Landfills Part 1

There are 3,091 active sanitary landfills in the U.S. and over 10,000 old municipal landfills - also called rubbish pits or dumps.

Rubbish Pit vs. Landfill

Anatomy of a Landfill Modern sanitary landfills are carefully engineered structures designed to isolate garbage from nearby water, soil, wildlife, and people.

How is a Sanitary Landfill Made? The cavities are dug out of the ground and then the walls are sealed with layers of clay and coated with plastic to prevent groundwater contamination from wastewater that accumulates.

The Liner Note the overlapping of the seams!

Today’s landfills are designed to stay dry inside, except for liquids that ooze from some garbage, and rainwater that trickles through. As water trickles through a landfill, it dissolves chemicals and other particles, creating a liquid called “leachate.”

There are four critical elements in a secure landfill: A bottom liner A leachate collection system A gas recovery system and a cover The natural hydro-geologic setting The natural setting can be selected to minimize the possibility of wastes escaping into the groundwater beneath a landfill. The three other elements must be engineered. Each of these elements is critical to success.

Cross-section of a Landfill

Cross-section of a Sanitary Landfill

What is done with the Leachate? The state-of-the-art system, constructed at the bottom of a landfill, has a special double liner to prevent leachate leakage. The contained leachate is run through pipes to above-ground storage tanks and hauled for treatment and disposal at a large regional wastewater treatment plant.

Landfill Storage & Drainage

Even though there are 2 liners that overlap to keep leachate from leaking out, there is always that slim chance. So to help protect the public, landfills are also designed with: Detection meters between the liners which are monitored continuously Monitoring wells around the site which are sampled quarterly to test the groundwater quality

Groundwater Protection Landfills first existed as rubbish pits with NO protection from leachate getting into the groundwater. Next, there came an improvement where a landfill had a clay liner. This afforded some protection, but not much. Now landfills are required to have both a clay and a plastic liner plus a leachate collection system to protect the groundwater from possible contamination.

The Capping of a FULL Landfill

So...landfill garbage degrades, right? Not really. Landfills are mostly anaerobic. Without the oxygen and water needed to break down organic materials, all garbage decays very slowly in a landfill. This means our garbage will probably be around for a very long time.

Top 10 Landfill Issues 1. Leakage through plastic membrane 2. Water Contamination from leachate 3. Air Emissions (methane & other gases) 4. Remediation of old toxins in landfills 5. Old municipal landfills contain hazardous waste 6. Location of old landfills needing remediation close to Iarge bodies of water 7. Landfill cover is usually ash from incinerators, not dirt 8. Monitoring of closed landfills will not be kept up 9. Detection of old garbage dumps 10. Who is liable when land changes hands?

Did you know that these items are prohibited from being placed into landfills? Tires Empty drums Used Oil, oil filters, & oil absorbents Batteries Appliances Computers, TV’s, & other electronics Yard Clippings: brush, grass clippings, leaves Medical Waste Sewage Asbestos Radioactive waste (including low-level) Polychlorinated Biphenyls (PCBs): Fluorescent, Incandescent Bulbs & Ballasts Non-household liquid waste such as paint, cleaners, and other hazardous chemicals Construction materials, roofing materials, & shingles Animal carcasses Refrigerators & Freezers Nuclear (Radioactive) Waste Any other hazardous waste