Limitations of Pumpand Treat Technologies

Pump-and-treat is the most commonly used technology for groundwater remediation and plume containment. However, recently pump-and-treat technology has been subject to increasing scrutiny and controversy. One significant problem with the technology is its inability to achieve cleanup goals within reasonable time frames (Galya 1994). At many sites where this technology is used, contaminant removal rates follow a relatively consistent pattern. After a period of initially steady reductions,

Concentration

What is Clean

Time

FIG. 9.17.18 Assumptotic behavior of pump-and-treat cleanup technologies. (Reprinted from K.E. Nyer, 1992, Groundwater treatment technology, 2d ed., New York: Van Nostrand Reinhold.)

groundwater contaminant concentrations tend to level off and remain fairly constant, with random fluctuations around an assumptotic limit (Tucker et al. 1989) as shown in Figure 9.17.18. The assumptotic concentration level may be higher than the specified cleanup target, and achieving cleanup goals within reasonable time frames may not be possible.

Therefore, pump-and-treat technology is not an effective approach by itself for the ultimate remediation of aquifers to health-based cleanup concentrations.

—Ahmed Hamidi

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