The amount of trash dumped in the Waimanalo Gulch landfill every day is expected to temporarily double as part of O'ahu's main incinerator is shut down for maintenance.

The H-Power garbage-to-energy plant will begin operating at half capacity soon, said plant business manager Rodney Smith.

The routine inspection and maintenance will require that roughly 1,000 tons of refuse be diverted to the landfill every day for more than two weeks, he said.

The 16-year-old H-Power plant, at Campbell Industrial Park, burns about 6 of every 10 tons of trash the island produces. It includes two huge boilers that are heated by burning trash, feeding steam to a turbine that generates electricity.

Adding more trash to the landfill could rekindle the debate over where O'ahu's growing refuse should be dumped.

The Waimanalo Gulch landfill, which opened in 1989, has been through a series of temporary fixes, including landfill expansions, changes in height limits and permit extensions.

The Leeward Coast community has complained for years about being host to the municipal landfill with the foul odors, windblown trash, traffic congestion and mud tracked onto Farrington Highway by trucks — especially when trash is diverted from H-Power.

The landfill's permit expires next year. The city, which owns the site, is seeking approval to expand the dumping area and continue operations for at least 15 more years.

The state Health Department fined the landfill nearly $2.8 million last year for various environmental violations, most of which had been corrected before the fine, which remains in dispute.

The amount of trash deposited at the site each day would decrease in the future if more is recycled, incinerated or otherwise disposed of.

Shutdowns of the H-Power plant are required every year or so.

Plans to expand H-Power so it would not have to divert refuse during maintenance have stalled for years as city officials ponder alternative technologies.

The landfill's operators, Waste Management of Hawai'i, have worked hard to address complaints and prevent new problems, according to company manager Paul Burns.

"We clearly understand that we are not a preferred neighbor," he said.

Portable fences have been erected around the landfill's "working face" — the area where trash is dumped and remains visible — to prevent debris from blowing away. The face is kept far smaller now than in past years, and the garbage is covered with dirt every day, Burns said.

The face appeared to be about 30 yards wide when The Advertiser visited the site last week, and very little trash was seen in surrounding brush. Strong odors were limited to the immediate area.

The face will be about twice as large while trash is being diverted from H-Power, but crews will be especially vigilant about preventing any from blowing away, Burns said.

Ash from the H-Power plant, which is dumped in one portion of the landfill, is being piled about 40 feet higher than a state operating permit allows, Burns said. And a faulty leachate sump that collects liquids seeping from garbage has yet to be repaired.

A modification of the permit has been requested so that the higher ash level is allowed, and plans to repair the sump also are awaiting approval, he said.

To reduce the landfill's visual blight, crews have planted grass to cover patches of bare earth surrounding the site, and irrigation pipes have been installed to facilitate growth.

The planned landfill expansion would be in the rear of the site, farther from the highway, homes and the nearby Ko Olina resort.

Mayor Mufi Hannemann has made it clear that the landfill must be operated more carefully than in past years, and he is pleased with the progress so far, city spokesman Bill Brennan said.

"He wants it to be as much to the residents' liking as it can be, given that it's a landfill operation," Brennan said.

One H-Power boiler will be shut down for routine inspection and maintenance while the other continues to operate, Smith said. When that work is done, the first boiler will be reactivated while the second is shut down and refurbished. The whole job should be completed by March 14, Smith said.

Garbage truck traffic into the landfill will increase significantly in the meantime.

Dozens of trucks bring 800 to 1,200 tons of trash to the landfill on most days, along with about 260 tons of ash from the H-Power plant, Burns said. Other trucks haul in dirt that's used to cover the garbage and ash, or sludge from Honolulu's main sewage treatment plant.

Adding a third boiler to H-Power would expand its capacity and allow it to continue operations at current levels when one of the other boilers is shut down for future maintenance work, Smith said. The plant is operated by Covanta Honolulu Resource Recovery Venture.

The city is considering that option, and also will evaluate proposals for other trash-disposal technologies, including some that had been rejected previously as too expensive or unproven.

Some City Council members and others also are backing a long-stalled plan to ship some city-collected trash to a Mainland dump, as some private trash haulers are planning to do.