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Spill Prevention and Leak Detection
We continue to employ spill-prevention counter measure plans for facilities that have a potential to release into waters of the U.S. At a minimum, all fuel, oil or waste oil storage tanks contain engineering controls for secondary containment. Our secondary containment engineering controls help ensure spills and leaks are captured and not allowed to exit APS property. Examples of secondary containment include double-walled tanks, concrete containment and liners.
All of our natural gas pipelines are internally inspected annually and any leaks are repaired immediately. We do not have any on-site natural gas storage facilities.
Coal piles at power plants are treated with a chemical surfactant to minimize dust. The power plants also implement secondary containment measures to collect any storm runoff from coal piles. Fly ash from the coal-fired power plants is stored in wet disposal ponds, sent to the mine for reclamation or sold for use in concrete products. We monitor ground water around the ash ponds quarterly and annually for self-evaluation and regulatory reporting.
Oil Spills
- In 2002, a network transformer failed and caught on fire. The local fire department responded and in the course of extinguishing the fire, washed an undetermined amount of non-PCB mineral oil into the storm drain.
- In a separate incident, a pole-mounted capacitor bank fell to the ground during a windstorm, releasing approximately one-half gallon of non-PCB mineral oil into an irrigation canal. The spill was cleaned up and the visible oil was removed.
- Approximately 60 gallons of oil containing 13ppm PCB spilled when a pole-mounted transformer fell to the ground. Less than two gallons reached a nearby irrigation canal. The spill was cleaned up and all visible oil removed.
Chemical Spills
No chemical spills were reported in 2002.
Other Releases
- During the maintenance of an underground pipe at the Four Corners Power Plant, it was determined that a portable pump was discharging sewage into Morgan Lake, the Plant’s cooling water reservoir. The discharge lasted for about 90-minues and approximately 50 gallons of sewage were released.
- The Palo Verde Nuclear Generating Station Unit 1 Cooling Tower overflowed because of a loss of power to all cooling tower fans. Over one-half million gallons of water flooded the surrounding area, flowing in to the storm-water collection system. Approximately 57,000 gallons flowed into an unlined ditch. Most of the water was recovered and sent to a lined retention basin.
- Approximately 400,000 gallons of water were released to the Palo Verde storm water collection system at the time of the overflow. All but 4,000 gallons was recovered and sent to a lined retention basin.
- Less than 500 gallons of water from a reverse osmosis water treatment system was released on-site at Palo Verde to an unlined ditch which carried the water to an unlined sedimentation basin.
- The Palo Verde Nuclear Power Plant Unit 3 cooling tower accidentally released approximately 160,000 gallons of water into the on-site storm water collection system and about 72,000 gallons reached an unlined sedimentation basin.
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