Quantifying Biogas Generation from Human and Biodegradable Wastes: A Case Studies of Three Estuarine Communities in Rivers State

Abstract

This study showed total excreta produced by 73 people (19 male adult, 19 female adult, 17 male children and 18 female children) was 18.97kg per day. Given an average household of 5, (2 adults and 3 children), 1321g (1.3kg) of feaces would be generated. Therefore, 500 households in any of the communities would generate 660,500g (660.5kg) of excreta. The cumulative volume of gas generated from 5kg of human excreta, combined with 15 kg of leftover rice; 5kg of vegetable waste and 25kg of water resulted in 0.167m3 biogas. By extrapolation, 500 households, generating 515kg of excreta; using 1,546kg of waste rice; 515kg of vegetables waste and 2,579kg of water, can generate 83.5m3 biogas. This quantity of biogas can power 55kw electricity generating set which can provide Community Street light for more than 6 hours. In the coastal communities of the Niger Delta where modern waste management practices are practically nonexistent, human excreta and household food wastes are discharged directly into the rivers and creeks, resulting in obnoxious effects such as foul smell, pollution and filth and even mosquito infestation. The outcome of this research has given a clear direction on how to treat domestic wastes (which in effect are resources) for bioconversion. As the world in general is changing from over reliance on fossil fuels, being wasting assets, coupled with the attendant pollution and degradation of the environment, investment into alternative energy sources such as biogas from wastes would contribute to the quest to reduce energy scarcity, guard against ecological disasters, elimination and/or control deforestation and erosion of the soil surface in particular and the environment in general. Therefore, for developing countries of Africa and especially Nigeria to surmount her current energy, environmental, food, health and unemployment crises, the anaerobic digestion of biodegradable wastes in general; excreta/household food wastes in particular should be given the attention it deserves.