How to Sample collapsed or obstructed wells
Use Waterra Pumps, Peristaltic Pumps or EcoBailers
How to sample collapsed or obstructed wells? Piezometers or wells that have lost their original diameter as a result of collapse or obstruction by other equipment can still be sampled. Waterra has three systems or devices that can be used to sample these types of wells or piezometers. The depth to water and the size of the remaining opening affect the choice of equipment and as always, a Waterra technician can help you select the best option from the list below.
How the Waterra Pump works
Option 1
Sampling collapsed or obstructed wells with a Waterra Pump
Openings as little as 0.5 in (1.25 cm) can be sampled using the Micro Flow System which has an outside diameter of 0.375 inches (10 mm). Because the Waterra Tubing is semi rigid, it can be pushed past obstructions. Of course, if the opening will accommodate a larger diameter system than the Micro Flow System then perhaps that should be used.
The Micro Flow System usually consists of: an SS-10 Foot valve, a length of Micro Flow Tubing and is usually pumped by hand.
- Thread the SS-10 Foot Valve securely into the Micro Flow Tubing
- Insert the tubing into the well valve first
- Work past the narrowing to the screened interval
- Begin pumping by hand by oscillating the tubing and foot valve assembly up and down in the monitoring well
- Sample when your pre-sampling protocol is complete
Waterra Words of Wisdom
The Waterra micro flow system is an exceeding inexpensive and effective way to sample collapsed or obstructed wells.
You May Need
Option 2
Sampling collapsed or obstructed wells with a Peristaltic Pump
- Open the pump head and insert a length of Waterra Peristaltic Tubing into the pump head
- Feed the Waterra sample tubing down the well past the obstruction to the desired depth
- Insert the appropriately sized sample tubing into the peristaltic tubing sufficiently so that is secure and won’t fall down the well
- Turn on the pump making sure that the rotation is pumping from the well
- Sample according to your protocol
Waterra Words of Wisdom
- Peristaltic pumps have a limited lift depending on your altitude; usually 24 feet (7.3 m) or so
- HDPE Waterra Tubing is stiffer than LDPE if you need to push past a narrowing to sample collapsed or obstructed wells.
Option 3
Sampling collapsed or obstructed wells with an EcoBailer
EcoBailers are available in 0.5 and 0.7 inch (12 and 18 mm) outside diameters and in PVC and polyethylene. These can be lowered down narrow or obstructed wells but the bailer can not be forced down. Narrow diameter EcoBailers are suitable for most contaminated environments. These disposable bailers are low cost and eliminate cross contamination. They are individually packaged; each with a bailer emptying spout.
- Attach a cord or rope to the top loop of the bailer
- Lower the bailer into the monitoring well by means of the cord or rope.
- Allow the bailer to sink to the screened portion of the well
- Pull the bailer up out of the well
- Remove the sample from the bailer with the use of a bottom emptying device or it can be poured from the top of the bailer by carefully tipping it
Waterra Words of Wisdom
- Bailers gravity drop and you can’t really push it down past the narrow section
- Bailers can potentially get stuck below the collapse or obstruction
- Bailer work can be labour intensive depending on what you are trying to accomplish
