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What kind of corrosion is this?

Hallo to everybody,

I am looking for help. My problem is that I have a water gallery in a hospital that it is with a corrosion. The tube is in iron and they are with Zn. Corrosion has ate almost all Zn. We found a lot of incrustation and sediment of iron. Near the hole (it is like pitting corrosion) there is also somebody thinking about MIC SRB corrosion. The water is added by CLO2. tube is 2 years old. We didn't find Cl near the hole. but we didn't find also bacterium SRB. Thanks for your help it is possible that CLO2 produce a corrosion? Water has a pH of 7.2.

Paola Pedrelli
Studio Alfa s.r.l. - Parma, Italy
2003

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Paola,

My first thought it WHY didn't someone use a suitable plastic material?

For a very dilute Cl02, use PVC. For a stronger solution use PVDF ... which is good, the book says, for up to 10-1/2 pH and scintillates in acid and takes a much higher temperature than PVC. (You didn't give pressure, size nor temperature ... but then many people forget to give pertinent data.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).
2003