The amenability of pre-treated source separated organic (SSO) waste for ethanol production

Every year, millions of tonnes of municipal solid waste are generated in the city of Toronto from residential and non-residential sources. A large fraction of the municipal solid waste is composed of organic materials. This valuable resource has traditionally been disposed of in landfills, which in turn contributes to the pollution of the environment and the generation of green house gases. This places a great emphasis on the need for the design and implementation of more sustainable waste management practices and the adequate supportive infrastructures in order to achieve sustainability. The city of Toronto has been experiencing a huge challenge over the past few years regarding its waste problem, and having inadequate infrastructure for effective waste management practices. In the year 2000, the City of Toronto established a goal of 100% waste diversion by the year 2010 (Task Force, 2001). In the year 2005, the City of Toronto collected approximately 100,000 tonnes of source separated organic waste (SSO) from single-family households (Butts, 2005). SSO is an excellent source of fermentable carbohydrates including free sugars, starch, cellulose, hemicellulose and other degradable organic materials. However, the main obstacle is the release of some of its carbohydrates, such as cellulose and hemicellulose, from their bondage to lignin before conversion to fermentable sugars. Cellulose and hemicellulose in SSO are bonded to lignin and are not easily separated and fermented to ethanol. Therefore, for utilizing SSO as a feedstock for ethanol production, a deep understanding of the nature of lignocellulosic materials is essential in order to overcome the challenges in the biological conversion to ethanol. As an initial part of a multi-staged project, this thesis is to examine the potential of SSO for utilization as a feedstock for ethanol production. A set of experiments were conducted on SSO in order to determine the amenability of SSO to ethanol production The experimental results show a relatively high amount of carbohydrates in the SSO samples, indicating potential of SSO to be utilized as an ethanol production feedstock. Comparing result of the characteristics study with other cellulosic feedstocks, indicates that SSO has a reasonable amount of fermentable sugars and can be utilized for ethanol production instead of using other cellulosic feedstocks such as herbaceous energy crops. A technology for the biological conversion of SSO to ethanol was proposed based on the current techniques and the results from the characterization study on SSO. It is foreseen that the findings of this study will enhance the overall understanding of the nature of SSO and the possibility of using it for ethanol production, and provide technical data and information for the decision makers in the assessment of the potential of SSO for ethanol production.