A novel wastewater treatment solution currently undergoing evaluation at the Wahiawa Wastewater Treatment Plant on Oʻahu (managed by the City & County of Honolulu) could offer a crucial, cost-effective path forward as Hawaiʻi faces a massive statewide infrastructure overhaul.
The Hawaiʻi Onsite Wastewater Technology Evaluation Program (HOWTEP) was officially launched during the Wastewater Innovation Tech Showcase on August 26, 2026, at the Wahiawa Wastewater Treatment Plant.
- Managing Organization & Funding: Executed by the University of Hawaiʻi at Mānoa Water Resources Research Center (WRRC), HOWTEP is a three-year pilot testing program funded by companion bills SB 1232 and HB 736.
- Regulatory Role & Mission: WRRC evaluates innovative systems and provides evaluation reports to the Hawaiʻi Department of Health (DOH) to support their decision-making and certification process. This directly accelerates the commercialization and approval of affordable wastewater technologies.
- Cesspool Mandate Support: The initiative advances accessible, decentralized wastewater solutions to help property owners meet the Act 125 mandate requiring the replacement, conversion, or closure of nearly 88,000 cesspools across the state by January 1, 2050.
- Academic & Community Platform: Beyond system certification, HOWTEP serves as a multi-purpose hub for WRRC to conduct research, offer hands-on student training, and perform community outreach.
The Honu Hub is the first technology to be evaluated under the HOWTEP platform.
- NSF Convergence Accelerator: The Honu Hub is supported by a $5 million grant from the National Science Foundation’s (NSF) Convergence Accelerator This program speeds up practical, team-based science solutions for real-world problems.
- Project Leadership & Collaborators:
- Principal Investigator (PI): Daniel Yeh (University of South Florida)
- Co-Principal Investigator: Zhiyue Wang (University of Hawaiʻi at Mānoa/WRRC)
- Senior Personnel: Tao Yan (Director of WRRC)
- Partner Organizations: WAI (Wastewater Alternatives and Innovations) and Swiftwater Solutions
- Path to Commercialization: Before the system can be sold to individual households in Hawaiʻi, it will complete pilot testing under HOWTEP and apply for regulatory certification from the Hawaiʻi Department of Health (DOH).
The Honu Hub is a decentralized wastewater treatment system designed to process sewage completely above ground. By packing its technology into a compact 52-square-foot footprint—roughly the size of a standard garden shed—the modular unit eliminates the need for expensive heavy machinery, extensive excavation, and costly landscape restoration.
For many homeowners, replacing a cesspool with a conventional septic system costs between $30,000 and $50,000—a financial burden amplified by difficult terrain, high water tables, and tight lot boundaries. The Honu Hub was specifically engineered as an affordable alternative designed to drastically lower these conversion costs.
How It Works
The self-contained unit utilizes a multi-stage treatment process to clean residential and commercial wastewater directly on-site:
- Equalization & Removal: Manages incoming flow while stripping out organics and nutrients.
- Filtration & Disinfection: Uses advanced membrane filtration to treat effluent.
- Reuse Potential & Savings: Produces discharge- or reuse-ready water, significantly reducing or outright eliminating the need for expensive underground drainfields.
“The WRRC team’s role in this is to help with research and development to improve the technology and study the fate and transport of emerging contaminants in this system,” Wang said.
Off-Grid and Connected
Designed for locations where infrastructure is limited or nonexistent, the Honu Hub runs off-grid using dedicated solar power, cutting utility expenses and providing emergency backup power for property owners.
To streamline oversight and lower long-term service costs, the unit features built-in Wi-Fi and satellite remote monitoring, allowing technicians and owners to track system performance, control settings, and diagnose issues remotely.
Target Applications and Regulatory Approval
Because the system sits above ground and is soil-type neutral, it offers a practical, budget-friendly alternative for Hawaiʻi’s high-priority cesspool conversion zones, including:
- Small residential lots and constrained redevelopments
- Island, coastal, and mountain communities with high groundwater or rocky terrain
- Coastal areas where underground installations are prohibited
- Workforce housing, public facilities, and remote commercial sites
The system is currently undergoing site evaluation at the Wahiawa facility while seeking regulatory approval for use in Hawaiʻi. Once approved, the technology could allow property owners to comply with state mandates affordably while protecting surrounding marine and freshwater ecosystems.
For more information on the Honu Hub, visit HonuWater.com.