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Pump
and Treat Works when Applied to the Proper Circumstances; and, when the
system is properly Designed, Constructed and Operated
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By
the earthDr!
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| Pump
and treat has been given a bad name by many professionals practicing subsurface
cleanups. Many of these people have made blanket statements that pump and
treat systems don't work because they have not met success in their cleanup
attempts. Failure has often resulted from design, construction, or operation
inadequacies. However, sometimes they were right, but only after the fact:
that pump and treat should never have been applied to their particular application. Re-directing clean ground water to flow to an affected receptor can often times be achieved. Using pump and treat to flush contaminants from dissolved product contaminated soils (solusols) is often doable, but flushing contaminants from separate phase contaminated soils (produsols) is not often practicable because of the large mass of contaminants retained in the soil pores and as films around soil particles. I have illustrated many situations of unsuccessful vapor remedies due to improper recovery system designs in trying to mitigate vapor problems resulting from seepage of dissolved product into structures. I have shown that it is often possible to induce clean ground water to flush contaminated ground water from beneath a home or other structure. My illustrations of situations where recovery wells have been improperly located are based upon witnessing the real world mislocation of recovery wells. Some subsurface remediation professionals don't even recognize that a plume can be split into two portions and, even if they do, they don't comprehend the utility of splitting a plume into two or more portions. And some of those that fuzzily understand the utility of splitting a plume, can't seem to properly locate the recovery well(s). Pump and treat is not the answer for all subsurface remedies, but it is probably under utilized much more than it is used in the wrong application. Hydraulically splitting a plume to induce clean ground water to flow beneath your home and thereby, flushing out contaminated ground water can be a quick fix, albeit only a Band-Aid. However, most times it can be part of the long-term remediation, but it can be done up front with minimal subsuface data collection and design. Often times splitting the plume is complemented by remediation of the source of the dissolved plume, namely the source-recharge area. Separate phase contaminated soil, produsols, should be remedied to cut off the contaminant mass loading to the dissolved plume. Hydraulic control to split the plume to induce clean ground water to flow beneath your home can most often be done even before much investigation of the upgradient source(s). Once the contaminant mass loading to the dissolved plume is remedied, the necessity of continuing to split the plume should soon be alleviated. The amount of time necessary to split the plume, beyond that point in time when the contaminant mass loading is remedied, is defined by the contaminant travel time, as a dissolved phase, from the source recharge area to the downgradient recovery well responsible for splitting the plume. |
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EMAIL:
earthDr@earthDRx.org |
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©
Copyright
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