Recent tests found no evidence that the Cooper Lake Hydroelectric Project is presently releasing PCBs into Kenai Lake. However, they did detect PCBs inside the plant.
Managers are confident they can contain the contamination during a powerhouse upgrade planned this spring. However, PCBs already may have reached Kenai Lake.
Chugach Electric Association hired Environmental Management Inc. to test this winter for PCB contamination. EMI found PCBs in the grease used to lubricate the turbines. Until 1989, Chugach discharged grease and water that dripped from the turbines into Kenai Lake, said Burke Wick, power plant superintendent for Chugach Electric Association.
It remains unclear how much contaminated grease has reached the lake since the plant was commissioned in 1960. EMI was unable to sample the lake bottom this winter.
Tom Lovas, the utility's director of energy supply, said Chugach is planning how to sample sediments from the lake bottom and from the rock channel that carries water from the powerhouse to the lake. However, that probably cannot be done until the ice leaves the lake.
Wick said grease dripping from the turbines no longer goes in the lake. The drippings now drain to an oil-water separator installed in 1989. Chugach ships oily waste from the separator off-site for disposal. It discharges the treated water into Kenai Lake.
This winter, EMI detected PCBs in oily waste from the separator, but not in the treated water.
"In other words, the oil-water separator was doing its job," said Chugach spokesman Phil Steyer.
Even so, he said, Chugach will install a carbon filter to further purify the water.
PCBs became a question after Chugach asked the Federal Energy Regulatory Commission for permission to make a $6.1 million upgrade to the powerhouse. FERC approved the request in October but asked Chugach to work with Fish and Wildlife and the Alaska Department of Fish and Game on plans to keep pollution from spilling into Kenai Lake during construction.
After the meetings, Ann Rappoport, field supervisor for the Anchorage ecological services office of Fish and Wildlife, wrote FERC that tests years ago detected PCBs in waste oil from the separator. Chugach did not know where the PCBs came from, she wrote, but it said three capacitors at the plant contain PCBs. She said it is important to determine the source, so that construction does not release PCBs to the environment.
She questioned whether rain and snowmelt Chugach discharges from the containment dike around an outdoor transformer are contaminated with PCBs.
But Steyer said oil in the outdoor transformer contains less than 1 part per million PCBs, and EMI was unable to detect PCBs in the diked area around the transformer.
Gary Liepitz, a habitat biologist with Fish and Game, questioned whether there are PCBs in gravel Chugach dredged in 1989 and 1996 from the rock channel that carries water from the powerhouse to the lake.
Chugach placed the dredge spoils on the powerhouse road and parking lot.
FERC declined requests by both Fish and Wildlife and Fish and Game to reconsider its approval of the upgrade, but agreed that Chugach should address the potential release of PCBs before construction begins this spring.
On Thursday, Chugach released its revised plans for containing contamination during the powerhouse upgrade.
"As a result of the revised plan, and a recent inventory of all possible sources of PCBs located at the site, Chugach is confident that no PCBs will be released into the environment as a result of the powerhouse modifications ..." Chugach said Thursday in a letter to FERC.
The revised plan says Chugach will drain the water from the powerhouse before work begins to avoid releasing contaminants to the lake.
Chugach will hire an experienced contractor to clean contaminated grease from the turbines and remove the three PCB capacitors. Wick said Chugach plans to remove the plumbing that supplied grease for the turbines and install greaseless bearings.
Liepitz said he is pleased that Chugach is cleaning up, but that does not address the possibility of past discharges. Chugach should test the old dredge spoils for PCBs, since they are potential sources of contaminated runoff, he said.
It should test gravel in the channel between the powerhouse and the lake, he said, since it likely will dredge there again, and that could release any remaining contamination.
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