Graduation Year

2013

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Civil and Environmental Engineering

Major Professor

James R. Mihelcic

Keywords

Anaerobic biodigestion, Global Warming, Life Cycle Assessment, Sanitation, Sustainable Development

Abstract

Over seventy percent of the 2.5 billion people who still lack access to basic sanitation worldwide live in rural areas (WHO/UNICEF, 2012). Despite concerns of water scarcity, resource depletion, and climate change little research has been conducted on the environmental sustainability of household sanitation technologies common in rural areas of developing countries or the potential of resource recovery to mitigate the environmental impacts of these systems. The environmental sustainability, in terms of embodied energy and carbon footprint, was analyzed for four household sanitation systems: (1) Ventilated Improved Pit (VIP) latrine, (2) pour-flush latrine, (3) composting latrine, and (4) biodigester latrine. Variations in design and construction materials used change the embodied energy of the systems. It was found that systems that used clay brick in the construction of the superstructure had an average cumulative energy demand 4,307 MJ and a global warming potential 362 kilograms of greenhouse gas equivalent (kgCO2 eq) higher than systems that used adobe brick in the construction of the superstructure. It was also found that systems that incorporate resource recovery, such as a composting or biodigester latrine, can become net energy producers over their service life, recovering between 29,333 and 253,190 MJ over a 20-year period, compared to the 11,275 to 19,990 MJ required for their construction and maintenance. Recovering the resources from the waste also significantly lowered the global warming potential of these systems from 2,079-49,655 kgCO2 eq to 616-1,882 kgCO2 eq; significantly less than the global warming potential of VIP latrine or pour-flush latrines (8,642-15,789 kgCO2 eq). In addition, two community wastewater treatment systems that serve 420-1,039 individuals considered in a similar study had a higher cumulative energy demand per household (44,869 MJ and 38,403 MJ) than the household sanitation systems (11,275-19,990 MJ). The community wastewater treatment systems had a lower global warming potential (2019-2,092 kgCO2 eq) than household systems that did not recover resources (8,642-15,789 kg CO2 eq), but higher than household systems that incorporate resource recovery (616-1,882 kgCO2 eq). The goal of this study is to provide insight to policy makers in the development field to promote decision making based on environmental sustainability in the implementation of improved sanitation coverage in rural areas of developing countries.

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