2013 NGWA Summit — The National and International Conference on Groundwater

Determination of the Radius of Influence for Chemical Treatment in an Unconfined Aquifer

Tuesday, April 30, 2013: 9:00 a.m.
Regency West 6 (Hyatt Regency San Antonio)
Rusty W. Wheat, LPG, Terra Environmental Corporation
Mike Wirt, CHMM, Principle Project Manager
Jason Stephens, Terra Environmental Corporation
Jeffrey L. Stone, Licensed, Driller, Indiana, Lt Environmental Drilling

The radius of influence (ROI) for treatment of contaminated groundwater is critical in the design of the groundwater remedy.  The ROI for oxidant chemical injection is not well understood in unconfined shallow groundwater aquifers.   The study site consists of shallow homogeneous fine grained sand aquifer underlain by continuous inorganic clay.   Injection tests prior to treatment indicated a pressure response with a radius of 15 feet.  The remedial design was conservatively based on a ROI of 5 feet.  Two rounds of chemical treatment at 44 locations within the treatment grid were performed.  Observation wells were monitored for water level, dissolved oxygen (DO), oxygen reduction potential (ORP), pH, temperature, total dissolved solids (TDS), BTEX, MTBE and naphthalene.  Vapor monitoring of subsurface utilities was also conducted.  Monitoring was performed prior, during and post treatment.  Monitoring data responses were compared to a simulated model study of the chemical injection to observe the ROI.  The results of the study have implications concerning subsurface pressure distribution, chemical distribution, parameter responses to injection, and effective ROI design.


Rusty W. Wheat, LPG , Terra Environmental Corporation

Rusty Wheat is the Principal Project Geologist for Terra Environmental Corp. He received a bachelor's degree in Geology from the University of Wyoming and a master's degree in Geology from Indiana State University. He is a Licensed Professional Geologist in the state of Indiana. Wheat has 23 years of experience as a consulting geologist.


Mike Wirt, CHMM , Principle Project Manager
Mike Wirt is the Principle Project Manager for Terra Environmental Corporation. He has a bachelors degree in Biology from Tri-State College. Mike has 38 years of experience in the environmental consulting business. Mike is a qualified CHMM.


Jason Stephens , Terra Environmental Corporation
Jason Stephens is a project manager at Terra Environmental Corporation. Jason Graduated from Cedarville University with a BA in Biology and received a Master of Environmental Science degree from Taylor University. Jason worked as a botanist and forest health program coordinator for the Indiana DNR for 3 years before joining Terra.


Jeffrey L. Stone, Licensed, Driller, Indiana , Lt Environmental Drilling
Jeffrey has over 15 year’s field experience in the Environmental Drilling Industry with hands on knowledge of DPT, HSA and Sonic drilling methods including but not limited to soil and groundwater sampling, soil vapor sampling, monitoring well installation and in-situ remediation. During this time he has been successful working for Local, National and Multi-National drilling firms performing duties ranging from Drilling Helper, Lead Driller, Project Manager, Drilling Manager to Business Development.