The process of soil remediation is subject to ongoing testing of new methods in order to figure out the best way to decontaminate soils although there are already some tried and tested methods currently in use.

Here is a look at some of the main decontamination methods presently used in order to remove a range of toxins from the soil.

Bioremediation

There are several biological methods available for remediating soils that have been contaminated with metal, for example.

The presence of uranium in the soil is an industrial challenge that could be tackled with bioremediation.

A key aim is to remove the metals from the soil and make it ready for re-use once the toxins have been removed from the soil. One way of doing this is through the use of organisms such as herbaceous plants.

A typical herbaceous plant would be rye, and this has the capacity to remove the toxins through absorption. After they have managed to remove the toxins the plants are harvested and the ashes safely deposited.

The process of bioremediation involves changing the current environmental conditions in order to encourage the growth of microorganisms, which has the impact of degrading the targeted pollutants at the same time.

This simple and organic method has certain merit, especially when you consider that the quality of the soil can be improved in the long term without substantial technical intervention.

It also has the benefit of proving to be a cost-effective remediation technique and it is also more sustainable than some of the other options available.

Chemical remediation

Using chemical reagents is another tried and tested method of remediation and it can be used to deal with contaminated soil and also groundwater.

The process of chemical oxidation is the most commonly used form of treatment although other variants of the technique include chemical reduction of contaminants and enhanced natural attenuation, which involves injecting appropriate chemicals to targeted areas.

A primary advantage of chemical remediation is that it allows the opportunity to treat the contaminated soil without the need to remove it, which can be particularly useful if access is problematic.

The chemicals are applied through the use of pressurized lances and that means it is often possible to access and treat the contaminated soil using a drill rig setup.

The process of soil washing

Another soil remediation option is to consider soil washing.

In general terms, washing soil involves sorting soils into various constituent parts such as gravels, sands and different fines. When soils are considered appropriate for treatment via washing it is feasible to isolate and target the relevant contaminants.

Soil washing will enable you to be able to successfully isolate and them remove the contaminated elements of that soil whilst leaving the remaining non-contaminated soil elements in place.

It is often found to be the case that a large percentage of the contaminants will be found within the fines and with that scenario, it means you should be able to be left with clean sand and gravel following the soil washing process.

Soil washing is often considered to be a useful method when you are keen to keep disposal volumes to a minimum. Any remaining contaminated materials can then be treated using either chemical remediation or bioremediation.

Thermal desorption

The basic premise of this specific remediation technology is to use a heat source in order to increase the level of volatility in the soil contaminants that you are attempting to remove.

Using thermal desorption allows the contaminants to be separated so that they can be removed from the solid, which would usually be soil, sludge, or filter cake.

There are two options available once these volatilized contaminants have been separated, they can be either collected or they can be thermally destroyed.

It should be noted that there can be an element of confusion about thermal desorption and despite the fact that a raised heat source is used to deal with the contaminated soil it is not the same as incineration.

It is because of this misconception that you will often see the process of thermal desorption referred to as low-temp, in order to create a clear distinction from high-temperature incineration which is not viewed favourably in the public perception.

In comparison, thermal desorption is almost universally accepted as a technology that manages to offer a permanent resolution to soil contamination at a cost-effective rate.

Aerobic

There are various forms of oxidative bioremediation and aerobic is the most common of them.

The process of aerobic bioremediation is regularly used at sites where there is a presence of petroleum products such as diesel fuel, which are classed as mid-weight, whereas lighter fuels such as gasoline can often be removed with relative ease using other available technologies such soil vapour extraction.

It is the case that aerobic oxidation can actually occur naturally under suitable conditions, however, those proper conditions require oxygen and this growth-limiting factor is often at very low levels in zones that have been contaminated with hydrocarbons.

The idea behind aerobic oxidation is to increase oxygen levels so that it encourages biodegradation beyond a level that would be naturally occurring.

These are some of the main methods of remediation that are widely accepted as offering a viable in varying circumstances of soil contamination.

One of the key aspects of successful remediation is being able to successfully identify the various characteristics of a site. Conventional site characterization methods are not always successful in gathering the most accurate data and that can often lead to a failed remedy.

A more reliable and accurate approach could actually turn out to be more cost-effective, which is why you may want to take a look at high-resolution methods and technology that allows you to see a geographic footprint and clear site characterization.

For more information, you might want to check out Cascade Environmental’s thermal remediation services .

Once you have that information in hand you will be in a better position to take the right soil remediation approach for a successful outcome.

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