Dairy wastewater is treated using a combination of methods, including mechanical, biological, and advanced processes, to remove organic matter, fats, and nutrients. Common approaches involve anaerobic digestion to produce biogas, activated sludge and aerated lagoons for biological decomposition, and membrane bioreactors (MBR) coupled with other processes like reverse osmosis for high-purity water recovery and reuse.

Mechanical treatment

Screening: Removes large solids and suspended materials from the wastewater.

Dissolved Air Flotation (DAF): Uses air bubbles to lift fats, oils, and other insoluble substances to the surface for removal.

Centrifugal separation: Separates solids from liquids to reduce the volume of sludge produced.

Biological treatment

Upflow Anaerobic Sludge Blanket (UASB) reactor: Treats wastewater in an anaerobic environment, which breaks down organic matter and produces biogas.

Activated sludge: Uses microorganisms in an oxygen-rich environment to break down organic pollutants.

Aerated lagoons: Large ponds with aerators to promote biological decomposition, often used for direct discharge to surface water.

Membrane Bioreactor (MBR): Combines biological treatment with membrane filtration to produce high-quality effluent for reuse.

Advanced and chemical treatment.

Electrocoagulation: Uses electrodes to remove organic matter, turbidity, and suspended particles.

Chemical Precipitation: Uses chemicals like ferrous sulfate to remove phosphorus and other dissolved substances.

Coagulation/Flocculation: Adds chemicals to aggregate small particles, making them easier to remove through subsequent processes like flotation.

Reverse Osmosis: A membrane-based process that achieves very high removal rates of dissolved solids, organic compounds, and other pollutants, allowing for extensive water recycling.

Microalgae cultivation: An emerging technology that uses microalgae to treat wastewater while also potentially producing biomass.