Millennium utilizes the Waterra Hydrolift above ground sampling pump. Each monitoring well is installed with its own dedicated High Density Polyethylene (HDPE) tubing. Attached at the end of the tubing is a foot valve made of the same material. The water is carried to the surface by agitating the tubing in irreversible lifts due to the ball check in the foot valve. The Hydrolift can generate up to 4 GPM using 1" or 5/8" tubing. This methodology utilizes dedicated materials which eliminates any possibility of cross contamination from well to well and increases productivity by eliminating decontamination procedures.
Millennium also offers low-flow purging and sampling with the YSI Bladder Pump. This is a down-hole technique. Low-flow well sampling consists of purging a well at a very low rate (0.1-0.5 L/min) to minimize drawdown and avoid disturbance within the well. The low-flow technique has several advantages including: reduced turbidity resulting in reduced variability in sampling results; reduced purge volume; reduced problems associated with excessive drawdown; and implementation of dedicated equipment reducing sampling costs and the potential for cross-contamination. While low-flow purging is known to reduce drawdown and turbidity, it also minimizes mixing and formation stress. Therefore, samples represent formation water and naturally mobile contaminants and not stagnant well water or mobilized contaminants.