A federal mandate to upgrade Honolulu's largest wastewater treatment plants could cost the city hundreds of millions of dollars and is unwarranted, city officials told residents last night at an informational session.

Federal officials at the hearing last night, however, said they are bound by the Clean Water Act to ensure municipalities around the country comply with rules regulating wastewater management.

The city estimates the cost of plant upgrades at $1.2 billion and that the work could take a decade or more. The city already is under pressure to make other sewer repairs and upgrades costing hundreds of millions of dollars.

Mayor Mufi Hannemann last night reiterated his desire to work out a "global settlement" with EPA to settle all outstanding issues and pointed out that the agency approved waivers in 1990 and again in 1998.

Hannemann said the creation of secondary treatment systems would take money away from projects aimed at shoring up aging infrastructure and sewer lines.

"What I cannot continue to accept is your insistence that we be denied our waiver. We have a cadre of scientists, experts and engineers who have helped the city in the past with their waiver requests all continuing to say that this forced secondary treatment is unnecessary," he said. "Please be considerate and understanding of the fact that we are fixing the collection system and that's where the problem is."

State Sen. Gordon M. Trimble, R-12th (Waikiki, Ala Moana, Downtown), said the city has done much to improve its sewage infrastructure. Trimble said the city has been responsive in times of crisis, lauding efforts in the aftermath of the 48 million-gallon sewage spill in Waikiki in 2006.

"I stand before you tonight and ask that you reconsider your tentative decision," Trimble said.

"The real need right now is improving the aging infrastructure. I don't like paying increased sewer fees but at least I see the mayor using it to improve the system," he said.

Prior to the 6:30 p.m. hearing, more than two dozen city employees and community members lined King Street waving signs protesting the Environmental Protection Agency's temporary decision.

A crowd of about 150 community members and city workers filled the 120 rows of white cafeteria tables at Washington Middle School. The audience included engineers and scientists with expertise in marine biology and water quality.

VOICES HEARD

Community members that came before the EPA to testify said that Hawai'i's high cost of living stresses available city resources and that money should be spent doing something other than creating treatment systems that may or may not be necessary. Many said they felt safe swimming in Hawai'i's coastal waters and said the city should be spending the money to improve outdated infrastructure.

Richard Brock, who retired last year after more than 30 years as a marine researcher at the University of Hawai'i, said the test protocols employed by the EPA are not applicable to O'ahu's environmental context. After reviewing all available studies, Brock said the EPA's requests were unfounded and not based in sound scientific fact.

"If you deny this waiver, can I send you my estimated $300-a-month estimated sewer bill?" Brock said.

Watson Okubo, monitoring section chief for the state Department of Health's Clean Water Branch, but testifying as a private citizen last night, said he hopes to enjoy the beach more when he retires.

"I used to supply fish and limu for 25 years to supplement my income and I haven't seen any degradation in near-shore waters," he said. "I don't think (secondary treatment) is necessary."

Last year the EPA issued two tentative federal decisions denying a special waiver to operate the city's two largest sewage treatment plants, at Sand Island and Honouliuli.

Waivers held for years by the two treatment plants allowed them to operate without performing a process called full secondary treatment, which is required at nearly all U.S. facilities of similar size.

The two plants handle the bulk of O'ahu's wastewater, but the city maintains that upgrading them is unnecessary and costly. The funds would be best spent on other projects, including repairs to the island's crumbling network of sewage pipes, officials have argued.

But the treated sewage discharged into the ocean from the facilities does not meet water quality standards set to protect marine life or human consumption of fish, according to the EPA's previous findings.

If the EPA findings are upheld, the city will have to negotiate a timeline for doing the work and how to pay for it.

"We're not polluting the ocean waters so there is no reason to deny us a waiver for secondary treatment. We certainly believe the science is on our side," said Bill Brennan, press secretary for Hannemann.

An order to upgrade the treatment plants would have to take into account the city's workload and finances, the EPA said. The EPA is trying to establish a schedule for getting the county into compliance.

Starting July 1, sewer fees will increase 18 percent from last year and are scheduled for another 18 percent increase in 2009 and a 15 percent increase in 2010.

Under pressure from the EPA and environmental groups after years of sewage spills, the city agreed in federal court last year to evaluate or replace six major pressurized pipes at an estimated cost of $300 million.

The deal came after a major Waikiki sewer pipe ruptured last year and sent 48 million gallons of raw sewage into the Ala Wai Canal and out to sea. The city is planning additional pipe replacement work that's expected to cost more than $100 million.

BACTERIA LEVELS

In March 2007, the EPA found that bacteria levels around the Honouliuli plant's discharge were higher than national standards adopted in 2004 to protect swimmers, surfers and others from gastrointestinal diseases.

Similar findings reported last year concluded that bacteria levels also were too high near the Sand Island plant's outfall.

After the plant began operating a new ultraviolet light disinfection system this year, bacteria counts dropped to acceptable levels, but there are other problems at the plant, the EPA found.

A federal judge ruled in October 2007 that the delays in construction and high bacteria levels led to 4,000 violations of the federal wastewater discharge permit for Sand Island.

Effluent from both plants proved toxic to sea urchins in laboratory tests and produced excess ammonia that can harm other aquatic organisms, according to the EPA.

Samples from both plants also contained excess levels of two pesticides, dieldrin and chlordane.

Secondary treatment exposes primary-treated wastewater to microorganisms, such as bacteria, which consume most organic matter. The microorganisms are then removed before the wastewater is discharged.

City officials and scientists have argued that secondary treatment was not necessary here because wastewater is discharged far offshore, in deep water at the center of the world's largest ocean.

In response to the Honouliuli finding, the city contended that the federal agency's "tentative conclusions are not supported by ... monitoring data, and are often arbitrary, conclusory, speculative, or not rationally related to the waiver criteria."

The quality of effluent from the plant has improved since the waiver was first granted in 1988, according to the document.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.