Using Microbial Blends to Maintain Lift Stations: The Science Behind Biological FOG Control

Lift station with grease accumulation.

Lift stations are frequent bottlenecks in wastewater collection systems, especially in areas with high inputs of fats, oils, and grease (FOG). When FOG cools and solidifies in the wet well, it forms buoyant layers of long‑chain fatty acids that resist natural degradation. These layers interfere with pumping, foul level controls, and create anaerobic zones that generate odors and corrosive gases.
Microbial blends offer a biological method for managing FOG accumulation by accelerating the natural decomposition pathways that occur too slowly under typical lift‑station conditions. Their effectiveness comes from the combined action of enzymes and specialized microbial communities.

FOG Chemistry and Why It Accumulates
Most grease entering a lift station consists of triglycerides—three long‑chain fatty acids bound to a glycerol backbone. At ambient sewer temperatures, these molecules solidify and float, forming a stable, wax‑like layer. This layer:

• Traps solids and debris
• Creates anaerobic microzones
• Inhibits oxygen transfer
• Provides a substrate for sulfate‑reducing bacteria (SRB)

Left unmanaged, the result is a persistent grease cap, elevated hydrogen sulfide (H₂S), and increased mechanical wear on pumps and sensors.

How Microbial Blends Initiate and Sustain FOG Breakdown
Microbial lift‑station treatments rely on a two‑stage biochemical process: enzymatic hydrolysis followed by microbial oxidation.

1. Enzymatic Hydrolysis: Breaking Down Complex Fats
Enzymes act as catalysts that initiate the decomposition of FOG. The most relevant classes include:

• Lipases
  Hydrolyze triglycerides into glycerol and free fatty acids.
• Esterases
  Break ester bonds in complex fats, increasing solubility.
• Proteases and Amylases
  Degrade food residues that trap or stabilize grease deposits.

This hydrolysis step is essential because long‑chain fatty acids are too large and hydrophobic for most bacteria to metabolize directly. Enzymes convert them into smaller, more bioavailable molecules.
 
2. Microbial Oxidation: Metabolizing Fatty Acids
Once hydrolysis has occurred, microbial communities take over. Effective blends include strains capable of:

• β‑oxidation of fatty acids
• Growth under low‑oxygen or variable redox conditions
• Adhering to surfaces to form stable biofilms

Through β‑oxidation, fatty acids are progressively shortened into acetyl‑CoA units, which enter central metabolic pathways. The end products are primarily carbon dioxide and water.
This represents true degradation, not emulsification or dispersion.

System‑Level Benefits of Biological FOG Reduction
Although the primary goal is grease control within the lift station, microbial activity produces several secondary benefits that improve overall system performance.

1. Reduced H₂S and Odor Formation
Grease caps create anaerobic pockets where SRB thrive. By eliminating or thinning the grease layer:

• Oxygen diffusion improves
• SRB activity decreases
• H₂S generation is reduced
• This lowers odor complaints and slows corrosion of concrete and metal surfaces.
  
  

2. Fewer Equipment and Sensor Failures
FOG adheres to:

• Floats
• Ultrasonic and pressure sensors
• Pump impellers
• Guide rails

Microbial degradation reduces the accumulation of fatty deposits, decreasing false level readings, pump inefficiency, and emergency callouts.

3. Lower FOG Loading at the Wastewater Treatment Plant

• FOG that bypasses the lift station contributes to:
• Scum accumulation in primary clarifiers
• Increased aeration demand
• Poor sludge settleability
• Higher polymer usage

Biological treatment upstream reduces the mass of long‑chain fatty acids reaching the plant, improving downstream stability.

A Preventive Approach to Lift‑Station Management
Microbial blends do not replace mechanical cleaning, but they significantly reduce the rate of FOG accumulation. By accelerating natural biochemical pathways, they help maintain a cleaner wet well, stabilize redox conditions, and reduce operational disruptions.

For systems with high FOG loading—especially those downstream of commercial food service—microbial treatment provides a consistent, low‑maintenance method for keeping lift stations functional and reducing downstream impacts.