Remediation & Earthworks

This involves stimulating microorganisms to grow and use contaminants as an energy source.

In situ treatment allows ground water to be treated without being brought to the surface, facilitating significant cost savings. However, it generally requires longer time periods, and there is less certainty in part because the efficacy of the process is more difficult to verify.

Not all organic compounds are amenable to biodegradation. However, bioremediation techniques have been successfully used to remediate ground water contaminated by petroleum hydrocarbons, solvents, pesticides, and other organic compounds.

Physical/chemical treatment uses the physical properties of the contaminants or the contaminated medium to destroy or separate the contamination.

This is often a very cost effective method and can be completed in shorter time periods. Equipment is readily available and is not engineering or energy-intensive.

The main difference between in situ and ex situ physical/chemical treatment is that it requires the pumping of groundwater, leading to increased costs and engineering for equipment, likely permitting, and material handling.

The advantage however is that it generally requires shorter time periods and there is more certainty about the uniformity of treatment because of the ability to monitor and continuously mix the groundwater.

Containment measures are often performed to prevent, or significantly reduce, the migration of contaminants in soils or ground water. Containment is necessary whenever contaminated materials are to be buried or left in place at a site. In general, containment is performed when extensive subsurface contamination at a site precludes excavation and removal of wastes because of potential hazards and/or unrealistic cost.

The main advantage of containment methods is that they can prevent further migration of contaminant plumes, and allow for contaminant reduction at sites where the source is undetermined, inaccessible, or where long term remedial actions are being developed. Available containment technologies include physical/biological barriers e.g slurry walls.