Any kind of technology, material, or standard that could put a dent in the 29 million tons of nonrecyled plastics in landfills would be a really important deal. I'm just hoping that such a standard wouldn't get stymied or watered down by the usual standards-setting process or any of the politics that's likely to ensue. This kind of thing is too important to be tripped up by such machinations.
This is an interesting departure from previous generations of biodegradable plastics. The polyolefin-starch blends which came out in the early 1990s, which were the first plastics to be marketed as biodegradable, had many shortcomings. First of all, only the starch component was actually biodegradable, leaving the polyolefin component in the environment. So, from an environmental perspective, they were no better than non-biodegradable plastics (and probably worse, since the smaller fragments of polyolefin were more mobile in the environment). Second, the starch component would sometimes degrade in use, rendering the product unusable - and would stubbornly fail to degrade in landfills. Third, if they were introduced into recycling streams, the biodegradable plastics would degrade the properties of the recycled product. All of these disadvantages tended to give the term "biodegradable plastics" a bad name.
Since then, there have been several other attempts at making biodegradable plastics. Among them, compostable plastics based on polylactic acid have been fairly successful from a marketing perspective. One of the big selling points is that they are made from natural materials (corn oil); of course, whether or not converting food crops into disposible plastics in the midst of a global food crisis is a good idea is debatable, to say the least. These plastics are intended to be composted, not landfilled. Recyclers won't accept them, and keeping them out of recycling streams continues to be an issue.
The biodegradable plastics described in this article are interesting in that they are normal commodity plastics with additives to allow them to be degraded by anaerobic bacteria in landfills. This should address some of the issues with previous generations of biodegradable plastics. One issue which I didn't see addressed, however, was the question of recyclability. What happens if these additives make their way into recycled products? If these plastics need to be kept out of recycling streams, how do you train environmentally-conscious consumers - who have learned that recycling plastics is the responsible thing to do - not to recycle them?
Another issue - brought up in the press release - is emissions. Perversely, one virtue of non-biodegradable plastics is that, since they don't break down, the carbon contained in them is effectively sequestered. Biodegradation of plastics releases carbon dioxide and methane, which are greenhouse gases. The press release mentions that the methane could potentially be captured and used as fuel, but either way, you are putting carbon in the atmosphere which otherwise wouldn't be there. It would be interesting to see a full life cycle analysis of this.
Another interesting twist is the fact that it's illegal in California to label any plastic product as "biodegradable." It would be interesting to see whether plastics with these additives might be able to get past this ban.
I think everyone agrees that reducing the volume of plastics in landfills would be a good thing. However, it remains to be seen whether biodegradable plastics are a good way to achieve this, or if the formula of reduce, reuse, and recycle is a better path.
Here is an interesting consideration about the plastics scrap stream: Many of these plastics would break down if they were exposed to the sunlight and the related ultraviolet light. I have seen that happen. But embedding them in a dark and dry landfill assures that they will last a very long time. So perhaps thefundamental concept of currenbt landfills is deffective. OF course it would take a bit more effrt to get the pllastics to where they would be subject to weathering, but that might be better than encapsulating them for "all eternity" as a nasty legacy for those who follow us.
Really, it might be better to encourage landfill decomposition of the waste instead of assuring it's longevity. Part of that could include a bit more effort towards the separation of plastic materials, also the separation of metals. The fact is that the density of the base materials in landfill is much greater than their density in ores when mmetals are mined. The conversion of the plastic waste stream into a useable base should also wind up consuming less energy. With plastics, this could include solar energy which is sort of "free".
@William: Actually, there is a class of biodegradable plastics, called oxobiodegradable, which are intended to break down under weathering conditions. They contain metal salts which are intended to speed up "normal" weathering. There are a few problems here: first, do they break down into something which is environmentally benign, or do you just wind up spreading hazardous organic chemicals far and wide? For example, if you broke polycarbonate back down into its monomer, you'd be converting a material which is relatively inert (bulk polycarbonate) into something which is thought to be an endocrine disruptor and possible carcinogen in humans and animals (Bisphenol A). Second, now that you've sped up "normal" weathering, will the material be able to perform as intended in the application? Third, as you've mentioned, there's a question of how to handle the waste to make sure it's exposed to UV rather than buried under a pile of trash. This seems like a simple problem, until you realize that you're talking about changing the way millions of tons of trash is processed. Finally, as with all biodegradable plastics, there's the problem of recycling (or, more accurately, making sure they don't get recycled).
Beth is definitely right that this is an extremely tough problem.
Yuu are certainly correct in that there would need to be a fundamental change in the entire philosophy of handling waste. There is no question about that. BUT just because doing it one way is what everybody has been doing does not make it the right way or the smart way. There are lots of examples of poor choices being continued because nobody was willing to admit that the initial choice was poor. Ego is a terrible handicap.
The huge amount of waste entombed presently should serve to show that it was not the best choice. But those in charge can't see any other way.
William K, a good number of engineers would agree with your thoughts when it comes to the disposal of tin lead solder. They still complain there was no science behind the choice to ban the small amount of lead that keeps tin solder from growing whiskers.
@William: you're right, "Because we've always done it that way" is one of the most maddeningly stupid justifications for anything, especially when the way we've always done it is obviously not working. However, inertia is something which needs to be taken into account in industries as well as mechanical systems.
We're seeing an interesting regulatory and standards dynamic in the tech sector. On the political front, there's lots of talk about how regulations are an impediment to business and have to be dismantled. It seemed (or seems) to me that this movement is very powerful. Yet when I look at what's happening on the ground, engineering companies are having to become MORE compliant with stds and regs, not less. An illustrative case is that of equipment safety regulations. Because there are regs in place in Europe, with which US vendors selling globally have to comply, those regs apply de facto domestically.
Alex has a good point. Because the electronics industry (many industries acturally) is global, U.S. companies have to adhere to European Union regulations. While the EU provides for input from industry, European reulations tend to be more advanced than anything we could expect on the federal level in the United States.
Globally, the whole industry has to meet the strictest regulations among the markets where products might be sold.
Many companies in the electronics industry are fine with regulations that do indeed make sense from an environmental POV. Much opf the complaints about EU regs have to do with regs that were passed without scientific scrutiny.
That aspect has changed in the EU in recent months. The EU responded positively to calls for scientific inquery by IPC earlier this year.
@Rob Spiegel, Alexander Wolfe, and everybode else talking about regulatory compliance: Ann is exactly right that this story really has nothing to do with government regulations. This is about industry and academia coming up with voluntary standards in order to better define what biodegradability means for a specific class of plastics. Given that, in a mostly unregulated environment (with the exception of California), the term "biodegradable" has been somewhat abused by applying it to plastics which had poor properties, were environmentally unfriendly, or both, this seems like quite a sensible move.
I'm puzzled by engineering complaints about government having too many regulations - Look at the most profound organism we know - the human body. The mind, the physical system, the interplay of organs, tissues, fluids. Study human physiology and you will realize that there are no small/short/truncated control loops. Every bodily fact enters into setting up a new stasis. Was it Einstein who said "make things as simple as possible, and not one bit simpler"? that's what we should notice and complain about in this world - governments that imperfectly regulate for political and financial reasons and still end up missing the target.
Eat food that hasn't been subjected to sanitary regulations, fly, get operated on, have a new house built, buy a new car, take prescription drugs. Now tell me with a straight face that ALL are better off if government would back off and let good old blatant free-market capitalism rule the transaction. Much more efficiently.
I tire of hearing these slogans from engineers; we know better.
I think one of the main points about this standard is that it will give an objective measurement for exactly how long it takes certain materials to biodegrade to certain levels using certain additives. In other words, it's not so much a "standard" that must be measured up to as it is a spec to indicate that certain conditions are being met and certain results are being achieved.
I would like to clarify a few points. Oxo-biodegradable additives add a very small amount to the cost. Using bio-based plastics however, would add approximately 400% to the overall cost.
Secondly, unlike bio-based plastics, Oxo-biodegradable plastic has the same performance as conventional plastics during its useful life. Several of the comments I read mention anaerobic decomposition, but this is highly undesirable as it creates methane and adds to the green house gas problem.
Oxo-biodegradable plastics are designed to deal with the problem of plastic litter in our open land environment and oceans. They have been tested to international standards and are verified by published science.
@Symphony Environmental: The plastics described in this article appear to be different from either oxobiodegradables or bio-based (PLA) biodegradable plastics. They are designed to be broken down by anaerobic bacteria in a landfill; as you point out, this will produce methane, but the accompanying press release discusses capturing this methane and using it for energy production. You're right that this is probably not the best solution from a climate change perspective.
Oxobiodegradable plastics are not without their problems, either. They can't be composted or recycled, and if they make it into a landfill, they won't break down. As you say, they are designed to break down in the open environment. What his means is that, perversely, you may be better off throwing them out of the window of your car than trying to dispose of them by normal means.
As Tim pointed out, biodegradable plastics are the "fat free donut" of plastics. This is a good analogy. If you want to lose weight, you shouldn't eat too many donuts; if you want to live a sustainable lifestyle, you shouldn't use so much disposable packaging or so many disposable products. My opinion is that, rather than searching in vain for a fat free donut, you're better off simply eating your fruits and vegetables - where "eating your fruits and vegetables" means reduce/reuse/recycle, instead of trying to come up with a guilt-free way to maintain our disposable lifestyle.
This particular study is focused on plastics derived from petroleum and natural gas, not bio-based plastics. The additives they are to be treated with will accelerate anaerobic biodegradation, which implies that the process is for hydrobiodegradable plastics. Using at least one of the additives, either methane or humus and CO2 can result, so yes, those add to the greenhouse problem.
But oxo-biodegradable plastics aren't entirely "clean", either. Their biodegradation, which involves metal salts as catralysts, leaves behind tiny fragments of metals and plastics.
It seems that the current state of plastics biodegradation solutions either add CO2, or don't entirely biodegrade, or both.
I have never seen a study verifying that an ordinary oxodegradable product such as a shopping bag will biodegrade given its normal treatment - taken to the landfill in the trash, where it will be covered in more trash within a day or two, if not immediately. Based on the published science, I agree with the DEPRA report, which found that they will not biodegrade in landfills. This DEPRA report was the reason why COOP and Tesco, the largest grocery chains in Great Britain, stopped using oxodegradable additives in their bags. As far as methane goes, it's being tapped and used in place of ordinary natural gas. In fact, much of the methane generated in landfills is eaten by microbes in the landfills. See http://earthnurture.com/LandfillCondTD.html to learn more.
Biodegradable polymers have been the fat free donut of the polymers. They have been something that always seem possible but never really worked well. The use of additives to help during anerobic decomposition is great. This opens the door to non-corn based polymers that can degrade naturally. It would be good to see the rough cost of the additive.
There is a new kind of plastic additive to induce biodegradation in conventional polymers. It is designed specifically to cause biodegradation of polymers in landfills and in natural bodies of water. I call this class of additives, microbiodegradable. This is completely different than oxodegradable additives. There is no UV light or heat treatment phase needed to initiate biodegradation. All degradation caused by using these additives is biodegradation, because no catalysts are used. See http://earthnurture.com to learn more.
Tim, this sounds very interesting. I believe that hydrobiodegradable and oxobiodegradable are terms describing the two basic classes of plastics, not of additives. Does your additive work for one of these classes? The additives described in the research mentioned in this article work anaerobically in moist and/or wet environments, e.g., landfills and bodies of water. That implies that your additive works with hydrobiodegradable plastics. Is that correct?
Hydrobiodegradable plastics are a plastic type, and the best known example is PLA. Oxodegradable additives are additives mixed with polyolefinic plastics, to act as a catalyst to chemically degrade them. The reason some moisture is required is to sustain the lives of the microorganisms. It has been said that the most germ-fee place in the average home is the toilet seat, because it is so dry. My additives work with all of the typical commodity plastics - PP, PE, HDPE, LDPE, LLDPE, PS, EPS, PET. I have designed one additive that will render PLA biodegradable in landfills. PLAs most prominent manufacturer says it is not biodegradable in landfills. See http://earthnurture.com for full details.
Enso is not a manufactuer of additives, it is a dealer specializing in an additive for biodegrading PET. They represent Bio-Tec, which makes the additive. My additives are in the same general class, but they are a more thorough, more recent technology.
@Salvatore: Your comment is almost unreadable due to the lack of spaces between any of the words. If you click on "Edit/Delete," you can fix this.
However, being a curious mind, I took a look at your website. It's interesting to know that you were working on this already in the late 1980s, and that there has been an ASTM standard for anaerobic biodegradation of plastics in landfills since 1994. Apparently this is not such a new topic.
My question for you is the same as my question for all of the other additive manufacturers - what happens if plastics with your additive make their way into the recycling stream? Will they degrade the properties of recycled plastics?
Given that environmentally-conscious consumers (the same ones who are likely to pay extra for a biodegradable product) have been trained to reduce/reuse/recycle, re-training them to not recycle could be difficult.
sjmonte, thanks for the (extremely long!) post, but it's completely unreadable because of the lack of spacing. It looks like you are copying and pasting directly from your website instead of from some kind of text document. Perhaps, instead of copying and pasting, you can provide links for us to check out.
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