How Does One "Cap" A Dump?

[Cartooniverse]

God knows I’m trying to keep this thing on track, before we all get sworn at roundly by a forum Mod. I truly wish to know how the methane is gathered and stored, and how is it filtered so that the other gasses that are released and then somehow gathered, are separated out so it’s useable methane.

They can’t just leave it in there, it’d explode eventually.

[DeVena]

Care is taken with old landfills that the methane doesn’t migrate onto the surrounding property. That’s why there’s a buffer area (where no waste has been place) around the entire facility.

Methane is heavier than air. It stores in low spots (buildings, culverts) where there is not much movement. Back in the day, one particular site had a small mechanic shed at a bottom of a hill below the operating face. They decided they needed a Coke machine in this building. So they closed up the building for the weekend. When they came to work Monday morning - no building. The methane built up in the closed building, the Coke machine’s cooler kicked on, small spark, big boom.

From my previous Link to HOW STUFF WORKS (which I strongly urge you to read the whole thing) :

Methane Collection System

Bacteria in the landfill break down the trash in the absence of oxygen (anaerobic) because the landfill is airtight. A byproduct of this anaerobic breakdown is landfill gas, which contains approximately 50 percent methane and 50 percent carbon dioxide with small amounts of nitrogen and oxygen. This presents a hazard because the methane can explode and/or burn. So, the landfill gas must be removed. To do this, a series of pipes are embedded within the landfill to collect the gas. In some landfills, this gas is vented or burned.

<insert neeto pictures here>

More recently, it has been recognized that this landfill gas represents a usable energy source. The methane can be extracted from the gas and used as fuel. In the North Wake County Landfill, a company collects the landfill gas, extracts the methane, and sells it to a nearby chemical company to power its boilers. The extraction system is a split system, meaning that methane gas can go to the boilers and/or the methane flares that burn the gas. The reason for the split system is that the landfill will increase its gas production over time (from 300 cubic feet per minute to 1,250 cubic feet per minute) and exceed the capacity of the boilers at the chemical company. Therefore, the excess gas will have to be burned. It is not cost-effective to compress the excess gas to liquid and sell it.

If you need more information, contact your State Environmental Agency’s Solid Waste Branch or read the regulations … Explosive Gas Control section of 40 CFR 258.

[Iteki]

*Originally posted by emilyforce *
**I was under the impression that PVC was an environmental problem (I think it was Neal Stephenson’s Zodiac that gave me this idea, though I don’t remember details, and I realize that’s not exactly an impartial source.) Should I be worried about folks using it to Tupperware up huge quantities of landfull debris? **

IIRC, Zodiacs baddy was PCBs. No idea what the difference is, but the image of the fishermen with blackheads freaked me out.