Water is the universal solvent, and groundwater usually has some characteristics of the soil and rock where it is found. Because iron is one of the most abundant minerals in the earth's crust, it is very common in groundwater. When there is too much iron in the water you can see a reddish-brown color, stained laundry, and poor tasting coffee. An equally common but less understood problem is infestation of water supplies with the iron bacteria.
Effects of iron bacteria :
The more serious problems occur when the iron bacteria build up in well systems. Iron bacteria do not cause health problems, but they can have the following unpleasant and possibly effects:
corrode plumbing equipment
reduce well yields (clog screens and pipes)
increase chances of sulfur bacteria infestation
Detecting iron bacteria :
There are certain indications that your well may have an iron bacteria problem. These are a red, yellow, or orange color to the water; slime on the inner walls of the toilet tank; and a smell that may resemble fuel oil, cucumber or sewage.
Preventing iron bacteria :
because it is difficult to get rid of iron bacteria once they exist in well systems, prevention is the best safeguard against accompanying problems. For well drillers, prevention means disinfecting everything that goes into the the ground with a strong (250 ppm) chlorine solution. Iron bacteria are nourished by carbon and other organics, and it is essential that these are not introduced into any part of the well system during the drilling process.
Treating iron bacteria problems :
Although there are both chemical and mechanical methods for treating iron bacteria problems, private well owners should expect to use the former until further study shows the effectiveness of heat or other means to disinfect smaller wells.
Two species of iron bacteria
Resources : Wisconsin Department of Natural
For several reasons, routine chemical disinfectants that effectively wipe out other bacteria are only modestly successful against iron bacteria. Iron bacteria build up in thick layers, each forming a slime around bacterial cells that keeps disinfectants from penetrating beyond the surface cells. Chemical reactions occur far slower at the cool temperatures common in wells, and bacterial cell need a long exposure to the chemical for the treatment to be effective. Even if chlorine kills all the the bacterial cells in the water, those in the groundwater can be drawn in by pumping or drift back into the well.
In addition to the chemical treatment, other methods are available to control the iron bacteria in community water systems. Stagnant water conditions can be avoided by looping dead-end plumbing lines and periodically flushing low-flow lines to reduce bacteria. Forcing hot water or steam into a well to disperse the slime and kill the bacteria has also worked well. In addition, flushing large quantities of heated water into the aquifer has been found successful in field tests.
Resources: Wisconsin Department of Natural Resources