Life-Cycle Emissions and Human Health Implications of Multi-Input, Multi-Output Biorefineries

Area of Science:

• Biotechnology and Bioengineering
• Environmental Science
• Chemical Engineering

Background:

• Scaling up biofuel production requires diverse feedstocks like agricultural residues and organic waste.
• Integrating lignocellulosic biomass conversion and anaerobic digestion in biorefineries offers economic and environmental advantages.
• Current research often overlooks comprehensive life-cycle impacts beyond carbon footprints.

Purpose of the Study:

• To quantify the life-cycle air pollution, marine eutrophication, acidification, and external costs of integrated biorefineries.
• To compare integrated biorefineries processing crop residues, food waste, and manure with traditional single-process facilities.
• To evaluate the production of liquid fuels, electricity, renewable natural gas (RNG), hydrogen, bioplastics, and animal feed.

Main Methods:

• Life-cycle assessment (LCA) framework applied to integrated biorefinery scenarios.
• Quantification of greenhouse gas emissions (CO2, CH4, N2O) and air pollutants (NH3, VOCs, NOx, SO2, PM2.5).
• Monetization of external costs including environmental and health impacts.

Main Results:

• Integrated biorefineries with organic waste codigestion can reduce CO2-equivalent emissions by 84-149%.
• Monetized life-cycle external impacts range from $1.07/gallon to -$0.75/gallon ethanol.
• Co-production of electricity or RNG alongside biofuels demonstrates significant environmental benefits.

Conclusions:

• Integrated biorefineries represent a sustainable approach to biofuel production and waste management.
• These facilities offer substantial reductions in environmental externalities compared to conventional methods.
• Policy and economic incentives could accelerate the adoption of integrated biorefinery technologies.