Grantee Research Project Results
Final Report: Sanitary Green Space: a Closed-Looped Sanitation System for GrowingGreen Communities
EPA Grant Number: SU839467Title: Sanitary Green Space: a Closed-Looped Sanitation System for GrowingGreen Communities
Investigators: Russel, Kory C , DeHeer, Adam , Sund, Nick , Young, Summer , Hershey, Emma , Alig, Sam , Ketterer, Hana , Hansberger, Dayna , Brunkhorst, Alissa , Eikani, Mia
Institution: University of Oregon
EPA Project Officer: Page, Angela
Phase: I
Project Period: December 1, 2018 through November 30, 2019 (Extended to December 31, 2021)
Project Amount: $14,971
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2018) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Safe and Sustainable Water Resources , P3 Awards
Objective:
Many residents in dense urban slums like those of Lima, Peru do not have access to safe sanitation facilities, resulting in contamination of their drinking water and pollution of their local environment. In order to meet basic needs, residents are typically forced to choose between crowded public toilets, open defecation, and private latrines that are expensive to build and maintain. Household-level sanitation services using container--based toilets have the potential to overcome many of the challenges associated with non--networked sanitation options. This sanitation model is particularly well-suited for low-income urban settlements where demand for sanitation services is high and traditional on-site sanitation and sewerage are not feasible or cost-effective (Tilmans et al., 2015; Russel et al., 2015). However, typical container-based sanitation (CBS) does not provide a treatment solution for urine or household greywater.
Our objective in Phase I was to fill an existing gap in container-based sanitation services by developing a sanitation solution for household liquid waste (urine and greywater). Furthermore, we hypothesized that we could recycle water and reclaim nutrients from human waste to grow plants rather than simply “treating” the water and throwing away valuable resources. Using the neighborhood of Pamplona Alta in Lima, Peru as our pilot location, we worked with customers of an existing CBS service provider, x-runner, to develop a low-cost and sustainable sanitation system that uses principles of biomimicry to create a “circular economy” whereby resources (composted human feces, urine, and greywater) are reused in a closed-loop cycle to provide basic sanitation and create public green space: a Sanitary Green Space system.
Using a Human-centered design approach and codesign techniques, we aimed to develop three iterations of the Sanitary Green Space system and test them for fecal indicator bacteria (fecal coliforms and E. coli). We anticipated that our project had the potential to improve human health and well-being, advance the economic competitiveness of sustainable sanitation businesses; and protect and preserve the environment by effectively and efficiently using water, materials, and energy, and minimizing the generation or emission of pollution or hazardous waste.
After field testing versions of the Sanitary Green Space in Lima, Peru, participants in the codesign workshops identified the potential for our system to treat water sufficiently for reuse in household cleaning activities. Prototyping has begun during Phase I to meet this objective and will continue during Phase II as the implementation pilot expands to additional households.
Research objectives of this project include:
- Evaluating the viability of wastewater treatment solutions to be used in combination with a container-based sanitation service
- Evaluating the capacity for household-scale wastewater treatment to contribute to the growth of publicly accessible green space
- Testing the safety to public health of on-site wastewater treatment used to create publicly accessible green space
Summary/Accomplishments (Outputs/Outcomes):
Following initial testing at the University of Oregon and in consultation with x-runner and its customers, three iterations of the Sanitary Green Space system were tested for implementation in Pamplona Alta, and a fourth iteration is already underway. To begin, we tested raw effluent for fecal indicator bacteria (fecal coliforms and E. coli) as a baseline for comparison with the Sanitary Green Space system. We then tested five distinct sand filter designs (v1) for incorporation into the system, and selected the best design for the next version (v2). Because the system had to accommodate household greywater such as dishwater, we added a grease trap to remove fats, oils, grease, and other organic solids. We then connected the system to a planting bed amended with composted human feces. This version was tested at the x-runner waste processing facility in Lima, Peru and continues to operate today. User testing revealed that the system needed to accommodate a higher volume of greywater created by home washing machines, so we increased the size of the grease trap and installed the five new prototype (v3) in Lima, Peru in December, 2018. Customers expressed satisfaction with this design.
The absence of pathogens in the test results of versions 1, 2, and 3 suggest that the Sanitary Green Space system is effectively reducing the spread of pathogens. We planned for large-scale real-world conditions pathogen testing for v3 to be carried out during the remaining project period of Phase I. However, the COVID-19 Pandemic forced the student team to evacuate from Lima Peru during v3 has not been deployed in Peru to date.
In addition, the flow of water produced by version 2 and the vegetative growth it has supported suggest that the system can effectively increase vegetative cover within the community. Vegetation grew profusely over six months of observation, and our test users communicated that they greatly appreciated the ability to grow more plants at their homes.
Pivoting
As a result of the pandemic and a cessation of international field activity, two student who had graduated and worked on the initial project Adam DeHeer and Nick Sund began a company Leap Frog Design to continue developing and commercialize the technology in the United States. They went on to secure funding from several sources including awards of both Phase 1 and Phase 2 National Science Foundation SBIR grants totally more than a million dollars.
Students still involved in the project pivoted from the international research to focus on deployment in Eugene, Oregon in collaboration with organizations working to provide transitional housing to the rapidly growing homeless population due to the COVID-19 Pandemic.
We built new domestic partnerships with SquareOne Villages and Community Support Shelters, both non-profit organizations that manage transitional and low-income housing developments in Eugene, Oregon. They invited us to field test two variations of our v4 system at several of their locations. Collaborative design workshops were carried out, with the goal of integrating the Sanitary Green Space technology with sink, laundry and showering facilities that meet city and state plumbing code. Sanitation is especially important when addressing issues around homelessness or extremely low-income housing as human wastes commonly goes untreated into local waterways (Noble et al., 2000; Smith et al., 2017). Moreover, being able to process greywater on site is a large cost reduction for organizations operating these communities.
The systems built at transitional housing communities were comprised of four cells connected through plumbing. The cells are inspired by Constructed Wetlands (Vymazal, 2007; Brix, 1994) and contain a large (10-13 mm) aggregate that captures fats, oils, grease and small debris such as food scraps or laundry lint. At the same time, these cells are planted with wetland species like Phragmites australis that oxygenate the water through their roots and encourage the breakdown of organic solids by bacteria. The cells also incorporate concepts from Slow Sand Filters (Aslan et al., 2007; Elliot et al., 2008) that contains a medium (5-7 mm) aggregate and salt-absorbing plants (halophytes) that consume dissolved salts and nutrients. Third, the cells are based on Hydroponics (Jensen, 1997; Jones, 2016) and uses a small (2-5 mm) aggregate. This helps reduce salt concentration and is more hospitable to food crops and vegetables. Lastly, the cells mimic a Biosand Filter (Stauber et al., 2006; Stauber et al., 2009; Duke et al., 2006) which uses fine-grain (0.15 to 0.20 mm) sand that clarifies the water while a microbiotic community of beneficial bacteria and microorganisms (‘schmutzdecke’) consume any remaining fecal pathogens. Having passed through all four cells, the dissolved salts, nutrients, and contaminants in the liquid waste is reduced to near zero and ready to be reused. Students have also created a construction manual for low-cost dissemination and replication of the system.
Conclusions:
Sanitary Green Space removes human waste from the environment, thereby reducing human exposure to deadly pathogens and risk of diarrheal disease. Additionally, by recycling household liquid waste, the system reduces household water budgets—returning that money to the local economy—while improving community resilience to water scarcity and drought. Finally, the system grows plants that can improve human health while creating green space that has the potential to encourage economic development. Sanitary Green Space also supports the growth of container-based sanitation (CBS) in Lima and around the world by providing a complete sanitation service that is more desirable to their users.
While we were poised to roll out a large-scale trial of the system, the COVID-19 pandemic struck and altered the trajectory of this project profoundly. At the same time, Sanima’s customers who participated in our co-design process developed a thorough understanding of the system and helped us design and refine the system to recycle the treated wastewater back to their households. Moving forward we are re-engaging Sanima and the work in Peru as well as creating new partnerships with local transitional housing organizations in Eugene, Oregon. Transitional housing communities face many of the same challenges as Pamplona Alta and other urban slums, such as lack of household plumbing and sanitation, easy access to clean drinking water, and access to green space.
Finally, the founding of Leap Frog Design by Adam DeHeer and Nick Sund and their success continuing to develop and commercialize a greywater system for the US market is an exciting outcome.
References:
Aslan, S., & Cakici, H. (2007). Biological denitrification of drinking water in a slow sand filter. Journal of hazardous materials, 148(1-2), 253-258.
Duke, W. F., Nordin, R. N., Baker, D., & Mazumder, A. (2006). The use and performance of BioSand filters in the Artibonite Valley of Haiti: a field study of 107 households. Rural Remote Health, 6(3), 570.
Elliott, M. A., Stauber, C. E., Koksal, F., DiGiano, F. A., & Sobsey, M. D. (2008). Reductions of E. coli, echovirus type 12 and bacteriophages in an intermittently operated household-scale slow sand filter. Water research, 42(10-11), 2662-2670.
Jensen, M. H. (1997). Hydroponics. HortScience, 32(6), 1018-1021.
Jones Jr, J. B. (2016). Hydroponics: a practical guide for the soilless grower. CRC press.
Smith, Catharine. “Meet The Americans Who Live With Open Sewers In Their Yard.” 2017. Huffington Post, https://www.huffingtonpost.com/entry/sanitation-open-sewers-black-belt_us_5a33baf5e4b040881be99da5, accessed 02/06/2018.
Stauber, C. E., Ortiz, G. M., Loomis, D. P., & Sobsey, M. D. (2009). A randomized controlled trial of the concrete biosand filter and its impact on diarrheal disease in Bonao, Dominican Republic. The American journal of tropical medicine and hygiene, 80(2), 286-293.
Stauber, C. E., Elliott, M. A., Koksal, F., Ortiz, G. M., DiGiano, F. A., & Sobsey, M. D. (2006). Characterisation of the biosand filter for E. coli reductions from household drinking water under controlled laboratory and field use conditions. Water science and technology, 54(3), 1-7.
Noble, R. T., Dorsey, J. H., Leecaster, M., Orozco-Borbón, V., Reid, D., Schiff, K., & Weisberg, S. B. (2000). A regional survey of the microbiological water quality along the shoreline of the Southern California Bight. Environmental Monitoring and Assessment, 64(1) 435-447. https://doi.org/10.1023/A:1006463706832.
Russel, K., Tilmans, S., Kramer, S., Sklar, R., Tillias, D., and Davis, J. (2015). User Perceptions of and Willingness to Pay for Household Container-Based Sanitation Services: Experience From Cap Haitien, Haiti. Environment and Urbanization 27(2): 525–40. doi:10.1177/0956247815596522.
Tilmans, S., Russel, K., Sklar, R., Page, L., Kramer, S., & Davis, J. (2015). “Container-Based Sanitation: Assessing Costs and Effectiveness of Excreta Management in Cap Haitien, Haiti.” Environment and Urbanization, 27(1): 89–104.
Journal Articles:
No journal articles submitted with this report: View all 5 publications for this projectSupplemental Keywords:
Transitional housing, homelessness solutionsRelevant Websites:
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.