CHAPTER ONE
1.0 INTRODUCTION
1.1 Background of the study
Biomass, particularly agricultural residues seem to be one of the most promising energy resources for developing countries (Patomsok, 2008). Rural households and minority of urban dwellers depend solely on fuel woods (charcoal, firewood and sawdust) as their primary sources of energy for the past decades (Onuegbu, 2010). Of all the available energy resources in Nigeria, coal and coal derivatives such as smokeless coal briquettes, bio-coal briquettes, and biomass briquettes have been shown to have the highest potential for use as suitable alternative to coal/ fuel wood in industrial boiler and brick kiln for thermal application and domestic purposes. Global warming has become an international concern. Global warming is caused by green house gasses which carbon dioxide is among the major contributors. It was shown that increased emissions of CO2 have been drastically reduced owing to the fact that the rate of deforestation is higher than the afforestation effort in the country.
The use of fuel wood for cooking has health implications especially on women and children who are disproportionately exposed to the smoke apart from environmental effects. Women in rural areas frequently with young children carried on their back or staying around them, spend one to six hours each day cooking with fuel wood. In some areas, the exposure is even higher especially when the cooking is done in an unventilated place or where fuel wood is used for heating of rooms. Generally, biomass smoke contains a large number of pollutants which at varying concentrations pose substantial risk to human health. Among hundreds of the pollutants and irritants are particulate matters, 1, 2-butadiene and benzene (Schirnding and Bruce, 2002). Studies showed that indoor air pollution levels from combustion of bio fuels in Africa are extremely high, and it is often many times above the standard set by US Environment Protection Agency (US-EPA) for ambient level of these pollutants (USEPA, 1997). Exposure to biomass smoke increases the risk of range of common diseases both in children and in adult. The smoke causes acute lower respiratory infection (ALRI) particularly pneumonia in children (Smith and Samet, 2000; Ezzati and Kammen, 2001).
Agro waste is the most promising energy resource for developing countries like ours. The decreasing availability of fuel woods has necessitated that efforts be made towards efficient utilization of agricultural wastes. These wastes have acquired considerably importance as fuels for many purposes, for instance, domestic cooking and industrial heating. Some of these agricultural wastes for example, coconut shell, wood pulp and wood waste can be utilized directly as fuels.
Fortunately, researches have shown that a cleaner, affordable fuel source which is a substitute to fuel wood can be produced by blending biomass (agricultural residues and wastes) with coal. Nigeria has large coal deposit which has remained untapped since 1950’s, following the discovery of petroleum in the country. Also, millions of tones of agricultural wastes are generated in Nigeria annually. But it is unfortunate that farmers still practice “slash-and-burn” agriculture.