Grantee Research Project Results
Final Report: Sustainable Sanitation Solutions for Low-Income Urban Households
EPA Grant Number: SU835718Title: Sustainable Sanitation Solutions for Low-Income Urban Households
Investigators: Davis, Jennifer , Escallón, Maria Fernanda , Tilmans, Sebastien H , Moua, Gao Nou , Luby, Stephen P , Lopez, Gib , Russel, Kory , Adams, Nick
Institution: Stanford University
EPA Project Officer: Hahn, Intaek
Phase: I
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 - Safe and Sustainable Water Resources , P3 Awards , Sustainable and Healthy Communities
Objective:
Typically, sanitation is delivered through networked, water-‐borne sewerage to a wastewater treatment plant or on-‐site treatment, but the density, poverty, limited water access, and informal or illegal status of these communities preclude installation of such resource-‐intensive, permanent infrastructure.
To address this challenge, we are developing a portable waterless, urine-‐diverting household toilet with sealable, removable and reusable containers or cartridges that enable the safe removal of wastes from dense informal communities. The toilet enables a full-‐cycle service model wherein containers are removed and delivered to resource recovery sites without potential for environmental exposure or spills. The containers are then cleaned for reuse and the wastes are converted into valuable end-‐products like compost, energy, or biochar. The end-‐ products are sold to help finance the service. In contrast to traditional sanitation solutions that require large capital expenses for users to construct sanitation facilities, our solution allows users to subscribe to a service which comes with a toilet and regular emptying, reducing barriers to entry.
After testing our toilet and service in Cap Haitien, Haiti, we determined that a critical missing element of our toilet design and other existing solutions is a “flushing” mechanism for dry cover material that isolates the waste from users after each toilet use. This mechanism helps preserve hygiene, but it is also essential to provide a pleasant user experience such that users will actually adopt, use, and pay for this system. We seek to develop a dry material dispensing system that standardizes the dosing of dry cover material currently in use, in order to further minimize exposure risk while maximizing user willingness to pay for the service.
Our low-‐cost dispenser for dry cover material (options include sawdust, ash, sugarcane bagasse, crushed peanut shells, etc.) delivers standard doses of material into dry container-‐based toilets, adequately covering and isolating waste. We sought to minimize the quantity of parts in the system, while still providing a user experience that mimics the water-‐flush toilet experience of pulling a lever and sending the waste "away." Users rotate a handle after using the toilet, and the waste is covered and isolated.
As a household-‐level technology, the design goal was for the dispenser to incorporate storage for four days' worth of material for families of 8. Household-‐level sanitation is a unique and innovative for urban slums.
Currently, virtually all sanitation solutions targeted for the urban poor in low-‐ and middle-‐ income countries share the following features:
- They confer considerable responsibility for both capital and O&M financing, as well as for facility management and maintenance, upon users.
- They depend critically on accompanying behavior change (at the individual, household, and/or group level) to realize potential health benefits.
By contrast, our design facilitates a sanitation service, rather than an asset, as the value proposition for households. Just as mobile phone companies have revolutionized telecommunications services for the ‘bottom billion’ by bundling capital costs within service plans (e.g., providing low-‐cost phones and then charging for air time), our model allows subscribers to improve their sanitation services immediately and radically with minimal upfront cost. As a result, the public and NGO resources currently focused on facilitating financing of sanitation facilities for low-‐income households can be liberated and redirected toward supporting the development of service providers, as well as building a supportive regulatory and institutional environment.
Summary/Accomplishments (Outputs/Outcomes):
We created a low-‐cost dry material dispensing mechanism for waterless or dry toilets in use in dense urban slums globally and ecosan toilets in remote areas in the United States. This device was first tested in simulated conditions at Stanford, using prototype toilets and a variety of different materials. The design goal of delivering 0.5L of dry material per dose, in a consistent location thereby covering waste, was achieved. The device met this goal with several common materials (ash, peanut shells, sawdust). This was accomplished by using a bi-‐directional auger, where incremental turns of the handle drive the auger to deliver cover material. Using widely available 3D printing technology, we were able to build the auger in modular units. However, the modular design also allows for local manufacturing in a variety of materials. Local craftsmen will be able to produce the auger in Haiti and Peru, while anyone with a 3D printer will be able to experiment and produce the parts worldwide. Currently, this device is beginning a pilot-‐test with households in Lima, Peru, in partnership with the container-‐based sanitation service provider x-‐runner. The results of this field test will be presented at the EPA P3 Expo in April 2015.
Conclusions:
The dispensing mechanism significantly improves upon the appeal and reach of waterless container-‐based sanitation systems. Now that the mechanism has been designed and user testing is underway, the dispensing mechanism will hopefully be offered to toilet owners in Haiti and Peru soon. This will allow for further verification of the hypothesis that dry material dispensing mechanisms increase the adoption rate of dry container-‐based toilets.
The primary benefits to users of our system will be reduced levels of environmental contamination in their communities, which in turn reduces negative health outcomes and improves levels of safety and satisfaction. Sanitation is inherently a public good and as such these benefits will accrue to residents of the entire community, at an increasing rate as adoption of the service increases. Developing this aspirational product design can help foster the growth of household-‐level sanitation services throughout low-‐income regions of the world with rapidly urbanizing populations. It can also help influence sanitation strategies and water resource management in arid regions as well as specific contexts in the United States.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 2 publications | 2 publications in selected types | All 2 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Tilmans S, Russel K, Sklar R, Page L, Kramer S, Davis J. Container-based sanitation:assessing costs and effectiveness of excreta management in Cap Haitien, Haiti. Environment and Urbanization 2015;27(1):89-104. |
SU835718 (Final) |
|
|
Russel K, Tilmans S, Kramer S, Sklar R, Tillias D, Davis J. User perceptions of and willingness to pay for household container-based sanitation services:experience from Cap Haitien, Haiti. Environment and Urbanization 2015;27(2):525-540. |
SU835718 (Final) |
|
Supplemental Keywords:
Sanitation, willingness to pay, sustainable urban infrastructure design, waterless toilets, Cap Haitian, Haiti, Lima, Peru, BangladeshRelevant Websites:
- Resource Sanitation: Household Toilets in Urban Settings Exit
- Stanford: Water, Health and Development Exit
The 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.