Abstract
D.Ing. (Mechanical Engineering Sciences)
Sustainable energy is a huge point of discussion amongst policy makers and academics alike. This stems from an increase in the world’s population, with shrinking finite energy sources that are currently used. The University of Johannesburg seeks to address this challenge through the development of a biogas digester plant.
The study analysed a gate to gate model of a domestic biogas digester, with the intention of both evaluating the environmental impact of the University’s biogas digester, while also making use of fundamental computations in performing a Life Cycle Assessment initiative, as opposed to using commercially available software. This was done in the hopes of gaining deeper understanding on the computational structure of Life Cycle Assessments, and this can then be translated to developing more region specific databases for future studies.
It was found that the designed digester produces more greenhouse gases (GHGs) during operation, than when the digester is manufactured and commissioned. This enabled a design alteration that minimised the GHGs prior to the completion of the design. Amongst a number of environmental impacts investigated, it is interesting to note that during the operational stage of the digester, there are chemicals that contribute to photochemical ozone depletion, and that in turn resulted in the recommendation of revising mechanical equipment that was initially proposed by the designer.