Evaluate the physical, chemical, and biological characteristics of the well to identify where problems or challenges are developing.
By Michael Schnieders, PG, PH-GW
As we are firmly into the winter season, many wells are taken off-line or see their operating schedules significantly reduced. This is often the result of a change in needs reflecting a variety of reasons that impact all aspects of groundwater usage: agricultural, residential, industrial, and municipal.
The wise well owner takes this time to evaluate well operation and maintenance needs.
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Traditionally, preventive maintenance in well operations has been delegated to pump maintenance and the occasional video survey conducted when the pump is pulled. In addition, if some production loss has occurred, a limited cleaning effort may be administered during the repairs.
In many daily operated wells, production capacity is gradually lost over an extended period of time. If pump performance is the reason, maintenance is initiated. But often more subtle problems go unnoticed in an effort to get the well back into or keep in operation.
This often occurs until loss is substantial or the water quality begins to deteriorate. This gradual loss of capacity or efficiency is commonly the result of biofouling, mineral scale accumulation, and sediment infiltration of the well environment.
Research at Water Systems Engineering Inc., which is located in Ottawa Kansas, has shown the most significant fouling events can be controlled if addressed early on. The maintenance efforts required to act early are often far less invasive and less costly than attempting to tackle them after they’ve advanced.
Removing the Biofilm
Most of the mineralization taking place in the well is due to the attachment of mineral particles or crystals to the sticky polysaccharide polymers produced by the bacteria (biofilm).
Similarly, by removing the biofilm, sediments that migrate towards the well avoid entrainment and the resulting mechanical blockage. Therefore, most fouling can be controlled by the monitoring and subsequent early treatment of the bacterial populations in the well.
In lab studies at Water Systems Engineering, we monitored well systems and measured bacterial activity both by a population count and by the growth patterns exhibited on plate studies. The more aggressive and higher populations seen signaled an initiation of blockage of the well flow pathways. In the beginning, the blockage occurs in or on the zones of entrance for the water into the well. Gradually, if left undisturbed, the fouling spreads, impacting the filter pack as well as the aquifer formation surrounding the well.
Once the fouling mechanisms have become more advanced, major rehabilitation efforts are typically required to dissolve and remove the blockage from the well. If the blockage is merely disrupted, such as in purely mechanical treatment efforts, considerable debris can remain in the well environment to provide building blocks for easily resumed blockage.
Time to Access
Based on this, I encourage many well owners to use this time to assess their well’s condition. Evaluate the physical, chemical, and biological characteristics of the well to identify where problems or challenges are developing.
Initiating preventative maintenance efforts at the onset of fouling can aid in improving operation of the well, quality of the produced water, and extend the lifespan of the well, not to mention incurring a lower cost and allowing the well owner to set a schedule for treatment.
Michael Schnieders, PG, PH-GW, is a professional geologist currently serving as the principal hydrogeologist and president of Water Systems Engineering Inc. in Ottawa, Kansas. Schnieders’ primary work involves water resource investigation and management, specializing in the diagnosis and treatment of fouled well systems. Schnieders was the 2017 McEllhiney Distinguished Lecturer in Water Well Technology. He can be reached at firstname.lastname@example.org.