County of Hawai’i issues emergency proclamation for Hilo Wastewater Treatment Plant
As a proactive measure to protect public health and safety, County of Hawaiʻi Mayor Kimo Alameda signed an emergency proclamation covering the Hilo Wastewater Treatment Plant, which is slated for a major rehabilitation project.
The emergency proclamation was signed on February 11, 2025.
The proclamation authorizes emergency management measures to be taken in the event of a wastewater infrastructure failure. Engineering assessments have noted mechanical defects, structural deterioration, and extensive corrosion at the treatment plant that could result in a sewage spill at the facility, while deficiencies have also been found in the sewer collection system in Hilo.
“It is our duty to protect the health and safety of our residents as well as our environment,” said Mayor Alameda in a press release. “By moving forward with repairs and upgrades to our Hilo Wastewater Treatment Plant, we are making critical investments in our infrastructure that will serve the community for years to come.”
To address these critical infrastructure needs, the County has awarded a $337 million contract to Nan Inc. for the Hilo Wastewater Treatment Plant Rehabilitation and Replacement Project. A Notice to Proceed is anticipated in early March and the project is expected to take approximately five years to complete.
Additionally, Mayor Alameda has directed staff to develop a response and mitigation plan so that the County is prepared to address a sewage spill at any critical infrastructure location.
“This emergency proclamation also allows us to take the necessary steps to ensure that we mobilize quickly and bring together all the necessary partners if a significant sewage spill happens anywhere in Hilo,” Mayor Alameda said in a press release.
About the project
The treatment plant project focuses on rehabilitating the primary and secondary treatment facilities by replacing critical infrastructure and integrating modern technology. Work will be done in phases to ensure the treatment plant remains operational during construction and safeguards will be in place to aid in emergency response.
Key repairs and upgrades include:
- Improved waste removal: By replacing the headworks system, large debris and sand will be removed more effectively.
- Better sludge treatment: New primary and secondary digesters, an anaerobic digester, and solids handling and digester control buildings will be constructed to improve waste processing.
- Upgraded equipment: Outdated equipment will be replaced, water quality processes will be improved, and advanced odor-control systems will be installed.
- Modern technology: A plant-wide supervisory control and data acquisition system will be implemented to automate and monitor plant operations. A new control and server room will be installed for better system management.
- Increased reliability: The main switchboard, pumping stations, and critical facilities will be upgraded to make the plant more efficient and reliable.
The treatment plant, built in the early 1990s, serves about 30,000 residents and treats 3 million gallons of wastewater per day on average. In March 2024, the County entered into an Administrative Order on Consent with the U.S. Environmental Protection Agency (EPA) to repair or replace the facility and address other wastewater infrastructure deficiencies.
