In Alaska's largest city, federal regulators are considering whether the town's water treatment plant will need upgrades, in part to comply with the endangered listing of the Cook Inlet beluga whale population.
The city's main water treatment plant is located near Point Woronzof, adjacent to the airport. It handles about 58 million gallons of sewage a day for 220,000 people, or about 127 gallons for every man, woman and child living in its service area.
The life cycle of wastewater that enters the Asplund Wastewater Treatment Plant goes like this. First, a series of mechanical rakes remove large debris like rags, feminine hygiene products and salmon bits sent down the pipes by local seafood processors. After that, the sewage is pumped into settling tanks that skim off the oil and grease that collect on top.
Sludge –- a combination of feces and organic debris -- is scraped off the bottom of the tanks. The sludge is dried, burned on site, and the ash is taken to the city landfill. Then, a dash of chlorine is added to the now treated water, and it's pumped into Cook Inlet. That process meets primary treatment standards -- meaning, in total, about 75 percent of the suspended solids are removed and 30 percent of oxygen-using compounds are removed. But most cities do much more.
Upgrade could cost $800 million
The Clean Water Act of 1972 requires sewage-treatment plants to be certified as tertiary --meaning they remove more than 90 percent of suspended solids and most of the oxygen-depleting organics. Compounds such as nitrogen and phosphorous are also removed.
Two other -- much smaller -- Anchorage wastewater plants on the edge of town, in Eagle River and Girdwood are certified as tertiary and remove much more from the sewage than the main Anchorage facility.
Anchorage Water and Wastewater Utility said that upgrading or replacing the main Anchorage plant to bring it up to the level of most U.S. cities could cost as much as $800 million.
As it is, Anchorage is one of only a few dozen sewage treatment plants in the U.S. to get a waiver from the Clean Water Act, allowing it to dump effluent with only primary treatment into local waters.
Since 1985, the Environmental Protection Agency, has issued the Anchorage plant waivers because it believes Cook Inlet's extreme tidal flows efficiently dilute the waste, and, so far, no known impacts to the Inlet's marine life have been uncovered.
But almost five years ago the U.S. Department of Fish and Wildlife listed Cook Inlet beluga whales as endangered. Since then, Anchorage officials have wrestled with how the listing might impact development, including its wastewater treatment.
Public comments sought
This fall, the U.S. Environmental Protection Agency will start taking public comments on whether the city's wastewater operations should receive a new waiver from the Clean Water Act
Anchorage's most-recent waiver renewal was issued in 2000, and it has been under administrative extensions from the agency since 2005.
"Delays are common with the waiver requests because of the workload at our agency, which, in Anchorage's case, has been complicated by the beluga whale listing," said Mike Lidgard, EPA manager. Lidgard added that the agency considers the Anchorage wastewater plant a "well-run facility" in compliance with federal regulations.
According to the EPA, only 32 sewage treatment plants out of 21,604 in the U.S., get the waiver. Of those, Anchorage's is the second largest, trailing only San Diego. Every other wastewater treatment system in the nation meets the Clean Water Act criteria of tertiary treatment, which is about three times more effective.
Is minimum enough?
Anchorage's waiver does not sit well with some environmental activists. "Just because we can get away with doing the minimum, doesn't mean we should," said Cherie Northon, director of the Anchorage Waterways Council. Northon believes the city should upgrade its main plant to tertiary status. She isn't alone. Cook Inletkeeper, a local water watchdog, says pollution is a major concern for the Inlet.
That's because of Southcentral Alaska's dwindling beluga population. Last year, according to the National Oceanic and Atmospheric Administration, 312 belugas were counted, up slightly from the 284 found the year before.
Also, with new technology, Northon said, the plant would be able to process and remove far more contaminants from the sewer water before it is pumped into the Inlet -- 800 feet offshore, near Point Woronzof.
But even with the belugas' endangered listing and the accompanying critical habitat area surrounding the Asplund facility, the Anchorage wastewater treatment plant may not need to upgrade.
Tissue samples from dead Cook Inlet belugas taken over the years by the National Marine Fisheries Service haven't found elevated contaminant levels.
"Never have the levels of pollutants in the fish the whale eats been above EPA standards" either, said Brett Jokela, director of the Anchorage Wastewater Utility.
With a lack of public outcry about the EPA waiver and little scientific evidence the Anchorage wastewater plant is affecting the Inlet's whales and fish, the city expects to have its waiver renewed, and plans to operate the plant the way it has been.
But the feds have the final say and a decision is looming, perhaps as early as late this year.
Contact Sean Doogan at sean(at)alaskadispatch.com
CORRECTION: Due to an editing error, the daily amount of sewage handled at the Anchorage Wastewater Treatment Plant was incorrectly reported as 263 gallons per person per day for the 220,000 people served. That is the maximum handled by the plant. The average is 127 gallons.