The primary goal of the GeoEnvironmental Science Program at Hocking College is to train students in skills and concepts important to protection, monitoring and remediation of polluted ground water.
Many graduates from this program are employed by environmental consulting companies that specialize in ground pollution problems. These companies conduct
site-specific characterization and monitoring of polluted groundwater and undertake subsequent efforts to remediate the problem.
To this end, many of the program's alumni play integral roles in studies determining the type of pollution present, how it got there, where it's spreading to, how fast it's moving, and how long it will take to arrive at sensitive locations such as streams, lakes or public and private water wells.
In the Hydrogeology and Subsurface Investigations courses of the GeoEnvironmental Science Program, students study the science-based approaches and techniques for investigating and remediating ground water pollution. Site-specific remediation projects are numerous and widespread through most urban and suburban areas, but the clean-up techniques utilized are largely unknown to the public.
The most widely used technique known as "pump and treat" is especially well suited to groundwater contaminants such as volatile organic compounds (VOCs) like gasoline, benzene, and acetone. In this approach, extraction wells are drilled and pumped to capture the plume of contaminated groundwater. Computer modeling helps determine precise placement and pumping rates for extraction wells (Figure 1).
Figure 1: GeoEnvironmental Science student computer-modeling placement & pumping rate of extraction well for optimum capture of plume of contaminated groundwater.
For VOCs, as the plume is pumped to the surface, air stripping towers are used to
remove the contaminants. In this technique, the contaminated groundwater captured by the extraction well is pumped to the top of the air stripping tower and then sprayed into the top of the tower (Figure 2).
Figure 2: Air stripping tower on site and a schematic of air stripping tower.
From there it flows downward through polypropylene packing spheres (Figure 4) that fill the tower. This greatly increases the surface area of the contaminated water. At the same time, a fan at the base of the tower blows air upward through the downward flowing water which allows the dissolved contaminants to escape as gases. The gases travel out the top of the tower and the now decontaminated water is piped from the bottom of the tower to a sanitary sewer or approved surface water body.
Figure 4: Packing sphere used to increase surface area of
water aid in volatilization of contaminants.
