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In-Vessel Bioconversion Facility at Sand Island

In-Vessel Bioconversion Facility at Sand Island

Honolulu, Oahu, HI
Client: City and County of Honolulu, Department of Environmental Services
Completed: 2007

Construction Management Project | Honolulu, Hawaii

Construction Management Services for the construction of the In-Vessel Bioconversion Facility located at the Sand Island Wastewater Treatment Plant. The In-Vessel Bioconversion Facility, a biosolids processing plant at Sand Island Wastewater Treatment Plant, was designed with cutting-edge technology to divert materials away from Oahu’s limited, near-capacity landfills, and converting them into valuable high-quality fertilizer for commercial use.

The $41.7 million project demonstrates the value of collaborative public/private partnerships.  The facility incorporates a number of cutting-edge processes including the construction of an Egg-Shaped Digester which digests or mixes wastes to ensure a consistent biosolid end product.  The digester also captures gases formed during the biosolid conversion process. These gases are used as a fuel source for the plant’s heat drying system.

Two high-performance centrifuges were installed for dewatering solids to create “dewatered cakes” for further processing.  In the heat drying and pelletization process, the biosolids are heated in a drum system where water is evaporated to produce dry, hard pellets.  These pellets are safely stored and eventually sold as fertilizer.   Air emission and odor control systems were installed to manage air emissions and odors throughout the plant.

2007 APWA Hawaii Chapter Project of the Year Award
2007 ACECH Honor Award for Engineering Excellence
Construction Manager and
Facility Operator ESD: Synagro-WWI, Inc.