An economic viability and environmental impact assessment of mango processing waste-based biorefineries for co-producing bioenergy and bioactive compounds
Manhongo, T. T., Chimphango, A., Thornley, P. & Röder, M.
Process feasibility, economic viability, and environmental impacts of model integrated biorefineries based on a 62.5 metric tonnes of mango processing waste per hour plant capacity, for co-producing bioenergy and bioactive compounds were evaluated using three scenarios for integration with a dried mango chips processing facility. Scenario I modeled an integrated biorefinery for anaerobic digestion (AD) of mango peel and wastewater for biogas production. Scenario II integrated extraction and recovery of pectin from mango peel while scenario III involved the sequential recovery of pectin and polyphenols from the peel before AD. In all scenarios, the biogas from AD is co-combusted with mango seeds to produce heat and electricity, thus representing integrated biorefineries for co-production of bioactive compounds with bioenergy. Scenario III is the most attractive option in terms of profitability, with a net present value of $ 57.2 million compared to – $ 86.4 million and $ 50.0 million for Scenarios I and II respectively. However, results from the life cycle analysis suggest that it is the least auspicious with a global warming potential (GWP) of 15.9 kg CO2 eq,/tonne of waste processed when compared to Scenarios I and II with GWP values of 12.1 and 12.8 kg CO2 eq./tonne, respectively. The results demonstrate both process and economic feasibility for the co-production of bioenergy and bioactives at the base plant capacity. Nonetheless, a trade-off between environmental and economic benefits should be established when making choices for implementing mango waste biorefineries since improved profitability is at the expense of higher environmental burdens.