Environmental impacts and economic benefits of waste milk carton recovery from schools

Abstract

Recycling waste milk cartons is being tested in several cities in China, but its environmental and economic effects have yet to be investigated systematically. This study examined a practical system of complete waste milk carton recycling and assessed the system considering life cycle environmental impacts, particularly carbon emissions and cost-benefits. The results show that electricity consumption contributes 42 % of the environmental burden, and water consumption contributes 22 %. Still, paper, plastic, and aluminum recovery counteract the negative impact, making the normalized life cycle impact reach −5.15E-15 based on the environmental footprint (EF) method. Similarly, the substitution effects of recycled materials can counteract the total carbon emissions, and the net emissions are −0.011 kg CO₂ per unit carton corresponding to 1 L milk, implying an excellent carbon trade opportunity when taking incineration or landfill as the baseline. Saving electricity and water and using clean power can significantly improve the system's environmental benefits. However, due to the small scale of this practical project, the system cannot generate net profit, and labor costs and land rent are the majority. Carbon trade, government subsidies, and extended producer responsibility are the recommended management strategies for improving waste milk carton recycling.