A bench scale PVD remediation system experiment.
Prefabricated vertical drains (PVDs) have been used for decades for soil improvement. Recent research has shown that PVDs can also be used to remediate contaminated fine-grained soils. A research program was undertaken at The University of Texas at Austin to study the use of PVDs in soil flushing (pump and treat). This research program included both analytical and experimental studies. The focus of this paper is the experimental part of the research effort. The design and results of two experiments are presented. These results provided insight into the operation and design of PVD remediation systems and exposed areas that need additional research. The laboratory results support prior research that indicate that PVD remediation systems can be an effective means of remediating contaminated fine-grained soils. In addition, the importance of keeping the injection and extraction rates similar to minimize consolidation was highlighted. The measured heads did not indicate that a significant amount of drawdown occurred over the course of the experiment. More research needs to be done on maintaining a consistent extraction rate and additional post experiment concentration measurements would be required if determining the tracer mass balance is the focus of any future experiments.