Submitted in fulfilment of the requirements for the degree of Master of Science in Engineering, University of Natal, Durban, South Africa.
Due to the spread of urbanisation and increased environmental awareness, odour has become a major problem in communities surrounding landfills. The aim of this research was to investigate odour emissions from landfills and develop a management tool that operators could use to assist in minimising the impacts of odour. The management tool would be in the form of real-time perditions of odour concentrations in the vicinity of a source. The Bisasar Road landfill in Springfield, Durban was a case study site for the research.
The methodologies used in this project can be divided into three broad categories. Firstly, flow visualisation experiments were conducted on the case study site to investigate the effects of complex terrain and the results compared to predictions from a dispersion model. Secondly, source characterisation was done on-site. Sources of odour were identified using a portable odour monitor (Electronic nose). Sources of odour were then sampled using sorbent tubes and analysis done using Gas Chromatography – Mass Spectrometry. Thirdly, numerical dispersion modelling was done. Five available dispersion models were assessed and compared against one another in order to select the most suitable model for this application. A software management tool or ‘Odour Management System’ (OMS,) was designed and implemented on a computer at the Bisasar Road landfill.
Qualitative results of the flow visualisation experiments show that terrain does have an effect on a dispersing plume path for short-range predictions. Comparisons between the flow experiments and model predictions are qualitatively consistent. Qualitative results were not obtained for the emission flow rate and emission concentration of landfill gas. The chemical composition of the fresh waste gas was determined. ADMSTM (Advances Dispersion Modelling System) was found to be the most suitable dispersion model for this application. The OMS has been installed on-site to produce odour concentration graphics every ten minutes. A fence line odour control system has been installed along approximately 600 metres of the landfill border based on work done as part of this project. Weather conditions and information provided by the OMS, assist in running the odour control system economically.