Monday, May 15, 2017

Iron Bacteria More than a Nuisance

Recently, we had a water clinic in Prince William County. After the results meeting we received the following email. "[Based on your description during the well clinic] it appears that I have iron bacteria in my water system.  When I had my well pump replaced in 2013, the old pump and the pipes in the well were all covered with orangey brown slime.  In addition, there are always orangey red particles trapped in my sediment filter before the water enters the treatment tanks, as well as orangey red stains on my shower tiles, and orangey red water in toilets.  Also, there are brown to black, hard to remove rings in toilets.
I have a water treatment system and I collected two (2) sets of samples, before and after the treatment.  My well water before the treatment contains 0.01 mg/L of Iron, but the greensand tank with Potassium Permanganate appears to reduce that concentration to below detection limit.  If so, then why do I have iron and/or iron bacteria in bathrooms past the treatment system?  Perhaps the iron in the toilet water comes from the rusting metal equipment and bolts inside the flush tanks, but that would not explain the rusty stains on my shower tiles.  My well is 400 ft. deep, with the pump at 320 ft., and the water level at 60 ft.  I consider shocking my well with chlorine solution, but first I would like to verify if that is the right approach."

The test for iron does not test for iron bacteria. Iron Bacteria are small living organisms which naturally occur in soil and water. These nuisance bacteria depend on oxidation of iron and manganese for “food.” These bacteria form the characteristic deposits of “rust”, and a slimy build up that does not test positive for iron. The most common bacteria known to feed on iron are thiobacillus ferrooxidans and leptospriillum feffooxidans. There are also acidohillic iron bacteria, like the autotrophi ferrobaccillus ferroxidans that are associate with the acidic environment or mines and not often seen in groundwater wells.

Iron bacteria can be a huge nuisance. These harmless bacteria can foul a well, damage pumps, stain plumbing fixtures, clog pipes, faucets, showerheads, and produce unpleasant tastes and odors in drinking water. Yet, water is very rarely tested for iron bacteria since very few certified laboratories conduct the test. Confirmation is usually based on visual symptoms in the water, including the slimy brown/red appearance (often most noticeable in the toilet tank) and a slight musty odor. There are no drinking water standards for iron bacteria since there are no health implications. A true “Iron Bacteria Test” involves an 8 day bacteria culture. These tests cost around $40-$80 and require a sterile sample bottle and collection method as all bacteria tests require. Also, once the iron bacteria have infected a well and plumbing system is very difficult to get rid of. Treatment of heavily infected wells may be only partially successful, but often that’s enough.

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 and are not easily explained by other causes. Iron bacteria do not produce the "rotten egg" smell common to hydrogen sulfide, but do create an environment where sulfur bacteria can grow and produce hydrogen sulfide. There is often a discoloration of the water with the iron bacteria causing a slight yellow, orange, red or brown tint to the water. It is sometimes possible to see a rainbow colored, oil-like sheen on the water. Though the classic symptom of iron bacteria is a rust colored slime, but may be yellow, brown, or grey.

You can order an Iron Bacteria Test from National Testing Laboratories- that’s where I got my test. They have an assay test for “Iron Related Bacteria” present in a water sample. Iron bacteria once introduced into the well will not get better, but continue to get worse destroying your pump and ultimately fouling the well. Along the way there will be a perceived deterioration in the quality of the water. Although iron bacteria can make water unpleasant in taste or smell, there is no health risk associated with the bacteria. They are harmless, but annoying. Elimination of iron bacteria once a well is heavily infested can be extremely difficult. Normal treatment for a problem such as this would be to chlorine “shock,” but iron bacteria can be particularly persistent and chlorine treatment of the well may be only partly effective.

If the wall is fouled then physical removal is done as a first step in these heavily infected wells where the functioning of the pump and well production have already been impacted by the bacterial slime buildup. 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 using (disinfected) brushes or other tools. Physical removal is usually followed by chemical treatment with chlorine (or less commonly acids). Chlorine is 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. Though typically a chlorine concentration of 200 parts per million for decontamination of a well, a higher concentration is recommended by the literature for iron bacteria. Recommended concentrations are between 500-1,000 parts per million. Be warned that too high a concentration can make the well alkaline and reduce effectiveness. In addition high concentrations of chlorine may affect water conditioning equipment, appliances such as dishwashers, and septic systems. You may want to check with the manufacturer of the appliances before chlorinating.

Though it is relatively easy to bypass equipment, iron bacteria may remain in the untreated units and reintroduce the iron bacteria into the plumbing system. The recommended strategy is to treat the well with a 500-1,000 parts per million of chlorine and then dilute the remaining water in the well. This can be accomplished by allowing a significant amount of the water to runoff to a safe disposal location using hoses until the water runs clear, and allow the well to refill and dilute the concentration then introduce the water into the house water system to disinfect the household treatment units, appliances and piping with lower concentrations circulated through the water system. I use chlorine test strips to get an idea of the level of chlorine in the well.

I found my iron bacteria problem before it fouled my well or plumbing system. Only a small amount of iron bacteria had begun to build up around the flapper in my toilet tanks. The ATU unit of my alternative septic system caused the iron bacteria in that tank to grow uncontrollably. The same thing happens with Iron Filters that use air injection-they actually increase bacterial slime and make things worse. Filters using chlorine injection work or a simple chlorine injection system works quite well at controlling the problems of order and staining quite well. However, it is best to knock the problem back in the well and then retreat every two to three years. Every time I treat my well and plumbing system, I finish the process by scrubbing my septic tanks and restarting the septic system. This reminds me that I need to open up my ATU tank and take a is probably time to treat my well again. 

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