Testing underway on new solar wastewater system to tackle Hawaii’s cesspool crisis

News admin August 27, 2026 0 Comments

Testing underway on new solar wastewater system to tackle Hawaii’s cesspool crisis

WAHIAWA (HawaiiNewsNow) – State and city leaders gathered at the Wahiawā Wastewater Treatment Plant on Wednesday to unveil the “Honu Hub,” a solar-powered wastewater treatment system meant to provide an off-grid alternative for homes currently on cesspools.

The compact, portable system is designed for single-family homes and can treat up to 600 gallons of wastewater per day.

The pilot project, funded by a National Science Foundation grant, represents a collaborative effort between the University of South Florida, University of Hawaiʻi, the City and County of Honolulu, and local nonprofit organization WAI (Wastewater Alternatives and Innovations).

“What we’re aiming to do is take a lot of the features from the wastewater treatment plant and miniaturize it and make it in a prepackaged form all right here,” explained Daniel Yeh, University of South Florida professor of environmental engineering.

“We can drop it into different places around the world. It runs completely off grid, so wherever you have sun, it will run,” Yeh added. “We can track it from anywhere in the world because we have a Starlink dish on there. So the idea is really to address the needs for places that don’t have pre-built infrastructure.”

Addressing Hawaii’s cesspool challenge

According to officials, Hawaiʻi has more than 80,000 cesspools statewide—the highest number per capita in the country.

“They release basically a major sewage spill every day — more than 50 million gallons — but we don’t see it because it’s underneath the surface, and this is untreated waste,” said Stuart Coleman, WAI co-founder.

Recent severe storms and flooding in Waialua and the southern district of Hawaii Island exposed infrastructure issues when they caused overflowing cesspools to flood yards and homes with raw sewage.

“In Waialua, we did see those cesspools flood homes,” said Rep. Amy Perruso, who represents the area.

State law (Act 125) mandates that all cesspools in Hawaiʻi must be upgraded, converted, or connected to sewers by 2050.

However, converting a single cesspool can cost homeowners between $30,000 and $50,000, presenting a substantial financial barrier for working families.

Testing solutions for island conditions

To address this, state lawmakers established the Hawaiʻi On-site Wastewater Treatment Evaluation Program under Act 198 to test new technologies under local conditions, such as high water tables, saltwater intrusion, and island infrastructure.

City Department of Environmental Services Director Roger Babcock said the test period allows officials to greenlight the system on a pre-approved list, simplifying the permitting process for local residents.

“So when a homeowner or their engineer goes to the Department of Health, pulls a permit, they list the type of system that they’re proposing to use and it gets approved,” Babcock said.

Perruso said the Honu Hub “offers the promise of a compact solar powered system with remote monitoring and nutrient recovery, exactly the kind of innovation we need for communities who may never be connected to a centralized sewer system.”

She added that she is proud the community of Wahiawā will “help demonstrate what a cleaner and more equitable wastewater future can look like for all of Hawaiʻi.”