Corrosion in brackish water vs seawater

[Deemter]

Hi,

I have a question about corrosion. I have to deal with brackish water and everyone at the plant "knows" that brackish water is more corrosive that seawater. Is this really true?

As I have understood can brackish water contain more biology which of cause can cause corrosion. But is the "clean" brackish water more corrosive that more salty seawater and if so why?


Best regards Deemter

 

[EdStainless]

You hit the key, biological activity.
If the waters were both treated (correctly) with biocide, then the corrosiveness would be based on choride content. There isn't much difference between 5,000ppm and 18,000ppm, but in some cases it matters.

If you move to the real world, then the brackish water will tend to be warmer, have more bilogical load, and more oxygen and nutrients. The problem with biofouling isn't that the bugs attack the materials. It is that first the biofilms create crevice conditions, then the waste and decay products from the bugs create acids under them. Then it is all over.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm