What Are Wastewater Surfactants?

A: One of the most pressing issues facing wastewater plants today is the effect of surfactants, or surface activating agents (a fancy name for soap), and how they affect the biological process. Surfactants are generally long, stable molecules that often foam up and can cause bulking and dispersion of the mixed liquor. When they start to break down, surfactants can form intermediaries that affect nitrification and ammonia removal. When water temperatures are cold, it is especially difficult to breakdown surfactants.

Surfactants come in from homeowners and from industrial contributors. These high molecular weight soaps are use in industrial formulations as well as in cleaning in schools and cafeterias, and by companies that have a high standard for cleanliness. Last winter, a municipal wastewater operator was called down to the wastewater treatment plant at 1 a.m. on a Saturday to find 6 feet of foam on the basins.  A company had rinsed out 5 gallons of surfactant out of an old barrel with no idea how it was going to foam in the wastewater plant.  The company apologized, only to repeat the same mistake six months later. This time the plant knew the culprit.

Every September we get calls from small municipal plants that suddenly start bulking and foaming. This is related to school just starting up and loads of new soap coming in.  We make two products that help with this type of foam: VitaStim 4001 and DeFoam 3000, which will knock down surfactant foam fast.

Surfactants “make water wetter,” meaning they lower the surface tension of the water. This is how a soap cleans and also how it breaks up the floc and creates a high TSS effluent. In many wastewater plants, because surfactants and similiar emulsion chemistries are so difficult to degrade, they will end up in an aerobic digestor. In this case we use our BugJuice to cause their degradation.

Another chemistry that is related to surfactants is the use of Quaternary ammonia in wastewater. Quaternary ammonia is a heck of a cleaner and often refered to as Quat.  Many types of Quat are used in cheese and milk plants and they will kill a plant dead.  In dairies Quat is used as part or their CIP (clean in place) process.

What will a surfanctant do in a wastewater process?

1. It will cause foaming.
2. It may cause bulking and dispersion of sludge.
3. It can cause toxicity issues.
4. It will cause fat head minnows to die in wet testing.

The good news is that operators who work with us can turn this negative experience into a positive one. We can show you how to turn a negative experience into a positive and actually turn around your plant and reduce sludge production.

At AQUAFIX, we have the expertise to help our customers resolve even the toughest cases where WWTPs lose nitrification and need fast answers.