Development of Source-Separation Latrine Technology for Sustainable Human Waste Management in Rural GhanaEPA Grant Number: SU834708
Title: Development of Source-Separation Latrine Technology for Sustainable Human Waste Management in Rural Ghana
Investigators: Chandran, Kartik
Current 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
Current Institution: Columbia University in the City of New York , Barnard College
EPA Project Officer: Page, Angela
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
The current latrine facilities in the village Obodan (Ghana) are overused and cannot accommodate the entire community. To avoid the long waits, stench and unsanitary conditions of the public latrines, community members construct their own unlined pit latrines, posing a serious risk of groundwater contamination and local pollution. A preliminary trial of a source-separated latrine is being developed to alleviate the demands on existing infrastructure with a more sustainable model of human waste management. Past projects (KVIP installed by our team in 2005) in Obodan have not been sustainable due to maintenance costs coupled with a lack of accountability in fee collection. Private latrines will have more individual accountability and ownership, which along with community involvement should lead to sustainable project.
Source-separated latrines separate urine from fecal matter at the toilet seat, thereby reducing the quantity of harmful pathogens in solid waste, and leading to safer and more sanitary waste storage. Collected liquid waste can potentially be decontaminated and used as valuable agricultural nitrogen and phosphorous fertilizer, providing accessible revenue to the community. The composted solid waste can also be reused as fertilizer if given sufficient time to properly decompose. This pilot phase will evaluate the feasibility of source-separation technology in Obodan and educate the community on its benefits. The pilot latrine will serve three families, or about 30 people. Once we gain feedback on the pilot, we will modify our design and implement more in the winter. We will follow the EPA reviewed protocol regarding headspace gases developed by Professor Chandran during measurements analyzing solid waste decomposition.
The biotransformation of the collected solid waste will be remotely monitored by measuring the accumulation of H2, CH4 and CO2 gases in the head-space of the collection chamber using an online gas analyzer. These gas levels will indicate the state of decomposition, which will be accelerated by periodic addition of sawdust, which should lower the organic carbon : nitrogen ratio to about 25:1 Thermocouples will also be installed to indicate elevated chamber temperatures typical of high decomposition rates. Operationally simple volume sensors based on solids levels will be employed to monitor the rate of waste accumulation to better size the future latrine chambers. To determine if the urine is suitable for reuse, the mineral content (N, P, K) will be analyzed on-site. The use of an online ammonia analyzer will be evaluated to provide long-term hands-free information. We will look to remove pathogens and cut down the usual six weeks of resonance time needed via a modular sand filtration unit. Measured pathogen indicator levels should be below the US standards of 200 fecal chloroform units / 100ml urine.