Environmental Sustainability of Waste Circulation Models for Sugarcane Biorefinery System in Thailand

Sugarcane leaves and trash burning during harvesting, and vinasse management, are major challenges of the Thai sugarcane industry. Identification of the appropriate valorization pathways for both the biomass waste streams using the sugarcane biorefinery concept is necessary. This study aims to assess the environmental sustainability of five CE models, including (1) sugarcane trash for electricity, (2) sugarcane trash to biochar, (3) sugarcane trash as a soil conditioner, (4) vinasse as a bio-fertilizer, and (5) vinasse for power generation. Life cycle assessment has been conducted using the ReCiPE midpoint impact assessment method. The results revealed that all waste utilization scenarios can help reduce the environmental impacts compared to the base case. The utilization of sugarcane leaves and trash for electricity generation brings about the lowest environmental impacts due to the environmental credits from the substitution of Thai grid electricity. The utilization of sugarcane leaves can reduce impacts on climate change, terrestrial acidification, and ozone formation by about 20–104%, 43–61%, and 12–54%. Recycling vinasse as bio-fertilizer and for biogas production for electricity generation can reduce climate change impact by about 28–29%. There is a significant improvement of the avoidance of pre-harvesting burning of sugarcane in the Thai sugar industry, which has led to the big potential of sugarcane leaves biomass utilization. Recommendations to enhance the efficiency of using sugarcane leaves and vinasse are discussed. The integrated waste circulation scenarios on cane leaves and vinasses in the sugar-electricity-ethanol biorefinery shows advancement in the bio-circular-green economy (BCG) aspects for enhancing the environmental sustainability of the Thai sugarcane industry.