The closing of the Hillside landfill has begun.
There are several technologies that will be implemented in the coming year in order to ensure the landfill is closed properly—and permanently. Allied Waste has extensive experience applying these technologies for accurate landfill closure.
Please see below for a brief explanation of how these technologies are put to use.
There are two sources of contamination (the "stink") from landfills:
- Leachate: the substance produced when liquid and garbage combine
- Gas: a natural byproduct of the decomposition of waste
The goals of closing a landfill are:
- CONTROL
Minimize the production and concentration of leachate and gas in the landfill - CONTAIN
Use liners and covers to keep the leachate and gas produced inside the landfill from coming out into the air - COLLECT
Use a complex, engineered system to collect any leachate or gas that may attempt to escape the landfill
How do you CONTROL the amount of leachate and gas?
Because leachate is created when waste comes in contact with liquid, such as rainwater, the first step in controlling its production is to keep rainwater OUT of the landfill. Less rainwater will allow for less leachate production, as well as less gas production. Keeping rainwater out is a big factor in reducing and eventually eliminating the odor caused by the landfill.
The roofs of most houses are shaped such that rainwater will run down the slope and off the roof. The concept is the same with a landfill. By filling and reshaping the landfill in a similar way, we can ensure that rainwater will run down the sides of the landfill and into storm water structures, rather than gathering in a pool at the top of the garbage and creating more leachate and gas..
How do you CONTAIN leachate and gas?
The final cover system keeps rainwater out of the landfill, using many layers of plastic tarps, clay and filters that act as a barrier to contain any leachate and gas from escaping from the landfill—never allowing it into the air you breathe.
These layers of material accomplish the following essential tasks:
- Remove rainwater that may sneak in, thus minimizing leachate and gas production
- Contains gas that is produced within the capped landfill
- Promotes vegetation atop the closed and capped landfill so the green space may be incorporated onto the site.
This cap design has been used successfully at hundreds of landfills.
How do you COLLECT leachate and gas?
Even after you control rainwater entry and contain any produced leachate and gas, it is imperative to realize that there will be leachate and gas production from the garbage and water that already exists in the landfill. Allied recognizes this, and in order to do as thorough a job as possible, will design and implement a collection system for continued leachate/gas production designed specifically for the Hillside Landfill.
The gas that is formed within the capped landfill will be taken out via system of vacuum wells and plumbing lines inserted into the landfill. In addition, two special layers within the final cover system are designed to direct gas out of the landfill and into control devices outside the landfill. Similarly, leachate will be pumped from within the landfill and directed to a treatment facility and discharged to the sewer system.