Gas & Groundwater Samples

Gas Samples

DPP, a Perth based company uses direct push technology to offer a fast, efficient means of detecting and delineating contaminated areas. We use a PRT (Post Run Tubing) system to collect soil vapour samples from the desired sampling depth. This is achieved by inserting the PRT adaptor and tubing through the drill rods after they have been driven to depth to provide a vacuum-tight, continuous run of tubing from the sample to the surface. This prevents sample contamination from up-hole, and assures that the sample is taken from the desired depth at the bottom of the hole.  As the tubing can be replaced after each sample the risk of rod leakage or contamination from sample carryovers is eliminated.

PRT Advantages

  • Fast, accurate and cost-effective way to sample soil gas
  • Eliminates problems associated with rod leakage and sample carryover.
  • Utilizes simple design for ease of use and vacuum-tight probing.
  • Sampling train and all connections can be checked to verify leak-free status.
  • Requires no management of inner tubing during probing.

Groundwater Samples

Direct push technology facilitates the use of permanent implants with stainless steel or disposable PVC screens that can be inserted down the bore of a probe rod and anchored at depth for soil gas sampling or groundwater sampling. This involves significantly lower costs than installing monitoring wells.

These implants are not carried in the rod during probe-driving but inserted down the bore when the appropriate depth has been reached. Once slid down the bore the implant is rotated to attach it to the anchor point used during driving. As probe rods are removed from the hole, the implant and associated tubing remain anchored to the bottom.

Typically used during the site characterisation phase of a project these ‘point-in-time’ sampling tools are best suited to identifying plume boundaries, hot spots, preferred pathways, or other points of interest. Once this information is collected temporary or permanent monitoring wells can be optimally placed to provide project teams with the most useful data.

The screens allow flexible tubing, a mini-bailer or a small-diameter bladder pump to be inserted into the screen cavity. This allows direct sampling from anywhere within the saturated zone.

Screenpoint Advantages

DPP, a Perth based company, uses the Screenpoint 16 groundwater sampling tools developed by Geoprobe. These allow the collection of representative groundwater samples from a discrete interval using a bailer, bladder pump, or other device. They offer;

  • Fast, efficient and highly cost effective groundwater samples
  • High-integrity interface samples from discrete intervals
  • Samples both dissolved compounds and NAPLs
  • Built to withstand percussive probing and completely sealed during driving
  • Screen sheath forms mechanical annular seal above the screen while sampling
  • No contaminated waste generated during installation
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