Green Drinking

No, not St. Patrick’s day.

No, I was taking the garbage and recycling to the curb tonight and moderately proud of the fact that there was a full recycling can and a half full trash can (both the same size and half the ‘trash’ was used kitty litter).  Then I got to wondering, I go through a fair number of canned colas, I wonder how I should be drinking my beverages.

So, to , to be as green as possible, should one drink their preferred beverage out of cans, plastic bottles or glass bottles?

First, I will post my hypothesis based solely on my current knowledge of the processes involved and why.  Then I will do some research to see if I can find the correct answer.  (It’s called science and this is how you do it.)

My predictions, greenest first…

kegs – well, they are washable and reusable, but you can really only use them for beer and I don’t know too many people who keep them for daily use.  It’s a shame there’s no keg for colas.

Aluminum cans – I thinking that there’s probably about the same amount of material in an aluminum can as there is in a plastic bottle and I think it is a much easier process to melt the can and reform it than for plastic.

Plastic bottles – I’m thinking that you can’t just melt and reform most plastics.  Some, I think you can, but not potable liquid containing plastics.  So you’ll probably have to do some chemistry or use exotic catalysts, which would make it more difficult than aluminum.

Glass – There’s more material in a glass bottle than the other types of the same size and glass has a high specific heat, so it would take a lot more energy to melt down a glass bottle than the same size plastic or aluminum container.  This is considering that the glass bottle cannot be just washed and reused.  I think that’s frowned upon by the government.

So, now off to find some data… be right back.


OK, after about 30 minutes of internet research, I’ve found a lot of crap to deal with and the answer isn’t easy.  In fact, the question as asked is pretty off the wall.

There’s LOTS of information out there, but it is difficult to find, what I would consider, reliable information.  The pro-aluminum studies (heavily pushed on aluminum manufacturers websites) tout certain advantages.  The pro-plastic studies (from the plastics associations) tout other advantages.  Even the glass people have their positive attributes.

First simple fact.  Recycle.  No matter what you drink, if you recycle it helps the environment and the economy.  Even, washing out a container out and reusing it once will help even more than just recycling alone.

OK, now for the research.

First of all, only aluminum cans are 100% recyclable.  PET (or PETE) plastics are recycled into other materials like polyester clothing, fiber fill for sleeping bags, and the like.  Only about 30% of glass is recycled into more glass bottles.  The rest is considered slag and used in other ways.

Benefits of recycling.  In 1999 (the most recent data for all forms of material), there were 2 million tons of glass recycled; 840,000 tons of aluminum recycled; and 550,000 tons of mixed plastics recycled.

The big winner in reduced greenhouse gas emissions at those recycling levels was aluminum with a reduction of almost 3.5 billion metric tons of carbon emissions SAVED.  Glass had lowest savings per ton, but because there was so much more glass recycled, it came in second in the total green house gas emissions prevented at only 320,000 metric tons of carbon.

In the amount of energy saved (i.e. not used thanks to recycling), aluminum was again the big winner, saving over 132,000,000,000,000 BTUs (that’s equal to almost 30 million barrels of oil).  Plastics were next, but at a much lower energy, they still saved more oil (well, oil is a precursor to plastic, so that makes sense).  Recycling glass, even all that we did saved the least energy, only 2.7 trillion BTU (about 472,000 barrels of oil).

In terms of avoided litter, again, aluminum wins.  Remember 100% of aluminum is reused, not so for other materials.  Even though, aluminum was less than half the amount of recycling than glass, it still saved more landfill space and litter.  Plastic had the lowest saved landfill space (it’s easily crushed).

So, in terms of this, aluminum cans are my beverage container of choice.  They are 100% recyclable and the energy and environmental savings for using and recycling aluminum are huge.

There is one down side.  The energy needed to manufacture aluminum bottles from raw materials is the second highest of any material. Which means, that for every can that must be replaced (because it wasn’t recycled), it takes more energy to make the replacement can.  But all things considered, it’s not that much, only about 50% more energy than it takes to manufacture PET or glass bottles (which are about the same).  It’s slightly less than HDPE (high density polyethylene) plastic bottles which are many used in reusable sports bottles, grocery bags, plastic bins, etc.

The next downside to aluminum is about the recycling process itself.  I hesitate to mention it as it comes from a plastic industry publication and I can’t find supporting data, it makes sense, but we all know that doesn’t mean anything in the real world (well, some people understand that).

In terms of recycling, aluminum produces between 50% more and 300% more waterborne pollution than PET plastics.  It also produces about twice the atmospheric emissions.   The article doesn’t state what the atmospheric emissions or waterborne emission are.  So, I might take that with a grain of salt.

So, my hypothesis appears to be confirmed.

Obviously, reusing bottles several times would be ideal, but for one-shot products, aluminum is my preferred material.

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