The city will spend nearly $30 million on the Kailua Wastewater Treatment Plant on Kane'ohe Bay Drive to stop the stench that has plagued the surrounding 'Aikahi community for decades.

"The odor is something we are dealing with every day," said Mary Shannon, an 'Aikahi Garden resident. "I just called them this morning," she said one day last week. "It's been really foul."

The odor becomes pronounced every so often, and Shannon said she was told the smell that day came after workers had cleaned a tank the night before.

Typically, she comes home from work and parks, holding her breath until she gets inside to escape the odor. Shannon said the problem has gone on for so long and appeared in the local media so often that she's ashamed to tell people where she lives.

"Nobody is really proud to live here," she said.

Over the years, the city has spent millions of dollars to stop the odor, but complaints still come in. At one point a City Council member proposed to move the plant to the Kapa'a Quarry area, but that suggestion went nowhere.

$25 MILLION PLAN

The upcoming initiative, which will also address noise, includes a $25 million project in which the city will take steps to control the odor and study the results, said Eric Takamura, director of the city Department of Environmental Services.

This includes installing gaskets to reduce the leaking of foul air, cleaning the odor control units more frequently and adding chemicals to the sewer collection system to treat odors before the wastewater reaches the plant.

The city has also roughly outlined longer-range projects to upgrade equipment or treatment processes that could produce odors if not addressed.

"I think we now have a lot more operational experience with the odor control system," said Takamura, adding that the city hopes to identify improvements that need to be made to the entire collection system in the near future.

The odor is primarily caused by the release of hydrogen sulfide and volatile acids, Takamura said.

Environmental groups sued the city in the 1990s over sewage spills and other countywide system problems for which a settlement was reached and a 20-year consent decree signed in 1995. The plant received $4.8 million in upgrades but the odor problem was never resolved, according to neighbors.

The part of the project that addresses peak wet-weather flows is in answer to the 1995 consent decree, but the projects that deal with odor and noise are not related to the decree, Takamura said.

There are several other reasons behind the new project. The state has fined the city for emission violations that have nauseated schoolchildren. Residents have also complained that they think the odor contributes to allergies and asthma problems.

STUDENTS SICKENED

The upgrades came as good news to some residents who have suffered from plant noise and odor for more than 20 years.

"They need to do something," said Christine Soares, a secretary at 'Aikahi Elementary School who has lived on the Kalaheo hillside above the school for about 30 years. "We can only hope this will do the trick."

The plant is surrounded by homes and the elementary school on two sides and vacant land owned by Marine Corps Base Hawaii on the remaining sides. It serves most of the region and 94,000 residents, collecting wastewater from Lanikai to Kahalu'u and as far inland as Maunawili Estates and Ha'iku Village.

But it's the 'Aikahi area closest to the plant that bears the brunt of the odor problems.

On really bad days, certain classrooms at 'Aikahi Elementary School can be "like a trap" for the odor, Soares said. She has kept a log of all the days that are "real sinus-blowers" where she has had to call the plant to complain. In the past six months, she has made a dozen reports.

"I think a lot of us put up with it because there are other nice qualities about the area," she said.

On at least one occasion the smell was so bad that children complained of nausea and headaches, prompting teachers to keep them indoors. But school principal Gay Kong said that for the past six months the campus has had no problem.

Kong praised the plant crew for working with the school and warning staff when the odor might be worse than usual, like the day of the school's May Day program this year.

"They're trying to do the best they can so it doesn't get in the way of our children," she said.

Randy Scoville, the school's vice principal, said the situation is "a huge, huge improvement from years before" and that the smell is only really bad during still days or when plant equipment breaks.

OVER CAPACITY

Kailua Neighborhood Board chairwoman Kathy Bryant suspected the problem might be because the plant was not originally built to serve the entire region.

In 1994, three separate systems in Kailua, Kane'ohe and 'Ahuimanu were combined into one regional system. The 'Aikahi facility became the only full treatment plant and its peak flow capacity increased so it could accept partially treated sewage from the other two plants.

"The plant was never designed to handle the capacity that it handles," Bryant said, adding that she was optimistic about the new improvements.

The city is also considering expanding the plant's peak flow capacity from 28 million gallons per day to 35.6 million gallons a day.

Donna Wong, with Hawaii's Thousand Friends, one of the environmental groups that sued the city over wastewater spills, said she's glad the city is taking some action but she's not convinced it can fix the problem.

"They've had this odor problem for years and it seems like they just keep throwing money at it and it doesn't solve the problem," Wong said, adding that she has no faith that the city can get the plant fixed, "because I think the whole facility is broken."

City Council chairwoman Barbara Marshall, who has endured the occasional odor as a Kailua resident, said the city can do its best to make sure everything is working properly, but "the only way that the city could ensure that no odors would ever be present would be to spend hundreds of millions of dollars to relocate the facility to another area."

"While I would personally favor such an option, I don't see that happening any time soon."

Reach Eloise Aguiar at eaguiar@honoluluadvertiser.com.