LCA Analysis of Anaerobic Digestion Plant Fed with Canteen Food Waste in a University in China

The amount of food waste in China's catering industry is approximately 17 to 18 Mt per year (about 20% of total food losses). China's National Development and Reform commission has currently ratified 100 pilot cities in five batches over 2011 to 2015 to implement food waste treatment projects. Almost the 80% of these projects is based on anaerobic digestion. So it is very important to understand clearly which is the environmental impact of these new bioenergy chains (especially in the small scale). For this reason a Life Cycle Assessment case study is presented in this work, based on a 156 kWe anaerobic digestion plant, fed with waste food produced by 29 canteens, which are present in the campus of the Huazhong University of Science and Technology (HUST). The obtained results show that, respect to the reference scenario, the presented case study has lower environmental burden in all the considered impact categories. When the waste food is compared with other feedstock to produce biogas, the only negative impact is on the eutrophication category. About 0.00084 kgPO4 3- are emitted per kWhe produced. This negative impact is mainly due to the reuse of the digestate as soil amendment.