Date of Award

Spring 1-1-2013

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Lupita D. Montoya

Second Advisor

R Scott. Summers

Third Advisor

Karl G. Linden

Abstract

A team at the University of Colorado at Boulder is working with the Bill & Melinda Gates Foundation to develop a novel technical solution for 2.5 billion people in the developing world with no access to basic sanitation. The university's Sol-Char toilet uses concentrated sunlight to convert human fecal sludge into biochar, which has potential as a value-added product. The feasibility of using feces-derived biochar as a solid fuel for heating and cooking is assessed, considering energy content and elemental analysis of biochars made under different reactor conditions, ease of briquetting, and durability of biochar briquettes. Fecal biochars made at 300°C were similar in energy content to wood biochars and bituminous coal, possessing a higher heating value of 25.6 MJ/kg, while fecal chars made at 750°C were significantly lower in energy content at 13.8 MJ/kg. Chars derived from simulant feces favored by other Bill & Melinda Gates Foundation sanitation research projects were found to differ significantly from fecal char in their energy content and briquetting characteristics. A frequently used correlation between elemental composition of chars and their higher heating values was adapted to be more applicable to feces-derived chars based on a review of fecal char literature and experimental results. Fecal chars made at low temperatures and briquetted with molasses and lime binders yielded briquettes of comparable strength and energy content to commercial charcoal briquettes, suggesting that briquettes made from human feces could be a significant contribution to the sanitation value chain.

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