Course: 22.423 - Capstone
Semester: Spring 2007
Instructor: John Duffy
Partner: Village Empowerment Peru Projects
Composting Solar Toilet: Village Empowerment Peru Project. Many villages served by the Village empowerment project have minimal to no electricity, communication or sanitation systems. Currently, there are few outhouses; of theses, most are unfit and are often not used due to unpleasant conditions. The design of a cost effective and easily maintainable composting toilet has the potential to improve public health (e.g. spread of disease, safe drinking water, etc.) and minimize negative environmental effects (groundwater contamination). In addition, composting will yield a fertilizer, thereby saving the expense of purchased fertilizers.
The primary goal of this capstone student project was to design a sanitary composting toilet for remote Andean Peru villages for considerably less cost than commercial models. The composting toilet provides a natural solution to sanitation challenges and provides villagers with a safe and free fertilizer. The final design consisted of an outhouse like structure and incorporated temperature controls and aeration to promote composting conditions. Students conducted steady state energy balance equations, mathematical models and a strength analysis. Economic gain and social and environmental impacts were also determined. Students concluded that there would be an economic gain of $17 (US) per person annually (based on assumptions of $300 (US) per hectare for chemical fertilizer purchased by Peruvians in 1995). In addition, students integrated consideration for indigenous lifestyles, values and economic status of the villagers in their design process.