Apple pomace management by anaerobic digestion and composting: a life cycle assessment

The food industry generates large volumes of organic by-products, which require proper environmentally friendly disposal. In the case of the apple-processing industry, apple pomace constitutes 25-30% of the original apple weight. The conventional treatment of food industry by-products involves composting, which releases greenhouse gases and contributes to climate change. This study presents an environmental assessment of apple pomace management technologies for industrial juice processing. The life cycle analysis (LCA) methodology was applied as a tool for evaluating the technological routes of composting (method conventionally used) and anaerobic digestion (AD) (an innovative technological route). The main change proposed to the current process would be the implementation of anaerobic reactors in the apple industry, avoiding the transport of apple pomace to the composting unit and producing bioenergy from the burning of methane-rich biogas. The results showed a reduction in the environmental impacts in the system composed of AD of apple pomace. In the categories related to eutrophication and acidification, a reduction of approximately 50% was obtained when comparing AD with composting. The global warming potential and greenhouse gas emissions showed a significant reduction with the adoption of AD, due to the conversion of biogas into energy and its use by the industry. In conclusion, the implementation of AD technology for the management of apple pomace can be a promising alternative to recover bioenergy and decrease the environmental impacts caused by the apple-juice processing industry. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.