Palmer struggles to attain lower ammonia levels

PALMER - Wind damage early this winter rumpled the black, insulated plastic coverings over two Palmer Wastewater Treatment Plant lagoons and city workers say fixing the covers is not possible until the weather warms.

The covers, which cost $1.2 million and were installed in the summer of 2010, are part of a solution to help the city reduce the levels of ammonia discharged from the treatment plant into a nearby salmon-spawning stream. Federal Environmental Protection Agency regulations regarding ammonia discharge recently changed, significantly reducing allowable numbers.

The city is operating under a 2007 discharge permit and is developing a Compliance Order by Consent with the state Department of Environmental Conservation, which now oversees wastewater discharge permits. The compliance order will outline the city's plan to meet the new, lowered ammonia levels.

City utility foreman John Berberich said the rumpled covers don't appear to be damaged but are very heavy to move. The city used a heavy-duty forklift to move the covers back over the open lagoon earlier this winter, but snow made further work impossible.

"Since it was the very end of the pond that was no longer covered, I determined that threat of injury far outweighed any treatment loss from having a 20-foot space not covered," Berberich said by email last week.

He said the uncovered area has not affected the city's ability to treat the wastewater. City workers will move the covers and take care of any repairs needed when the weather warms enough to make access safer. Berberich said repairs would likely be done in-house and at little cost to the city.

City struggles to comply

with federal ammonia levels

Palmer installed the covers, essentially two sheets of black plastic with several inches of insulation sandwiched between them, in the summer of 2010. The covers were part of an effort to reduce the amount of ammonia being discharged into a small creek at the base of the Matanuska River bluffs south of town. New, more efficient blowers also were installed to aerate the lagoons and speed bacterial breakdown.

When the city began the process to renew its five-year operational permit in 2005, officials from the Environmental Protection Agency examined the wastewater treatment plant and observed salmon spawning in the small clear stream near the outfall.

The resulting 2007 discharge permit includes a provision that Palmer needed to meet new ammonia levels - set at 8.7 parts per million in winter and months when salmon aren't spawning and 1.7 ppm during July and August. Previously, the city's limit was 34 ppm.

City consultant Ralph Hulbert said no one in Alaska had a permit requiring limits that low.

"That's not unusual because regulators have previously tasked the city of Palmer with complying, as a pioneer, because it's capable," Hulbert said.

Cutting ammonia levels so low meant rethinking how the city wastewater plant functions. Initial proposals pegged the cost of complying with the new lower 2007 levels at $25 million to $50 million, and even then, Hulbert said, there was doubt those levels could be met.

More disturbing was that the 2012 permit, now being drafted, must use the actual volume of the clear stream rather than the volume of the Matanuska River, which previous numbers were based on. The resulting year-round permit level of 1.7 ppm for ammonia would be especially difficult to meet in winter, Hulbert said.

As Hulbert described it, ammonia plays a part in the life cycle of all living things. As biological waste decomposes, ammonia is a step in producing nitrogen essential for cell growth. Ammonia is broken down slowly - the nitrosomonas bacteria that break it down are very temperature sensitive, and must have both time and contact to work, Hulbert said.

Winter is when Alaska communities have the hardest time complying with low ammonia discharge levels, which surge to as much as 40 ppm.

In summer, sunlight on the uncovered pond promotes algae growth, which helps speed the conversion of ammonia to nitrate, which is used for more cell growth. Summer discharges are very low in ammonia but high in algae, which is the base of the salmon food chain.

No known "northern tier" wastewater treatment plants are currently operating with ammonia levels below 2 ppm, Hulbert said.

The covers and blowers have helped cut the city's ammonia levels in half, Berberich said by email. The city is investigating how to install another tool - an ammonia reactor, or large pad that gives bacteria a lot of surface area to break the ammonia down. It's not yet clear how much a reactor will cost or which type of reactor will be most useful for the city.

Meanwhile, Hulbert took another approach: is the ammonia hurting salmon? He and volunteers (mostly his family) have counted spawning salmon in the unnamed stream and three others nearby since 2008. They found the stream has a greater salmon escapement count than the popular fishing stream Wasilla Creek. Nearly 1/3 of all the salmon that return to the Matanuska River spawn in the tiny creek, Hulbert said.

Hulbert and his family also observed caged and free swimming salmon fry in the effluent mixing zone and elsewhere in the creek.

"Fry preferred the mixing zone and grew three to six times faster than those outside the mixing zone, whether free-swimming or caged," he said.

Finally, Hulbert and his family studied whether the discharge caused problems for salmon eggs, since impacts to salmon eggs is the basis for EPA's ammonia limits. Salmon bury their eggs where groundwater comes up into the stream - Hulbert and his son found although the stream itself had high ammonia levels, the water in the gravel where the eggs were buried had essentially no ammonia.

With all these findings in hand, the city has asked DEC to reconsider ammonia levels based on demonstrable effects on salmon.

Nancy Sonafrank, who manages the Water Quality Standards Assessment and Restoration program for DEC, said her office received Palmer's request to reconsider allowable ammonia levels. The standards office reviews water quality standards every three years to see if upgrades are needed.

Sonafrank said Palmer's request is under review. The standards office planned to monitor national action regarding allowable ammonia levels during its triennial review but did not plan to take action on new regulations. However, that doesn't mean Palmer's request - or its trouble complying with the new lower regulations - will be ignored.

"We are involved ... with the issues that the Palmer plant is struggling with," she said. "We're aware, we're engaged. As for how we help Palmer, it's truly how, not if."