Zero-Waste (ZeWa) water and energy recovery systemEPA Contract Number: 68HERC21C0035
Title: Zero-Waste (ZeWa) water and energy recovery system
Investigators: Rogers, Tate W
Small Business: Triangle Environmental Health Initiative
EPA Contact: Richards, April
Project Period: March 1, 2021 through August 31, 2021
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2021) RFA Text | Recipients Lists
Research Category: SBIR - Clean and Safe Water , SBIR - Water , Small Business Innovation Research (SBIR)
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 energy positive 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.