The Plastics Environmental Council (PEC) is sponsoring research to produce the first standard specification for landfill biodegradation of petroleum- and natural gas-derived plastics treated with additives to speed up anaerobic biodegradation. Such a standard would be a huge help in coping with the estimated 29 million tons of post-consumer nonrecycled plastics that end up in landfills.
Plastics are generally not biodegradable unless they've been specifically engineered to do so, as materials used in food service items are in many areas of California. Petroleum-derived plastics don't usually biodegrade unless they've had certain chemical additives introduced to them during the manufacturing process. The additives don't affect the plastics' performance, and products that contain the additives can be processed with existing recycling methods.
An additive made by ENSO Plastics, a PEC member, includes organic compounds that bond hydrostatically to the material's molecules. When the material is placed in an environment like a landfill, the additive attracts anaerobic microbes that colonize the plastic, digest the additive, and further digest the plastic by depolymerizing it. The final products are either methane or carbon dioxide and humus.
The PEC-sponsored large-scale research and development program will be conducted by the Georgia Institute of Technology and North Carolina State University and aims to produce a specification and a certification seal. The specification will reliably project landfill biodegradation rates for a given PEC-certified product in a given range of landfills over a given range of moisture conditions. The PEC expects the development of the specification to build confidence among regulators, consumers, and businesses in the effectiveness of plastics additives. It estimates the certification seal will be available in 18 months.
The study will be the first of its kind to verify biodegradation rates of plastic waste treated with additives under both laboratory and field conditions, Robert McKnight, the PEC's chairman, said in a press release.
Professor Morton Barlaz of North Carolina State and his team will examine waste degradation rates under both field and laboratory conditions. To produce the specification, they will study petroleum- and natural gas-derived plastics that have been treated with additives from PEC member companies.
The additives are organic substances that encourage anaerobic landfill bacteria and fungi to break down the materials and convert them to biogas methane, carbon dioxide, and biogenic carbon. "Research done so far using standard test methods suggests that the treated plastics could biodegrade completely within five to ten years, depending on landfill conditions," Lisa Detter Hoskin, a principal research scientist at the Georgia Tech Research Institute, who co-chairs the PEC's technical advisory committee, said in a press release. A network of accredited laboratories will test products made with the biodegradable additives to ensure they degrade within a specified period.
PEC member companies include Biofilms, Bio-Tec Environmental, C-Line Products, ECM, Ecolab, Ecologic, FP International, Pure Plastics, and Wincup.