Economic assessment of food waste co-digestion with sewage sludge in five Asian cities

Food waste not only causes waste treatment loading but also leads to loss of resources. Food waste co-digestion with sewage sludge is regarded as one of the optimal technologies to treat food waste and for the recovery of bio-energy and phosphorus. Besides, focus on the recovery rate and efficiency, environmental impacts and other benefits should also be considered when a new technology or policy is evaluated. In this study, the economic and recycling benefits of such treatment technology were assessed in five different cities in Asia. The comprehensive economic assessment was based on life cycle assessment and three kinds of economic benefits, i.e., energy production, P recovery, and greenhouse gas emissions. Hence, the aim of this study is to show the differences in economic benefits from various treatment processes in five cities in Asia. The benefits of food waste co-digestion with sewage sludge were evident from the results of this study. The results indicated that new energy production always dominates the economic values while the economic value from P recovery was relatively low since the P fertilizers are not expensive in Asia. However, differences in economic values were considered for the different Asia cities.