Pouring Milk Down the Drain is a Criminal Offence for Businesses

Pouring expired milk down the sink can carry a financial or custodial sentence for businesses in the UK. Although many businesses are unaware of this, milk must be disposed of as Category 3 ABP (Animal By-Products) via an appropriate contractor.

You may not know it, but milk is a highly polluting substance – which is why it has been classified as Category 3 ABP. Milk is particularly harmful because of its high ‘oxygen demand’: bacteria that feed on it use up oxygen that is otherwise used by fish and other living things in the watercourse, effectively suffocating aquatic life. 

What to do with expired milk? 

There are strict guidelines on how you can dispose of milk. It can be used in composting or anaerobic digestion, or, if it isn’t spoiled, it can be processed to make feed for farm animals, pet food, or organic fertilisers and soil improvers.

If it cannot be disposed of in these ways, it could also be sent to incineration as a fuel for energy recovery. The final option, in line with the Waste Hierharchy, would be to dispose of it in landfill.

You cannot pour milk down the sink due to the high Biochemical Oxygen Demand (BOD) required to break down this material. Surprisingly, milk has one of the highest BOD of common pollutant. This table, obtained from SEPA, highlights this point:


BOD (mg/l of oxygen)


80,000 – 120,000

Silage effluent

60,000 – 70,000

Pig slurry

20,000 – 30,000

Cattle slurry

15,000 – 20,000

Dairy Washings

1,000 – 2,500

Raw Sewage

300 – 400

Clean river sewage

Less than 5

For your business to properly dispose of milk, you will need to use an appropriate contractor to handle this waste stream.

Proper disposal of milk and dairy products

It isn’t just milk that needs to be disposed of in this way, but all dairy products including, and not limited to:

  • Yoghurt
  • Cream
  • Ice cream
  • Hard cheese
  • Soft cheese
  • Butter
  • Soft spread

If incorrectly disposed of, these products can cause environmental impacts that are extremely damaging to waterways, harming both water quality and wildlife. So next time you have expired milk, make sure you follow the correct procedures to prevent this from happening.

DS Smith offers a food waste recycling service, including the disposal of milk and other materials which are classed as Category 3 ABP (Animal By-Products). Unlike other companies, we segregate your materials to give you the best value, prevent contamination, and help you to waste less and recycle more.  

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