Honolulu In-Vessel Bioconversion Facility

The City and County of Honolulu (CCH) partnered with Synagro to develop a system to recycle and reuse the biosolids produced in their main wastewater treatment plant, thus providing a model for a closed-loop environmental system. CCH contracted with Synagro to design, build and operate an in-vessel bioconversion facility located at the Sand Island Wastewater Treatment Plant. The facility consists of an egg-shaped anaerobic digester, centrifuge dewatering and a heat-drying and pelletization facility to produce an Exceptional Quality designated product. The pellets produced provide a natural substitute for synthetic fertilizer to Oahu’s agricultural and landscaping communities.