Several rural farms have installed anaerobic digestion systems as manure management systems. Such systems are also used to provide electricity and heating. In these systems, biogas is generated from anaerobic digestion of biomass waste and combusted in a boiler and an engine-generator set, to produce heat and electricity respectively. This paper calculates the size and mode of operation of a biomass waste to energy conversion system that would result in maximum revenue for a given herd size. A Tabu Search optimisation technique is used. A number of equally good solutions are generated. These solutions are plotted on a Pareto front and the best solution is defined as one that lies on this Pareto front. Optimisation of a biomass waste to energy conversion system reduces reliance on electricity from the grid. It also reduces reliance on the use of propane or other fossil fuels for heating.

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This paper presents a tool for the analysis of conversion of organic waste into energy. The tool is a program that uses waste characterization parameters and mass flow rates at each stage of the waste treatment process to predict the given products. The specific waste treatment process analysed in this paper is anaerobic digestion. The different waste treatment stages of the anaerobic digestion process are: conditioning of input waste, secondary treatment, drying of sludge, conditioning of digestate, treatment of digestate, storage of liquid and solid effluent, disposal of liquid and solid effluents, purification, utilization and storage of combustible gas. The program uses mass balance equations to compute the amount of CH 4 , NH 3 , CO 2 and H 2 S produced from anaerobic digestion of organic waste, and hence the energy available. Case studies are also presented.

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