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Interesting. How are they managing the continued break-down of the garbage that's still buried a few (dozen?) feet below? The article doesn't convince me that

Interesting. How are they managing the continued break-down of the garbage that's still buried a few (dozen?) feet below? The article doesn't convince me that this dump is totally reformed, just that life has developed on top. This also isn't a "sustainable" solution as we will continue to need dumps for the foreseeable future...

aeternum 6y ago
They've been doing this in the midwest for quite awhile. Many cities simply build a park on top of the dump when it fills up. Methane buildup is still an issue but I believe some cities actually pipe it into town and burn it for heat.
- Fezzik 6y ago
  Same out West - if you live in Seattle, the park right next to The Pits on Lake Washington (where the pits are for Sea-fair hydroplane races) used to be a landfill. My grandparents grew up across the street from it. It doesn’t smell at all.
hinkley 6y ago
Because landfills are not meant to break down. If they did, that would mean who-knows-what kinds of fluids leaching into groundwater, and that would be very bad. They cap them with materials designed to make sure water sheds off the top of the landfill instead of percolating through. So essentially we've capped these things, but they're intended to stay as they are now basically forever. Stop me if you've heard this one before.
- pottertheotter 6y ago
  There can be quite a bit of organic material in SWFs that breaks down, although most of that process is completed within ~20 years of being deposited. Modern facilities often incorporate electricity generation plants powered by all of the methane produced from the breakdown of organics. Also, a landfill has a bottom liner that is usually much more robust than the top (a couple feet of clay and a thick membrane) plus leaching pipes to carry away leachate. I don't believe the final cap is intended to completely shed water, but it is meant to divert a lot of it from getting into the landfill.
  - hinkley 6y ago
    From what I understand you have a synthetic barrier, several feet of clay above it (which holds water but doesn't pass it very fast), then a layer of loose aggregate above it, and soil above that. Gravel over an impervious layer is, for all intents and purposes, a drain. Unless the slopes are all wrong so the water pools in the middle.
  - shum1 6y ago
    I found some videos on youtube that give a more visual explanation of this: https://www.youtube.com/watch?v=iwNWjBxGadA https://www.youtube.com/watch?v=iwNWjBxGadA
    - hinkley 6y ago
      It's worth noting that the business model for this group is to treat a landfill a little differently to boost methane production. But in the end they're still keeping the leachate on site, and some of the water escapes as vapor (they dewater the methane before burning it).

aeternum 6y ago

They've been doing this in the midwest for quite awhile. Many cities simply build a park on top of the dump when it fills up. Methane buildup is still an issue but I believe some cities actually pipe it into town and burn it for heat.

Fezzik 6y ago
Same out West - if you live in Seattle, the park right next to The Pits on Lake Washington (where the pits are for Sea-fair hydroplane races) used to be a landfill. My grandparents grew up across the street from it. It doesn’t smell at all.

hinkley 6y ago

Because landfills are not meant to break down. If they did, that would mean who-knows-what kinds of fluids leaching into groundwater, and that would be very bad. They cap them with materials designed to make sure water sheds off the top of the landfill instead of percolating through. So essentially we've capped these things, but they're intended to stay as they are now basically forever. Stop me if you've heard this one before.

pottertheotter 6y ago
There can be quite a bit of organic material in SWFs that breaks down, although most of that process is completed within ~20 years of being deposited. Modern facilities often incorporate electricity generation plants powered by all of the methane produced from the breakdown of organics. Also, a landfill has a bottom liner that is usually much more robust than the top (a couple feet of clay and a thick membrane) plus leaching pipes to carry away leachate. I don't believe the final cap is intended to completely shed water, but it is meant to divert a lot of it from getting into the landfill.
- hinkley 6y ago
  From what I understand you have a synthetic barrier, several feet of clay above it (which holds water but doesn't pass it very fast), then a layer of loose aggregate above it, and soil above that. Gravel over an impervious layer is, for all intents and purposes, a drain. Unless the slopes are all wrong so the water pools in the middle.
- shum1 6y ago
  I found some videos on youtube that give a more visual explanation of this: https://www.youtube.com/watch?v=iwNWjBxGadA https://www.youtube.com/watch?v=iwNWjBxGadA
  - hinkley 6y ago
    It's worth noting that the business model for this group is to treat a landfill a little differently to boost methane production. But in the end they're still keeping the leachate on site, and some of the water escapes as vapor (they dewater the methane before burning it).