SBIR-STTR Award

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to provide homeowners with an affordable on-site wastewater treatment solution. Hawaii’s coral reefs are under threat from products of hundreds of thousands of onsite treatment systems across the state seeping into the groundwater and eventually reaching the coastal ecosystem. The proposed onsite wastewater treatment technology could will address this with wide-ranging environmental benefits. The State of Hawaii has legislated the replacement of residential cesspools by 2050 in order to reduce the pollution in streams and the ocean. Unfortunately, upgrade costs are so high that 90% of Hawaiian cesspool owners can’t afford the upgrade. The proposed technology can reduce the cost of upgrades by 5-10x. While the initial application will be in Hawaii, the technology will have national applicability. The proposed system uses an algal bacterial biofilm to passively aerate wastewater recirculated from a septic tank to conduct nitrifying, denitrifying, and heterotrophic operations. Previous investigations into abPBR use for onsite treatment have shown the capacity for high nutrient and BOD removal, but only with active maintenance and pumped recirculation. This project proposes a novel system with this performance but without high maintenance or energy demands. A novel convection-based passive recirculation process will be the primary focus of this study, with a focus on determining how experimentally determined passive recirculation rates and internal temperatures align with computational models, as well as standards for on-site residential wastewater treatment systems. The project will also explore susceptibility to and impact of disrupted recirculation due to gases coming out of solution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The broader/commercial impact of this Small Business Innovation Research (SBIR) Phase II project addresses the poor performance and unaffordability of existing, onsite, wastewater treatment technologies. In Hawaii, the state government has mandated the upgrade of 88,000 cesspools across the state by 2050, but studies have shown that 97% of homeowners will not be able to afford the upgrade. Further, an estimated 55% of Hawaiian homeowners will need to install a system other than a conventional septic system due to site sizing, grading, and sensitive receiving environment constraints. The proximity of Hawaiian homes to the ocean makes them particularly susceptible to rising sea levels that disrupt soil-based treatment technologies like septic systems. This is a problem in many coastal communities in America, but perhaps most notably in Miami-Dade County, FL where an estimated 64% of county septic tanks will begin to fail annually by 2040. Existing upgrades to septic systems exist but they take the form of septic system add-ons or package plants that invariably drive up the cost of treatment systems. This SBIR Phase II project is developing a wastewater treatment technology similar in shape and size to a solar hot water heater. The system is designed to operate passively, similar to a septic tank, but utilizing photosynthesis within a symbiotic algal-bacterial biofilm to provide high quality aerobic treatment on par with expensive package plants. The aboveground typology of the treatment unit protects the treatment process from high groundwater levels even during extreme flooding events, preventing the spread of disease and pollution. Further, situating the unit aboveground greatly simplifies the installation process to avoid expensive excavation costs and unearthing of homeowner backyards. This team has successfully piloted a proof-of-concept with Phase I funding. Moving into Phase II, the team will perform design iteration on the key geometric and operational parameters of the treatment unit and subject prototypes to sequential pilot tests in the field. The objective is to identify optimal manufacturing and design criteria for a resilient commercial treatment product that meets industry standards for use in sensitive receiving environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.