Natural Attenuation: Using Statistics to Understand Ground Water Contamination

Dec. 28, 2000
At Work on Groundwater Treatment Processes

When ground water contamination is discovered at a site, a host of questions must be answered before it can be effectively removed or minimized. Battelle Memorial Institute, an international research organization headquartered in Columbus, Ohio, has recently developed a statistical approach for assessing natural attenuation of contaminants. This approach can be used to estimate how quickly contaminants can be remediated using biological methods.

The statistical approach, that utilizes geostatistical techniques such as kriging, is designed to address key questions such as how big is the area of the contamination (plume)? Is it growing, shrinking or stable? How fast is the size of the plume changing and how long will it take for the contamination levels to fall below a specified acceptable level? How quickly is contamination naturally lessened or thinned (natural attenuation)? What is the rate at which biological processes reduce contamination (biodegradation)?

Battelle's statistical tool was applied at a government military installation where trichloroethylene (TCE and chromium were discovered in groundwater. The Battelle team used data collected from 152 wells over a period of three years to analyze the rate at which contamination was decreasing in three levels of the aquifier. Although TCE appeared to be decreasing by 12 percent per year in the middle portion of the aquifier, no conclusions could be made about decreases in the upper and lower levels. On the other hand, the analysis concluded that chromium levels were decreasing in all layers of the aquifier at rates that ranged from 25 to 90 percent per year.

Tad Fox, Battelle's principal investigator, noted that the statistical approach gave government personnel confidence that both best-case and worst-case scenarios had been identified with respect to the rate of change in contamination levels. This statistical approach was first presented in a paper at Battelle's Fourth In Situ and On-Site Bioremediation Symposium in 1997.

Sponsored Recommendations

Get Utility Project Solutions

June 13, 2024
Lightweight, durable fiberglass conduit provides engineering benefits, performance and drives savings for successful utility project outcomes.

Meeting the Demands of Wastewater Treatment Plants

May 24, 2024
KAESER understands the important requirements wastewater treatment plant designers and operators consider when evaluating and selecting blowers and compressed air equipment. In...

Modernize OT Cybersecurity to Mitigate Risk

April 25, 2024
Rockwell Automation supports industry-leading Consumer Packaged Goods company, Church & Dwight, along their industrial cybersecurity journey.

2024 Manufacturing Trends Unpacking AI, Workforce, and Cybersecurity

April 25, 2024
The world of manufacturing is changing, and Generative AI is one of the many change agents. The 2024 State of Smart Manufacturing Report takes a deep dive into how Generative ...