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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge

Bongani Dladla

The sustainability of micro-algae cultivation using the novel floating, flexible Photo-BioReactor in coastal cities: a Case study of Durban, South Africa

The exploit of fossil fuels to meet current energy needs is leading to irreversible climate change and environmental pollution. First generation biofuels, primarily produced from food crops and mostly oil seeds are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic development. Threats to food security, land use changes, excessive use of fertilizer and depleting water resources are also of concern regarding the sustainability of crop-based biofuels. This has necessitated the need for alternative environmentally sustainable, renewable energy resources. One such alternative is algae cultivation for biofuel production using the novel flexible, floating Photo-BioReactors (ff-PBR) in coastal environments.


Waves, algae, sunlight and wastewater combination are a good recipe for renewable energy and improved water quality in coastal cities. This system utilizes wastewater discharge from sea outfalls as a nutrient source to cultivate algae while sequestrating carbon dioxide and treating the wastewater. The City of eThekwini (Durban) is considering using the ff-PBR technology to meet its transportation energy demands. There has not been any environmental sustainability assessment done on the proposed technology. This research seeks to examine whether large-scale, commercially viable, environmental sensitive microalgae cultivation for biofuel production is possible for the City of eThekwini (Durban) and assess the environmental burden associated with such production using a Life Cycle Analysis tools.


Results confirm the competitiveness of microalgae-based biofuels in water, land demand, and eutrophication potential. The proposed system requires higher energy input compared to other biofuels production. For an improved sustainability assessment and comparison to existing biofuel production, the system must be assessed as Waste Water Treatment- MicroAlgae Cultivation system.