Unpopular Science?

How can this be? I'm having trouble understanding how moderate quantities of PET bottles cannot be recycled to produce another plastic product. Can someone provide additional information to support the efficiency of simply sending them all to the landfill?

Or is this proposal based on the idea that reducing carbon footprint is the only environmental issue that is important and any other environmental or even non- environmental consequences are inconsequential?

Ed Weldon

Hi Ed,

An excerpt from the Swiss study

The 20 liter size make great 'hot caps' and sun shades for starting plants early in the spring.

They don't seem to collect the heat as I was worried they would. I cut the bottom out and made an opening in the side to let air draft up through them.

Bit of a nuisance to store for next year but that is OK.

Its a bit like WD40 really. Nice work Ed. How about these guys, I want one.

Although I have know additional info for you , may I suggest that all the costs associated with collecting , storing, tansporting from all different distances , handling , cleaning , and processing is far more costly than just using raw materials.

Personally I prefer to toss them in the trash compactor and crush them into bricks then toss the bricks in the boiler and make heat from them in the winter.

Hate to live downwind of you in the winter then!

The problem with landfilling PET is that it really doesn't break down at the surface very fast. As we all know any thing that is biodegradable at the surface, like wood or paper or food, generates CO2 (and sometimes methane or other organic volatiles). Bury them in deep dry cells, and the CO2 remains sequestered as carbon solids (no water no gas formation). Current practice actually allows small amounts of water to enter the cells and drive degradation reactions. Leave the dry cells in very deep, very cold places, and eventually the overburden turns them into Coal. PET on the surface, PET anywhere is not contributing much in the way of CO2, so it is a little accounting slide of hand to bury one stable carbon solid to offset other degradable solids, which do contribute to the atmospheric carbon loads.

How many tons of PET are produced in the world each year?

What percentage goes into production of consumable food/beverage/potable water packaging?

What percentage comes from raw petroleum feedstocks?

I'd like to find a relative comparison with other carbon sources. I'm wondering if this is much ado about little.

Ed Weldon

Do a proper landfill with a 12" base of clay. Cap it good and save it for mining at a later date.

A proper landfill waste unit is supposed to be clay and polyethylene lined

This question makes me pretty mad. Whether to recyle is more complex than just how much carbon is saved. Here are some reasons:

* We have finite resources and should conserve them by reusing and recycling where-ever possible (although I will admit glass may be excluded from this reason)

* Landfill produces unstable land which can be difficult to use for many years afterwards and can contaminate aquafers and other water sources around it for generations. If you fill it with material that does not rot down, like some plastics (or at least may be in the soil for 100's or 1000's of years) the land will never be useable for the foreseeable future.

* We are running out of places to use for landfill. Once all the obvious places have gone, like old quarries, we will have to turn to land that would be better used for a different purpose, like building or growing crops

* Carbon is not the worst green-house gas. There are a lot of other gases given out during manufacturing processes which have many times the effect of CO2.

* If everyone made an effort, quantities of recycling would be greater, there would be more investment in methods and infastructure to accomodate it and the whole process much more efficient. This should be passed on as a saving to the consumer, so we could all save money in the end.

So if you want to save resources, save and earth and save money, reusing and recycling almost always makes sense.

If the plastic doesn't rot, the settlement is finite, The land subsidence occurs in landfills primarily because materials decay thereby reducing the volume of supporting solids. Non-decaying materials do not release volatile organic gases like CO2, this represents a lower carbon footprint as the carbon is sequestered.

Why would glass be excluded, it takes more energy to convert sand to glass. Many plastics can not be melted and remolded, but you can clean and re-use the containers.

The complexity of recycling can actually increase the carbon foot print as the process of recycling, if you were truly familiar, involves a great deal of sorting and processing equipment. If the plastic product is easier to gmanufacture with less energy usage than the separation, sorting and reprocessing then it is reasonable to decide to reduce the carbon foot print by not recycling. Remember the carbon in enduring plastics is sequestered (not available to cause the atmospheric change).

Available cost effective land for use as landfills is a problem. Note the issue is cost effective. We are not running out of land for landfills, we are running out of cheap land for landfills.

Landfills that pollute waters are primarily due to leachates from decaying materials. Thus plastics that do not decay do not contribute to water pollution. The worst stuff in a landfill are things are those which decay. Keep the landfill waste units dry and nothing happens to the waste, thus it becomes sequestered carbon.

You can actually farm over a landfill if covered properly, you can not build buildings of any large loads though. You might however do waht most facilities do and reclaim the lands overlying the landfills for natural habitats and parks.

I submit that there is an immense amount of land in California suitable for landfills. We're talking marginal arid land on the west side of the southern San Joaquin Valley (you see just a tiny fraction of it from Interstate 5) that is useless for agriculture other than marginal cattle grazing due to a lack of irrigation water and the rolling hill topography. Given the low cost of rail transport (426 miles per gallon for a ton of material) promoted by advertisements of one of the major US railroads the distance issue seems trivial. That's like $3 to move a ton of garbage from the Bay area or southern CA. Yes, I'm sure some small mammals and hawks would be inconvenienced by a landfill. But let's be realistic.

Still, I'm having a lot of trouble understanding why PET containers may not be economically recyclable in the grand scheme of saving our environment. But that's me......

Maybe indeed the answer is to segregate them in great pits in the ground to be mined by some future generation less well endowed with natural resources than we are today. What other "semi-recyclables" would fall into that category?

Ed Weldon

And California represents the most densely populated State, excluding the eastern seaboard, and much of what is considered not viable for much agriculture here would be viable in other Sates. The whole State of Nevada, Utah, Arizona, Idaho, Montana, Colorado, etc. tend to be drier than the Central Valley. Also, the current design trends in wast units is to aim for the cheapest possible closure, but for only slightly greater marginal increase in cost they could fully seal the caps also, and with a few more feet of cover the land overlying the landfills would be viable for any farming, farming only utilizes typically the upper 2 to 3 feet or so of the soil profile. Place a HDPE cover overlain by a 10 foot deep soil cap and the land would be farmable for most everything except extremely large orchards. Actually, something similar to this is already done without the HDPE cover and the depth of soil, to make the land re-useable as parks (though it can potential increase infiltration into the cells). The problem becomes the cost of the additional closure requirements relative to recycling costs may change with such. Also, mammals,kit foxes, hawks, giant garter snakes, burrowing owls, etc. love the land surrounding the landfills, it is a typical problem when you try to close a landfill that such species become a concern for closure activities (which represent more invasive activity than usual).

The real problem in many of the cases of moving waste becomes the NIMBY effect and the undue environmental burden on the impoverished. No one wants someone else garbage, and wealthier municipalities tend to try to find the cheapest, sometimes cheaper than is safe, solutions outside of their own jurisdiction, if they can. On the other hand it brings work into those communities where waste is disposed of, and if done correctly the risk is minimal (keep the liability on the waste geenrator and they might try to keep the risk of a release to a minimum).

Oh something else i just noted, the comment about finite resources. while I agree everything is finite, carbon is not anywhere near a critical shortage or even approaching that level. Cosider that every living thing on the planet is composed of carbon, as well as a huge amount of the rock. Additionally it comprises a large amount of the water and air, not a majority but a substantial amount. So carbon as a resource is a bit ludricous as a basis for conserving resources, now oil or coal (as these are much more specific high energy forms) may be justifiable to conserve. We can readily obtain carbon if we have the energy resources available, mine it from water, from carboonate rocks like limestone (which would utilize the carbon waste from making concrete from limestone), from carbon dioxide in the atmosphere. We just need to havesufficient energy available to convert the carbon from one naturally occurring and abundant form into another.

Landfills do not have to produce unstable land, The reasons ladnfills are unstable from a geotechnical standpoints is the subsidence due to decay. However, ideally in a proper dry cell decay should not occur, since they are supposed to remain dry. However, landfills tend to be constructed by local agencies as cheaply as possible to meet minimum regulatory requirements. Landfill closures are always being pushed to seek more permeable cap options with less post closure maintenance and responsibility/liability. In a properly built landfill where budgets and labor costs are not such substantially dominant forces behind the finished product, the subsidence issue is not as much of a concern. Besides even modern sloppily built landfills make extreemely suitable open space/parks areas.

We are not anywhere close to running out of lands to landfill on. Have you ever seen Wyoming or Nevada, or even Bakersfield for that matter. What we are running out of is cheap close places to dump without other jurisdiction being involved, which creates greater long term liabilities plus transportation costs are a killer and the indgenous population frequently doesn't want other people garbage with out some benefits. There is no room in NYC, San Francisco, or LA admittedly. Maybe so many people should not be so concentrated that the leave not room for managing their own wastes and resources within their own jurisdictions. Heck, China is building whole new islands out of their solid waste. This whole concept of not enough land is all BS. What it should be when people talk about such thing is that there is not enough cheap land near them.

You are correct carbon dioxide is not as strong a green house gas as many other, water and methane being the most substantial and notable for being orders of magnitude stronger than CO₂. Both of which occur in gaseous forms in vastly greater quantities from natural processes, like organic decay of plants in reducing environments, or evapotranspiration. Of course is the change we are seeing really unusual would be a good question here, considering that ice on the poles has only been common in the last 47 million years. and the global average temperatures were near twice as warm as present just about 50,000 years ago in the midst of the ice ages, of which we may just be coming out of. Mauybe man is just accelerating the natural process back toward the equlibrium sate over whih the earth had existed for most of the geologic record since life has been on the planet. Maybe trying to stop the evolution of the environment or slow it is contrary to the state the earth environmental conditions tend towards? Of course maybe accelerating it is not helpful either.

The idea of carbon footprint is, for many people, quite complicated and involves: a) some understanding of sub-concepts, plus, b) the connected sequence of ideas related to carbon-dioxide release, sequestration, and climate change.

Why not just, for the general audience, gloss over these complexities (leaving enough content so one cannot be accused of blatant omissions, and instead say these partly refined materials are being put aside for future generations? Establish systems that make this claim somewhat justified--after all, we don't know what future generations might be able to use.

What you get is a POSITIVE image--"We are doing at least a modest kind of savings for our progeny to come," instead of the complex NEGATIVE anticipated threats / risks of climate change, the need to AVOID avoid global warming gasses...overcoming persisting objections, and the like.

(Straddler of the line between some scientific
literacy, and the liberal and humane arts)

Positive image until some enviro-activist sends some more detailed information to a ignorant news reporter, who then researches it a little bit and come to know a little more than was disclosed and the whole thing blows up as a cover up of the facts. Better to disclose everything up front and then try to summarize.

I'm joining this thread a bit late, but for what it's worth - Wellman Plastics in South Carolina have been recycling PET plastics for many years. The main applications, as far as we knew (they were quite secretive), were pillow/duvet fillings and for manufacturing carpets. The FDA forbid the re-use of recycled bottles for food/drink use. The PET is/was obtained from a random mix of PVC and PET bottles, crushed into bales. Special apparatus was manufactured to singulate the bottles and feed them down a chute. In the 1990's, our company manufactured a special high speed x-ray fluoresence analyzer that would detect the presence of chlorine (from the PVC bottles) and reject those bottles, leaving a stream of PET bottles.

The recycling economics are very subject to current polymer prices. Some states subsidise the recycling process on the basis that they are saving landfill.

Of course saving landfill space is a specialized concern of municipalities and solid waste agencies because of the long term liabilities and cost associated with those facilities. However, anything comprised of carbon that gets landfilled in a good dry cell sanitary landfill would equate to carbon sequestration from a global climate change stand point. thus recycling on one hand reduces the risk to groundwater resources and liabilities to the local agencies responsible for the point source, but increases the non-point source risk to the atmosphere in a manner such that there can be no direct assignment for direct liability. Obviously plastic is a problem, but glass is highly energy intensive and subject to ready contamination. Maybe we should switch back pottery for beverage storage, it is made from dirt just lying around everywhere, and as such readily disposable back (of course glass is also made from dirt but you have to heat it substantially more). Maybe things should not be made disposable, of course that might be bad for the economy since so many industries are dependent of turn over of products and new product production. However, that would solve much of the landfill versus recycle debate under climate change considerations.