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4 Common Generators of Foam in Wastewater 

If foam is not monitored and kept at bay it can cause issues like inaccurate level indicators in tanks or the foam can grow so much that it escapes the tank, causing unsafe and slippery conditions. There are also different types of foam, it can be fluffy white foam that blows across the parking lot or dark dense foam that billows out of the manhole like a mushroom grown wild and it can also be somewhere in between the two. The trick to successfully treating foam is to figure out how the foam was generated.

Here are four of the most common reasons foam is generated:

  1. Mechanical motion in the water, such as aeration or mixers turning at high speed – We have all seen this one in action. Tanks
    usually have a light fine foam that is generated by air. This is normal, and if it stays light and dissipates, there is nothing to worry about.
  2. Heavy solids in the water – When the “solids-load” in your tank is too high, foam collageyou get a dense dark foam, as pictured on the right. This is serious and indicates a treatment issue that needs to be addressed. Once the solids load is decreased, the foam usually stops.
  3. Surfactants in water – Surfactants, a common ingredient in cleaners, can cause foam. There are two options to treat this type of foam. Option one is simple, replace the cleaner with a non-surfactant cleaner. This is not always an option due to cleaners being spec’d in or a resistance to change the current process. If you cannot stop the surfactant upstream, you must apply either a foam dispersion or anti-foam agent. These are commonly called defoamers.
  4. Bacteria growth and death – When there is bacteria growth in a system, there is also bacteria death. Both generate foam. This is usually a dense brown foam. Again, the proper defoamer can solve this problem when there is no way to remove the bacteria.

How do you choose the correct defoamer? 

Defoamers work by reducing the surface tension of the foam and cause it to burst. Foam can be self-healing and grow without the defoamers. When choosing a defoamer it is important to match the defoamer to the foam type, consider your system needs, find our the defoamer dispersion time in seconds and the ingredients in the defoamer. There are many different types of defoamers that can have anything from a silicone to water as a base. They can come ready to use or in an emulsion that needs to be mixed before use. Silicone defoamers are great work horses, unless you have a micro-filtration unit, then they are an operator’s nightmare.

If this all seems overwhelming, don’t panic. The easiest way to figure out the best defoamer for you is to simply ask the experts. Our AquaPure team are more than happy to go through your systems needs and figure out the best defoamer for your process or emergency. Even if there is a three-foot wall of foam headed towards you, our Aquapure experts can help you remove it with ease.  Check out our defoamer video that demonstrates one of our defoamers in action. You can also contact us today with any defoamer questions you have, request an AquaPure technician to come to your facility for a House Call or visit our defoamer web page that lists some of our defoaming products that we offer.