Low Flow Groundwater Sampling and Purging
Low flow purging and sampling methods require pumping rates to be maintained at 0.5 litres per minute or less. These methods rely on stability monitoring
of chemical parameters using flow cells to determine the end point of purging prior to sampling. This methodology has been developed primarily to optimise sampling conditions for VOC's.Other key criteria for using low flow methods:
There should be no prior distubance of the water column 
before pumping (i.e. dedicated pumping systems are preferred) Must maintain minimal drawdown of the water column (to minimise pressure changes) Good for:
Sampling from short screened monitoring wells VOC sampling Reducing the volume of purge water for disposal. Issues:
Use in long screened boreholes (>6m) is questionable Time intensive Specialist technical knowledge in designing sampling protocols is advisable Suitable equipment from Waterra: Peristaltic pumps, Submersible pumps with low flow controller, Bladder pumps, Water quality equipment with flow-through cells.
See Also:
Groundwater Sampling Methods
Fixed Volume Groundwater Purge and Sampling
Zero Purge/Passive Groundwater Sampling
Research and Development in Groundwater Sampling Methods
Borehole Purge Volumes
Waterra Tubing Diameters and Volumes