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The Engineering of Landfills

practical.engineering

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Re: The Engineering of Landfills

#21

Post by SargeDebian »

abracadaniel wrote: post #5
trallnag wrote: post #3

Why are landfills like this still a thing? Why not burn everything and only dump what's left?

Some places do. Waste to energy plants are a thing. One of the big challenges is running a large, stable, chemical reaction on unknown fuel. It’s difficult to burn things hot enough to reduce potentially dangerous compounds while also having variable input. Then, the gasses need to be monitored to avoid dangerous compounds reforming as the exhaust cools.

And sometimes people throw things in that explode.

Re: The Engineering of Landfills

#22

Post by nullindividual »

cm2012 wrote: post #9

So many people misunderstand landfills. All the garbage produced in the U.S. for the next 1000 years could fit into a landfill 100 yards deep and 35 miles across on each side. That is, landfills take a trivial amount of space. Putting stuff in a landfill is way better for global warming since its not burned, the carbon is buried. Almost all plastic waste in developed countries ends up in landfills, not the natural en…

Tires are a source of microplastics, as well.

https://assessments.epa.gov/risk/document/&deid=361070

https://www.sciencedirect.com/science/article/pii/S004896972...

Re: The Engineering of Landfills

#23

Post by aziaziazi »

briffle wrote: post #6
trallnag wrote: post #3

Why are landfills like this still a thing? Why not burn everything and only dump what's left?

My county has one that does 90% of our garbage, and its not an easy problem. The key part is scrubbing the smoke to get rid of the polutants, and then cleaning the ash to also get rid of things like mercury. The only way they can seem to make a buck is to charge high rates to dispose of 'medical waste' that helps with costs.

Curious: why medical wastes?

90% : Sweden or Japan ? https://sensoneo.com/global-waste-index/

Re: The Engineering of Landfills

#24

Post by greenavocado »

Sohcahtoa82 wrote: post #14
trallnag wrote: post #3

Why are landfills like this still a thing? Why not burn everything and only dump what's left?

Because some things release Very Bad Chemicals(tm) when burned. Better to just bury them.

Often it's just as bad or worse to bury them because they will work their way into the water table and then it's gg for decades

Re: The Engineering of Landfills

#25

Post by dEnigma »

newsclues wrote: post #15
bko wrote: post #2

I found this interesting: > Another option is to put it to beneficial use to create heat or even electricity. The Puente Hills landfill I showed earlier has a gas-to-energy facility that’s been running since 1987, and even though the landfill is now closed, it currently provides enough electricity to power around 70,000 homes. And towards the end > Landfills seem like an environmental blight, but really, properly des…

[flagged]

To be fair you can store a lot of stuff inside a bag with only minimal use of bag material, so in many cases this can make sense.

Re: The Engineering of Landfills

#26

Post by mikojan »

bko wrote: post #2

I found this interesting: > Another option is to put it to beneficial use to create heat or even electricity. The Puente Hills landfill I showed earlier has a gas-to-energy facility that’s been running since 1987, and even though the landfill is now closed, it currently provides enough electricity to power around 70,000 homes. And towards the end > Landfills seem like an environmental blight, but really, properly des…

Landfills certainly require more power to operate than that gas scheme can provide later.

It all sounds and reads like a fairytale but none of this is sustainable.

Re: The Engineering of Landfills

#27

Post by gruez »

the_gipsy wrote: post #16
cm2012 wrote: post #9

So many people misunderstand landfills. All the garbage produced in the U.S. for the next 1000 years could fit into a landfill 100 yards deep and 35 miles across on each side. That is, landfills take a trivial amount of space. Putting stuff in a landfill is way better for global warming since its not burned, the carbon is buried. Almost all plastic waste in developed countries ends up in landfills, not the natural en…

I'd guess that it's cheaper to ship a lot of garbage to developing countries.

Is it? Land is dirt cheap in the US. Surely it's cheaper to bury it locally than ship it half way across the world? Even for the plastic that's being shipped half way across the world, they're ostensibly done for recycling purposes (ie. they're buying the plastic waste), and the unrecycleable plastics end up being mismanaged.

Re: The Engineering of Landfills

#28

Post by barbazoo »

bko wrote: post #2

I found this interesting: > Another option is to put it to beneficial use to create heat or even electricity. The Puente Hills landfill I showed earlier has a gas-to-energy facility that’s been running since 1987, and even though the landfill is now closed, it currently provides enough electricity to power around 70,000 homes. And towards the end > Landfills seem like an environmental blight, but really, properly des…

> I wish more environmentalists would be excited about engineering solving environmental ills and relied less on knee-jerk reactions.

Are many ... not? Seems like a weird complaint, I haven't encountered an "environmentalist" (whatever that even is) that is against landfills in general or the engineering of it. I'd rather we didn't produce as much garbage as we are and I hate that our city makes me wrap my garbage in more garbage otherwise they won't pick it up. But I still find the engineering impressive.

Re: The Engineering of Landfills

#29

Post by d110af5ccf »

abracadaniel wrote: post #5
trallnag wrote: post #3

Why are landfills like this still a thing? Why not burn everything and only dump what's left?

Some places do. Waste to energy plants are a thing. One of the big challenges is running a large, stable, chemical reaction on unknown fuel. It’s difficult to burn things hot enough to reduce potentially dangerous compounds while also having variable input. Then, the gasses need to be monitored to avoid dangerous compounds reforming as the exhaust cools.

> It’s difficult to burn things hot enough to reduce potentially dangerous compounds

And that's before accounting for people illegally tossing things that contain heavy metals (such as batteries).

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