Filamentous Foam – Microthrix, Nocardia-like Organisms (NALO)

Filamentous foaming is a biological condition most commonly associated with organisms such as Microthrix and Nocardia-like organisms (NALO). These filaments are hydrophobic and readily attach to existing floc, allowing them to accumulate at the surface and form thick, stable foam. Filamentous foam is typically brown or tan, greasy, and persistent. It often resists collapse when sprayed with water. This type of foam reflects a deeper imbalance in the activated sludge process and is frequently linked to high sludge age, low food-to-microorganism ratios, cold temperatures, and elevated FOG loading.

In systems where FOG is a primary driver of filamentous foaming, treatment must focus on breaking the selective advantage that grease-associated filaments possess. Qwik Zyme L plays a key role in this strategy by biologically degrading fats, oils, and grease into simpler compounds via enzymes (lipases). By reducing the availability of long-chain fatty substrates, Qwik Zyme L removes the hydrophobic food source that promotes filament growth and surface stabilization. This not only reduces foam formation but also improves overall biological accessibility of organic material, helping restore balanced microbial competition within the aeration basin.

In conjunction with Qwik Zyme L, Foam Buster works by providing key nutrients to encourage uptake of the newly formed short chain fatty acids (VFAs). This two-step mechanism ensures complete breakdown and uptake of FOG, thus eliminating the main driving force behind foaming filaments.

Non-filament Based, Anaerobic and Aerobic Foaming

While biological tools are essential for long-term filamentous foaming, DeFoam3000 serves a different but complementary role. DeFoam3000 is a fast-acting defoamer designed to physically collapse foam by reducing surface tension. It works best on foams such as surfactant foam, young sludge foam, or most foams generated in anaerobic digesters. In heavily solids-laden foam, like filamentous outbreaks, Defoam3000 may provide temporary visual relief but should not be relied upon as a standalone solution, as the foam structure is reinforced by biomass and grease rather than surface tension alone.

Non-biological foaming, such as surfactant or chemical foam, differs drastically from filamentous foam in appearance and behavior. This type of foam is usually bright white, light, and fluffy, and it collapses easily when sprayed with water. It is typically caused by detergents, industrial cleaners, polymers, or episodic discharges rather than biological imbalance. In these cases, Defoam3000 is highly effective, as the foam contains relatively low solids. Source control and pretreatment remain the primary long-term solutions, but Defoam3000 provides reliable immediate control without impacting biological health.

Determining the Type and Cause of Foaming

Laboratory analysis remains central to understanding the type of foaming and determining the cause. Microanalysis allows operators to distinguish filamentous foaming from non-biological foam and identify whether FOG-associated filaments are present in aerobic systems.

For anaerobic systems, it is critical to determine which mechanisms may be out of safe operating conditions. Any changes such as pH, loading rates, temperature, trace metals content, and more create instability within digesters, quickly resulting in a foaming event. DeFoam3000 will rapidly collapse the foam created, giving operators immediate control so that a long term solution can be identified and implemented.