Hawaiʻi County celebrated the groundbreaking of critical upgrades to the Hilo Wastewater Treatment Plant 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The $337 million upgrade project will replace outdated equipment, improve treatment efficiency, and strengthen environmental safeguards.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, which is being delivered by Nan Inc., is scheduled to be complete in 2030.

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 to bring the facility and related infrastructure into compliance.

To support public safety before and during construction, Mayor Alameda signed an emergency proclamation that allows the County to act quickly in the event of a failure at the plant or within the sewer system.

Photo credit: Hawaiʻi County Mayor’s Office