Optimum strategies of regional kitchen waste treatment against a background of carbon mitigation

Reducing carbon emissions of kitchen waste treatment (KWT) is regarded as an effective way for achieving the goal of carbon mitigation. In this study, a hybrid method, combining life cycle analysis (LCA) and an interval linear programming model, was proposed. The carbon emissions of four technologies (i.e., landfilling, incineration, anaerobic digestion, and composting) for KWT were evaluated based on the LCA framework. Strategies for the multiple technologies were obtained using the interval linear programming model. This method can effectively identify the potentials for carbon mitigation in the KWT technologies with consideration of their eco-economic performance. To confirm the effectiveness of the method, a case study was conducted in the urban agglomeration of the Pearl River Delta (PRD) region in China. Three scenarios (i.e., S1 to S3) were proposed for multiple KWT modes from single-city and urban-agglomeration perspectives. The results of LCA showed that the carbon emissions were smallest (i.e., 95.77 kg CO2 eq/tonne) for anaerobic digestion among the technologies. In terms of desired strategies in the KWT management, the application proportions of anaerobic digestion and composting would significantly increase under S2 and S3, while the proportion of incineration would be smaller than that under S1. Considering variations of eco-economic performance under the multiple scenarios, the KWT strategies under S3 would be recommended in terms of their contributions in carbon mitigation. It was recommended that the capacity of KWT should be improved 12.75–15.37 Mt and 6.86–7.95 Mt in order to adopt the strategies under S2 and S3.