2 storage room R06 - Change the design of the hoist crane in the Chlorine room for better handling of one ton cylinders R07 - Add additional reclaimed fire hydrant at N/E corner of facility R08 - Train staff on newly acquired 800hz radios for communication with emergency response personnel with County of San Diego |