If you want healthy soil to help you grow vegetation or generally improve the quality of the surrounding environment, you may want to investigate the different methods of soil remediation. Which type is most appropriate is dependent on your specific situation, so you will need to evaluate them before making a decision.
When contaminants in soil or groundwater take the form of a gas, air sparging is the most appropriate method of remediation. Research is ongoing into making this technique as efficient as possible. It is particularly useful when dealing with hydrocarbons. Pressurised air is injected into the soil to force out the contaminants. You do not have to extract the soil first, unlike with many other techniques. This means it is commonly done on-site by a specialist land remediation company.
Like air sparging, bioremediation is an on-site technique; however, it uses organic methods rather than applying machinery. Bacterium is selected that will feed on the contaminants in the soil. An expert land remediation company will maximise the attractiveness of the soil to bacteria by controlling factors such as acidity, temperature and fertiliser. When bacteria have consumed all contaminants, they will die. The difficulty with bioremediation is that if the soil is not dry and at an appropriate temperature, it will not be effective. In colder weather, it may be necessary to cover the site and keep it well insulated.
Thermal soil remediation
This is a type of soil remediation that uses heat to extract contaminants; again, it requires a specialist land remediation company. Particularly useful for oil and other petroleum products (hydrocarbon compounds) and contaminated water, it works by heating the soil until any contaminates evaporate. This generally takes place in an oven, with a conveyor belt to take things in and out. Once the contaminates have been evaporated, they can be captured and cooled. It is then easy to dispose of them separately; meanwhile, the soil can be cooled before it is ready for reuse.
Rather than the outright removal of contaminants, encapsulation prevents them from spreading. A mix of concrete, lime and cement can be used to separate polluted soil from healthy soil. Unfortunately, the mixture will prevent you from using the soil for growing other plants and vegetation in the future. The soil will still be dead, but the surrounding area will be protected.