Amid growing pressure to reduce pollution risks from O'ahu's sewage and to decrease the amount of debris flowing into the island's main garbage dump, two costly projects that affect both situations remain hampered by problems.

An important disinfection unit at the Sand Island Wastewater Treatment Plant is five years behind schedule and has cost $40 million more than the city's original $60 million estimate.

The project — a first-of-its-kind application — is complete but has yet to begin a crucial yearlong period of continuous operation and testing to prove its effectiveness.

Before that period concludes, the U.S. Environmental Protection Agency is expected to call for a major plant upgrade that could cost $800 million more and require major changes to the system of pumps and pipes that feeds into the disinfection unit.

The second delayed project, a $38 million facility that converts dried sewage sludge from the Sand Island plant into organic fertilizer pellets, remains inoperable after it was damaged by an early-morning fire one month ago.

In the meantime, about 36 tons of dried sludge "cake" are trucked to the city's Waimanalo Gulch dump each day as that site nears its permitted capacity. The dump's operating permit expires in less than a year, but the city hopes to expand the site and extend its operation.

SOLUTIONS IN WORKS

Officials say problems with the sewage disinfection unit and fertilizer facility should be resolved within months, and that they are committed to making sure both projects are operated safely and efficiently.

The disinfection unit — which zaps treated sewage with powerful banks of ultraviolet lamps to destroy pathogens — is now fully operational, said Allen Perry, city metro region wastewater superintendent.

But a few lingering problems must be corrected, and some preliminary tests must be completed before the yearlong proving period begins, he said.

The electric power that feeds the unit has sometimes spiked and damaged key parts or caused equipment to be shut down.

That can't happen during the proving period, because the unit must operate without interruption — or face more delays, Perry said.

A recent power fluctuation lasted only 10 seconds but destroyed 30 of the plant's 1,680 ultraviolet lamps, which cost nearly $300 each.

Electricity to run the unit is expected to cost up to $9 million per year, so different light intensities and operating methods are being tested, city environmental services director Eric Takamura said.

The light must be strong enough to disinfect the sewage properly without wasting electricity or wearing out lamps prematurely.

"We're trying to optimize the system to keep the costs down," Takamura said. "Every time we test under a different scenario, we have to wait for lab results to come back."

Testing during the proving period will help determine whether the city must operate the unit continuously in the future, or only run it under certain weather and flow conditions that could push discharged effluent back toward O'ahu's shoreline.

The unit is designed to handle up to 150 million gallons of sewage per day, and has five channels that can be opened or closed as there are peaks and lulls in the city's sewage flow.

Each channel has 336 ultraviolet lamps that can be submerged in the sewage during operations.

The unit was originally scheduled to be completed in July 2002 at a cost of under $60 million, but work was delayed by design changes and construction problems that increased the cost to $100 million.

The fertilizer facility was to be completed by mid-2004 to help comply with a federal consent decree that requires the city to recycle some of its sewage sludge.

But the project was delayed by community opposition and City Council concerns about possible health risks from use of the fertilizer pellets, which the city insists are safe.

FIRE CAUSES DELAYS

Construction was completed in December, and production testing began early this year. But the fire that broke out before dawn on June 14 has pushed the schedule back again.

The facility had been shut down for the night before the fire broke out, and the cause of the blaze remains under investigation, said site manager Kenny Huy of Synagro, a company that will operate the facility for the city.

Repair work is on schedule and should be completed by the end of September, and insurance should cover the cost, which is still being estimated, Huy said.

The company is awaiting final approval from the state Health Department to begin selling the fertilizer pellets, which also could be used in some city parks and golf courses.

The fire mainly burned fiberglass odor-control ducts, insulation and plastic water pipes. The blaze also broke or melted several large windows and singed parts of the facility.

But a key part of the facility — an egg-shaped "digester" 116 feet tall — was not damaged and remains operational.

Officials expect that more than 90 percent of the dried sludge that now goes to the dump will be made into fertilizer pellets when the facility is fully operational.

The project was recently named a 2007 project of the year by the Hawai'i chapter of the American Public Works Association.

The city expects to hear sometime after October whether the EPA plans to require the sewage plant to upgrade from enhanced primary treatment to a more comprehensive process, called secondary treatment.

The process breaks down the biological content of sewage more thoroughly, and is performed at most U.S. wastewater treatment plants.

The Sand Island plant, and another at Honouliuli, have operated for years without secondary treatment, under special waivers from the EPA.

The federal agency announced in March that the Honouliuli plant should be upgraded, which city officials estimate would cost $400 million. A similar decision is expected in October regarding Sand Island, and officials estimate an upgrade there could cost $800 million.

Mayor Mufi Hannemann and other city officials contend the upgrades are not necessary because the plants discharge treated sewage effluent in deep water far offshore. Most plants that perform secondary treatment discharge into lakes, rivers or shallow coastal waters.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.