Thursday, July 7, 2011

Response to Statement by the Biodegradable Products Institute about the biodegradability paper.


I found a statement by Steven A. Mojo, Executive Director of the Biodegradable Products Institute (BPI) about the paper that I co-wrote with my advisor Dr. Morton Barlaz entitled Is Biodegradability a Desirable Attribute for Discarded Solid Waste? Perspectives from a National Landfill Greenhouse Gas Inventory Model that is patently false:
First, the author, James Lewis,[sic] leads the reader to believe that since a biobased material will quickly biodegrade under aerobic conditions, such as composting, that it will also do so under the anaerobic conditions found in landfills. 
Firstly, all publicity is good publicity IF they spell your name right. Secondly, this statement is not at all based in fact. Our results for the methane generation from PHBO were based on anaerobic reactor studies of PHBO published in Biomacromolecules in 2002 (Federle et al, 2002). We spend 400 words describing exactly how this was done in the section of the paper entitled Modeling of Individual Waste Components. Claiming that we used aerobic composting decomposition data or results to model anaerobic degradation in a landfill is completely false and clearly contradicted by the actual paper in question. I really hope that someone at BPI reads this and corrects the statement. 
His only other argument is that biodegradable plastics are a minuscule part of the waste stream, so their emissions aren't important. I rebutted that argument in my previous post:
Firstly, our calculations were performed on a per mass basis, which means we calculated the amount of greenhouse gas emissions per ton of waste discarded in a landfill. Therefore, it makes no difference that other waste materials are landfilled in greater amounts. Secondly, it's irrelevant from a planning perspective because we can't substitute biodegradable plastics for food waste or yard waste or paper, which constitute traditional biodegradable materials. The fact that some of those materials may emit more methane (which we quantify and discuss in the paper), is completely irrelevant since those materials perform completely different functions. People can't substitute food for bioplastics, so it doesn't matter from a decision standpoint that food waste may lead to more emissions.
Cited Literature

  1. Levis, J. W., Barlaz, M. A. “Is Biodegradability a Desirable Attribute for Discarded Solid Waste? Perspectives from a National Landfill Greenhouse Gas Inventory Model” Environ Sci Technol, 2011, doi: 10.1021/es200721s
  2. Federle, T. W.; Barlaz, M. A.; Pettigrew, C. A.; Kerr, K. M.; Kemper, J. J.; Nuck, B. A.; Schechtman, L. A. Anaerobic biodegradation of aliphatic polyesters: Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) and poly(epsilon-caprolactone). Biomacromolecules 2002, 3, 813–822.

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