In well water yellow or red iron bacteria is a problem. What do you recommend as a per-treatment prior to RO?
Dear Ebrahiem,
Water is a universal solvent and typically found in groundwater characteristics of soils and rocks, where they are located. Iron is one of the minerals present in the earth's crust which explains the fact that iron is present in groundwater. When there is too much iron in the water we can see a red tint and brown water, a taste of bad coffee and stains on the cloth because of the rinse water. Another problem caused by iron bacteria is contamination of drinking water production station. The biggest problem appears once the iron bacteria have developed in the water system, wells and other reservoirs. Iron bacteria have no harmful effect on health but have the following unpleasant effects:
causing malodour
corrodes lead equipment
clog pipes and other water supply systems
Promotes the development of sulfur bacteria.
To the extent that it is relatively difficult to get rid of iron bacteria once it has contaminated drains or other water reservoirs prevention is the best way to protect against these problems. To do this it should be disinfected with highly concentrated chlorine solution (250 ppm) all the water from the soil. Iron bacteria feed on carbon and other organic matter and it is essential to eliminate this source of food simultaneously. There are two methods of disinfection of iron bacteria: a chemical and mechanical processing. For several reasons the conventional chemicals that are effective with other bacteria have a very reduced power disinfectant against iron bacteria. Iron bacteria grow thick film and forming the vessel which prevents the disinfectants to be in contact with the cell of the bacterium. The chemical reactions are slower at low temperatures and the cell of the bacteria must be in contact with the disinfectant for a time for the reaction to be effective. Even if chlorine kills all the bacteria in the tank keep in mind that when groundwater pumping bacteria will again eliminate. In addition to the chemical treatment, other methods are available to control iron bacteria in water distribution networks. The conditions where stagnant water is occurred should be avoided. Also using hot water under pressure it is possible to remove the mud and kill bacteria.
With my best regards
Prof. Bachir ACHOUR
Dear Ebrahiem,,
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 sticky slime which is typically rusty in color, but may be yellow, brown, or grey.
In the management of water-supply wells, iron bacteria are bacteria that derive the energy they need to live and multiply by oxidizing dissolved ferrous iron. The resulting ferric oxide is insoluble, and appears as brown gelatinous slime that will stain plumbing fixtures, and clothing or utensils washed with the water carrying it. They are known to grow and proliferate in waters containing as low as 0.1 mg/l of iron. However, at least 0.3 ppm of dissolved oxygen is needed to carry out oxidation.
In order to remove iron bacteria from water, the chemical treatment must have the capability of penetrating the slime, removing the live bacteria, dissolving the decaying debris totally so the nutrient is gone, and removing everything from the water. That not only requires the proper chemistry but good development techniques, a monitoring process on the site to determine when the water is clean, and good removal pumping from the bottom of the source,
Treatment techniques which may be successful in removing or reducing iron bacteria include
1) physical removal,
2) Pasteurization, and
3) Chemical treatment.
Treatment of heavily infected wells may be difficult, expensive, and only partially successful.
Physical removal is 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 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.
Regards,
Prem Baboo
Dear Prof Ebrahiem,
I read about a selective bacterial removal approach includes different strategy, the idea is to force them to take their life cycle and then separate them, using MFC. please refer to this paper
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4408190/
if you have some samples we can do this experiments together with our improved MFC unit
Best regards
- Filtration. Use a sequence of different porosities and granulations în order to remove all particles from the well water and finally a tangential filtration for red bacteria (followed by a red bacteria concentrator). RO will separate the eventual Ca, Mg ions for making a pure water. For drinking will Be needed some Na ions for mineralization and pH balance. Hope this wil help..
Dear Prof Ebrahiem,
I think using membrane process might be useful. Strengthening coagulation (using oxidizing agent) prior to ultrafiltration might be useful.
Best regards
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