SBIR-STTR Award

Triangle Environmental proposes the Zero-Waste (ZeWa) water and energy recovery system; a netenergy positive onsite wastewater treatment system to eliminate brine and produce three output streams for reuse. Aging sewer infrastructure coupled with a growing population and sewer demand in the US have fostered a shift to higher usage of onsite wastewater treatment systems (OWTS). In the US, decentralized wastewater systems are used in 25% of existing residential homes and 33% of new development. The revenue for the OWTS market is growing as well, which was projected to nearly double from 2010 ($2.35 billion) to 2020 ($4.57 billion). Although becoming more prevalent, OWTSs are either very basic (i.e. septic tanks) or utilize technologies that create concentrated brine and/or sludge streams which require occasional emptying & transport via vacuum truck, and further treatment at wastewater treatment plants (WWTPs). The proposed ZeWa system seeks to not only eliminate these brine streams, but capture the high energy content they contain and convert them to high-value onsite reuse products. By optimizing all reuse potential of wastewater, ZeWa can shift black- and greywater treatment nationally to net energypositive while offsetting energy costs across the municipal water & wastewater, septage, and agriculture sectors. The ZeWa system is an onsite black- and greywater treatment technology that maximizes the chemical energy potential contained in wastewater to produce zero-waste and three valuable output streams: a. clean water for non-potable reuse, b. concentrated fertilizer for local nutrient supply, and c. Class A biosolids for local soil amendment. The ZeWa system consists of three subsystems; 1. sludge treatment and energy recovery subsystem (STERS), 2. water recovery subsystem (WRS) and 3. nutrient recovery subsystem (NRS). The team already possesses functional prototypes of the WRS and NRS for testing. The key innovation and primary goal of Phase I is the development and testing of the STERS to validate the onsite treatment of a blackwater sludge/brine stream with only energy produced directly from the blackwater sludge. This validation will facilitate two key breakthroughs in onsite domestic wastewater treatment: 1. elimination of concentrate/brine streams through recycle and treatment of the concentrate and 2. elimination of required emptying and transport of sludge in OWTS via vacuum truck. The technical risk for this proposal is low as the ZeWa system, and specifically the STERS, leverages and integrates components developed by the team over the past decade of onsite wastewater treatment research.

The Zero-Waste (ZeWa) system is an onsite black- and greywater treatment technology that maximizes the chemical energy potential contained in wastewater to produce zero-waste and three valuable reuse output streams: A) clean water for non-potable reuse, B) concentrated fertilizer for local nutrient supply, and C) Class A biosolids for local soil amendment. Over the course of Phase I, a lab-scale ZeWa system was designed, built, and tested with real blackwater (human urine, feces, and flush water) and greywater (laundry and bathroom sink). Each ZeWa subsystem successfully demonstrated the expected performance targets consistent with Triangle Environmental Team members' previous experience using different components for blackwater treatment. The system produced final solid and liquid outputs which met national and international standards for reuse (EPA, NSF, and ISO). The solids treatment subsystem was able to achieve complete treatment of the solids stream to Class A Biosolids standards. In addition, the water and nutrient treatment and recovery subsystems displayed effective processing of the liquid portion of the blackwater stream, greywater, and a combination of both, creating two valuable outputs for reuse: a high-quality product water for non-potable reuse and a nutrient-rich concentrate for potential agricultural application. This finding suggests that greywater and blackwater streams could be combined for easy and efficient household treatment in the eventual pilot-scale implementation of the system. Overall, the complete ZeWa system was able to reduce raw blackwater COD by 99.3%, TSS by ~100%, Total N by 91.7%, and Total P by 90.6%. In Phase II, Triangle Environmental will build upon Phase I successes and learnings to first design, build, and test the updated solids handling system. The updated solids system will be incorporated into a fully integrated and automated ZeWa pilot and showcase skid system (500 gallons per day) for Phase II testing and commercial partner engagement. The completed system will be first be piloted at a local wastewater treatment plant in representative operational environments including with blackwater, greywater, and combinations of both (such as septage and sewage). Further testing of the system will be completed at a number of potential pilot locations, depending on commercial partner direction.