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:
- 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.
- Heavy solids in the water – When the “solids-load” in your tank is too high, you 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.
- 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.