Biodiesel production from microalgae grown on domestic wastewater: Feasibility and Egyptian case study

Biodiesel has been identified to be a suitable biodegradable substitute to petro-diesel. The Egyptian consumption rate of fossil diesel is approximately 37 kt per day from which 50-60% are imported. Using algal biofuels has led to a potential techno-economic assessment of 1.0 million ton (MT) biodiesel to be produced from microalgae grown on domestic wastewater via heterogeneous transesterification catalysis using sodium orthosilicate (Na4SiO4) as catalyst in order to minimize the diesel shortage in Egypt and mandating B5 by 2020. Process equipment and units required have been sized with an accuracy of +/- 20%. Mass balance, total capital investment (TCI), total production cost (TPC) and economic potential (EP) have all been assessed based on the marketed biodiesel price of US$1000 per ton and an evaluated Nannochloropsis sp. algal biomass cost of US$400 per ton. An algal biodiesel project of 1.0MT has been proven to be feasible with return on investment (ROI) and pay-back period of 41% and 2 years, respectively. A break-even analysis has disclosed that the cost of algal biodiesel that renders the project feasible is should be above US$843 per ton while the cost of algal biomass should not exceed US$461 per ton. Furthermore, sensitivity analysis was evaluated on variations in microalgae lipids content using ROI and payback time. The results obtained using Tornado Chart recommended that the minimum oil content should be 35% for profitable algal biodiesel business. Finally, a comparison between the investigations of algal biofuel versus Jatropha curcas biodiesel was performed, and positive prospects were detected for industrializing algal biodiesel whenever Brent Crude Oil Spot exceeds US$100 per barrel.