Interview with Steven Mojo, Executive Director of the Biodegradable Products Institute

Is it true that using bioplastics in packaging may not always be a more sustainable solution than using traditional, petroleum-based resins?
You need to look at the lifecycles of these bioplastic materials. You need to look at their manufacture, as well as their use, and then at their disposal. And then you need to compare that to the incumbent materials to see how complete the lifecycles are. As several companies have demonstrated, as the process for making these biobased materials is better understood and better defined, the life-cycle benefits begin to improve.

The original complaints that it takes too much energy to make these biobased materials compared with the incumbents may have been true. But you are looking at different levels of manufacturing in terms of the expertise and the knowledge and the quantity. So you`re comparing a startup business to one that has been around for decades, and you`re saying that this new material isn`t as efficient as the older one. And yes, you`re right, it is not as efficient, but that`s not to say that it won`t be someday.

Steven Mojo, Executive Director of the Biodegradable Products Institute

Can the terms "biodegradable" and "compostable" be used interchangeably?
No, because one describes a process, while the other describes where and when the process will take place. When you say something is "biodegradable," it means that under the right conditions, microbes in the environment can completely break down the material and use it as a food source. Biodegradation is a process that can take place in many environments, including soils, compost sites, water treatment facilities, marine environments and even in the human body. This is the process that converts organic carbon into energy and maintains life. Not all materials are biodegradable under all conditions. Some are susceptible to the microbes found in a wastewater treatment plant, while others need the conditions and microbes found in a compost pile or in the soil.

When we say materials are "compostable," we are talking about where the process will occur and in what time frames. When products are designed to be composted, they should meet ASTM Intl. [] specifications D6400 (for Compostable Plastics) or D6868 (for Compostable Packaging). Products that meet the requirements in these two specifications will disintegrate rapidly in a professionally managed compost facility, will biodegrade quickly under the composting conditions, will not reduce the value or utility of the finished compost by leaving plastic fragments and will result in humus that supports plant life.

What future trends do you see for biopolymers?
I believe that you will see the properties continue to get better. I think that converters will learn how to process them better, and as a result, the price for the end-application differential will continue to come down. I also think you will see a better understanding of what the life-cycle benefits are of these materials. And I believe that you`ll continue to see the growth in food-waste diversion efforts - if people understand that food scraps, both pre- and post-consumer, are a resource that can be recovered and used as a feedstock for a process that`s going to give them a useful product. Right now, we`re just wasting those resources, and food scraps are one of the largest unrecovered waste streams that we have. When we send those to the landfills, they contribute to the production of methane, which is released into the atmosphere as greenhouse gas emissions. Landfills are the number-one generator of man-made methane into the atmosphere, according to the EPA.

Certainly in the past two to two-and-a-half years, sustainability in a variety of formats has grown in interest, from light bulbs to greenhouse gas to using less gasoline because the prices are higher. It is coming more to the forefront; it will be a question of how it plays out in the marketplace and how it translates into consumers` willingness to spend more for environmentally preferable choices. Some consumers are willing to spend a significant premium now, and others aren`t. I think over time the premium will become more acceptable or will become smaller, and market penetration will increase.

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sent: 2012-03-12 19:57:06

The main complaint I have with this story is that it does not emsahpise that the study only looked at “waste” bags, these are bags that I assume contain non-organics/non-recyclables because the study assumes that the end of life for these bags is incineration. No scenarios are presented where bags are disposed in other ways. It makes sense, if you assume incineration, that the impact will be dominated by the mass of raw materials. This study proves nothing regarding the use of biodegradable bags in composting or anaerobic digestion programs. If the study had to look at PE bags vs. bio bags with composting as the end of life assumption, the extra costs of dealing with shredded plastic in the compost would probably produce different results. It’s about using the right bag for the job.