Dairy Industry Wastewater: Fats, Oil, and Milk Solids

The dairy industry (Milk, Cheese, Yogurt, Ice Cream) uses huge amounts of water for cleaning and processing. While the waste isn't "toxic" like chemicals, it is incredibly potent biologically.

Spilling one liter of milk into a river consumes as much oxygen as the sewage from 50 people.

The Pollutants Profile

Dairy wastewater is unique. It looks white ("White Water") but changes quickly.

The CIP Challenge (Clean-In-Place)

Dairy plants clean their pipes automatically using CIP cycles:

1. Caustic Wash (High pH): Hot Sodium Hydroxide removes fats.
2. Acid Wash (Low pH): Nitric/Phosphoric acid removes "Milk Stone" (Calcium scale).
3. Sterilization: Hot water or chlorine.

Impact: This sends shockwaves of pH (Acid then Alkali) to the ETP. If you don't neutralize this first, you will kill all the bacteria in your ETP.

The Treatment Strategy

Step 1: Screening & Equalization (EQ)

• Screens: Catch plastic caps, labels, and large cheese chunks.
• EQ Tank: This is CRITICAL. It mixes the Acid CIP water with the Caustic CIP water to self-neutralize. It also stores high flow surges during washdowns.

Step 2: Fat Removal (The DAF)

You cannot send fat to a biological tank. It floats, forms a crust, and coats the bacteria so they can't breathe.

• Technology: Dissolved Air Flotation (DAF).
• Process: We inject micro-bubbles into the water.
• Chemicals: Coagulants are added to break the emulsion.
• Result: The bubbles lift the fat to the surface, forming a thick "float" layer that is scraped off.

Step 3: Biological Treatment

Once the fat is gone, dairy waste is essentially sugar water—delicious food for bacteria.

• Option A: Anaerobic (UASB): Best for high COD (>3000). It converts the waste into Methane (Biogas) which can run the boiler.
• Option B: Aerobic (SBR/MBR): Used as a second stage to polish the water. The bacteria eat the remaining lactose and proteins.