Iron & Sulfur Bacteria

Iron Bacteria

"Iron bacteria" are a diverse, widespread ecological group, often incriminated as a cause of yellow color, iron taste and smell in drinking water, but are not considered to be pathogenic. Those bacteria have the unique ability to obtain energy by oxidizing free iron in water from the ferrous to the ferric state. Masses of iron bacteria are typically encrusted with ferric oxides, giving them a distinctive golden brown color. Iron bacteria and sulfur bacteria are often found together.
Iron bacteria are often enveloped in thick, slimy or gelatinous material that contribute to biofilms and iron buildup that can quickly foul pipes and filters. This problem is known as iron bio fouling. It often causes side effects such as intermittent sulfide odor and reddish water. It may also cause pitting corrosion on steel and iron. Some water systems may make the problem worse. These include inappropriate well, filter, or plumbing design and construction or inadequate water treatment.

Sulfur Bacteria

Hydrogen sulfide gas (H₂S), produced by sulfur bacteria, can occur in wells anywhere and gives the water a characteristic "rotten egg" taste or odor. Hydrogen sulfide gas can result from a number of different sources. It can occur naturally in groundwater, in wells, or in water distribution systems. It can be produced by sulfur bacteria or chemical reactions inside water heaters. In some instances it can result from pollution and it is a good idea to have well water tested for coliform bacteria if sulfur bacteria are resent.
Sulfur bacteria produce a slime layer and can trap and promote the growth of other bacteria such as iron bacteria. The slime can clog wells, plumbing, and irrigation systems. Hydrogen sulfide gas in water can cause black stains on silverware and plumbing fixtures. It can also corrode pipes and other metal components of water distribution systems.
Water heaters can provide a warm environment where sulfur bacteria can live. A water heater usually contains a metal rod called an "anode" which reduces corrosion of the water heater tank. The anode is usually made of magnesium metal. Magnesium can supply electrons that aid sulfur bacteria in the conversion of sulfate to hydrogen sulfide gas. A plumber can usually address this problem by changing the electrode.

Control of Iron and Sulfur Bacteria

The usual way to control iron and sulfur bacteria is by chlorination as soon as the problem appears. Shock chlorination should solve the immediate problem. However bacteria tend to build up again in a few days. It is best to periodically disinfect wells by shock chlorination with weaker chlorine concentrations or by installing a chlorination unit that will constantly chlorinate the water. A licensed well contractor can advise you on what opinion is best.

Iron and Sulfur Bacteria Testing at Pyxis Laboratories

Water suspected of containing sulfur bacteria or iron bacteria can be collected and submitted to a laboratory for analysis. Pyxis Laboratories has the qualified staff to guide you on sample collection and to perform the analysis. For further information contact us by email at customerservice@pyxislab.com or call at (503) 254-1794.