Treating FOG Filaments Like Nocardia and Microthrix parvicella
How Qwik-Zyme L and Foam Buster Target the Root Cause of FOG Filament Overgrowth
Fats, oils, and greases (FOG) are found in all types of wastewater and sewage treatment facilities. FOG appears in the form of fatty acids, animal fats, milk, fish oils, and triglycerides. Most biological wastewater treatment systems are not readily equipped to manage and successfully treat FOG in influent streams — floc-forming bacteria cannot easily digest long-chain fatty acids. That limitation opens the door for filamentous organisms to move in and thrive.
The Filament Advantage
Wastewater foaming events are frequently driven by fats, oils, and greases. Common filaments like Nocardia and Microthrix are better equipped to uptake and digest FOG, giving them a strong competitive edge over the floc-forming bacteria in activated sludge processes. As these filaments consume FOG, they grow in abundance and begin starving out native biomass.
The result is a low F:M environment in which settling challenges, cloudy effluent, and a lack of nutrient removal become common. As filaments flourish, foaming intensifies. Because FOG is naturally buoyant, and Nocardia and Microthrix depend on it as their primary food source, these filaments also float — forming thick, persistent surface foam that will remain until the root cause is addressed.
Microthrix parvicella 1000x
Why Traditional Solutions Fall Short
FOG problems are often treated reactively. Chlorination, heavier wasting, and chemical defoamers are widely used, and while some of these can help reduce filamentous outbreaks, they often fall short on their own and come with inherent limitations.
Chlorination may kill filaments, but not without risk. When applied conservatively (2–3 ppm in RAS lines ONLY), it can help damage filaments and lower their competitive advantage. However, overuse or poor placement can be harmful to existing biomass responsible for nutrient reduction. And in some cases, fragment filaments and make outbreaks worse.
Mechanical defoamers should not be used whatsoever, though. That one does not have any advantages. Defoamers will push the foam down underneath and the existing foam will actually pick up more filaments that are suspended in MLSS, thus actually creating more foam over time.
Mechanical methods — such as DAFs, EQ tanks, or screens — help to limit FOG from being introduced to downstream processes BUT they can be quickly overwhelmed and can potentially limit key nutrients for downstream biology
Heavier wasting is ABSOLUTELY necessary as it will help lower the plants sludge age (old sludge is a common cause of FOG filament outbreaks) AND it will help physically remove existing filaments from the system. An old sludge age will exacerbate just about any filamentous outbreak, not just Nocardia and Microtrhix. It can, however, lead to an overcorrection and drop the sludge age too much
All in all, these are simply additional mechanical measures that can be taken to help aid a Qwik-Zyme L and Foam Buster treatment. It’s important to note that while ¾ of the methods lifted above can help, doing those without Qwik-Zyme L and Foam Buster is not sustainable as it does not provide much stability to a biological system since they are somewhat temporary solutions, unlike Qwik-Zyme L and Foam Buster.
Bioaugmentation: A Targeted Solution
Rather than forcing biology to react to changing conditions, bioaugmentation gives wastewater bacteria the tools they need to perform at a higher level. This includes the addition of key nutrients, bacteria, enzymes, or combinations thereof — increasing metabolic efficiency and improving system stability.
Floc-forming bacteria lack the enzymes needed to degrade FOG, especially lipase, which breaks down fats and oils. To overcome this, Aquafix developed Qwik-Zyme L, a liquid blend of highly concentrated lipases tailored to help wastewater biology degrade FOG more efficiently.
By converting long-chain fatty acids into readily consumable short-chain fatty acids (VFAs), Qwik-Zyme L removes the primary food source of foaming filaments like Nocardia and Microthrix. When paired with Foam Buster, which boosts VFA uptake and promotes healthy floc formation, this duo can fully neutralize filament growth and associated foam.