Remediation Strategies for Contaminated Soil

To start, there are four steps taken to determine both the level of contamination and what remediation strategy to employ. The Preliminary Assessment determines if there are probable areas of contamination and through a Site Investigation, the area of concern is visually inspected and soil samples are taken and analyzed at a state certified lab.

During the Remedial Investigation an extensive study of the site is carried out on the site and may include further soil sampling. It is the final step in determining the extent of contamination as well as if the contaminant is migrating.Remedial Action Selection is the process of selecting the most appropriate strategy for clean up of the site. If the contamination level is determined to be at a level that doesn’t pose a threat to human health or the environment a “no action” remedy can be selected. A remedial action plan is then developed that describes what steps will be taken in the cleanup process. Contaminated soil can be removed or treated in-place or “in-situ”. Vapor extraction and biological treatment are two examples of in-situ treatment. It’s best use is in situations where large amounts of contamination are present or removal is difficult.

If it is determined that removing the soil “ex-situ,” is a better option, it can either be treated on-site or taken to an authorized facility for disposal or treatment. Two methods of on-site treatment are above ground biological treatment and soil aeration. In bio-remediation the contaminants are destroyed through the use of organic agents and it is a solution that is beneficial to the environment.

The removal process for contaminated soil involves excavating the affected area through the use of a backhoe or excavator. The decision on what equipment to use is based on the size of the area being removed as well as how accessible it is. Excavation is frequently used if in-situ remediation is either too expensive or when timing is important. It is also a cost-effective method if the contaminated area is small.

The removed soil can either be treated on site using a mobile treatment facility or disposed of off-site. If treated on-site the treated soil can be used to backfill the excavated area. If the soil is going to be disposed off-site it will be directly placed in one or more dump trucks for disposal.

Soil aeration is another treatment method of spreading the removed soil. This process uses piping and pumps to push the air and while it may be more cost effective than bio-remediation, it requires the use of special controls to ensure that the treatment is in fact working and bringing contaminant concentrations down to an acceptable level. During the process of soil aeration, soil samples must be taken at specific intervals to measure the level of contamination remaining.In some cases an interim remedial measure may be used to contain or stabilize the contamination until further evaluation is carried out and completed. A capping system or free product removal system can be used to contain the contaminated area. It can also be covered with tarps to prevent the soil from possibly washing away or blowing in the wind.

The amount of time required to remediate contaminated soil depends on several factors including the size of the contaminated area along with the depth, the accessibility of the contaminated area and the distance to the nearest treatment or disposal facility. The type of remedial action employed can also affect the length of time needed to either destroy or lower the contaminant to an acceptable level and may also require long term monitoring and maintenance. With so much at stake and so many choices to make in determining the proper remedial action, you should always consult an environmental contractor who is well versed in the latest methods of soil remediation as well as having experience in mitigating the type of contamination affecting your property. Need help? Contact Us Quick Environmental for timely cost effective solution.