Abstract:
Nutrient and Energy trapped in household biodegradable solid waste and
wastewater has to be recycled to meet the escalating energy demand and lack of
urban sanitation in developing countries. Human feces in developing countries like
Ethiopia area major causes of environmental pollution and community health
impairment, particularly in slum areas where many people live together under low
basic sanitation coverage. Hitherto, the management option involves a simply
containment, treatment and disposal which is practiced in most cities of developing
countries. Human waste recycling with appropriate and low cost technologies can
prevent environmental contamination and protects public health. In addition,
such approaches have great importance to recover energy and develop natural
fertilizer from feces. However, such human waste management options are not yet
explore efficiently. This article presents results of a study evaluating the feasibility of
using human feces-derived char as a solid fuel for heating and cooking and a potential
way to use the feces ash after energy recovered for agricultural application
experimentally. The proximate analysis showed that feces have a composition of 61.
86% moisture contents, 27.28% volatile maters, 4.69% ash contents and 6.17% fixed
Carbon. The pyrolyzed feces at 300 0C had 23.7 MJ/kg of energy content which has
met the FAO standard for biochar. Both the micro- and macronutrient content of feces
ash were in the recommended range needed for plant growth. On the basis of the
energy content, the determined combustion efficiency of feces char in this study, we
found the material to have potential as a supplementary, renewable energy source in
the developing world. Similarly, the nutrient content of the feces ash can substitute
chemical fertilizer for agricultural application. The energy and nutrient values are
comparable to those of commercial fertilizers and charcoal briquettes respectively,
making feces recycling a potential substitute that also contributes to the
preservation of the environment and public health.
