Material flow analysis and carbon footprint of water-packaging waste management

Packaged drinking water represents one of the fastest growing commodities on a global scale, and several alternatives to plastic have been proposed, such as glass, cardboard or aluminum. The research has a twofold goal: (i) first, it calculates the amount of water-packaging waste generated in Italy in 2020, distinguishing among PET, glass, aluminum and cardboard materials, and it applies the material flow analysis through the STAN 2.7.101 software; (ii) second, it evaluates the carbon footprint of the management of the primary water-packaging waste, considering recycling, incineration with energy recovery and landfilling by using the CO2ZW tool. The research estimates the adverse environmental impacts of the selected management pathways considering 1 kg of water-packaging and 1000 L of packaged water. The results show that each year 1311 kt of waste and almost 289 ktCO2eq of direct and indirect emissions are associated with recycling, incineration with energy recovery and landfilling of water-packaging in Italy. PET bottles record the highest environmental impact with 0.77 kgCO2eq per kg of treated waste, with incineration representing a significant burden (1.80 kgCO2eq per kg of treated waste) compensated by recycling. The research discusses opportunities and challenges toward a more sustainable waste management of water-packaging, highlighting the need to increase recycling rates among final consumers and reduce incineration with energy recovery, which significantly contributes to the release of carbon emissions. Last, heavy bottles should be substituted with ultralight ones, since waste management emissions can be reduced by 13% by replacing 490 g of glass bottles with 390 g ones.