City and County of Honolulu – Department of Environmental Services and Department of Design and Construction Kaneohe-Kailua Wastewater Conveyance and Treatment Facilities Project

Bowers and Kubota picBowers + Kubota is managing a project that will help avoid sewage spills in Honolulu when completed.
By Alan Dorich

The island of Oahu, Hawaii, is considered both a paradise for tourists and an environmentally sensitive, pristine environment. “You definitely don’t want to be fouling it up with sewage spills,” Robert J. Kroning says.

Kroning is the director of the Department of Design and Construction for the City and County of Honolulu (City) on Oahu, which has undertaken multiple projects to avoid such pollution. One of those is the Kaneohe-Kailua Wastewater Conveyance and Treatment Facilities project.

It involves the creation of a tunnel stretching three miles from the Kaneohe Wastewater Pre-Treatment Facility to the Kailua Regional Wastewater Treatment Plant. The finished tunnel will convey wastewater flows between the plants and provide storage to avoid overflows and spills due to wet weather.

While the existing system uses a force main, the new tunnel will be a deep sewer that will convey sewage by gravity. “We believe in the long term that it will be more efficient because there are less mechanical parts that we have to operate,” Kroning says.

Up to Standard

The Kaneohe-Kailua Wastewater Conveyance and Treatment Facilities Project is one of several that will allow Honolulu to adhere to a 2010 consent decree to improve overall island sewage treatment, Kroning says. “It was due to a large number of spills we’ve been having over the years,” he recalls.

“The EPA said, ‘This is unacceptable, you need to fix that,’” Kroning says, noting that the City negotiated a program with EPA to fix the problem. “The two largest treatment plants are also required to upgrade to include secondary treatment.”

The consent decree agreement includes roughly $5 billion worth of projects that are underway throughout the island of Oahu. “This Kaneohe-Kailua Wastewater Conveyance and Treatment Facilities Project is just one of them,” he says.

Phased Out

Bowers + Kubota Consulting (B+K) is the City’s construction manager for this program, which has been divided into three phases. The City and County of Honolulu Wastewater Division Chief Guy Inouye says that the tunnel phase component – Hawaii’s largest sewer tunnel – will be finished in early 2017.

General contractor Southland Mole is utilizing a tunnel-boring machine manufactured by The Robbins Co., based in Solon, Ohio. “It was specifically designed for this project, shipped over and was built on site,” Kroning recalls. bowers and kubota box

Hensel Phelps will serve as the general contractor on the second and third phases. The second phase includes an influent pump station component, Inouye says. “It takes the sewage from the gravity tunnel and it lifts that into the Kailua treatment plant,’ he says. The pump station will be finished in the summer of 2018.

The third phase consists of a tunnel influent facility at the beginning of the tunnel within the Kaneohe Wastewater Pre-treatment Facility (WWPTF). “That should be done by the end of 2018,” he says.

While this marks the City’s first wastewater division project with Southland/Mole Joint Venture and Hensel Phelps, it previously worked with B+K. “Bowers has a strong local presence and we use them on other projects, to include other non-wastewater projects,” Kroning says.

More than 80 percent of the company’s project staff consists of Hawaii residents, which fulfills a local requirement, he says. “There’s a strong desire to have as much local workforce on the project [as we can] to help support the local economy,” he says.

Tunneling Through

The tunnel project required the creation of a large shaft to launch the tunnel-boring machine, Inouye says. “It’s roughly 85 feet in diameter,” he says. “The same shaft will be used for the pump station.”

Tunneling went well, Kroning says, although its progress was a little slower than anticipated. “But in the end, I think you expect those things on a major project like this,” he says.

Another challenge involved groundwater. “Once you start boring into the ground, you release all kinds of water that’s flowing through the aquifers,” Kroning explains.

“Having to manage that was an interesting challenge, especially because of the environmental sensitivity in the area,” he says. “We couldn’t take it and dump it in the ocean.”

One of the solutions was to take the water to the wastewater treatment plant in Kailua. However, “That was a tricky situation,” he says. “They have a requirement that they can only handle certain amounts of metal and nutrients that go through there.”

The project team also prepared a dry bed area to release water to as an alternative discharge option. Kroning says, “The dry bed acts as a natural filter system, cleaning the effluent before it gets back into the water system.”

On Schedule

The City and County of Honolulu is pleased with the work of its contractors. “It looks like we’re on schedule to meet the consent decree,” Kroning states. “[We’ve had] a few bumps in the road here and there, but the contractors have been straightforward and ready to work with us to come up with solutions to solve the problems that we face.”

They also have avoided accidents. “All of our contractors have a very robust safety program,” Inouye says, noting that the builders have kept safety “paramount” on their minds.

He adds that the overall reception to the project has been positive, although it had a rocky start. “The first reaction from the public was one of concern, due to traffic, vibration, noise, dust and all of those things,” Inouye recalls.

But the city’s investments in public information have helped. “We’ve had a good relationship with the public and our neighbors,” he says.

More work may be ahead for Honolulu, Kroning adds. “The desire is to try to do more of this around the island,” he says. “We really like the notion of being able to prevent future spills.”

This may involve another tunneling project, he adds. “There’s one in particular where we’re starting the planning phase,” he says.

Premier Professionals

Based in Waipahu, Hawaii, Bowers + Kubota is a multi-disciplined firm offering architectural design, civil and electrical engineering design, construction management, program management and project development services. “Since our establishment in 1980, we have completed numerous projects of a wide variety of scale and complexity throughout Hawaii and [the] Pacific Rim,” Mike Young, Bowers + Kubota Consulting Project Director (for the KK Program), says.

“[We are] committed to building on our strong record of accomplishments and outstanding reputation by utilizing our strengths, comprehensive abilities and unique expertise to provide premier professional services to our clients,” Young says.

Bowers + Kubota operates with the goal of providing best value with the philosophy of “TEAM – Together Everyone Achieves More,” Young says. “We view ourselves as an extension of our clients and place great emphasis on how to best anticipate their needs and remain proactive throughout the duration of a project.

“Our team of architects and engineers is dedicated to providing new and innovative techniques for our clients that result in successful and award-winning projects,” Young says. “Our goal is to ensure the final product meets and/or exceeds the users’ current and future requirements.”

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