Atlanta Gas Light Site Cleanup Underway
 

Georgia Power has returned to the Atlanta Gas Light Site to remove 4000 cubic yards of soil approximately 30-40 feet underground.  The Site was extensively cleaned up in 2000 and the expectations were that the residual groundwater contamination would decrease to drinking water standards.  Even though contaminants in water did come down and the area shrunk considerably, drinking water standards were not being met.

   An investigation of the area causing the problem revealed some tar like substance had leaked deep into the ground and was the source of the contamination.  Unlike water, the liquid like source of the problem moved as a Dense Non-Aqueous Phase Liquid (see diagram below) and follows the path of least resistance.  Often, this is the hardest  type of contamination to track since it can move down, then sideways, and down again.

   The goal of the current removal action is to remove all the soil that could possibly contain these ribbons of tar like material sitting deep underground and below the water table.  The wet soil will be placed on a dewatering pad, the water collected, and the soil removed from the Site.  In place of the soil, a Portland cement and bentonite (clay) mixture will fill the excavation.

  The entire project is expected to take between 3 and 4 months to complete, followed by groundwater monitoring to assess success of the removal.

 Crews install the dewatering pad and prepare to pour cement for the decontamination pad for trucks leaving the Site.  
 

See follow-up story.