Life cycle assessment and society willingness to pay indexes of food waste-to-energy strategies

Food waste (FW) has received increasing attention because of its immense production quantities and significance to resource and environmental impacts related to disposal approaches. We combined life cycle assessment (LCA) with society's willingness to pay (WTP) index to evaluate energy, water, and environmental impacts on three food waste-to-energy (FWTE) options in China. For anaerobic digestion (AD) mode, the results showed that 1140 MJ of energy consumption could be saved by power generation from methane, power transmission, and biodiesel production from per ton of FW; the cost of climate change for treating FW was 137.8 kg CO(2)e t(-1) FW, failing to be climate-sound due to the end life of digestate in practice. The total impact to AD mode in the form of monetized value for WTP was 13.3 CNY t(-1) FW, of which the collection and transportation, pretreatment, AD reaction, wastewater treatment, biodiesel production, and residue landfilling stages contributed by 10.5%, 6.5%, 19.3%, 27.6%, 4.7%, and 75.7%, respectively, while biogas utilization offset it by 43.9%. Notably, a considerable amount of water used in AD prevented it from showing an advantage compared to incineration (-5.1 CNY t(-1) FW), which performed best overall attributing to the generated electricity compensated for primary energy demand, water, and terrestrial acidification to a great extent. Landfilling turned out to be an unappealing FW disposal method due to the low landfill gas capture ratio. Given that AD is touted for its environmental benefits, potential approaches-such as developing a reliable and supportive technology to facilitate digestate recycling into agriculture-were discussed to improve its competitiveness and attractiveness. Our study employed a way to accumulate and compare impact indicators to better interpret FW management impacts and advantages, considering energy recovery, resource recycling, and the environment.

Automated summary

This study combines life cycle assessment with society's willingness to pay index to evaluate the impact of three food waste-to-energy options in China. Anaerobic digestion mode saves energy consumption but incurs climate change costs. Landfilling is considered an unattractive FW disposal method due to low landfill gas capture ratio.