ORP and Sulfur Denitrator

[Pufferlover95]

I have a question for you @Randy Holmes-Farley

I just installed a sulfur denitrator and my ORP has risen rapidly in the last 24hrs.

I’ve read your article on ORP and know that nitrifying bacteria can affect ORP. I’m new to this type of reactor but from what I understand the goal is to create anaerobic bacteria which will help reduce nitrates.

I guess my question is what type of ORP changes should I expect by running this reactor? Does anaerobic bacteria increase ORP more than aerobic bacteria? Will the ORP continue to stay elevated or will it eventually come down? What is the relationship of ORP and a sulfur reactor?

And just to be clear, I’m not trying to control ORP, I just want to better understand it.

Thanks in advance!

 

[Randy Holmes-Farley Verified Community Expert]

Did the pH drop? A pH drop raises ORP.

 

[Pufferlover95]

Did the pH drop? A pH drop raises ORP.

It dropped a little bit. Does the reactor majorly affect pH?

 

[Randy Holmes-Farley Verified Community Expert]

Sulfur denitrators deplete alkalinity and lower pH, the degree to which that happens depends on how fast nitrate is being reduced.

FWIW, that pH drop is too small to account for the rise. Nitrate itself doesn't impact ORP, and I would not expect high ORP materials to be released by the reactor.

Let's see what happens going forward.