Biomedical Engineering Reference
In-Depth Information
Geochemical
parameters
stable?
Low-flow purge
Well surging
Continue surging.
Geochemical
parameters
stable?
Re-connect flow-through
cell
Collect 1 L groundwater for laboratory filtration
OR
Filter 1 L groundwater using Sterivex™ filters
Ship samples overnight
at 4°C
Field documentation
Figure 6.4. Flowchart of groundwater sampling for MBT analysis.
1. Connect a flow-through cell and hand held multiparameter instrument to a low-flow
pump (e.g., peristaltic pump) and begin purging. Record the start time and field
measurements for pH, oxidation-reduction potential (ORP), specific conductance,
temperature, dissolved oxygen and turbidity.
2. Disconnect the flow-through cell after parameter stabilization. Collect samples as
appropriate for VOC, natural attenuation or other project-required parameters. Con-
tinue to purge the well after collection of samples for chemical/geochemical analyses is
complete. At this time, samples for MBT analysis can be collected. However, based on
site-specific planning documents and knowledge of historical turbidity levels, well
surging may or may not be appropriate prior to MBT sample collection. If surging is
appropriate, proceed to step 3. If surging is not needed, proceed to step 5 (a) or (b).
3. Lower a disposable polyethylene bailer into the well to the midpoint of the screen and
move the bailer up and down within the water column to surge the well. It is important
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