Soil and Ground Water Remediation System Design and Installation

Active Environmental has provided consulting services and project management for over 100 facilities with petroleum or chemical residuals identified in soil and/or ground water.  The soil remediation systems have included excavation of impacted soil and/or installation of equipment to perform soil vapor/ground water extraction.  The ground water remediation systems have included pump and treat, injection of oxygen/hydrogen release compounds and the installation of equipment for air sparging.

Source Soil Removal and Monitored Natural Attenuation
This option is generally efficient and cost effective for removing source materials and/or impermeable materials in the subsurface. However, the presence of impacted impermeable clays in the upper regions of the subsurface will most effectively be addressed through excavation and disposal. The processes of biodegradation, volatilization, dispersion, and hydrolysis act to naturally attenuate concentrations of petroleum distillates dissolved in ground water at impacted sites.  The use of demonstrated natural attenuation as a corrective action at a site requires documenting these processes.

Air Sparging/ Soil Vapor Extraction
Air Sparging utilizes an air pressure pump to introduce air into the subsurface. The forced air (O2-Oxygen) into the subsurface volatilizes the petroleum hydrocarbons in the ground water and adsorbed onto the soil particles in the subsurface. Air sparging is most effective in porous soils but has been demonstrated to work in moderately stiff clay materials.  Soil Vapor Extraction (SVE) can remediate soils in situ by use of active ventilation. When the petroleum distillate adsorbs to the subsurface soils, the SVE remediation method creates a vacuum with airflow throughout the soil column to actively ventilate the contaminated soils which in turn volatilizes the petroleum hydrocarbons adsorbed onto the soil particles.  The petroleum vapors are carried throughout the soil column to the extraction wells.

Chemical Oxidation
A chemical oxidant such as hydrogen peroxide may be used to oxidize organic and inorganic compounds in soil and ground water. A large portion of the chemical oxidant goes toward oxidizing both straight chain hydrocarbons and natural organics in the soils. The chemical oxidant is only effective if it is exposed to the contaminant in the subsurface.

High Vacuum Multi Phase Extraction (MPE) 

MPE works very well in highly permeable soils and with the presence of Liquid Phase Hydrocarbons (LPH).  The main drawback to using the high vacuum extraction technology is that the permeable saturated zones produce a very large volume of extracted water and can increase the amount of operations and maintenance used for the management of the remediation system, therefore increasing the long term cost of the remediation activities on the site.