Honolulu is gearing up to fight yesterday's tentative federal decision to deny a special waiver for the city's largest sewage treatment plant, which could require hundreds of millions of dollars in upgrades to meet national standards.

The announcement by the U.S. Environmental Protection Agency regarding the Sand Island plant came nine months after a similar finding for the city's second-largest plant, at Honouliuli.

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.

If the findings are upheld, the next challenge for the city will be to negotiate how soon upgrade work must be done — and how it will be paid for. The city estimates the cost of upgrading both plants at $1.2 billion.

The work could take a decade or more, and the city is already under heavy pressure to make other sewer repairs and upgrades costing hundreds of millions of dollars. An order to upgrade the treatment plants would have to take into account the city's workload and finances, the EPA said.

"It has to be realistic, because the goal is to get into compliance," said EPA spokesman Dean Higuchi. "When you want to get into compliance, you need to make sure that it can be done, as opposed to setting unrealistic goals that will never be achieved."

Such work is typically financed by city bonds that are paid off through the collection of monthly sewer fees from homes and businesses. Fees are already scheduled to increase over the next three years to pay for other sewer work.

Hawai'i's congressional delegation could seek federal money for the city, but it's too soon to tell whether that's likely.

"I think people ought to stand back and take a deep breath and wait for the EPA to make its final conclusions and get some of the commentary in, and then start looking at alternatives short of having to spend hundreds of millions of dollars on secondary treatment plants," said U.S. Rep. Neil Abercrombie. "There are a lot of things short of that which may deal with the problem at hand."

NEW CHALLENGE

Abercrombie said he doubted the city would secure new waivers for the plants, however.

"I think they've gone with waivers about as far as they're going to go," he said.

The city has appealed the Honouliuli decision with the EPA and will mount a similar challenge for the Sand Island plant over a 10-week period when the agency must accept responses from officials and the public.

"Just as we did with the Hono-uliuli tentative denial, we will oppose the Sand Island tentative denial with an appropriate scientific and technical response," said Honolulu environmental services director Eric Takamura. "We will take the necessary and appropriate amounts of time to formally respond to the EPA, given the gravity of this decision for the customers of this county."

Final decisions will be rendered after EPA review of the comments, but there is no certain timetable. The agency can seek fines and court orders against municipal governments that fail to comply with such decisions.

But that's not the EPA's goal, Higuchi stressed.

"We really want to get things working, as opposed to collecting fines that are basically not going to benefit the people in the communities," he said.

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 similar U.S. facilities.

The two plants handle the bulk of O'ahu's wastewater, but the city contends that upgrading them would be unnecessary and too expensive. The money would be better spent on other projects, including repairs to the island's crumbling network of sewage pipes, officials argue.

Under growing pressure from the EPA and environmental groups after years of sewage spills, the city agreed in federal court this 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.

The city is planning additional pipe replacement work that's expected to cost over $100 million more.

BACTERIA LEVELS HIGH

Yesterday's tentative ruling had long been expected, but Mayor Mufi Hannemann had been pushing for a "global" settlement with the EPA that would resolve all the city's sewage disputes, including the treatment plant upgrades.

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

The agency found last year that bacteria levels were also too high near the Sand Island plant's outfall. After the plant began operating a new ultraviolet light disinfection system this year, bacteria levels dropped to acceptable levels, but there are other problems at the plant, the EPA found.

Construction of the disinfection unit and a related project were several years behind schedule. A federal judge ruled in October that the delays 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.

Honolulu officials — and some scientists — have argued for years 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. Most Mainland plants discharge into rivers, lakes or shallow waters along coastlines that stretch thousands of miles.

"I'm annoyed, upset and hoping that they'll reconsider," City Council Chairwoman Barbara Marshall said of yesterday's EPA announcement. "I don't think they know what they're doing."

Waivers were made available because the federal government recognized that all waters are not the same, she said.

"Deep ocean is very different from streams and rivers and lakes on the Mainland, and that's what the law was designed for," she said. "If I thought there was any hazard to it at all, I would be the first to be out there saying that we should do this no matter what the cost."

The EPA has scheduled a hearing for the public to comment on the Sand Island finding, to be held on Feb. 5 at 6:30 p.m. at Washington Middle School.

In a voluminous 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.

The EPA said it believes the improvements are needed at both plants, and that it wants to work with the city to make the work possible.

"These upgrades will ensure that Hawai'i's residents, visitors and marine life benefit from the full protections provided by the Clean Water Act," said Wayne Nastri, the EPA's administrator for the Pacific Southwest region.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.