Material flow analysis and global warming potential assessment of an industrial insect-based bioconversion plant using housefly larvae

Abstract

The significant increase in the demand for biomass waste treatment after garbage classification has led to housefly larvae treatment becoming an attractive treatment option. It can provide a source of protein while treating biomass waste, which means that nutrients can be returned to the natural food chain. However, the performance of this technology in terms of its environmental impacts is still unclear, particularly with regards to global warming potential (GWP).This study used a life cycle assessment (LCA) approach to assess a housefly larvae treatment plant with a treatment capacity of 50 tons of biomass waste per day. The LCA results showed that the 95% confidence intervals for the GWP in summer and winter were determined to be 24.46–32.81 kg CO2 equivalent (CO2-eq)/ton biomass waste and 5.37–10.08 kg CO2-eq/ton biomass waste, respectively. The greater GWP value in summer is due to the longer ventilation time and higher ventilation intensity in summer, which consumes more power. The main GWP contributions are from (1) electricity needs (accounting for 78.6% of emissions in summer and 70.2% in winter) and (2) product substitution by mature housefly larvae and compost (both summer and winter accounting for 96.8% of carbon reduction).