An attempt by three environmental groups to speed up improvements to the city's sewage treatment system suffered a severe blow when a federal judge dismissed most of the claims brought in a lawsuit filed by the groups.

U.S. District Judge David Ezra on Friday granted a motion by the city to dismiss the more serious allegations in a July 2004 lawsuit filed by the Sierra Club Hawai'i Chapter, Hawai'i's Thousand Friends and Our Children's Earth Foundation. The lawsuit accused the city of lagging in its work to upgrade sewage treatment plants and meet federal regulations.

The lawsuit said the city has repeatedly violated the federal Clean Water Act and it cited more than 1,200 sewage spills at city plants since 1999. The city also was accused of failing to meet effluent discharge standards at the Sand Island and Ho-no'uli'uli treatment plants and operating without a valid permit, the lawsuit said.

But in a written ruling Friday, Ezra sided with the city and said most of the allegations were without merit.

Jeff Mikulina, director of the Sierra Club here, said yesterday that the plaintiffs were disappointed with Ezra's ruling. He said they will likely file a motion for reconsideration.

"We couldn't disagree more with the judge's decision," Mikulina said. "We think it's pretty clear that the city and county has a sewage problem that needs to be fixed. That's what the suit sought to accomplish."

He said the city was failing to meet the terms of a 1995 consent decree with the federal Environmental Protection Agency that called for nearly $1 billion in improvements over a 20-year period. The agreement was reached after the EPA filed a lawsuit against the city in 1994 following several major sewage spills.

The city argued in April that the lawsuit by the environmental groups was "entirely duplicative" of the 1994 lawsuit, and that the EPA has the responsibility of enforcing the consent decree.

Ezra agreed and said the groups were "precluded from relitigating" many of the claims in the lawsuit.

"When the EPA is prosecuting (Clean Water Act) violations, it should be accorded 'preeminent role' because it is charged with enforcing the CWA on behalf of all citizens," Ezra wrote.

Ezra's order was applauded by Mayor Mufi Hannemann and Eric Takamura, director of the Department of Environmental Services. Soon after he was elected in 2004, Hannemann said sewer improvements was a major priority in his administration.

"The public's money can now be more appropriately and wisely used for the purpose of upgrading the city's wastewater collection, treatment and disposal system instead of litigating these claims," Takamura said.

Reach Curtis Lum at culum@honoluluadvertiser.com.