Plastic

[starfish62]

I was cruising the lower Yucatan, just north of Belize, for some time and had accumulated quite a bit of plastic garbage over several weeks. The area was very remote. I went ashore on a small island, went well above the high-tide line, dug a deep hole, poured in the plastic, splashed on some gas and lit the whole thing. It burned for quite awhile (okay, I have pyromaniacal tendencies and kept splashing on a bit more gas), until I had a very small--maybe a tenth of the size of the original volume of plastic--mass that was quite hard. I covered it up with sand and went back to the boat, but was always a little bothered about what I had done.

Does anyone know whether burning is a viable way to "break down" plastic so that it doesn't pose the environmental hazard it would otherwise? Does burning hasten breakdown into smaller carbon elements? Or is that just wishful thinking? Linda & I really enjoy cruising remote areas, and try to minimize plastic on board--and trash in general--but a couple of times a month it builds to the point where something has to be done. Opinions?

[Robertcateran]

Depends on the plastics. Chlorinate ones such as PVC can produce some nasty chemicals when burnt at too low a temperature while simple hydrocarbon plastics such as polyethlene and polypropylene break down pretty well though they can make some short term nasties that break down fairly quickly. To keep things in perspective, burning salty tannin rich material such as driftwood can produce some pretty nasty chlorinated chemicals that take a while to break down. Burning plastic bags in a hot fire is certainly a better bet than leaving them to kill turtles. Better would be to try to reduce the use of them in the first place. Nets found on beaches aare regularly burnt in the GUlf of Carpentaria as the only practical means of disposing of them

[MarkJ]

I guess its what the local council would do. Incinerate it and bury the leftovers.
Granted what Robert says about correct temperature.

We try to remove all the packaging when we drag provisions on board. But its difficult as the bundles are handy to keep the goods intact.

We met some people who spent 5 months in some remote Kiribati island. I don't know what they could do but similar to you.
These days most people have a supply of soft drinks, soda water etc, so 5 months supply of PET bottles could only be stowed bundled in more plastic (or cartons)... and the space the empties would take....

It'll be interesting to watch others ideas.


Mark

[starfish62]

Originally Posted by Robertcateran

Depends on the plastics. Chlorinate ones such as PVC can produce some nasty chemicals when burnt at too low a temperature while simple hydrocarbon plastics such as polyethlene and polypropylene break down pretty well though they can make some short term nasties that break down fairly quickly. To keep things in perspective, burning salty tannin rich material such as driftwood can produce some pretty nasty chlorinated chemicals that take a while to break down. Burning plastic bags in a hot fire is certainly a better bet than leaving them to kill turtles. Better would be to try to reduce the use of them in the first place. Nets found on beaches aare regularly burnt in the GUlf of Carpentaria as the only practical means of disposing of them

Thanks!! We take measures to minimize plastic on board as well, but frequently--spare electrical parts packaging, light bulbs, waterproofed items--plastic cannot be avoided. It's the turtle-choking, bird-killing element that most bugs me and that I try to avoid. PVC's are minimal onboard as waste, but thin plastic films are very difficult to avoid.

[James S]

Excellent question.
I wonder, is there a practical way to fuse it all together with out actually burning it...then perhaps the fused lump would/could be buried or stored for future disposal?

[Robertcateran]

Most of these plastics are thermoplastic so moderate heat without flame should melt most of them. You can even use plastic bags to weld plastic kayaks with careful use of a candle for heat. You could melt them into plastic fishing lures. There is very little mass in them so it would take a few to make even one lure

[GordMay]

Bury plastics whole.

According to the US Environmental Protection Agency, there is little to choose between landfill and incineration in terms of greenhouse gas emissions.
Landfilling plastic (and some kinds of paper) is in fact better than burning, because it locks the carbon into the ground instead of releasing it into the atmosphere.

See also:
Guidelines for the Implementation of ... - Google Book Search

[delmarrey]

Why not just crush it into heavy bundles, sink it to the bottom of deep seas and let the barnacles take care of it. Barnacles seem to take care of the bottom of plastic boats fairly well.

[starfish62]

Originally Posted by GordMay

Bury plastics whole.

According to the US Environmental Protection Agency, there is little to choose between landfill and incineration in terms of greenhouse gas emissions.
Landfilling plastic (and some kinds of paper) is in fact better than burning, because it locks the carbon into the ground instead of releasing it into the atmosphere.

See also:
Guidelines for the Implementation of ... - Google Book Search

That article seemed to be discussing things on an industrial scale. When cruising well offshore, cans and glass go overboard but I keep all plastics--crushed down as much as possible--until I reach shore somewhere. After a month or two I have a mass that will maybe fill a five-gallon bucket. After burning in a pit with some gas on it, it shrinks down to something the size of a coconut, or smaller. There might be some greenhouse gas emmission, but we're talking on the scale of the crew after all you can eat taco night.

It seems to me--a non-chemist--that this is a safe, effective and responsible way to get rid of the stuff at the level of consumption of a cruising sailboat. Wouldn't burning it expedite breakdown?

[GordMay]

Originally Posted by starfish62

That article seemed to be discussing things on an industrial scale...
... There might be some greenhouse gas emmission, but we're talking on the scale of the crew after all you can eat taco night.
... It seems to me--a non-chemist--that this is a safe, effective and responsible way to get rid of the stuff...

On an industrial scale, and with industrial incinerators, it might be ok to burn plastics.

However, open beach fires, barrels or even wood stoves, do not reach high enough temperatures (min. 1,800 deg. F, or 982 C) to destroy many of the dangerous chemicals created when plastic burns.
Plastics (particularly PVC) result in emissions of chlorine, heavy metals, carbon monoxide, furans, and dioxins (tetrachloro-dibenzo-dioxin.) when burned.

I would NOT stand anywhere near the fire, and breathe the fumes.

See also:
"Is Combustion of Plastics Desirable?" ~ by Bruce Piasecki, David Rainey, Kevin Fletcher
Is Combustion of Plastics Desirable? » American Scientist

[David M]

Just getting the plastic out of the ocean unquestionably was a good thing for marine life. Whats done with it after its on shore seems to be the hot debate. Its really hard to determine the lesser of two evils...the volume plastic takes up or the nasty toxins that are released when it burns.

Last week I flew between Avalon and Long Beach. Looking down from 750 feet at the water, at one point I saw an enormous tideline of floating plastics. It really made me wonder what we are doing to our oceans and what the long term effect will be of treating it as a garbage dump.

[bstreep]

Next time I get a big old #10 can of beans out, I'm going to try putting it on my BBQ grill at the house - with the outside burner - and melt some stuff. Sounds like fun!

[MidLandOne]

I am not sure what the problem is with disposal of plastic on cruising yachts.

While we only go 3 to 4 weeks between shore facilities where plastic can be properly (well hopefully properly ) dumped, and I know many have to go longer, the basic fact is that it doesn't take up anymore room empty than it did when full of whatever product it contained or protected. In fact it can often be crushed so as it takes up less storage volume than it originally did. There is plenty of seawater around to rinse it before stowing the used plastic if needed for hygiene.

So, I don't understand the problem - if you have the room on board to take it with you in the first place would seem to me that one must have the room to keep it on board when used . We find that so.

[MarkJ]

We have been pretty good on our passages not taking much plastic in the first place and then stowing it for on shore disposal.
When we arrived in Sydney after 16 days at sea the Quaranteen guy was amazed at our 2 small bags of rubbish.

Arriving in Tonga was, well, a different matter. I wondered where it went.

Carefully sorting rubbish on board and throwing over all but plastic, then compressing the plastic doesnt take much room.
And if that plastic is clean it wont smell the boat out.

Robertcateran You can even use plastic bags to weld plastic kayaks with careful use of a candle for heat.

While at sea could I add 4 feet to my boat?


Mark

[Stillraining]

Pack it in Pack it out