How & why to clean a well using glycolic acid (hydroxyacetic acid) .

This article series explains how to clean, restore, disinfect, or shock a well, when, why, and exactly how to do

Page top sketch illustrating both deep and shallow water well construction and depths is provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ].

Well Cleaning & Restoration: Glycolic Acid Treatment

Procedures for "Shocking a Well" with glycolic acid to clean mincerals, biofilms, scale: improve well performance

Well water delivery may decline over time for a variety of reasons including deposits of biofilms, mineral scale, and iron-bacteria.

Use of glycolic acid as a well cleaner, followed by well disinfection using a standard well shocking techinique given at the end of this page, are widely-accepted and approved procedures for cleaning these particular deposits from water wells.

Glycolic Acid is used extensively to rehabilitate the flow efficiency of water wells. Glycolic Acid accomplishes this by removing hard water scale (calcium, magnesium, manganese salts), various iron deposits and polysaccharide deposits.  - DuPont cited below.

[Click to enlarge any image]

Glycolic Acid Cleaning & Restoration Well "Pre-Treatment"

The following is excepted from well cleaning adived from DuPont, cited in detail below.

Determine the current well flow in comparison with historical flows. Flow will deteriorate with time as formation damage occurs.

This will help set a goal flow for the well cleaning. When iron metabolizing bacteria are present, the well is treated with chlorine bleach to loosen the bioslime organic deposits.

Scale is loosened by applying high frequency shock via detonating blasting caps in the well bore.

Purge the well. Large amounts of rock and gravel can indicate serious problems with the screen and gravel pack.

These should be corrected before proceeding. Determine the pH of the well water. 

Glycolic Acid Application Procedure for Wells

The recommended procedure for the use of DuPont™ Glycolic Acid 70% Solution for the treatment of water wells can be summarized as follows:

1. Amount of Glycolic Acid

Add 70% Glycolic Acid at a rate of 1/2 gallon per cubic foot standing in the well bore.

This provides approximately a 5% concentration of acid in water. Refer to Table 1 to calculate total acid requirement for wells 2 inches to 30 inches bore diameter. The Glycolic Acid can also be pre-mixed with water in a preparation tank. 

Example: for a well bore or well casing that is 6-inches in diameter you would add 0.090 gallons of 70% Glycolic Acid per foot of water (static head) in the well to get a 5% (wt) solution.

See

WELL DYNAMIC HEAD & STATIC HEAD DEFINITION - table of well water volumes - to find the static head of your well.

Watch out: do not add chemical treatments to a water well based simply on "well depth" - as that is almost always a different (larger) figure than the actual amount of water in the well - its static head - when the well is at rest.

The DuPont instructions PDF given below on this page include a table of glycolic acid amounts for wells of other diameters.

2. Cleaning Procedure

After adding the acid, surging the well should be considered to facilitate mixing and to achieve penetration into the well formation. By starting and stopping the pump, surge the column of water to the top of the well every 3 to 4 hours or more often to help dislodge scale.

An alternative is to surge the well by dropping and retrieving a large plug into the well bore. Allowing the acid to remain in the well for at least 24 hours or more is recommended.

3. Removal of Cleaning Solution

Pump the water to a location (ground or biological treatment facility) in conformance with local environmental regulations. To facilitate suspension of solid matter, the following procedure might be used:

a) Purge slowly at first and then at about 25% of full flow.

b) At 15 to 30 minute intervals, stop the pump long enough to allow the well to drop to its static level.

4. Before Use of Well Water

Continue pumping until the pH of water is within 0.5 pH units of the original value before treatment.

This affords a concentration of approximately 25 ppm or less. This could occur in 1 to 3 hours after starting the flushing operation.

Table 2 [in the DuPont PDF below] shows the relationship of free Glycolic Acid concentration and pH. 

5. Repeat the above steps as necessary to achieve the optimum rate of flow.

Note: The ideal pH for cleaning is about 1.0. Periodically check the pH of the well bore contents.

Consider adding more Glycolic Acid if the pH rises above 3.

As an alternative, consider repeating Steps 1–4. 

- Dupont 2020 cited in detail below

6. Post Treatment - disinfect the well

The well is treated with hypochlorite bleach to eliminate any bacteria that might have been returned to the well.

This helps to reduce the future build up of iron scale resulting from iron metabolizing bacteria (gallionella ferruginea). 

See those details

at WELL CHLORINATION & DISINFECTION

Glycolic Acid Well Treatment Procedure Example

The following is only an excerpt intended to give a general understanding of how scale or biofilm or iron might be removed from a drinking water well, excerpted from Blue Earth Products well cleaning procedures and other sources cited below.

Watch out: before undertaking any well flow restoration or well cleaning project be sure that you've obtained an accurate diagnosis of the condition of the well and the cause of trouble.

Watch out: be sure to follow well treatment manufacturer's instructions for the safe and effective use of any well treatment chemical or method.

Excerpts:

Wells often loose capacity because of biological and mineral buildup. Biofilms often exacerbate the problem by contributing directly to mineral buildup as a biproduct of their life cycle. Clearitas efficiently breaks up these biofilm formations improving fluid flow in the well formation.

Primary Biofilm Removal Treatment After purging from the well the remnants of the above treatments, treat the well with a solution containing Clearitas 101 at 20,000 mg/L, Glycolic Acid at 750 mg/L and chlorine at 500 mg/L as follows:

For each 100 gal of bore hole volume, premix 275 gal of chemical solution (water plus 5 gal of Cleartias 101, 1.1 gal of 12.5% bleach, and 0.25 gal of 70% Glycolic Acid).

care to add the Glycolic Acid last to avoid the evolution of chlorine gas. Be certain to provide adequate ventilation.

The final solution should have a pH of around 5.0. Using a clean IBC tote is an ideal mixing container. Introduce premixed treatment into well from the top to displace borehole fluid and nearby aquifer water.

Water used for this treatment should be from the well prior to pulling the well pump. After placement of chemical, run a surge block repeatedly through the screened area to agitate and loosen biofilm (2 hours assumed). Let well sit for 24 hours.

After 24 hours, mix the well with a surge block for 30 minutes.

If pH is < 4.0 and chlorine concentration is greater than 100 mg/L, let well sit for another 24 hours.

If pH is > 4.0 or chlorine is less than 100 mg/L, supplement chemicals to original levels by adding from the surface, mix with the surge block. Let well sit for and additional 24 hours.

After 48 hours of total contact, mix the well with a surge block for 30 minutes .

If the pH is < 4.0 and chlorine is greater than 100 mg/L, let well sit for another 24 hours.

If pH is > 4.0 or chlorine is less than 100 mg/L, supplement chemicals to original levels by adding from the surface.

Let well sit for and additional 24 hours.

After 72 hours, purge chemicals out of well and neutralize as necessary.

Purge well for 24 hours. During purging, recycle 2 to 5 gpm of flow back into the well to purge chemical from the stagnant area above the pump. - Blue Earth Products (2022) cited in detail below.

 

Well Cleaning & Restoration by Glycolic Acid Research & Resources

• ADOE, Water Well Management Level 2 Training Module. Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada, Alberta Environment, Alberta Water Well Drilling Association and Alberta Agriculture, Food and Rural Development
• ADOE, Water Wells that last for Generations. Alberta Agriculture, Food and Rural Development; Alberta Environment; Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada
• Australian Drilling Industry Training Committee Limited (ADITC). Drilling. The Manual of Methods, Applications, and Management. J.S. McMillan Printing Group, Australia. 2002.
• AWDA, Water Well Management Level 2 Training Module. Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada, Alberta Environment, Alberta Water Well Drilling Association and Alberta Agriculture, Food and Rural Development
• Blue Earth Products WELL CLEANING GUIDELINES [PDF] instructions for the planning and implementation of well chemical cleanings,
  
  Blue Earth Products, 5055 West Patrick Lane, Suite 101 Las Vegas, NV 89118 USA, Tel: 1.800.259.4456 P: 702.851.4760 Web: https://blueearthproducts.com/ Email: kjuillet@blueearthproducts.com - retrieved 2022/11/19, original source: https://blueearthproducts.com/wp-content/uploads/Well-Cleaning-Guidelines-v0.pdf
  
  Excerpts:
  
  Wells often loose capacity because of biological and mineral buildup. Biofilms often exacerbate the problem by contributing directly to mineral buildup as a biproduct of their life cycle. Clearitas efficiently breaks up these biofilm formations improving fluid flow in the well formation.
  
  Primary Biofilm Removal Treatment After purging from the well the remnants of the above treatments, treat the well with a solution containing Clearitas 101 at 20,000 mg/L, Glycolic Acid at 750 mg/L and chlorine at 500 mg/L as follows:
  
  For each 100 gal of bore hole volume, premix 275 gal of chemical solution (water plus 5 gal of Cleartias 101, 1.1 gal of 12.5% bleach, and 0.25 gal of 70% Glycolic Acid).
  
  care to add the Glycolic Acid last to avoid the evolution of chlorine gas. Be certain to provide adequate ventilation. The final solution should have a pH of around 5.0. Using a clean IBC tote is an ideal mixing container. Introduce premixed treatment into well from the top to displace borehole fluid and nearby aquifer water.
  
  Water used for this treatment should be from the well prior to pulling the well pump. After placement of chemical, run a surge block repeatedly through the screened area to agitate and loosen biofilm (2 hours assumed). Let well sit for 24 hours.
  
  After 24 hours, mix the well with a surge block for 30 minutes. If pH is < 4.0 and chlorine concentration is greater than 100 mg/L, let well sit for another 24 hours. If pH is > 4.0 or chlorine is less than 100 mg/L, supplement chemicals to original levels by adding from the surface, mix with the surge block. Let well sit for and additional 24 hours.
  
  After 48 hours of total contact, mix the well with a surge block for 30 minutes . If the pH is < 4.0 and chlorine is greater than 100 mg/L, let well sit for another 24 hours. If pH is > 4.0 or chlorine is less than 100 mg/L, supplement chemicals to original levels by adding from the surface. Let well sit for and additional 24 hours.
  
  After 72 hours, purge chemicals out of well and neutralize as necessary. Purge well for 24 hours. During purging, recycle 2 to 5 gpm of flow back into the well to purge chemical from the stagnant area above the pump.
• Chempoint GLYCOLIC ACID for WATER WELL STIMULATION [PDF] Chempoint, Univar Solutions, 411 108th Ave NE, Suite 1050 Bellevue, WA 98004 USA, Tel: 425.906.6211 Web: https://www.chempoint.com/contact-us - retrieved 2022/11/19, original source: https://www.chempoint.com/insights/chemours-glycolic-acid-for-water-well-stimulation
  
  Offices also in Netherlands and Mexico.
• Chemours GLYCOLIC ACID WTER TREATMENT & WATER WELL STIMULATION [PDF] The Chemours Company 1007 Market Street P.O. Box 2047 Wilmington, Delaware 19899 US .
  
  Canada: The Chemours Canada Company 151 Bloor Street West - 12th Floor Toronto, ON M5S 1S4 Canada
  
  Offices also in Brazil, Genea, Korrea, Mexico, Shanghai, Singapore
  
  - retrieved 2022/11/19, original source: https://www.chemours.com/en/-/media/files/glycolic-acid/glycolic-acid-treatment-water-well.pdf?rev=cf3d070023444f53a7f210604ebf7579
  
  Excerpt:
  Glycolic Acid is used extensively to rehabilitate the flow efficiency of water wells. Glycolic Acid accomplishes this by removing hard water scale (calcium, magnesium, manganese salts), various iron deposits and polysaccharide deposits.
• Clu-In A REVIEW OF BIOFOULING CONTROLS FOR ENHANCED IN SITU BIOREMEDIATION OF GROUNDWATER [PDF] (2005) - retrieved 2022/11/19, original source: https://clu-in.org/download/contaminantfocus/dnapl/treatment_technologies/er-0429-whtpaper.pdf
  
  Excerpts Enhanced in situ bioremediation (EISB) is increasingly being used for the remediation of chlorinated solvents and recalcitrant chemicals (e.g., perchlorate, nitrate, hexahydro-1,3,5- trinitro-1,3,5-triazine [RDX]) in groundwater, both for plume containment and source area treatment.
  
  Biofouling occurs when bacteria attach, grow and block the well screen, filter pack, or formation surrounding a nutrient delivery well, thereby limiting or preventing the proper function of the well.
  
  The bacteria may originate in the aquifer itself or may be introduced during well installation, amendment addition, or groundwater recirculation (Cullimore, 1999). Most groundwater environments contain an active and diverse microbial population, but growth is limited in the absence of high concentrations of nutrients (Fry et al, 1997).
  
  Bacterial growth within delivery wells is generally accelerated by adding the provided nutrients to promote the desired EISB reactions.
• Cullimore, R. Microbiology of Well Biofouling, Lewis Publishers, CRC Press, Boca Raton, Florida. 1999.
• DuPont™ GLYCOLIC ACID [PDF] Web: www.glycolicacid.dupont.com - retrieved 2022/11/19, original source: https://chemical-centre.com/f/glycolicacidbrochure-extended.pdf
  Customer Service: 888-243-4608, North America
  Customer Service International: 01-302-892-7536
  
  Excerpts: Glycolic Acid (hydroxyacetic acid) is the first member of the series of alpha-hydroxy carboxylic acids, which means it is one of the smallest organic molecules with both acid and alcohol functionality. Although Glycolic Acid occurs naturally as a trace component in sugarcane, beets, grapes and fruits, DuPont synthesizes the product through a sustainable manufacturing process in Belle, West Virginia.
  
  The efficiency of industrial and potable water wells decreases with time. This can be the result of:
  
  • Gradual damage to the water producing formation. • Mechanical deterioration to the down-hole well screen/ gravel pack filter system.
  
  • Accumulation of deposits on the screen and gravel pack filter system.
  
  • Iron bacteria.
  
  The deposits result from hard water scale (calcium, magnesium and iron salts) accumulation or deposits of iron oxide and bioslime.
  
  The deposits can also result from build up of clay. It should be noted that reduced water production can result from many factors in addition to scale build up.
  
  Each water well should be viewed as a distinct case. The specific cause for the reduced production should be defined by water analysis, underground surveys, well history, etc.
  
  The typical useful life of a well is 35 years. Only after reviewing this information can the appropriate remedial action be selected. Consultation with a professional water well rehabilitation company is recommended.
• Fry, N.K., J.K. Fredrickson, S. Fishbain, M. Wagner, and D.A. Stahl. Population structure of microbial communities associated with two deep, anaerobic, alkaline aquifers. Applied and Environmental Microbiology. 63(4): 1498-1504. 1997.
• Mansuy, N. Water Well Rehabilitation, A Practical Guide to Understanding Well Problems and Solutions, CRC Press Lewis Publishers, Boca Raton, FL. 1999.
• NLM, GLYCOLIC ACID PROPERTIES, TOXICITY, COMPOUND SUMMARY [PDF] National Institute of Health (US), National Library of Medicine, - retrieved 2022/11/19, original source: https://pubchem.ncbi.nlm.nih.gov/compound/Glycolic-acid
  
  Includes discussion of toxicity of glycolic acid.
• Smith, Stuart A., CGWP, RECENT INNOVATIONS in WELL REHABILITATION [PDF] Ground Water Science, 295 S. Lawn Ave. Bluffton, OH 45817 USA, Tel: 1-419-358-0528 Author's Tel: 1-330-787-0496 - retrieved 2022/11/19, original source: https://groundwaterscience.com/resources/tech-article-library/94-recent-innovations-in-well-rehabilitation.html
  
  Covered in this article: [some paraphrasing by InspectApedia.com editors]
  
  Chemical improvements - Brominated compounds, Chlorine, Hydrogen peroxide, Organic acids, Blends, P-containing acids, Polymers, heat
  Blended Methods treatments
  Fluid percussion, ultra-high pressure water-jetting
  CO2 Injections
  Suction flow control
  Improvements in materials, comtrollers, monitoring of equipment operation & well ewater levels.
  ...
  Organic acids: Contractors who perform well maintenance (as well as this author) are abandoning the use of chlorine compounds in favor of certain organic acids for use in both well cleaning and preventive maintenance treatments.
  
  You will never sterilize the aquifer and well system, and we are finding that the biofouling bacteria become accustomed to the chlorine and actually make more oxidized iron and organic byproducts.
  
  No total bacterial kill is achieved with chlorine. The clogging zone also simply reestablishes itself further out in the formation, beyond the reach of the treatment process.
  
  In addition, frequent use results in the formation of chlorinated (also brominated) organic compounds (those famous disinfection byproducts DBPs).
  
  ... Blended and "extreme" chemical method treatments
  Force treatments - Gas Impulse Percussion (in its various forms)
  CO2 treatment (Aqua-Freed and Aqua-Gard), chemical reformulations and other derivative concepts
  Suction flow control (and other well gizmos and gadgets)
• SSWM, WELL REHABILITATION [PDF] SSWM, Sustainable Sanitation & Water Management seecon Müligass 7 6130 Willisau Switzerland Tel: +41(0)61 261 40 04 - Web: https://sswm.info/ - retrieved 2022/11/19 original source: sswm.info/sites/default/files/reference_attachments/ISWD%204000%20Well%20Rehabilitation.pdf
  
  This copy is from International School of Well Drilling, 5039 Creekview Lane, Lakeland, FL 33811 USA, Tel: 863 648 1565 Email: director@welldrillingschool.com Website: welldrillingschool.com retrieved 2018/06/12, original source: welldrillingschool.com/courses/pdf/WellRehabilitation2.pdf
  
  Article Excerpts:
  Well Rehabilitation is defined as restoring a well to its most efficient condition by various treatments or reconstruction methods (Groundwater and Wells). This continuing education unit discusses the causes of deteriorating well performance and methods, both traditional and of more recent introduction, of addressing this area.
  
  There are numerous causes of poor and deteriorating well performance. Causes may include inherent characteristics of the aquifer which supplies water to the well, the well design, its construction, water quality and other environmental factors, and even the operation of the well.
  ...
  Well rehabilitation is the step taken when a well has deteriorated beyond the point when maintenance programs will resolve the decrease in yield or when sand pumping reaches unacceptable levels.
  
  When well rehabilitation cannot restore the water quality and water quantity to acceptable levels the final step has been reached, well abandonment and new well construction.
  
  Obviously the final step is the most costly. No unit of study on well rehabilitation can fail to mention well maintenance.
  
  Rules of thumb in the industry show that preventive maintenance costs are 10-20% of the costs of hiring a well rehabilitation specialist; and that formal well rehabilitation costs will be 10-20% of the costs of new well construction. It goes without saying therefore, that time and attention paid to ongoing well maintenance is a sound investment and always the wisest course of action.

 

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-11-19 by InspectApedia (Editor) (mod) - white deposits - fibrous debris coming out of well following well shock with glycolic acid - Texas

@M. Fields,

Well now that we know you were trying to rehab a well to improve its flow, rather than just dis-infect the well, that glycolic acid treatment explains everything.

Using glycolic acid is described by various sources (added to the article above) including the Chemours Co. :

Glycolic Acid is used extensively to rehabilitate the flow efficiency of water wells.

Glycolic Acid accomplishes this by removing hard water scale (calcium, magnesium, manganese salts), various iron deposits and polysaccharide deposits.

So it would be no surprise that in a mineral-heavy well, the glycolic acid treatment you used would produce a LOT of foamed-up loosened mineral crud, probably principally calcium Ca and Magnesium Mg and sometimes this treatment also removes iron in its various forms as well.

Thanks for that added info.

See our conversation and details now at

WELL CLEANING BY GLYCOLIC ACID

https://inspectapedia.com/water/Well-Cleaning-Glycolic-Acid.php

On 2022-11-19 by M. .Fields (mod) - Texas well flow restoration with glycolic acid

2 days ago [M. Fields]

@InspectApedia (Editor), lol that is a bucket. This is just a photo showing the material that has been expressed from the well. This is after a glycolic acid shock.

This was the last step before digging a new well due to very little water production. The piping and pump and fittings have all been replaced. I apologize this is not a chlorine shock. I just read that in your response. This is a Mid Texas well.

Well was tested and the only not mineral contaminant was Iron Bacteria. The only thing I can gather is that there was a Bacteria Bloom hanging out and the acid dislodged and killed it. Im just worried if that is not it then what could it be.

As far as the shocking it seems to have done the job it was prescribed to do and is now producing water at a much higher rate.

However I still have the fuzzy white string like material coming out. My instructions state that I am suppose to Chlorine shock the well next.

- re-posted here by Mod from website home page https://inspectapedia.com/

On 2022-11-16 by InspectApedia (Editor) (mod)

@M. Fields,

Wow I'm stumped. I suspect it's a product of reaction between what you dumped into your well and the well water or a contaminant in the water or piping system, or a detergent.

What did you put into your well?

How much did you put in?

It does not sound as if you followed proper procedure.

Please see WELL CHLORINATION & DISINFECTION inspectapedia.com/water/Well_Chlorination_Shocking_Procedure.php

Well Chlorination Procedure - When and how to shock a drinking water well

and let's follow-up

We'll want to know

- the country and city of location

- well diameter, depth, piping materials

- well construction - what your photo shows looks a lot like a plastic bucket with a wire handle - not a proper well casing and cover, and some plastic piping with one valve open and one shut.

- water chemistry: was your well tested? for what contaminants?

On 2022-11-16 by M. Fields: what is this white deposit coming out of my well?

Re-posting from website home page:

M. Fields · 3 hours ago

I typed this before but not sure it made it. I recently shocked my well and every 6-8 hours surged the pump for a few minutes. on Day 2 I ran the pump until I could smell it and to my surprise a white fuzzy material came out with it.

not a little but a LOT.

after some time it began to look as though I took a can of spray foam and sprayed it everywhere.

Now 5 days in the mass of it has been spewed out but I still have some white fuzzy material coming out. It now looks almost like wet toilet paper. (although it is not)

Can you tell me what this may be?

[Photo at the top of this discussion]

...

Continue reading at WELL CHLORINATION & DISINFECTION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• WELL DYNAMIC HEAD & STATIC HEAD DEFINITION - table of well water volumes
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• WELL WATER CONTAMINATION: CAUSES, CURES - home

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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