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Minnesota Department of
Health
Iron bacteria are small living organisms that
naturally occur in soil, shallow groundwater, and surface waters.
These 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.
Iron Bacteria May Help Other Organisms Grow
Iron bacteria are not known to cause disease.
However, they can create conditions where other disease-causing organisms may
grow.
They can also affect how much water the well
produces and may cause clogging issues.
To be safe, test the water for nitrate and
coliform bacteria. Make sure the well is properly constructed, located, and
maintained.
How to Detect Iron Bacteria
Tastes and Odors
· Swampy,
oily or petroleum, cucumber, sewage, rotten vegetation, or musty.
· May be
more noticeable after the water has not been used for a while.
Color
· Yellow,
orange, red, or brown stains and colored water.
· Rainbow
colored, oil-like sheen.
Red Slimy Deposits
· Sticky
rusty, yellow, brown, or grey slime.
· “Feathery"
or filamentous growths (especially in standing water).
You can confirm that it is iron bacteria by
having the water tested at a laboratory.
Prevent
Iron Bacteria
Iron
bacteria are in most soils in Minnesota. Drilling, repair, or service work can
also introduce iron bacteria into a well or water system.
Here are some ways to
prevent iron bacteria from entering your well:
· Only
place disinfected water in a well for drilling, repair, or priming pumps. Never
use water taken from a lake or pond.
· Make sure
the well casing is capped, watertight, and extends at least 1 foot above
ground.
· Avoid
placing pumps, well pipes, and well equipment on the ground when doing repairs.
· Disinfect
the well, pump, and plumbing after repairs.
Treatment
to Address Iron Bacteria
Some
treatment techniques may remove or reduce iron bacteria.
Eliminating iron bacteria
can be difficult and expensive. Sometimes treatment techniques may only be
partly effective.
Contact a licensed well
contractor or water treatment professional to determine the best approach for
your situation.
Physical Removal
Physical removal is usually the first step in
very infected wells. A licensed well contractor will:
1.
Remove
and clean the pumping equipment.
2.
Scrub the
well casing with brushes.
3.
The next
step is usually chemical treatment.
Chemical Treatment
This is the most common treatment technique for
iron bacteria. There are three groups of chemicals people use for this:
· Disinfectants are the most common chemicals used to
treat for iron bacteria. The most common disinfectant is household laundry
bleach, which contains chlorine.
Contact a licensed well contractor to disinfect your well, or use
the instructions on the Well Disinfection webpage.
· Surfactants are detergent-like chemicals, such as
phosphates. Surfactants are generally used with other chemical treatment.
It is important to use a disinfectant (such as chlorine) if
phosphates are used; bacteria may use phosphates as a food source. Only trained
professionals should do a surfactants treatment.
· Acids can dissolve iron deposits, destroy
bacteria, and loosen bacterial slime. Acids are typically part of a series of
treatments involving chlorine and sometimes bases.
Only trained professionals should do an acid treatment. Be very
careful you properly use and dispose of these chemicals. Never mix acid and
chlorine.
Pasteurization
Pasteurization injects steam or hot water into
the well to keep the well water temperature at 60 degrees Celsius (140 degrees
Fahrenheit) for 30 minutes. Pasteurization can be effective, but expensive.
Chlorine
Chlorine is cheap and easy to use, but it may
not always get rid of iron bacteria. You may have to treat with chlorine more
than once.
Both the concentration of chlorine and how long
the chlorine solution is in contact with the bacteria are important.
Some people have used continuous chlorine
injection into the well, but the Minnesota Department of Health does not
usually recommend this.
The continuous chlorine injection may hide other
bacterial contamination and cause corrosion problems.
Shock Chlorination
"Shock" chlorination is the process of
using a strong chlorine solution to disinfect the well and system. The chlorine
concentration should be close to but not greater than 200 parts per million
(ppm).
A concentration greater than 200 ppm reduces how
effective the disinfection is. Before adding the chlorine solution, the
well should be pumped until clear or physically cleaned.
Should
I test my well water for anything besides iron bacteria?
Yes. Both natural sources and human activities
can contaminate well water and cause short-term or long-term health effects.
Testing your well water is the only way to
detect most of the common contaminants in Minnesota groundwater; you cannot
taste, see, or smell most contaminants. Minnesota Department of Health recommends
testing for:
· Coliform
bacteria every year and
any time the water changes in taste, odor, or appearance. Coliform bacteria can
indicate that disease-causing microorganisms may be in your water.
· Nitrate
every other year.
Bottle-fed infants under six months old are at the highest risk of being
affected by levels of nitrate higher than 10 milligrams per liter in drinking
water.
· Arsenic
at least once. About
40 percent of wells in Minnesota have arsenic in the water. Drinking water with
arsenic in it for a long time can contribute to reduced intelligence in
children and increased risks of cancer, diabetes, heart disease, and skin
problems.
· Lead at
least once. The
well and water system may have parts that have lead in them, and that lead can
get into drinking water. Lead can damage the brain, kidneys, and nervous
system. Lead can also slow development or cause learning, behavior, and hearing
problems.
· Manganese
before a baby drinks the water. High levels of manganese can cause problems with memory,
attention, and motor skills. It can also cause learning and behavior problems
in infants and children.
Other contaminants sometimes occur in private
water systems but less often than the contaminants listed above. Consider
testing for:
· Volatile
organic chemicals if
the well is near fuel tanks or a commercial or industrial area.
· Agricultural
chemicals commonly used in the area if the well is shallow and is near cropped fields or
handling areas for agricultural chemicals or is in an area of geologic
sensitivity (such as fractured limestone).
· Fluoride if children or teenagers drink the water.
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