A Word About Recycling with Ollie Maier

Continuing with closing the world’s largest landfill. You may remember we first covered how large this landfill was and how much garbage it took in each day for New York City and the surrounding area. The following week we went into the city’s decision to close it in 2001 and turn it into a park area. This required legislative action and hiring contractors, both in-state and from other areas to insure it was done properly and within desired budget.

You may remember near the end we stated, “Closing a landfill site isn’t easy. There are a number of regulations and safety measures to consider. Among the many things to contend with are the landfill’s byproducts – landfill gas and leachate.”

Continuing with our information taken from the story in a recent Waste Age newsletter, we continue.

“While the closure of any landfill requires intense planning, the work being done to safely cap and redevelop the Freshkills Landfill is predicted on intense oversight.”

In addition to three companies contracted to close the landfill and make it into a park, the New York State Department of Environmental Conservation (NYSDEC) is involved in overseeing the whole operation to ensure it meets regulations for landfill closure.The NYSDEC will also conduct air, surface water and groundwater monitoring on a regular basis to ensure that the landfill infrastructure functions properly.

As part of this, sophisticated engineering standards are in place throughout the site to deal with the leachate and landfill gas in a way that ensures the safety and health of the public.

To take care of the gas produced by the garbage in the landfill, the landfill gas system runs on a network of wells and pipes that pump the gas through a vacuum. After collection, this gas is either burned or processed for energy at an on–site recovery facility. By using such a process, emissions, non–methane organic compounds (NMOCs) and other pollutants are reduced by almost completely. This process also helps contain the gas and its odor from entering the atmosphere.

Covering the material in the landfill will be six different layers. These include: a soil barrier layer, gas venting layer, impermeable liner, drainage layer, barrier protection layer and planting soil layer. Each layer has a unique design and function to help contain the waste.

A small explanation of the reason for each:

1. The soil barrier layer is a base layer put over the solid waste. It is graded and compacted to standard requirements. And later, this layer may need to be regraded to ensure the slope falls within the minimum and maximum grades of 4 to 33 percent as specified by the NYSDEC to help with stability and drainage.
2. The gas venting layer is made up of a geocomposite material which aids in moving landfill gas toward vents or extraction wells.
3. The impermeable liner or hydraulic barrier is put on the subbase material to prevent water from reaching the waste. It is normally made of clay or plastic. It’s also used to block gas from escaping landfill.
4. The drainage layer is added in some parts of the cover for drainage of the above layer. This ensures that soil doesn’t become oversaturated.
5. The barrier protection layer is soil added for the protection of the impermeable liner from weather conditions which might cause cracking and heaving. “With a minimum thickness of 24 inches (greater where trees are located), this layer helps store excess moisture until it can be drained or used by plants and foliage.”
6. The planting soil layer or topsoil layer is required to be at least six inches thick.

“Sandy loam soil is used because of its fertile nature that is conducive for vegetation growth and for its propensity to prevent soil erosion.”

By having these layers, the leachate management system can work to remove would-be pollutants through collection and treatment of the liquid waste byproduct.

Note: Please don’t think I lied to you when I mentioned last week this would be the final article concerning the closing of the world’s largest landfill and the making of it into a park. It isn't. My intentions were good. Unfortunately, I haven’t yet covered anything concerning the making of it into a park, so I will do that next time. I assure you, I will switch to another subject after that – but I hope you are still finding this somewhat interesting.

Till next week, do have an enjoyable and safe one.

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Ollie is a local citizen concerned with the environment and helping others. A retired Air Force fighter and instructor pilot, he is a graduate of Leadership San Marcos and received his degrees at Texas State University where he worked on staff before totally retiring. For questions or comments, he invites you to call him at 512-353-7432 or e-mail omaier@txstate.edu.