Sewer Chemistry

[Randy Holmes-Farley Verified Community Expert]

I made an interesting discovery as I was cleaning out an old drum trap for the drain line on a tub in my home.

The drum trap may have been installed more than a hundred years ago (not sure if indoor plumbing was part of the initial construction). I know it's been at least 27 years since it was cleaned out since we never have. Anyway, as I was using a shop vac to suck out the disgusting-smelling stuff, I heard two clunks in the reservoir of the vacuum.

Later, I cleaned out the shop vac and found two coins. A copper penny from 1941 and a nickel from 1972.

Curiously, both are shiny bright, although also somewhat corroded. The most interesting thing is that the nickel is coated with copper. It looks to be the same copper color as the penny.

The drain pipes are brass in that area, and so there may have been copper in the drain water even without the penny present, although the penny may have provided copper too.

It is known that nickel metal will displace copper ions in solution, with the copper plating out:

http://www.sciencephoto.com/media/706833/view

Presumably that has been slowly happening in my drain.

Happy Reefing.

 

[sfin52]

Those are a great find.

if we treat our tanks with copper could we use nickel to remove it.

 

[siggy]

Very interesting indeed, My company wired a chrome plating plant but the process was reversed, Using Potassium cyanide as the catalyst if that makes cents

 

[Larry L]

if we treat our tanks with copper could we use nickel to remove it.

Is nickel less toxic in a reef tank than copper?

 

[Randy Holmes-Farley Verified Community Expert]

I don't think it would happen in seawater. Too many other types of corrosive chemistry going on, especially oxidation by O2 and other oxidizers.

I think the fact that the trap was anaerobic (based on the smell) prevented normal oxidation and dissolution of the copper or nickel as would happen if you just put them in aerated seawater.