A wastewater treatment system designed for homes without access to municipal sewers is undergoing testing in Hawaiʻi as a potential option for cesspool conversion and resilient wastewater service.

Team Honu showcased the solar-powered “Honu Hub” Aug. 26 at the Wahiawā Wastewater Treatment Plant. Funded by the National Science Foundation, the compact system is designed as a decentralized, off-grid wastewater treatment plant for homes in small communities.

The system uses an equalization tank to regulate wastewater flow before treatment. Nutrients, nitrogen and solids are removed, followed by membrane filtration to remove bacteria and other pollutants and disinfect the water. Depending on regulatory approval, treated water could be discharged or reused onsite.

The Honu Hub also incorporates solar power and a Starlink satellite connection, allowing it to maintain power and communications when surrounding infrastructure is disrupted. According to Team Honu, the system maintained power and connectivity during Tropical Storm Lala.

The University of Hawaiʻi at Mānoa’s Water Resources Research Center is independently evaluating the technology through its Hawaiʻi Onsite Wastewater Treatment Evaluation Program (HOWTEP). The system is expected to undergo a year-long testing process, with the Hawaiʻi Department of Health expected to make an approval decision within six months.

If approved, the technology could provide another option for Hawaiʻi homeowners seeking to replace cesspools ahead of the state’s 2050 conversion deadline.