National Ground Water Association

(LAS VEGAS, NV — December 4, 2012) Proactively cleaning water wells mostly on an annual basis is an effective strategy for maintaining good water quality, efficient well operation, and lower operating costs, said a well rehabilitation expert at the National Ground Water Association’s 2012 Expo and Annual Meeting.

Neil Mansuy of Subsurface Technologies Inc. said he has had a paradigm shift over the years in how to approach well rehabilitation to combat well clogging and associated issues.

“I’ve spent a lot of years of my career trying to hunt down and kill bacteria,” said Mansuy, explaining that he’s come to realize that it’s never going to be possible to sterilize aquifers and wells.

“Even a properly constructed well doesn’t always prevent the presence of bacteria” because bacteria is naturally occurring and therefore pervasive in the environment.

Instead, Mansuy said he now puts emphasis on regular cleaning to minimize the environment in well systems for bacterial growth that can lead to a build-up of hard-to-remove deposition of minerals and scale on well casings, well screens, and other well components.

Common problems that result from not regularly cleaning wells include:

• Clogging of well screens, which results in lower production
• Loss of efficiency, which results in more expensive water due to higher operating costs
• Deterioration of water quality
• Unsafe bacterial results.

Mansuy said it’s important to remove slimes or biofilms created from bacteria interacting with minerals in the water. He said these are best removed in the earlier stages because they are soft and more easily removed. Left unattended they can harden and clog openings in well screens or build up on well casings — creating an anaerobic zone underneath the buildup that can cause pitting of the well casing.

“What happens when we wait too long? We’re not properly managing assets,” said Mansuy. In other words, deferring well cleaning ends up being more expensive than regular maintenance because the loss of efficiency drives up operating costs.

Mansuy also said that measuring specific capacity is not a good indicator of well plugging because water production from some zones in the well may increase for a time as a result of less production in other zones due to plugging.

When it comes to well cleaning, Mansuy advocated multiple steps including:

• Pretreatment, which may include wire brushing, the use of chemicals, or the introduction of some form of energy to loosen buildup
• Combinations of treatments to more thoroughly clean the well
• Development or redevelopment of the well — usually by swabbing and pumping the well at the same time — to remove from the well system all the debris or biofilm-related materials loosened by the various treatments.

Mansuy noted that effective treatments should penetrate several feet into the formation surrounding the well to fully address clogging issues and prevent premature reclogging of the well.

The 2012 NGWA Groundwater Expo and Annual Meeting exhibit floor opens Wednesday and will also be open Thursday. Educational offerings will also continue both days with the event concluding on Friday.

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NGWA, a nonprofit organization composed of U.S. and international groundwater professionals — contractors, equipment manufacturers, suppliers, scientists, and engineers — is dedicated to advancing groundwater knowledge. NGWA’s vision is to be the leading groundwater association that advocates the responsible development, management, and use of water.

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