Tag Archives: astm d6400

Funky Compost Toter

I was out for a stroll recently and I scoped out this roughed up compost toter.  Looks like it gets a lot of use.  Of course, I had to open it up and take a look inside.


It looks like they don’t use any sort of liner… I don’t blame them, they’re expensive!  However, having a raw container like this gets pretty nasty.

I could smell it pretty well before I opened the lid, that’s for sure.  The wonderful aromas of an unlined compost toter can’t do anything but hurt the “movement”.  Then again, I guess it’s not so much different than a can full of garbage (garbage being defined as “wet” waste, which includes food).

On the underside of the lid, there were plenty of friends hanging out:

These look like compost mites to me…nothing wrong with having them around, they’re just indicative of a moist environment.  This toter didn’t appear to have any air holes present, so when that lid is shut for a while, the contents just get anaerobic and extra funky.

While I would love to encourage not using liners wherever possible, this is what happens when you don’t.  It doesn’t really bother me, but obviously it won’t make the average person too excited about composting.

When the Left-Hand doesn’t know what the Right-Hand (PLA) is doing.

originally found here: http://woodsend.org/2013/09/left-hand-doesnt-right-hand-pla-doing/

American and European consumers are very familiar with PLA widely marketed as compostable for just about everything from chip-bags to golf-tees.  This renowned PLA, a biological plastic made from a “left-hand” lactic-acid molecule, also has a quirk:  it requires a pre-heat phase before it will actually biodegrade. That trait is referred to as Tg or “glassy transition” in the trade.  Tg is a feature of all plastics and can occur over a very wide range of temperatures, but none as convenient as PLA’s at 55-58°C, making it eligible to be called compostable,- that is, if the compostability test is conducted at or just above the Tg  temperature.

To be certified compostable means a standard is upheld such as ASTM 6400 for USA or EN 13432 for Europe. Coincidentally, these rules require compost test vessels to be held at 58°C during the entire test, referred to as industrial conditions. “This requirement effectively eliminates the Tg variable from being part of the test”, says Brinton.  Brinton’s lab has experimented with clients in attempts to create blends of L-PLA  possessing lower Tg for routine composting,- mostly unsuccessfully. “The temperature barrier of PLA is synthetic, not natural”, comments Brinton, “and now many people believe industrial composting is the only real composting”.

The Tg trait of bioplastic might go unnoticed were it not for the entrance of a cousin to PLA, right hand “D-PLA”. Tests conducted at Woods End labs on the right-hand enantiomer created by the Product Development Center at the  University of Maine, show this same material which appears identical to PLA-L has none of the high temperature Tg limits.  “This means it is compostable under any circumstance, just like leaves and hay and grass clippings.” says Brinton who has confirmed in trials that it decomposes rapidly even at room temperature. Therefore, the enforced distinction of “industrial” vs. “other” composting that is used to define the market for L-PLA, “well that distinction can eventually go away”, says Brinton.

Woods End admits there is a question if D-PLA has suitable properties for food packaging, and if not, what its best use would be as a consumer compostable product. Also, L-PLA is recylable and being a true bio-based plastic presents a good life-cycle profile especially if it can be made from non-food sources. Both products have a future. In any event, thinking outside artificial Tg limits should allow the industry to re-focus on composting as an inclusive and not exclusive trait in nature.

This is probably the most interesting composting related article I’ve read in quite some time, and it raises tons of questions.  I hope D-PLA is as magical as it sounds.
When composting bioplastics at home, it’s no easy task…I’d say that most composters would have a difficult time breaking it down in any reasonable amount of time, and the initial pre-heat phase this article describes must be part of the problem.
Without a massive and semi well-managed volume of material, it’s hard to obtain the 58C/136F for long enough to get the PLA started with decomposition.
If D-PLA really is “just like leaves and hay”, that will change the game altogether.  Is it as strong as the current PLA being used for garbage/compost bags?  Does it store on the shelf for as long without falling apart?
If D-PLA breaks down just like leaves do, let’s hope it’s safe.  Keep testing this one, University of Maine…

Nice Compostable Cup… How About the Top?

Behold the Ecotainer, the compostable cup.  Behold the lid, which will never compost…ever.

Maybe I’m just being a jerk, but this is what I’d call a mixed message.  Maybe they just ran out of their normal wax paper lid that day and had to default to crappy plastic.  Maybe the preferred non-plastic lid cost more.  Maybe the paper cup cost more than they wanted it to…which leads me to my first point:

I hope the cost of the cup didn’t break the bank.  There’s plenty of paperboard cups on the market that don’t say anything about being compostable, even though they are by default.  It reminds me of how aerosol cans are labeled “No CFCs”…although they have been banned since 1978.  Unnecessary labeling.

While I realize that paper isn’t devoid of issues, I’d rather turn my food-soiled paper products into easy compost than put my unappealing food contaminated plastics in the recycling, uncertain if that material will see another life.

Quick Questions with Peninsula Compost’s Nelson Widell

Wilmington Organics Recycling Center- Part 2

Recently I sent a few questions over to Nelson Widell at Wilmington Organic Recycling Center.  I’ve visited the facility a few times, and I had some questions about contamination and sorting, as well as bioplastics and pressure treated wood…so here we go:

Tyler: How much compost is created each day?

Nelson: We are producing about 200 tons per day of compost.

Tyler: What would you say the average contamination rate is for your incoming loads?

Nelson: Contamination is approximately 3% by weight.

Tyler: What’s your least favorite common contaminant you receive from incoming loads? (in compost receptacles available to patrons, I always see ketchup packs and plastic utensils)

Nelson: The plastic circular label stickers put on bananas and tomatoes is the least favorite contaminant.

Tyler: Describe the sorting system in place to sift out plastics/other contaminants at the end of the cycle.

Nelson: We screen the end product on rotary trommel screens with an air sifter for plastics.  The air sifter is essentially a giant vacuum cleaner and sucks plastic away from compost because it is lighter.

Tyler: How do you test for pressure treated wood versus non pressure treated wood for composting?

Nelson: Testing for Arsenic levels is the way to make sure we aren’t getting pressure treated wood.

Tyler: My understanding is that bioplastics take longer to break down, exemplified by Sun Chips bags, and compostable plastics sticking around through several home compost cycles.  Is this the case even in your massive hot composting setup?

Nelson: The bioplastics are OK in our system because of the higher heat we generate.

Tyler: Do bioplastics take more than one full cycle to break down?  Does the temperature get up around 160 degrees?

Nelson: Temperatures are up to 160F and it’s impossible to find bioplastics after it runs through one time.

Tyler: Do you receive horse/cow/chicken manure at the facility to improve the compost, or are you technically making mulch?

Nelson: We receive animal manure, but it doesn’t necessarily improve the compost appreciably.  Manures make no difference since the broad base of materials we process include plenty of nitrogen and protein already.

Tyler: How often do you get “fake” non ASTM D6400 liners that end up leaving plastic behind, such as oxo biodegradables?

Nelson: It isn’t possible to detect “fake” non ASTM liners since we are currently receiving well over 500 tons per day.

Tyler: So then at the first stop, you just rip open any non-green bags (first obvious sign) and put them aside for trash?  Is your end of process plastic waste mostly skeletons of non biodegradable bags?  Chip bags?  Condiment packs?

Nelson: Our front end processing includes breaking the bags and mixing in the slow speed shredder but no bag removal. That’s done on the back end after composting since at that time the material is dry and more readily and cleanly separated both by screen sizing and wind sifter.

Tyler: Any plans to build more facilities?  Not that Wilmington is far, but Philly could certainly use one…

Nelson: We are planning additional facilities in Chicago, Massachusetts, and Baltimore.

Just How Important Are Biodegradable Plastics?

It seems like over the last year or two, all the major companies have been jumping on board not only with a “green” product line, but with biodegradable plastics. I’d like to focus on the three major food service items that have been getting makeovers: cups, utensils and trash bags.

To narrow it further, forget about items listed simply as “degradable”… what isn’t? This is deceptive. “Biodegradable plastics” or “compostable plastics” that will completely compost in a commercial compost facility are what to look for. PLA (polylactic acid) is one of the most common corn based plastics used.

Are they worth it? I’m not so sure. Assuming they’re non-toxic and biodegrading as described, most people will not be able to compost these items in their backyard piles. This instantly reminds me of the Sun Chips bag, which upset people because they didn’t disappear immediately, let alone for a seemingly indefinite period of time.

The issue with bioplastics is that they need extended high temperatures in order to break down properly. Commercial composting facilities are the only places that really seem to do this easily, and a quick interview or two revealed that they have trouble with them.

Biodegradable plastic trash bags actually appear useful, if not for their high cost, lack of durability and fraudulent imitators. Make sure they are certified to the ASDM D6400 standard, which composting facilities will most likely require. Otherwise, you may end up with an oxo-biodegradable bag, which does not fully compost.

It’s no secret that landfills aren’t aerobic havens of biodegradation, however. What’s the point of spending more on a bag that might just remain as it is? There’s no light in a landfill, and oxygen is not freely mixing anywhere. My experience with these bags is that they fall apart if waste is held in them for too long, so in a way that’s comforting that they will degrade at least to an extent.

Of the three items mentioned, I think that biodegradable trash bags are a fair choice as we will always have material to send out somewhere, be it large quantities of recycling or trash. If everyone recycled and composted to the max, we would still need bags here and there to maintain order.

Next up is the biodegradable cup. I find cups to be avoidable in many situations with enough planning, and I enjoy trying to bring my water bottle with me everywhere I go. One way to do this is to get a nice filtering water bottle so you desire a better taste with no exceptions. Let’s face it- we don’t have water coming out of the tap, it’s fluid at best. Quit the soda and ditch the chlorine taste.

Anyway, Styrofoam cups are much cheaper than bioplastic cups and always will be although there’s essentially no recycling market for them. Who cares, they’re cheap and made of mostly air, right? It’s still a toxic product breaking into smaller pieces to be readily bioaccumulated while doing nothing to change our throw away behaviors.

Finding a compostable paper cup is harder than I once thought. Through some extensive research, I’ve found that most paper cups have a plastic liner inside. That must be a source of the plastic I pull out of my finished compost every once in a while! if you can find a paper cup with a wax liner (soybean wax, not paraffin wax), you are in luck. I haven’t been able to find one, but supposedly they exist and will compost.

I wonder how many plastic utensils get recycled. I’d be willing to wager slim to none, unfortunately. How about the corn or potato based utensils? They seem like a good idea, but this is another case where habitual reduction will outweigh material usage.
I keep one fork at my work desk, and I’ve used it for 5 years. If everyone did this, our disposable flatware needs would diminish quite a bit. I think this is more reasonable than carrying a portable spork around. I tried it, but I kept forgetting it when I needed it.

Little changes can lead to big outcomes, and bioplastics are not the greatest answer. It is possible that they may provide some short term relief, but even that’s questionable. They fall short on addressing the real problem at hand: our (fixable) throwaway culture.