Tag Archives: life cycle of products

Landfill Biodegradable Products engage in Carbon Negative Activity


The phrase carbon negative activity can have many interpretations that I feel needs clarification.  Carbon is sequestered in plastic as we all know, but when the plastic is biodegradable, the off gassing of methane (comprised of C02 and Methane) from the biodegradation process is combustible.  If this bio-gas is utilized in methane to energy generators, the result is considered a “green” source of energy.  However, carbon is still emitted from the process, the benefit is that we used energy from bio-gas instead of using energy from say…coal.  Utilizing methane from a landfill is only part of a possible process of creating a carbon negative cycle.  There’s a major running debate right now as to the carbon positivity/negativity of landfill biogas generation.  The back-to-back papers at the SPC conference last Spring in San Diego by Adam Gendell and Mort Barlaz spoke to two sides of this issue.  As more data flows in from many different projects currently underway, we will have a more definitive understanding of how to apply it to carbon life-cycle analysis, in the ultimate goal of realizing carbon negativity!

In the hopefully not so distant future, we will have plastic that has come from renewable sources that are not land-crop depended, but will still utilize carbon available in our atmosphere, to help in the carbon sequestering process.  ONLY when carbon is being pulled out of the atmosphere, and less carbon is being put back into it (by engaging activities like methane to energy), can someone be truly carbon negative.  Having an ENSO biodegradable plastic is part of the whole picture that is entirely up to progressive sourcing of material, and responsible end of life process.

Thank you,

Del Andrus



What percentage of methane is collected in landfills?

I recently came across an article by James Levis called Collecting landfill gas good step. This article is a reaction to a paper that Levis co-wrote with Dr. Morton Barlaz titled “Is biodegradability a Desirable Attribute for Discarded Slid Waste? Perspectives from a National Landfill Greenhouse Gas Inventory Model.” That very paper started the jumping off point for the sudden out spurt of biodegradable plastic methane emissions articles all over the web this summer.

Spinoff headlines ranging from  “Study: Biodegradable plastics can release methane” to the reckless “Biodegradable products are often worse for the planet” were at the forefront of attention.

I had reacted to such articles in a previous blog which you can read here but after reading Levis Collecting landfill gas good step article, I came across some statistics that I just had to share!

greenhouse gas emissions methane

Levis stated in the article “ The foundation of this research is a life-cycle accounting of the greenhouse gas (GHG) emissions associated with discarding waste in both national-average and sate of the art landfills”    Now here is some interesting information,

An estimated..

35% of waste is discarded in state of the art landfills which collect generated methane and use it in beneficial ways

31% of waste is left in landfills without any gas collection occurring

34% of the waste is in landfills that collect and flare the gas


The results of the research showed that there are significant benefits to collecting and beneficially using landfill gas. Levis addressed reactions to the research, one of the most common comments being “these materials are intended to be composted, therefore the results are irrelevant.” Levis reacted to the response by stating, “But these materials are generally not composted, and most areas of the country do not have the infrastructure for source-separated compostable collection and treatment of these emerging biodegradable materials. Therefore we need to understand the effect of their disposal in a landfill.”

Another common response to the research included that the conclusions were too broad, that they neglected emerging materials like bioplastics that do not appreciably degrade in landfills. Levis responded by stating that the argument seems misguided because these types of materials are not even technically biodegradable and the study’s only mention of bio-based, non biodegradable products was to say that it would lead to green house gas emissions in a landfill.  Levis closed the article by stressing the importance of analyzing the entire life cycle of a product to know if it is better to use a conventional or biodegradable material in the production, as well as environmental and economic factors, before making your final judgment.