What are the different ways used to treat polluted soils?

Question

What are the different ways used to treat polluted soils?

Answer 1

Petroleum can also be "composted" by removing the contaminated soil and treating it with a bacteria (name I can't recall), this particular bacteria digests the petroleum converting the carbon to new bacteria and the hydrogen to water.

Answer 2

There are many different ways depending on what is contaminating the soil.  The most simple is to excavate the soil and dispose of it as hazardous waste.

With petroleum contamination, since it breaks down fairly readily there are a few things that can be done other than excavation.  Air can be blown into the soil stripping contamination from soil particles then the air is sucked out of the ground, filtered, and released to the atmosphere.  

Microboes can be injected into the soil which consume the contamination as a food source.  

Contaminated groundwater can be pumped from the ground and cleaned or disposed of (cleaning groundwater will help strip contamination from soil particles).  

A liscenced engineer can design a cap or other engineered control to keep the contamination in place but prevent people from being exposed to it.  

Permits can be obtained to leave the contamination in place until it is naturally attenuated.

There are many other ways in use or in development, it is a growing field.

Answer 3

I have seen it done a few ways depending on the contaminate.

1)  If it is something like toxic metals and such usually the soil is just removed and taken to a special landfill.  

2) Petroleum type chemicals in soils are usually removed and then put through an incinerator to burn off the chemicals.  

3)  Then there is the cheap and dirty way....  bring in some fresh soil and mix it with the bad until the levels per area are within acceptable levels.