CITY BREAKS GROUND ON MAJOR INFRASTRUCTURE UPGRADES AT KAILUA REGIONAL WASTEWATER TREATMENT PLANT 

HONOLULU– Mayor Rick Blangiardi joined City Council Member Esther Kiaʻāina, Department of Environmental Services (ENV) Director Roger Babcock, and construction partners at a groundbreaking ceremony for two major capital improvement projects at the Kailua Regional Wastewater Treatment Plant (KRWWTP).

“These projects represent more than $85 million in critical infrastructure to protect the health of Windward Oʻahu’s communities and the environment for generations to come,” said Mayor Rick Blangiardi. “The vital importance of rehabilitating biotowers and replacing a dewatering building may be unfamiliar to many of us, but they represent crucial investments in our neighborhoods and are a part of our ongoing focus on modernizing the City, because that is what our residents deserve.”

“Kailua is a vibrant, coastal community,” added City Council Member Esther Kiaʻāina. “Its residents deserve improved infrastructure that safeguards public health and protects our environment. This investment means cleaner beaches and a healthier and sustainable community for all of us.”

The groundbreaking ceremony was held Thursday, June 18, 2026, at 12:30 p.m. at the Kailua Regional WWTP. A traditional Hawaiian blessing was provided by Kahu Kordell Kekoa.

The projects are part of a broader Capital Improvements Program at the plant, which also included completion of an Ultraviolet Disinfection upgrade in 2025.

Biotower Rehabilitation: $23,579,000

Contractor: Hawaiian Dredging Construction Company, Inc. (HDCC)
Project Design: Brown & Caldwell                                                                                               Construction Period: October 2025 – January 2029

Biotowers are a critical component of the plant’s biological treatment process, using microorganisms to break down contaminants in wastewater before it is discharged. This project rehabilitates the two existing biotowers and associated pump station wetwell. Work includes complete replacement of biotower media, secondary influent distributors, and geodesic dome roofs, as well as concrete repair and recoating of structural elements and installation of a new air compressor and controls system for the distributor arm. The wetwell will also be refurbished with new slide gates and protective coating. Construction is expected to last approximately three years.

New Dewatering Building: $61,697,316

Contractor: Nan, Inc.                                                                                                                       Project Design: Community Planning and Engineering
Construction Period: March 2026 – February 2029

The dewatering process removes excess water from sludge prior to its disposal or beneficial reuse — a key step in the plant’s solids management system. This project replaces aging infrastructure with a modern, more reliable facility. Work includes demolition of the existing Dewatering Building, Odor Control System, Old Digester Control Building, and Final Clarifier Division Box, followed by construction of a new multi-level Dewatering Building to house processing equipment and biosolids storage. The project also includes renovation of digesters, replacement of sludge pumps, and installation of a new Odor Control System with carbon treatment technology. The project replaces aging systems but does not increase the plant’s overall treatment capacity. Construction will take an estimated three years to complete.

Community Considerations

The City is committed to minimizing impacts to the surrounding Aikahi community during construction. Construction activities are limited to 7:00 a.m. to 6:00 p.m. Monday through Friday and 9:00 a.m. to 6:00 p.m. on Saturdays, with no work on Sundays or holidays. All construction activities and deliveries will be confined to the treatment plant, with deliveries accessing the facility via the west gate near H-3/Kāneʻohe Bay Drive. Contractors are also required to monitor and mitigate odors throughout construction, including draining and cleaning wastewater structures before opening them where possible.

“These are not optional improvements, they are essential to the safe and effective treatment of wastewater for our Kailua and Windward communities,” said ENV Director Roger Babcock. “Our team is proud to move this work forward and to partner with contractors who share our commitment to quality and community care.”

The Kailua Regional WWTP provides wastewater treatment services for the Kailua and Kāneʻohe communities on Oʻahu’s Windward side.

ENV operates and maintains Oʻahu’s wastewater treatment plants, pump stations, and collection systems. infrastructure that safeguards public health and the long-term health of Hawaiʻi’s coastal waters. 

Department of Environmental Services
City and County of Honolulu
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