Definition of compostability criteria for packaging: Initiatives in Italy

The management of solid waste is changing. The traditional approach based on landfilling of mixed refuses is shifting toward a system based on the at-source sorting of waste into specific fractions. The biological treatment of the organic fraction is considered to be an appropriate form of disposal not only for the “traditional≓ feedstock such as food scraps and vegetable and garden waste, but also for biodegradable packaging, when not recyclable in other ways. Any change from a complex system to another is difficult since many factors are to be organized and optimized. Industry must develop and manufacture compostable products, municipalities must build composting plants and organize source-separated collection, and regulatory bodies must define widely acceptable criteria of compostability. In Europe, the European Union has assigned the last task to the CEN, to provide common criteria and avoid hindrance to commercial exchanges. In Italy the UNI, the national standardization organization, has produced a working document to contribute to the discussion on the European level. In this paper the UNI scheme is described. A condensed version of this paper was presented by one of the authors (F.D.I.) at the 5th annual meeting of the BEDP Society, held in Nashville, September 22–26, 1996, during a session covering International Standards for Biodegradation Testing.     

Degradation of Commercial Biodegradable Packages under Real Composting and Ambient Exposure Conditions

The use of long-lasting polymers as packaging materials for short lived applications is not entirely justified. Plastic packaging materials are often soiled due to foodstuffs and other biological substances, making physical recycling of these materials impractical and normally unwanted. Hence, there is an increasing demand for biodegradable packaging materials which could be easily renewable. Use of biopolymer based packaging materials allows consideration of eliminating issues such as landfilling, sorting and reprocessing through taking advantage of their unique functionality, that is compostability. Composting allows disposal of biodegradable packages and is not as energy intensive compared to sorting and reprocessing for recycling, although it requires more energy than landfilling. The aim of this work was to study the degradation of three commercially available biodegradable packages made of poly (ld-lactide) (PLA) under real compost conditions and under ambient exposure by visual inspection, gel permeation chromatography, differential scanning calorimetry, and thermal gravimetric analysis. A novel technique to study the degradability of these packages and to track the degradation rate under real compost conditions was used. The packages were subjected to composting for 30 days, and the degradation of the physical properties was measured at 1, 2, 4, 6, 9, 15 and 30 days. PLA packages made of 96% l-lactide exhibited lower degradation than PLA packages made of 94% l-lactide, mainly due to their highly ordered structure, therefore, higher crystallinity. The degradation rate changed as the initial crystallinity and the l-lactide content of the packages varied. Temperature, relative humidity, and pH of the compost pile played an important role in the total degradation of the packages. A first order degradation of the molecular weight as a function of time was observed for the three packages.