Preventative Well Maintenance

A proactive approach.

By Edd Schofield

Whenever you look at treating a well, you need to address the age of the well and its physical condition. Additionally, you need to know what other mechanical or chemical treatments the structure has already been subjected to historically.

I always ask, “Can the patient survive the surgery?” Or to be more exact for us, “Can the well survive the proposed treatment?”

Then we tackle the water and its chemical and microbiological makeup as an equal part of the well rehabilitation being considered.

Clean from Top to Bottom

I always recommend that a well be mechanically cleaned top to bottom as a starting point and then fully flushed. This step targets buildup in the well, the easier stuff that will consume treatment chemicals. The evacuation also prevents the loosened material from being driven deeper into the filter pack when we initiate jetting or swabbing.

Many believe that once they’ve thoroughly cleaned a well system, it’s good for many years without a second thought. The real answer? . . . Maybe.

You need to remember that the minute you turn the pump on, you’re resetting the clock. Once it’s back online, most of the issues you addressed have not completely gone away. Most of the same influences and conditions that caused the plugging in the first place are also now reset.

So, what can we do? The answer is to be more proactive. We can take a preventive maintenance approach.

I always recommend that a well be mechanically cleaned top to bottom as a starting point and then fully flushed.

Pickling the Well

As far as preventive maintenance procedures are concerned, there are all sorts of practices that can be prescribed. Again, it is going to be a reflection of the well’s history, construction, use, and fouling tendencies.

One of the easiest and surest methods of keeping a well healthy is to never shut it off. The idea that no good can come from idle teenagers is true for idle wells.

If a well is required to operate seasonally with extended time offline, then pickling the well might offer some success. The practice is one where you utilize different chemical treatments based on the fouling history.

If mineral scale is common, the introduction of a light dose of acid and a biodispersant is good. If the problem is typically biological related, a light dose of chlorine or a chlorine compound might be useful.

The system is plumbed such that the solution is allowed to circulate from top to bottom for some 12 hours before pumping the treatment solution to waste. Such a proactive treatment can be a best practice before turning the well off for the season.

In addition to tracking the well’s efficiency, monitoring the water chemistry or microbiology can be helpful in guiding maintenance choices. Oftentimes, once a well has been fully evaluated, monitoring can be reduced to a few simple parameters that reflect the fouling tendency of the well. For example, tracking total iron and iron bacteria are useful parameters for alluvial wells that suffer from iron-related fouling.

Some of the tests can even be run by the owner or contractor. Monitoring biological conditions can be achieved through the use of simple BART tests. A BART test [Biological Activity Reaction Test] offers a predictable indicator in a test tube, telling you that trouble may again be just around the corner.

BART test kits are affordable desktop indicators of the presence and populace of numerous iron-related, slime-forming, or sulfate-reducing bacteria. These tests can give anyone a peak into the biofouling potential. Specifically, these tests are most useful when you’ve got prior experience with biofouling in a well.

Whether you run the tests yourself or employ a lab, the information is quite valuable for guiding maintenance activities. Think of it like getting your blood work done as part of an annual physical. Once the lab work indicates an issue, you can be proactive in addressing the problem before it becomes threatening to the well.

Anticipate and Address

The key here is to be diligent, once you’ve identified a persistent problem with any well. Anticipate and address the issues before they require another major well rehabilitation effort. Be proactive and take the time and use the available resources to predict the next event of an impaired well before it becomes a real operational problem.

Numerous articles have been published in Water Well Journal that address many of the maintenance procedures that we can employ today. There are also two good books on a proactive approach to
well rehabilitation: The Operational Stage of the Well by Thomas M. Hanna, Michael J. Schnieders, and John H. Schnieders and Chemical Cleaning, Disinfection and Decontamination of Water Wells by John H. Schnieders.

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At the end of the day, operators and contractors who believe they need to rehabilitate a well first and foremost need to know what’s the root cause of the well’s problems. These questions and their answers need to be clearly defined, typically with video logs or lab work, before initiating any kind of mechanical or chemical cleaning of any well structure.

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Edd Schofield is the technical sales manager–chemicals for Johnson Screens and has been with the company since 1988. He served as the Groundwater Foundation’s McEllhiney Distinguished Lecturer in Water Well Technology in 2007. He can be reached at edd.schofield@johnsonscreens.com.