Hawai’i County celebrates groundbreaking for Hilo Wastewater Treatment Plant upgrades

The County of Hawaiʻi celebrated the groundbreaking of critical upgrades to the Hilo Wastewater Treatment Plant on July 31, 2025, marking the beginning of construction on long-needed improvements to the wastewater facility. 

The $337 million upgrade project will replace outdated equipment, improve treatment efficiency, and strengthen environmental safeguards. Work includes construction of a new headworks facility, upgrades to primary and secondary treatment systems, new solids handling and odor control buildings, and major electrical and control system improvements. 

The project is being delivered by Nan Inc. and is scheduled to be completed in 2030.

Mayor Kimo Alameda, elected officials, County leadership, and project partners joined together at the plant site to recognize this milestone and emphasize the importance of investing in safe, modern wastewater infrastructure for the Hilo community. 

“Our wastewater system has needed attention for a long time, and we are finally turning that page,” said Mayor Alameda in a press release. “With this investment, we are making sure that the Hilo Wastewater Treatment Plant operates at the high standards our community deserves. In the meantime, we will be working closely with our contractors to keep everything running smoothly and safely. I want to thank our dedicated wastewater staff. They are the unsung heroes who keep these vital systems working day in and day out.” 

Originally built in the early 1990s, the facility serves approximately 30,000 residents and treats an average of 3 million gallons of wastewater daily. In March 2024, the County entered into an Administrative Order on Consent with the U.S. Environmental Protection Agency (EPA) to bring the facility and related infrastructure into compliance.

“This project has been a long time coming, and today’s groundbreaking reflects the determination of everyone who’s kept this plant running while we worked to get here,” said County Environmental Management Director Wesley R. Segawa in a press release. “We know how critical this facility is to the community, and this upgrade represents years of effort from our team, our partners, and the many people behind the scenes. Our operators, mechanics, lab staff, and engineers have held the line through challenging conditions. Now it’s our job to give them the tools and support they need to build a system the community can rely on for the long term.” 

To support public safety before and during construction, Mayor Alameda signed an emergency proclamation earlier this year. The proclamation allows the County to act quickly in the event of a failure at the plant or within the sewer system. It provides flexibility to access emergency resources, streamline procurement, and coordinate with state and federal agencies. This proactive measure strengthens the County’s ability to respond swiftly to potential spills, protect public health, and safeguard the environment while construction is underway. 

Alongside this project, the Department of Environmental Management is actively hiring for the Wastewater Division. Opportunities are available in engineering, operations, technical support, maintenance, and leadership. The department welcomes both entry-level and experienced candidates who want to protect public health, preserve our environment, and support Hawai’i Island’s infrastructure.