When a company picks up your bottles, cans, and newspaper from your house, or you drop it off here at Bourne recycling, they sort it and bundle it into these large bales where they are then bought by vendors to be taken and made into new products.
Everything that’s not recyclable is put into a landfill. Now, I can understand why the concept of a landfill is somewhat repulsive, because that was my gut reaction too. Though it’s not perfect, I think this is one of the better options we have available to us right now for waste disposal because of the way that the landfill is managed. The current practice for landfills is to line the “valley” where the trash goes with a plastic liner, and then fill it with trash so that as it decomposes, the trash is not contaminating the soil beneath it. At the current site there are areas that weren’t lined, and that area ceased being used in 1999. The current solid waste managers are digging that old stuff up in order to sort out things that should’ve been recycled, and to put a liner under it so that it’s doesn’t continue to leech into the soil as it degrades. Now, once the valley is filled with non-recyclable items, another platic cover goes over it and it’s covered with one of three types of cover: ash from another facility, “dirty” dirt that contains some kind of contaminant like oil or gasoline, or leftover particulates of crushed items.
From there, grass naturally grows in the cover and it looks like any other hill, though they have to manage it so that trees don’t grow because they will puncture the liner and cause issues.
The hill you see in the background of this photo is an old landfill. The facility has some provisions in place to avoid releasing methane into the atmosphere. The pipe you see sticking out of the earth is called a gas extraction well. There’s a complicated network of them all over this hill that concentrate the gas (containing about 45% methane) that’s emitted as the waste in the landfill breaks down.
The facility operators use a flare to destroy the methane in the gas mixture and the chemical reaction produces carbon dioxide. While this process creates heat and carbon dioxide, it neutralizes a comparatively more potent greenhouse gas. The landfill gas also contains hydrogen sulfide (H2S) which is produced when gypsum wallboard (CaSO4) breaks down. Hydrogen sulfide not only smells terrible, but when burned produces sulfur dioxide, which is a component in acid rain. So, before the gas goes into the flare to burn off the methane, another chemical process takes place. The wet scrubber removes hydrogen sulfide. The wet scrubber will then produce sodium sulfate (NaSO4), an inert solid that is pumped back into the landfill.
The gas extraction wells take care of gas that is being released from covered landfills. When a crew is working in a landfill it can leave an open area where gas (again, containing methane) can escape. In order to prevent this area from leaking methane, they use horizontal collectors to take the gas to be processed. The process of chemically altering the decomposition gas cuts down on the smell, reduces air emissions into the atmosphere, and reduces the amount of stuff they have to move off the premises.
So what’s next for Bourne Recycling? The next step is finding the highest paying vendor who is interested in taking the methane from the landfill gas and using it – one idea is for a power plant that would use the gas as a fuel for engines connected to a generator that would produce electricity. The hope is that they can find a more constructive use for the methane that is produced naturally in the landfill.
I learned about several other aspects of the Bourne Recycling Center, and they have high hopes for the future. The gas extraction well is actually cutting-edge technology, and the building you can only kind of see from the picture cost $700,000 – and it didn’t cost the taxpayers a cent.
For more information on the plan for the Bourne Recycling Center, please visit: http://www.townofbourne.com/Departments/PUBLICWORKS/IntegratedSolidWasteManagment/SiteOverview/tabid/333/Default.aspx.