Water, Sewer & Waste
Synagro – Sand Island
Client: Hensel Phelps
Scope of Work: Jet Grout Columns
Project Year: 2024
The Synagro project at Sand Island Wastewater Treatment Plant in Honolulu, Hawaii, involves expanding and upgrading the In-Vessel Bioconversion Facility. This project aims to increase the capacity for treating biosolids, enabling more efficient recycling and reuse of wastewater byproducts. Synagro’s design-build-operate approach includes constructing new anaerobic digesters, sludge storage tanks, and a digester control building. The facility processes biosolids into Class A Exceptional Quality pellets, which are virtually pathogen-free and used as organic fertilizers for agriculture, landscaping, and city parks.
The project also supports environmental sustainability by capturing biogas for fuel use, reducing landfill dependency, and minimizing the carbon footprint of wastewater treatment. Scheduled to be completed by 2028, this $174 million effort ensures compliance with national wastewater treatment standards and addresses growing demands due to residential and tourism-related wastewater loads.
The Project
The Synagro project at Sand Island upgrades biosolid treatment, expanding capacity, producing organic fertilizers, and reducing landfill use, biogas emissions, and environmental impact, supporting Honolulu’s sustainability goals.
The Solution
Pacific Foundation is installing jet grout columns at the Sand Island site to treat subsurface conditions and create a watertight bottom seal. This solution enhances soil strength, prevents water infiltration, and supports effective biosolid processing.
The Result
Upon completion, the Sand Island facility will increase biosolid treatment capacity, produce more organic fertilizers, reduce landfill use, and capture biogas for fuel, contributing to Honolulu’s sustainable waste management and compliance with national standard.
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