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The Engineering of Landfills

practical.engineering

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Re: The Engineering of Landfills

#211

Post by strken »

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…

Landfill leachate is quite terrifying. You end up with a bunch of reactions between whatever random assortment of garbage found itself on the same truck, and the resulting liquid is acidic enough to dissolve pipes as well as heavily contaminated with heavy metals.

I am fine with landfills, but they're one of those engineering marvels -- like bridges, microwave ovens, sky scrapers, aircraft, high voltage transformers, cranes, or motor vehicles -- that are about taking something inherently dangerous and letting us interact with it safely.

Re: The Engineering of Landfills

#212

Post by eru »

cogman10 wrote: post #123
toomuchtodo wrote: post #106

Earlier quoted context omitted.

How do you feel about plasma gasification to ensure robust destruction of anything non-inert? I love landfills too! But humans are various shades of tricky, lazy, cost adverse, and untrustworthy (think limited liability) as it pertains to long term custodianship and management of things bad for people and the environment. TLDR You must engineer around the human. Potentially harmful physical matter that requires waste…

The big problem with plastic waste is getting it to the landfill (or incinerator) in the first place. Once the plastics are captured, I don't see too much benefit in incinerating it beyond freeing up landfill space. But that's really not a major issue as you can always dig a deeper and wider landfill. In fact, a major downside of incinerating the plastic is you end up with greenhouse gasses as a byproduct.

> But that's really not a major issue as you can always dig a deeper and wider landfill.

The submission suggests that landfills ain't dug, but just piled high. Digging a hole costs more time, money and effort than not digging a hole.

Re: The Engineering of Landfills

#213

Post by eru »

scoofy wrote: post #182
toomuchtodo wrote: post #179

Earlier quoted context omitted.

https://www.nytimes.com/2024/08/28/opinion/solar-power-free-... By the end of this year, the world will be deploying 660GW of solar annually. Within 18 months, that figure rises to 1TW/year (based on current manufacturing ramp trajectories). On the contrary, I’m unsure how you think we don’t have the clean power for this, not even accounting for the power you can generate from the syngas that is a byproduct of the pr…

Because solar isn't balanced and we haven't fixed the duck curve. We're burning obscene amounts of nat gas, petroleum, and even coal currently. Until those numbers are at-or-near zero, every ounce of renewable electricity needs to be offsetting dirty electricity.

I mostly agree with you. However:

> Because solar isn't balanced and we haven't fixed the duck curve.

Well, landfill management is something you could (mostly) only run whenever you have excess (solar) power on the grid. So it's an excellent consumer for intermittent generators.

Re: The Engineering of Landfills

#214

Post by eru »

toomuchtodo wrote: post #150
cogman10 wrote: post #133

Earlier quoted context omitted.

Point taken. Though I do wonder how much of the methane released is from plastic decomposition and how much of it is from food/biomaterial decomposition. I'd naively assume the primary emission would come from readily decomposable materials and that most plastics would remain fairly stable for a lot longer than yesterday's half eaten hamburger.

Indeed, waste sorting might improve the situation, but all available evidence indicates there is no will to do this (caveats being parts of Europe, Japan, the Nordics, and anywhere else diverse multi stream waste management can be effectively operated), which leads me to believe gasification is the superior path (with a bypass stream for glass, brick, earth, rock, and metals, primarily to prevent process efficiency r…

What benefit would you get from gasification compared to just straight up burning the trash?

Re: The Engineering of Landfills

#215

Post by eru »

ianburrell wrote: post #154
toomuchtodo wrote: post #150

Earlier quoted context omitted.

Indeed, waste sorting might improve the situation, but all available evidence indicates there is no will to do this (caveats being parts of Europe, Japan, the Nordics, and anywhere else diverse multi stream waste management can be effectively operated), which leads me to believe gasification is the superior path (with a bypass stream for glass, brick, earth, rock, and metals, primarily to prevent process efficiency r…

What has been successful in my city, Portland, is separating the food and yard waste. The food and yard wastes are composted. Composting produces methane, but there is a trial to capture the methane which is burned as natural gas. Capturing methane from compost should be easier than whole landfill. It also keeps the organics instead of losing them.

You don't really lose anything in a landfill. You just lock it up for a while.

We can 'mine' landfills in the future, if that becomes economically viable.

Re: The Engineering of Landfills

#216

Post by eru »

x-complexity wrote: post #188
barbazoo wrote: post #143

Earlier quoted context omitted.

That would be quite the strawman but whatever works for them.

> That would be quite the strawman but whatever works for them. These types of people exist, and in worryingly large numbers.

See also the German 'Green' party whose policies have led to lots and lots more CO2 emissions over the years.

Re: The Engineering of Landfills

#217

Post by eru »

alexanderchr wrote: post #204
bluGill wrote: post #121

Earlier quoted context omitted.

I'd prefer you use wind to get the energy(or solar but there isn't much sun when you need heat) and burn nothing.

So would most of us, but somewhat impractically, Sweden tends to be at its coldest when it’s dark and windless.

Investments in long range, high wattage cabling to connect grids might be useful. There's plenty of sun light further south.

Of course, you need to run the numbers to make sure it actually makes sense. Both economically and from a resource point of view. Cables ain't free to build nor maintain.

But there's probably a trade to be made with the carbon capture people to sell them trash plastic to bury (or to have them pay you to bury your plastic. No need to actually ship the actual plastic around.)

Re: The Engineering of Landfills

#218

Post by dylan604 »

stouset wrote: post #208
dylan604 wrote: post #196

Earlier quoted context omitted.

What, 3 out of 4 isn't good enough for you? The high rise part of the comment is an example of "one of these things is not like the others" in that of course people all about the money will like high rises. It also doesn't matter what you think Donald Trump does or does not believe. He has a 4 year track record, and is on record making comments about what he will do if elected again.

The Trump administration backed away from policies meant to reduce carbon emissions, and promoted policies meant to increase energy independence through increased reliance on and use of fossil fuels. The same administration also rolled back nearly 100 separate environmental regulations. It supported developing energy reserves on federally protected land, including national forests and near national monuments. Trump h…

I don't know what I read to get a totally opposite meaning of the original comment, but rereading it now does make this ID10T level of WTF

Re: The Engineering of Landfills

#219

Post by strken »

jrmg wrote: post #140
breck wrote: post #56

Earlier quoted context omitted.

> 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. Damn, I had to think about this for a second, but you are right. How the hell did I not realize this before? Can you please popularize this more? Maybe compress into a pithy phrase.

The supposed triviality of this size is not sitting well with me. What’s described is a 100 yard deep hole. So about 27 stories. It’s 35 miles per side, so 35 x 35 = 1225 square miles in area. That’s bigger than any city in the mainland US[1]. It’s a 27 story deep hole that’s twice as big as Houston. Three times as big as the city of LA, and over half the size of the urban metropolitan LA area[2]. Four times the size…

The largest open cut mine in the world, Bingham Canyon, is more than ten times as deep.

While it's not a good idea to just chuck stuff into an abandoned mine, the effort to excavate a hole that size is doable for a single site operated by a single company employing 2000 workers over a century. It's pretty trivial in comparison to any other environmental problem.

Re: The Engineering of Landfills

#220

Post by toomuchtodo »

eru wrote: post #214
toomuchtodo wrote: post #150

Earlier quoted context omitted.

Indeed, waste sorting might improve the situation, but all available evidence indicates there is no will to do this (caveats being parts of Europe, Japan, the Nordics, and anywhere else diverse multi stream waste management can be effectively operated), which leads me to believe gasification is the superior path (with a bypass stream for glass, brick, earth, rock, and metals, primarily to prevent process efficiency r…

What benefit would you get from gasification compared to just straight up burning the trash?

https://en.wikipedia.org/wiki/Plasma_gasification#Advantages
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