Podcast Q&A 11: Why Use a Static Mixer for Chlorination Systems?

Hello. Welcome to the Clean Water Made Easy Podcast Question & Answer. This is Q&A Episode #11.

Each week in our main podcast, I try to go deeper into various well water treatment systems and specific applications or problems. I also like to do these quick Q&A episodes to answer some questions that we get. Every day we get tons of phone calls, emails, and chats through our website.

I try to pick an interesting one and I answer it. As a matter of fact, we’ve received a chat message from Joanne who asked: “What do static mixers do for chlorination systems? Can I use a static mixer in place of a contact tank?”

Thanks for your question.

When injecting chlorine into your water to cure specific problems such as removing odors, killing bacteria or oxidizing iron, you need to mix the chlorine into the water rapidly and that’s what a static mixer does.

A static mixer looks like a piece of pipe, there are different sizes, but say a common 1-inch one is about 14 inches long. If you could look inside it, you’d see a series of little pins or baffles inside them arranged in a specific way. As the water is flowing through, the chlorine or peroxide metering pump, is pumping a little amount of chlorine into the water as the water is flowing.

The idea is the chlorine system pumps it into the pipe and as the water enters the static mixer, it dissolves the chlorine very well into the water. It’s a thorough and rapid mixing. That’s what a static mixer does.

However, with chlorination there’s this concept of you want to have a certain amount of concentration of chlorine, usually it’s somewhere between 1 and 5 parts per million but it depends on how much iron, odor, manganese or whatever you’re trying to correct. I have another episode that goes into detail about that, episode #8. In episode 8, I go over the chlorination systems. So there’s the idea of the concentration and then the time. That’s called the CT value. You have your concentration and time.

A static mixer will rapidly mix the chlorine into the water but it doesn’t give you time. Depending on what you’re trying to do, you might need a contact tank. If you’re after disinfection then it’s better to use some kind of contact tank to get time because the bacteria needs a little bit of time with the chlorination for it to be thoroughly killed and sanitized.

The best thing to do is to use both the static mixer with the contact tank. Say you’re injecting chlorine in order to kill odor and oxidize iron before an iron filter. Then you only need about 10 to 30 seconds of time before the water that has been chlorinated goes into the iron filter media. So in that case, static mixer is great. It’s just 2 different things, static mixer and contact tank.

Static mixer gives you more rapid mixing time and more efficient transfer of the chemical into the water so you get a better job so therefore you can use less chemicals. The idea is after you inject the chemical or peroxide you don’t want any to be left in the water or have very little left in the water. So the static mixer will help that.

We often use them in combination with a contact tank to get mixing and time in order to achieve the results of what you’re trying to do –whether it’s to sanitize the water, kill the odors, or treat iron & manganese, whatever.

Do you have any questions and you’d like to have your question answered? Just go to our website, there’s a chat box you can chat with us. Ask questions there. You can email us. My email is [email protected]. Or you can email [email protected].

Hope that helped and hope you folks have a nice day. Thank you.

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