Removing Fe to Improve Water Quality for Dairy Cows

Last week I wrote about the palatability of drinking water when iron (Fe) is above 4 ppm.  Now let’s look at some ways to get Fe out of your water if you have a level that will interfere with water intake.

Below about 3 ppm, Fe can be removed, just like Ca and Mg, with a regular water softener, if the softener is set up for it.  This can be helpful in removing the Fe which Fe-reducing bacteria thrive on.  These bacteria, which form slimy, filamentous films in water pipes and troughs may also affect water intake.  Either get the Fe out of the water (starve the bacteria), or be diligent in keeping water troughs clean (never a bad idea……).

Above 3 ppm, other methods have to be applied to improve water quality for dairy cows.  Most will involve oxidizing the Fe and removal of the resulting complexes.  Injection of a Chlorine (Cl) source will bind with the Fe and form complexes which will settle out.  Either sodium hypochlorite or chlorine dioxide will work, but in either case a reaction tank is necessary after the Cl injection to allow time for the formation of the complexes and precipitation.  The drinking water must then be drawn from above the layer of reddish water which will form at the bottom of the tank.  Alternatively, the water can be run through a mechanical or activated carbon filter for removal of the Fe complexes.

Careful monitoring of the residual Cl levels is required! Too much, and you risk disinfecting the rumen.  A swimming pool test kit will allow testing to keep residual Cl levels (at the tap) below about 0.3 ppm.  This will also provide effective disinfection of the water troughs for other environmental or ion (sulfur or manganese) dependent  bacteria.

Greensand filtration is another means of oxidizing Fe found in drinking water for dairy cows.  This method requires routine backwashing and recharging to retain the oxidizing activity and will require additional pretreatment if Mn is present.  Ozone injection is another, but more expensive, means of oxidizing Fe.  Like chlorination, both of these methods will require filtration to remove the resulting Fe complexes.

Water chemistry is very complex and the design of an effective treatment system requires a complete understanding of all the constituents, pH and potential contaminants.  One source of excellent information is the Penn State Water Resources website.  When it comes time to consider the options for your particular water source, work with professionals who have NSF and WQA certifications.

About Charlie Elrod

With 30+ years of experience in the dairy industry, I have a well-rounded perspective of what makes a dairy work. In that time I built and operated my own dairy, worked as a herdsman, practiced as an A.I. and E.T. technician, conducted research in nutrition and reproduction, developed educational programs for dairy industry professionals and provided contract technical support to global feed and ingredient companies. In my role with Balchem Corporation, I have the opportunity to bring that experience to bear in product development, testing, clinical and field research, and supporting our customers. My interest in water stems from a lifelong interest in geology and an innate curiosity about how something so fundamental as water can have such profound effects on cows.
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One Response to Removing Fe to Improve Water Quality for Dairy Cows

  1. A. AYDIN says:

    Hydrogen Peroxide, H2O2, could be also used as an oxidizing agent as well. In this case, there is no concern for residual treatment left in the water. It will actually have a positive effect on appetite.
    It would ber best to have a settling tank with a discharge valve at the bottom before the sand or any other type filter. The precipitated oxidized iron can be removed periodically from this tank to minimize the use of the filtering system regardless of the oxidizing agent that is being used.