Podcast Q&A 11: Why Use a Static Mixer for Chlorination Systems?
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Note: This podcast transcript has been edited for clarity and length.
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 explore 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. We receive hundreds of phone calls, emails, and chats daily through our website.
I try to pick an interesting one and answer it. In 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.
How a Static Mixer for Chlorination Works
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 for chlorination does.
A static mixer looks like a piece of pipe. There are different sizes, but 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 arranged in a specific way. As the water flows through, the chlorine or peroxide metering pump injects a small amount of chlorine into the water.
The chlorine system pumps it into the pipe, and as the water enters the static mixer for chlorination, it dissolves the chlorine quickly and thoroughly. It’s a highly efficient method of chemical mixing. That’s what a static mixer is designed for—rapid, complete blending.
Static Mixers vs. Contact Tanks: Do You Need Both?
However, with chlorination, there’s this concept of needing both concentration and time. This is known as the CT value. Usually, chlorine concentration is between 1 and 5 parts per million, depending on what you're treating—iron, odor, manganese, or bacteria. I go into more detail about this in Episode 8 of the podcast.
A static mixer for chlorination will give you rapid mixing, but it won’t provide contact time. For disinfection, time is critical. Bacteria need a few seconds—or sometimes longer—with the chlorine in order to be fully killed and sanitized. That’s why many systems also use a contact tank.
When to Use a Static Mixer for Chlorination with a Contact Tank
The best practice is to use both—a static mixer for chlorination, followed by a contact tank. For example, if you're injecting chlorine to remove odors or oxidize iron before an iron filter, you might only need 10 to 30 seconds of contact time. The static mixer provides quick and thorough blending, and the tank gives the time needed to complete the reaction.
The mixer also allows you to use fewer chemicals since it improves efficiency. The goal is to inject chlorine or peroxide and have minimal residual left in your water. A static mixer for chlorination helps achieve that by improving how well the chemical disperses.
We often install them in combination with contact tanks to get both the proper mixing and the required contact time—whether you’re trying to sanitize water, remove odors, or treat iron and manganese.
Do you have any questions and would like them answered? Just go to our website. There’s a chat box where you can chat with us and ask questions. You can also email us. My email is [email protected], or you can email [email protected].
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Frequently Asked Questions (FAQs)
1. What is a static mixer used for in water systems?
It’s a device installed in the water line to evenly distribute injected chemicals like chlorine. It improves mixing efficiency without requiring moving parts or electricity.
2. How does it work with chlorine injection?
As water flows through the mixer, internal elements create turbulence that blends the chlorine thoroughly into the water stream for consistent treatment.
3. Why is proper mixing important when adding chlorine?
Uneven distribution can lead to areas of under- or over-chlorination. A mixer helps ensure uniform contact, which is essential for effective disinfection.
4. Do I need one for my well water setup?
If you're using a chlorination pump, a static mixer is highly recommended to help blend the chlorine into the water before it enters the retention tank or home plumbing.
5. Can it help with issues like odor or bacteria?
Yes, better mixing improves chlorine contact time and effectiveness, which can help eliminate odors, bacteria, and other contaminants more reliably.
6. Where should it be installed in the system?
Place it just after the chemical injection point and before any contact tank or filtration system to maximize mixing.
7. What size mixer should I get?
That depends on your pipe size and water flow rate. Residential systems commonly use mixers sized for 1″ or 1.5″ plumbing.
8. Will it help reduce chlorine taste or smell?
Yes. Even mixing leads to more efficient reactions, which can reduce leftover chlorine that causes taste or odor issues.
9. Does it require maintenance?
Not typically. With no moving parts, it’s low-maintenance, though occasional inspection is a good idea in systems with sediment or iron.
10. Is it the same as a contact tank?
No. A mixer blends the chemical quickly; a contact tank gives it time to work. They’re often used together for optimal results.
