An agreement that requires the city to upgrade aging sewers and make improvements at Oahu’s two main waste-water treatment facilities signals an end to years of litigation and is being hailed by environmental watchdog groups.

The proposed agreement among the city, state and U.S. Environmental Protection Agency was announced yesterday.

"This is a significant and long-sought-after win for the environment and a much-needed change in management of the city’s sewage treatment system," said Robert Harris, director of the Sierra Club’s Hawaii chapter. "Under the settlement, the city will improve our waste-water system in a systematic, long-term fashion to protect the health of citizens and our coastal environment."

The Sierra Club, along with environmental groups Hawaii’s Thousand Friends and Our Children’s Earth Foundation are all part of the proposed consent decree with the city, EPA and state Department of Health. The agreement calls for what has been described as "long-neglected" sewer improvements needed to help end sewage spills.

The agreement also would address issues raised by the EPA about the treatment of waste water at Oahu’s two main treatment plants at Sand Island and Honouliuli, allowing the city to undertake upgrades to those facilities on a longer-term basis.

Mayor Mufi Hannemann announced the proposed consent decree yesterday with Jared Blumenfeld, administrator for the EPA’s Pacific Southwest region, who was in Honolulu for the announcement.

"The settlement will require aggressive near-term actions to improve critical aspects of the city and county’s (sewage) collection system," Blumenfeld said. "Then the longer-term schedule of construction will lead to secondary treatment for the two plants.

"Our clear priority is collection. Only when the collection system is done will secondary-treatment upgrades be made."

The mandated upgrades and improvements are likely to raise sewer fees for residents, although an exact timetable and fee schedule have not yet been released.

"Yes, there will be increases, but increases, I believe, on a schedule that we can afford," Hannemann said.

If approved, the consent decree would settle lawsuits filed by environmental groups alleging deficiencies in the city’s waste-water treatment procedures. Among those was one filed in 2004 by the Sierra Club.

Hannemann had previously opposed the EPA on efforts to require secondary treatment, which involves removing organic matter from sewage, saying the upgrades would be too costly and arguing the city had scientific proof that it was not harming the environment.

Although the city had previously received waivers exempting the treatment plants from having to perform secondary treatment, the EPA was poised to deny an extension of the waivers, officials said.

While the city and the EPA disagree over whether the secondary treatment is needed, Hannemann said he decided to pursue a settlement to end years of litigation that already have cost the city about $10 million.

The proposed settlement now goes to the City Council for approval through its regular process. The Council’s Executive Matters and Legal Affairs Committee is scheduled to receive a briefing in executive session tomorrow.

"In general we need to work our way through this lawsuit, and to the extent there’s a global settlement on this, that’s probably a good thing," Council Chairman Todd Apo said. "We know what we need to do, and we’re able to plan long term how we’re going to handle these things as a county."