Many wastewater unit operators find Nocardia or M. parvicella foams the most challenging problem facing their wastewater treatment plant. As filamentous organisms develop in an existing ecological niche and are hard to bring under control.
The foaming is caused by extracellular materials produced by the microbes. Unlike many extracellular polymers, the nocardia EPS has a hydrophobic component. When aerated, the hydrophobic polymers create a foam containing EPS, Nocardia organisms, water, and insoluble fatty acids/grease/oils. Nocardia forms are actually interesting bacteria with excellent metabolic capabilities with respect to grease degradation. Unfortunately their tendency to foams makes them unsuitable for aerated basins. As it is not normal surfactant or biological foam, anti-foams have limited effect on the Nocardia foam. Control is most often done using hypochlorite/water spray directly on the foam. Some operators have reported using flocculant & antifoam have helped reduce the scum problem.
Back in the 1990s, a few companies studied filament control using specialized surfactants & enzymes to disrupt the filament EPS and sheath. It was effective on several common filament types, but remained in limited use due to the low cost and widespread availability of hypochlorite as the primary control option.
Instead of trying to make a product that covers all filaments, I have begun studying the potential of an enzyme blend with appropriate dispersants to directly "attack" the Nocardia EPS. Using the enzyme blend with existing sprayers, the stable foam will be disrupted and normal secondary clarifier wasting will help bring the excessive Nocardia population under control.
I'd like to test the various enzyme blends on the widest range of Nocardia foams. So if any of your have an ongoing problem with Nocardia foam, I'd like a sample. Just contact me an we can make arrangements for the Aster Bio lab to study and run the samples. Any help you can give here is much appreciated and will possibly turn into a new cost effective way to quickly bring Nocardia foam under control.
Erik Rumbaugh has been involved in biological waste treatment for over 20 years. He has worked with industrial and municipal wastewater facilities to ensure optimal performance of their treatment systems. He is a founder of Aster Bio (www.asterbio.com) specializing in biological waste treatment.
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