WorldWide Drilling Resource

22 MAY 2019 WorldWide Drilling Resource ® Environmental Monitoring by Thomas Kwader, Ph.D., P.G. Removing Sediment from Well Water Have you gotten calls about well water that occasionally has a small amount of sand, silt, or sedi- ment? If the problem is getting worse over time, the well (or tank) may be filling up with sediment due to the pump pulling water from the well or tank every time the pump cycles on. If you are able to measure the current depth of the well, compare that depth to the original drilled depth, and the well has become “shallower” over time, the well may no longer be fully developed and additional development or rehabilitation may be required. This development would normally be performed by a licensed water well contractor. In some states, a permit may also be required - check with the local permitting authority. To remove those sediments, the well must be redeveloped using a large pump, bailer, and/or surge block. A compressed airline (½- to ¾-inch) should be lowered to the bottom of the well and pulses of high pressure be released down the pipe in two- to five-minute intervals to “blow” the water and sediment from the bottom of the well. During the process, watch to see if the well is gradually increasing in depth and the water is beginning to become clearer and void of sediment. I recommend catching the water expelled in a clear glass or clean white bucket. Continue the procedure until the depth becomes stable and the water clarity remains clear. If the expelled water does not become clear, there may be a hole in the casing or screen. It could be that a clay layer exists near the screen, or producing section of the well. Lowering the pumping rate or installing a filter may also be an option. It may also be helpful to overpump the well occasionally (run the pump wide open and discharge near the wellhead to lower the pipe friction and increase the pumping velocity in the well) to clear the well. Another possible solution is to install a large pressure tank near the well to allow the sediment to settle in the bottom of the tank which will require periodic draining and cleaning to remove the accumulating sediment. Tom Tom Kwader may be contacted via e-mail to michele@worldwidedrillingresource.com ENV