Amy Banzaert, Wellesley College

The role of engineering in addressing some of humanity’s most pressing problems is critical. This talk will focus on a specific problem and technological solution — indoor air pollution from cooking in developing countries — and also discuss the educational activities the speaker is developing at Wellesley College to engage students in problems like this one in the context of a liberal arts education.

Part I: Biomass-derived cooking fuels are used by three billion people. The drawbacks of such fuels, typically wood or wood-derived charcoal, include health hazards, negative environmental effects, and perpetuation of poverty. Briquettes made from various waste materials have been proposed as an alternative fuel to address these issues. The purpose of this work is to understand whether such fuels are viable as compared to wood charcoal considering toxicity, usability, and economic criteria.

Briquettes produced in Haiti from paper waste without carbonization were studied and found to be highly problematic from the perspective of emissions and cooking performance. More particulate matter was emitted by a factor of thirty, the carbon monoxide emissions normalized to energy released were higher by a factor of three, and the briquettes were one third as energy dense as wood charcoal. Experimental carbonized briquettes made from fabric scraps and carbonized forms of the paper waste briquettes were studied and also produced emissions far in excess of wood charcoal. These types of briquettes are being disseminated and no prior art on their emissions has been identified; the associated health concerns are significant.

Briquettes made from carbonized agricultural waste (AWC) in a process developed by MIT’s D-Lab were investigated. These briquettes were comparable to wood charcoal in terms of energy density and carbon monoxide and polycyclic aromatic hydrocarbon emissions. Particulate matter emissions from these briquettes were far higher during the initial stages of the burn, but lower during the later burn stages. Ultra-fine particles from wood charcoal and AWC were characterized, offering a novel understanding of these emissions for carbonized cooking fuel in total and over the course of a burn. The effect of variations in raw material inputs on combustion emissions was documented.

Field studies were conducted on AWC, assessing cooking fuel emissions in households in Nicaragua, ascertaining end user perception of the fuel, piloting production with a women’s cooperative, and conducting an economic analysis of the viability of this production model. Emissions were found to be competitive with wood, user perception was overall cautiously positive, production was hypothetically profitable but only if systems are introduced effectively, and the ability to make charcoal was welcomed as a money saving and income-generating opportunity.

In summary, AWC has promise as an alternative fuel but care must be taken in terms of the economic model and minimizing deviation from the studied briquette formula. As such, fuels made from non-agricultural waste should not be introduced until the emissions hazards and cooking performance limitations are addressed.

Part II: What is the role of engineering in addressing the world’s most pressing challenges, and what is the intersection between engineering and the liberal arts? Traditionally, that intersection was intentionally nonexistent, but truly “wicked” problems require a truly interdisciplinary approach. Preparing students of all disciplines to address these challenges demands an educational approach that helps liberal arts students speak the language of engineering and technology, and vice versa. Examples of class projects, one-of engagement activities, and international fieldwork being developed for Wellesley College’s new engineering program will be presented.