Feb 6, 2014

Posted by Shanell Calloway in Uncategorized | Comments Off on Leachate must be controlled

Leachate must be controlled

What is Leachate? It is the terrible soup that is found in sanitary landfills, it is the result of rain water mixing with the waste that is dumped into a landfill. Years ago this caustic concoction was allowed to simply seep into the groundwater and it eventually found its way into the water supply, the result was heavily polluted drinking water.

Fortunately those days are long gone, but leachate is still with us and probably always will be. Leachate today is being controlled in leachate tanks which are often a liner which is installed into a huge prepared pit prior to the introduction of sanitary waste, in this way the leachate is captured and not allowed to get into the underground water supply.

Depending on what is put into the landfill, the leachate can be harmless or extremely toxic so the leachate tanks must be designed and made from materials which can take on all forms of waste material and the consequences. Normal leachate contains very high concentrations of nitrogen, organic carbon and chloride. This is just the beginning, rainwater which finds its way into the landfill often carries with it excess pesticides and heavy metals. As the leachate percolates it turns into a horrible black or yellow soup that has an acrid odor.

As groundwater is the source of drinking water for a large portion of the American population, holding the leachate in large leachate tanksĀ is absolutely imperative. It does not take long to show up in wells and other sources of water.

Modern landfill sites are purposefully prepared to capture the leachate and then it is treated. As it is impossible to stop rainwater from getting into the site, the leachate tanks have a layer of material which is impermeable put into the bottom. As the leachate collects in the bottom of the tank, it is closely monitored and treated. Once it has been treated, then it is put into the environment as a harmless liquid, little different than that which is the results of sewage treatment.

If the landfill site is full and the municipality wishes to reuse the site, the old leachate must be dug out and a new bottom put in place. As this is a very expensive proposition the landfill is usually abandoned as the damage has been long done anyway.


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