Live data from Hacker News

The Engineering of Landfills

practical.engineering

1–10 of 333 posts

Re: The Engineering of Landfills

#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 designed ones play a huge role in making sure waste products don’t end up in our soil or air or water. It’s not possible to landfill waste everywhere... But my point is: landfills are a surprisingly low-impact way to manage solid waste in a lot of cases. I hope the future is a utopia where all the stuff we make maintains its beneficial value forever, but for now, I am thankful for the sanitary engineers and the other professions involved in safely and economically dealing with our trash so we don’t have to.

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

Re: The Engineering of Landfills

#4
post #3

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

Assuming incineration has lower externalities than landfills[1], you're... expressing surprise that a cheaper, suboptimal technique is ever used?

[1] I don't know if that's true.

Re: The Engineering of Landfills

#5
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.

Re: The Engineering of Landfills

#6
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.

Re: The Engineering of Landfills

#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 environment. The plastic pollution in the ocean is from developing countries and things unrelated to our soda bottles.

Modern landfills (as this article describes) are really efficient and have basically no leakage to the environment. As mentioned, you can make beautiful parks on a closed landfill with no smell. Technology is amazing.

Re: The Engineering of Landfills

#10

Since our city started collecting green waste separately, it's interesting to see what goes into our garbage. It's basically non-recyclable soft plastic, cat litter, and dog poo bags.

The big shift for me was when I moved to an area with seperate food recycling. The general rubbish is much cleaner, although probably more toxic in a landfill, as it is just the soft plastic or anything soiled.
Post reply on HN