City and County of Honolulu Mayor Rick Blangiardi, along with the Department of Environmental Services, announced a major $174 million infrastructure project to upgrade the In-Vessel Bioconversion facilities at the Sand Island Wastewater Treatment Plant (WWTP).
The upgrades will be executed by Synagro-WWT, Inc., with Hensel Phelps handling construction and Yogi Kwong Engineers, LLC serving as the construction manager. This project aims to significantly enhance the capacity and efficiency of the state’s largest treatment plant.
Key components include relocating and rebuilding the Effluent Water Reuse Pump Station, removing the old pump station and various underground utilities, and providing power to the Maintenance and Lab Buildings. The project will also involve constructing new underground utilities, electrical improvements, and site civil work.
Major upgrades include adding two new anaerobic digesters, two sludge storage tanks, a Digester Control Building, and a new tunnel and basement. Additional enhancements will include a new boiler system, hot water pumps, modifications to existing digesters and piping, and the relocation and installation of flares, a propane gas tank, and new chemical dosing systems.
Scheduled for completion by October 2028, this project represents a critical investment in Honolulu’s wastewater infrastructure. It will improve the efficiency and capacity of the Sand Island WWTP, supporting the city’s growth and development. The new anaerobic digesters and sludge storage tanks will enable the plant to handle increased waste volumes, contributing to a cleaner and healthier environment for Honolulu’s residents.