Grantee Research Project Results
Final Report: Development of Source-Separation Latrine Technology for Sustainable Human Waste Management in Rural Ghana
EPA Grant Number: SU834708Title: Development of Source-Separation Latrine Technology for Sustainable Human Waste Management in Rural Ghana
Investigators: Chandran, Kartik , Liu, Christine Chiang , Bains, Anjali Kaur , Egan, Andrea Keefe , Cheema, Suraj Singh , Chen, Eric Yilluen , Wang, Claire
Institution: Columbia University in the City of New York , Barnard College
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2010 through August 14, 2011
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2010) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Sustainable and Healthy Communities , P3 Challenge Area - Safe and Sustainable Water Resources , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
“Scalable Source-Separating Latrines: Implementing Sustainable Energy, Waste Management and Agricultural Solutions in Developing Communities” focuses on the dire sanitation needs in the Greater Obodan Region, villages located in the Eastern Region of Ghana. In 2005, Engineers Without Borders-USA Columbia University (EWB-USA CU) designed and implemented a Kumasi Ventilated Improved Pit (KVIP) latrine system in Obodan in order to address the preexisting waste management needs of the community. However, an assessment conducted in the summer of 2009 showed that the KVIP was inadequate and causing various problems to the community including overuse, pungent fumes, odors and maintenance difficulties. In Phase I of this project, the team improved the waste-management system in Obodan through the implementation of a pilot source-separated composting latrine system.
A source-separated latrine, or urine-diverting toilet, uses a specialized bowl in which the urine enters the front and flows out through a pipe, while the feces is diverted to the back of the bowl and falls into a chamber. This separates the two substances and helps to keep the feces container dry, making it easier and safer to handle while reducing odor and the breeding of flies in the latrine facility. This system also allows for sustainable reuse as liquid fertilizer for crops, since human urine uncontaminated by fecal matter compares well with urea as a source of nitrogen and other important nutrients for plants. Once research and tests have been conducted to determine that the urine is safe for use, it can be used as fertilizer. Through composting, the fecal matter turns into harmless soil substrate that can be removed by members of the community and be used on their farms. Thus, because of the source separation, the community no longer needs to hire an outside vendor to clean out the latrine.
Summary/Accomplishments (Outputs/Outcomes):
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Fewer unlined pit latrine users; preference of private latrine over other options
Discussion and assessments by the community and the team showed that private source-separated latrines are preferred over more individual latrines or an improved KVIP. The construction of a source-separated latrine reduces the need for unlined pit latrines and provides a more sanitary, sustainable and economical facility. -
Significantly reduced maintenance cost to pump waste out of pits
The double-chamber source-separate latrine utilizes staggered pit usage. When one chamber is being used, the other is composting. After up to 6 months, the composted waste can be manually and safely dug out. The composting process is aided by the addition of sawdust, ash, and food scraps. Digging out the waste only occurs twice a year and is on a much smaller scale than that of the KVIP. -
Urine as crop fertilizer
Tests are currently being conducted to determine the urine’s nutrient content and fertilizer potential. To achieve that potential as a fertilizer, lack of cross-contamination of urine with pathogens from solid waste must be confirmed. Urine collected from the pilot latrine (zero retention time) this past January had no fecal coliform present, and the sample will be used as a base reference for future tests. After more studies, pineapple crop yield tests will be performed on villagers’ farms to compare pre- and post-use of urine as fertilizer. Villagers have expressed excitement about the possibility of reusing the waste on their farms, as fertilizer is an expensive variable cost. -
Biofuels derived from composting solid waste as power
The source-separating latrine system has significant energy potential. The team is currently investigating energy extraction from methane produced by the source-separated latrines. Current experiments involve inoculating samples of feces from the source-separated latrine with various composting substrates that the villagers in Obodan have access to, including ash, sawdust, pineapple husks, urine, and composted solid waste. Our team is also studying the reaction of organic waste into volatile fatty acids, which dictates whether the energy produced is methane, ethanol, butanol or biodiesel. This energy can potentially be used to power a water distribution system to be constructed in Obodan this summer. -
Solid waste as soil substrate ( and added fertilizer) after mixing with composting substrates
Solid waste carbon:nitrogen (C:N) ratios indicate compostability. Investigations on the use of various substrates are also being performed to determine the best system for accelerating the composting process and whether the substrates will increase the effectiveness of the waste as fertilizer. After solid waste is collected and the composting cycles are completed, pineapple crop yield tests will be performed on the villagers farms. -
Improvement (or at least no adverse effects) in groundwater quality
Continuous water assessments on the trips have shown that groundwater quality is not adversely affected by the construction of source-separating latrines. Water quality testing indicated that the groundwater is cleaner than expected, after there were zero to minimal levels of total coliforms, fecal coliforms, E.coli, and total heterotrophic bacteria present in the village’s borehole water. Other developing communities across the world may not be so fortunate, so source-separated latrines could still prove to help alleviate groundwater contamination resulting from unlined pit latrines. -
Community feedback
During household surveys this past January, the villagers expressed an interest in gender-divided latrines. There will be a privacy wall in the new latrines constructed this summer. The villagers also mentioned that a small bowl outside the latrine for hand-washing would be appreciated. This design also will be included in our future source-separated latrines.
Conclusions:
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People/prosperity/planet, sustainability
The goal of this project is for Obodan and similar communities to begin and maintain a cycle of reuse which is sustained by providing increased crop yields, free fertilizer, an alternative energy source, and a clean sanitation facility. Additionally, the system has a minimal maintenance cost, making the project practical to sustain. The accumulating solid and liquid waste first produces soil substrate and fertilizer to be used on farms after being properly treated. Pineapple husks, ash and sawdust can be used as composting substrate, feeding other sources of waste back into the cycle. Energy can also be produced through the composting solid waste; this energy can power the village’s upcoming water distribution system, a separate project that is currently pursued by the team. The source-separated latrine system would also decrease contamination of groundwater through the need for fewer unlined pits, thereby reducing the risk of water-borne illnesses. Furthermore, the labor costs of source-separated latrines give the community incentive to have shared responsibility over operation and maintenance. -
Impact on developing world
The successful implementation of a source-separated latrine system in a developing community will serve as a guide for other similar communities who lack basic sanitation infrastructure and need sources of energy and fertilizer. By showing how a sustainable solution to waste management can exist, the project will encourage surrounding communities to consider such options for their own villages and towns. More broadly, the project may serve as a catalyst for the reassessment of how all communities, both developing and developed, approach human waste. By advocating the reusability of human waste, it can encourage other societies to adopt more sustainable methods of treating waste; the byproducts of the source-separated latrines can also alleviate communities from poverty. Source-separated latrines can also decrease the risk of groundwater contamination by reducing the number of unlined pits in a community. -
Education
The source-separated latrine design is an innovative system that requires some training. The pilot design was introduced in summer 2010 and the users of the latrine have been educated on its functionality. Since human waste reuse is a relatively new concept in the community, it requires a comprehensive education plan on usage and maintenance. Community meetings and household visits included explaining the process of converting sterile liquid waste into crop fertilizer, switching the toilet seat to the other chamber every six months, periodically adding composting substrates and digging out the compost. Special detail was provided to the village leaders and the users of the pilot latrine, who will be responsible for the subsequent training of new households that will be using future latrines. The new latrine will be a strong platform for education in improved sanitation practices, and the facility will hopefully be a model for other nearby communities to learn from. We are currently working with our main village contact, Samuel Gamson, the Assemblyman for the Greater Obodan Region, to educate the village’s junior and senior high schools on the latrine and its maintenance, thus ensuring that future generations can sustain the projects. The past two summers engineering education programs were held in the nearby town Nsawam for junior and senior high school students by members of the EWB-USA CU team. The education programs are one-month long held during the school vacation for Nsawam-region high schools in August, and many students from the Greater Obodan Region attend the program. Source-separation technology will be integrated into our curriculum this coming summer. -
Scalability
This model of source-separating latrines can be used throughout developing regions since it addresses the issues present in many rural areas (agricultural needs, water quality issues, poor waste management facilities) while being relatively simple to construct. The pilot latrine took 10 days to construct this past July, and building upon experiences from that process, future source-separated latrine should only take one week to complete. It was constructed purely from village labor, and minimal skilled labor is required other than basic mason and carpentry skills, which are often present in rural villages across the world. Since construction materials were purchase locally, the village would be able to solve any future problems independently. Private source-separated latrines are relatively small and can be easily scaled down to the size of the household(s) using them. -
Improved quality of life
The source-separation technology leads to improved waste facilities, improved water quality, and utilization of energy, soil substrate and fertilizer derived from the waste. This leads to a better quality of life for villagers in developing communities as they are provided with improvements to the basic human rights of water and sanitation, and with opportunities to grow economically.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
KVIP, Ghana, Source Separation, Waste Recycling, Groundwater Contamination, Willingness to Pay, Sustainable Waste Treatment, Biogas, Biofuel, Pathogen DecayRelevant Websites:
Columbia University Engineers Without Borders Exit
Implementing Sustainable Sanitation and Water Management in Ghana Exit
NEW YORK CITY WATER SUMMIT (PDF) 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.