There are currently two main types of waste disposal: incineration and landfill. There are problems with each.

Incineration releases environmentally damaging gases (carbon dioxide, dioxins, etc). Landfill releases methane (a "greenhouse gas") as the garbage slowly decomposes.

I suggest garbage should be pyrolysed (ie baked) in a low oxygen (ie airtight) kiln. This will result in the following end products: charcoal, ash, syngas (hydrogen and carbon monoxide) and other gases.

Advantages:
-the charcoal and ash can be buried in a more inert and compact form than regular landfill
-the carbon in the charcoal is "sequestered" when buried
-the gases produced are less environmentally damaging than from an incinerator (eg less carbon dioxide). I'll also take a wild guess that less nasties such as dioxins would be produced
-the syngas can be used to power the kiln

-- xaviergisz, Jul 31 2009

Garbage converted to Charcoal http://www.greenpla...rash-into-charcoal/
there are other examples of industrial garbage cookers [xenzag, Aug 01 2009]

CHP http://www.chp.ca.gov/
[normzone, Aug 03 2009]

CHP reborn https://web.archive...p://www.chp.ca.gov/
normzone's link lives to fight another day! [Loris, Jun 08 2022]

Time Capsule cavity wall insulation Time_20Capsule_20ca...20wall_20insulation
Insulation and long-term storage [Loris, Jun 09 2022]

Hold on, just going to root through a bin.
Right, the contents consisted of: tin plate (shouldn't be in there), soya milk cartons (shouldn't be buying soya milk), coffee packets (should be buying it in paper), bubble wrap, clingfilm, polythene, in other words all the things i don't bother to reuse or recycle. The last three are from a supplier, so i'm not as responsible for them as the others. If it were heated anaerobically, i can see that maybe the polythene would produce something useful, but i'd expect the clingfilm to produce something chlorinated, whereof i like not the sound.
Given that that stuff is in my bin, the tin plate is pretty useful, the cartons can be shredded and melted together into boards, the coffee packets are composites and therefore probably pretty unreusable, so my problem is, how to separate the PVC from the polythene? If you heat that lot up, how much chloriny stuff would stay in it and what would you do with it? Do you fractionate it?
Not a criticism, just a thought.
-- nineteenthly, Jul 31 2009


/ Landfill releases methane (a "greenhouse gas") as the garbage slowly decomposes./

Biogas from landfills is now widely captured and burned - usually for small scale energy used at the landfill. I have never read or heard of anything done to optimize biogas production from a landfill - water addition, starter culture etc. I suspect that the anaerobic processes that generate biogas also convert much waste to charcoal-like substances - old style charcoal kilns are similar in many ways to landfills. It gets hot under there and bakes itself.
-- bungston, Jul 31 2009


Hmm... I was wondering what that flavour was.
-- pertinax, Aug 01 2009


I don't know enough chemistry to tell what would happen to plastic baked in a low oxygen kiln. My guess would be it would be similar to baking hydrocarbons with the non-carbon elements evaporating off. It's possible that the chlorine evaporating off the plastic would combine with the hydrogen evaporating off the plastic and organic waste to form hydrochloric acid. The gases would be scrubbed to remove as much nasty chemicals as possible.

The collection of biogas from landfills has always struck me as being inefficient way of utilising the 'power of garbage'. I agree with bungston that there is a lot of room for improvement in this area, and probably a lot of money to be made.
-- xaviergisz, Aug 01 2009


There are already high pressure, high temperature, vessels that seem to cook all waste into hydrocarbons and water. Baked, not widely known to exist.

[Vernon] and [Unabub...] had a shot at it with various ideas....
-- 4whom, Aug 02 2009


It seems that clingfilm is no longer made from chlorinated plastics, but other things are.

I'm saving my coffee packets to use as insulation in the roof. Probably silly, but I can't bear to throw away that lovely laminated stuff.

Garbage contains a lot of heavy metals; perhaps the charcoal could be used to smelt mined or recycled heavy metals, thus turning a vice into a virtue.
-- spidermother, Aug 03 2009


Does a Combined Heat and Power (CHP) plant throw all the crap combustion products into the air?.
I might have to Google this.
-- gnomethang, Aug 03 2009


[normzone]'s chp.ca.gov link is dead. Did you mean Canadian Health Promotion https://www.canada.ca /en/public- health/services /health-promotion /centre-health- promotion.html ?
-- pashute, Jun 08 2022


//[normzone]'s chp.ca.gov link is dead.//

Fear not, for archive.org is here!
However, it might be less edifying than one would like - it's to the The California Highway Patrol homepage.

I think perhaps someone had mentioned "combined heat and power" as an unexpanded acronym at some point before gnomethang's comment, and normzone patternmatched to this, possibly because of the at-the-time popular series CHiPs.
-- Loris, Jun 08 2022


//I'm saving my coffee packets to use as insulation in the roof//

If they're the type I imagine, that's a sort of three way aluminum, paper plastic laminate, is that particularly insulating?

Over the last 10 years or so in science, I've received, and thrown away, probably a 1000sq ft of polystyrene cryoboxes used for delivery of frozen things. I've often thought of slowly adding a foot of hyper-efficient insulation to my house. Although it would be a horrendous fire risk.

// as an unexpanded acronym//

Should be CHAP, Shirley?
-- bs0u0155, Jun 08 2022


//Although it would be a horrendous fire risk//
Given that you can buy polystyrene insulation panels off-the- shelf, I would hope not.
-- neutrinos_shadow, Jun 09 2022


//Over the last 10 years or so in science, I've received, and thrown away, probably a 1000sq ft of polystyrene cryoboxes used for delivery of frozen things. I've often thought of slowly adding a foot of hyper-efficient insulation to my house.//

I know - they're so beautiful, right?
I had that idea too, and posted something similar with an additional fringe benefit (link).
Some places let you return the boxes for reuse or recycling, which is better, although I'm not sure of the actual return rate.

//Although it would be a horrendous fire risk.//

I'm not clear on why cavity wall insulation isn't a fire risk per-se, but the regulations seem to allow it.
-- Loris, Jun 09 2022


//I know - they're so beautiful, right?//

The grey ones from BioRad? I think? were the best

//but the regulations seem to allow it//

It's the same regulations that consider some Tyvek stapled to framework of bradnailed undersized lumber a "house".

I'm assuming insulation polystyrene has flame retardants in it.
-- bs0u0155, Jun 09 2022


<Quick Google of the local brand...> Yes, has flame retardant mixed in. That makes sense. I can't (quickly) find out if the cool-boxes also contain it.
-- neutrinos_shadow, Jun 09 2022


//I can't (quickly) find out if the cool-boxes also contain it.//

The flame retardant is a bromine compound, and if I remember correctly, that's what makes its way to the surface on old plastics making them go light brown, now while I've never seen an old poly box go brown, I also don't have control information on old insulation.
-- bs0u0155, Jun 10 2022



random, halfbakery