Design, manufacture and evaluation of a hydraulically installed, multi-sampling lysimeter. Final report

Abstract

There is a need for a quick, simple, reliable, and inexpensive on-site method for sampling soil pollutants before they reach the groundwater. Vadose zone monitoring is an important aspect of sound groundwater management. In the vadose zone, where water moves via percolation, this water medium possesses the ability to transfer hazardous wastes to the nation`s groundwater system. Obtaining samples of moisture and contaminants from the vadose zone is necessary if potential problems are to be identified before they reach the water table. Accurate determination of spatial distribution, movement, and concentrations of contaminants is essential to the selection of remediation technologies. There is a need for three-dimentional subsurface characterization technologies to identify the location of hazardous plumes and their migration. Current subsurface characterization methods for dispersed contaminants primarily involve a time consuming, expensive process for drilling wells and taking samples. With no major water flow in the vadose zone, conventional monitoring wells will not function as designed. The multi-sampling lysimeter can be readily linked with physical and chemical sensors for on-site screening. The hydraulically-installed suction lysimeter was capable of extracting soil pore liquid samples from unsaturated test soils without the need to predrill a well. Test results verified that the lysimeters installed with a hydraulic or mechanical ram were able to collect soil pore liquid samples in excess of the amount typically required for monitoring and analysis on a daily basis. Modifications to the prototype design eliminated moving parts and the need for inflatable packers. The elimination of the packer system and the use of porous nickel contributed to increased system ruggedness.