UK HQ Your time

Understanding FOG in Food Processing

Fats, oils, and grease (FOG) represent one of the most challenging contaminants in food processing wastewater. These substances can form surface scum, clog pipes, interfere with advanced biological treatment processes, and create environmental hazards if not properly removed before discharge.

FOG Sources

Animal fats, vegetable oils, cooking grease, butter, dairy products, and petroleum-based lubricants from processing equipment all contribute to FOG loading in wastewater.

Operational Issues

Untreated FOG causes pipe blockages, pump failures, odour problems, surface scum formation, and interference with advanced biological treatment processes.

Regulatory Limits

Most jurisdictions enforce FOG discharge limits of 10-15 mg/L, with some requiring levels below 5 mg/L for direct discharge to sensitive receiving waters.

DAF Flotation for FOG Removal

Dissolved Air Flotation (DAF) is the industry-standard technology for FOG removal, achieving 90-99% removal efficiency through microbubble attachment and surface skimming.

Microbubble Technology

Our DAF systems generate microbubbles (20-50 microns) that attach to oil droplets and fat particles, creating buoyant flocs that rise to the surface for removal.

  • 20-50 micron bubble size
  • High surface area attachment
  • Gentle solids handling
  • Minimal emulsion formation

Chemical Enhancement

Polymer preparation and continuous dosing systems enhance flocculation and improve FOG capture rates, especially for emulsified oils and stable fat dispersions.

  • Optimised coagulant selection
  • Automated polymer preparation
  • Dose control based on loading
  • Reduced chemical consumption

Automated Operation

PLC-controlled systems with variable speed drives and level sensors ensure consistent performance with minimal operator intervention. Integrates with SCADA platforms for remote monitoring.

  • Automatic sludge removal
  • Flow-proportional operation
  • Remote monitoring capability
  • Low maintenance requirements

FOG Removal Performance

FOG Removal Rate
90-99%
Typical Inlet FOG
50-500 mg/L
Typical Outlet FOG
< 10 mg/L
Hydraulic Loading
Up to 15 m/h

Multi-Stage FOG Removal

1

Pre-Treatment

Screening removes large solids and protects downstream equipment from damage and fouling.

2

Flow Equalization

Balancing tank smooths flow variations and provides consistent loading to the DAF system for optimal performance. See equalization tanks and the sizing calculator.

3

Chemical Conditioning

pH adjustment and coagulant/flocculant addition via chemical dosing systems destabilise emulsions and enhance FOG agglomeration.

4

DAF Flotation

Microbubble flotation separates FOG from water, with surface skimming for sludge removal.

5

Sludge Management

Dewatering systems reduce sludge volume for efficient disposal or beneficial reuse.

Explore More Food Processing Solutions

High Organic Loads

Specialised treatment for elevated BOD and COD levels from organic residues in food processing wastewater.

Explore High Organic Loads

Water Reuse Potential

Enable water recycling opportunities to reduce freshwater consumption and operational costs.

Explore Water Reuse Potential

Regulatory Compliance

Meet discharge limits for BOD, COD, TSS, nitrogen, and phosphorus with compliant treatment systems.

Explore Regulatory Compliance

Struggling with FOG in your wastewater?

Our DAF systems deliver proven FOG removal performance for food processing facilities.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.