A.W. Research Laboratories, Inc.

My Water Smells

Iron Bacteria in Well Water

Does this describe your water......red stains in the sinks?....swampy, oily, or other unpleasant tastes or smells?...red, slimy growths in the toilet tank? If so, your well or water system may have iron bacteria. Iron bacteria are small living organisms which naturally occur in soil, shallow groundwater and surface waters. These nuisance bacteria combine iron (or manganese) and oxygen to form deposits of "rust" bacterial cells, and a slimy material that sticks the bacteria to well pipes, pumps and plumbing fixtures. The bacteria are not known to cause disease, but can cause undesirable stains, tastes and odors; affect the amount of water the well will produce; and created conditions where other undesirable organisms may grow.

Detecting Iron Bacteria

Clues which indicate that iron bacteria may be present in well water are:

Tastes and Odors

Iron bacteria often produce unpleasant tastes and odors commonly reported as: "swampy," "oily or petroleum," "cucumber," "sewage," "rotten vegetation," or "musty." The taste or odor may be more noticeable after the water has not been used for some time. Iron bacteria do not produce hydrogen sulfide, the "rotten egg" smell, but do create an environment where sulfur bacteria can grow and produce hydrogen sulfide.

Color

Iron bacteria will usually cause yellow, orange, red, or brown stains and colored water. It is also sometimes possible to see a rainbow colored, oil-like sheen on the water.

Red Slimy Deposits

Iron bacteria produce a slick slime which is typically rusty in color, but may be yellow, brown, or grey. A "feathery," or filamentous growth may also be seen, particularly in standing water such as a toilet tank.

Prevention of Iron Bacteria

Iron bacteria are present in most soils in Minnesota. Iron bacteria can be introduced into a well or water system during drilling, repair, or service. Elimination of iron bacteria once a well is heavily infested can be extremely difficult. Normal treatment techniques may be only partly effective.

Good housekeeping practices can prevent iron bacteria from entering a well:

· Water placed in a well for drilling, repair, or priming of pumps should be disinfected, and should never be taken from a lake or pond.

· Well casing should be watertight, properly capped, and extend a foot or more above ground.

· When pumps, well pipes, and well equipment are repaired, they should not be placed on the ground where they could pick up iron bacteria.

· The well, pump, and plumbing should be disinfected when repaired.

Control of Iron Bacteria

Treatment techniques which may be successful in removing or reducing iron bacteria include physical removal, pasteurization, and chemical treatment. Treatment of heavily infected wells may be difficult, expensive and only partially successful

Physical Removal

Typically done as a first step in heavily infected wells. The pumping equipment in the well must be removed and cleaned, which is usually a job for a well contractor or pump installer. The well casing is then scrubbed by use of brushes or other tools. Physical removal is usually followed by chemical treatment.

Pasteurization

Pasteurization has been successfully used to control iron bacteria. Pasteurization involves a process of injecting steam or hot water into the well and maintaining a water temperature in the well of 60° C (140 degrees Fahrenheit) for 30 minutes. Pasteurization can be effective, however, the process may be expensive.

Chemical Treatment

This is the most commonly used iron bacteria treatment technique. The three groups of chemicals typically used include: surfactants; acids (and bases); and disinfectants, biocides, and oxidizing agents.

Surfactants are detergent-like chemicals such as phosphates. Surfactants are generally used in conjunction with other chemical treatment. It is important to use chlorine or another disinfectant if phosphates are used, since bacteria may use phosphates as a food source.

Acids have been used to treat iron bacteria because of their ability to dissolve iron deposits, destroy bacteria, and loosen bacterial slime. Acids are typically part of a series of treatments involving chlorine, and at times, bases. Extreme caution is required to use and properly dispose of these chemicals. Acid and chlorine should never be mixed together. Acid treatment should only be done by trained professionals.

Disinfectants are the most commonly used chemicals for treatment of iron bacteria, and the most common disinfectant is household laundry bleach, which contains chlorine.

Chlorine

Chlorine is relatively inexpensive and easy to use, but may have limited effectiveness and may require repeated treatments. Effective treatment requires sufficient chlorine strength and time in contact with the bacteria, and is often improved with agitation. Continuous chlorine injection in the well has been used, but is not normally recommended because of concerns that the chlorine will conceal other bacterial contamination and cause corrosion and maintenance problems.

INFORMATION TAKEN FROM THE MINNESOTA DEPARTMENT OF HEALTH WEBSITE

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