Sustainable Sanitation Solutions for Low-Income Urban HouseholdsEPA Grant Number: SU835718
Title: Sustainable Sanitation Solutions for Low-Income Urban Households
Investigators: Davis, Jennifer , Escallón, Maria Fernanda , Moua, Gao Nou , Russel, Kory C , Tilmans, Sebastien H
Institution: Stanford University
EPA Project Officer: Hahn, Intaek
Project Period: August 15, 2014 through August 14, 2015
Project Amount: $14,996
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2014) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Water , P3 Awards , Sustainability
Many residents of dense urban communities in developing countries lack access to safe sanitation facilities. In order to meet basic needs, residents are forced to choose between crowded public toilets, open defecation, or private latrines that are expensive to build and maintain. Narrow alleys prevent vehicle access, such that pit latrines must be emptied manually. These conditions increase the risk of fecal contamination of drinking water sources and the urban environment.
To address the challenges of density, poverty, limited water access, and the often informal status of these communities, we are developing a portable waterless, urine-diverting household toilet with sealable, removable and reusable cartridges that enables safe removal of human waste. The toilet enables a full-cycle service model wherein cartridges are removed and delivered to resource recovery sites without environmental exposure or spills. The cartridges can then be cleaned for reuse, while the waste can be converted into valuable end-products like compost, energy, or biochar, that can help finance the service.
During testing of our toilet and service in Cap Haitien, Haiti, we determined that a critical missing element of our design is a “flushing” mechanism. Such a device would add a standard dose of dry cover material (such as lime, sawdust, ash, or crushed peanut shells) following each use of the toilet, which will help maintain hygienic conditions and provide a more pleasant user experience.
Our design emphasizes a sanitation service (portable toilet rental with regular emptying), rather than an asset (a conventional pit latrine), as the value proposition for households. Just as mobile phone companies have revolutionized telecommunications services by bundling capital costs within service plans, our model allows subscribers to improve their sanitation services immediately and radically with minimal up-front cost. The proposed project will enhance the value of this service to users, by responded to their expressed preferences for an experience that more closely mimics that of a water-flush toilet.
The expected outcome is a low-cost, dry material dispensing mechanism for waterless toilets, adaptable to other dry toilets in use globally and to ecosan toilets in remote areas in the United States. The system helps reduce contamination of the environment and drinking water by isolating feces and facilitating their transport to waste management facilities.