T31 waste exemption: recover monopropylene glycol from aircraft antifreeze fluids

The T31 exemption allows airports to filter and distill waste aircraft antifreeze fluid to recover monopropylene glycol.

Types of activity you can carry out

Includes filtering and distilling aircraft antifreeze fluids that have been collected following de-icing of aircrafts to recover monopropylene glycol.

Types of activity you cannot carry out

You cannot:

  • treat waste antifreeze fluids for disposal to, for example, a sewer
  • treat hazardous waste

Type of waste you can treat

The waste codes are those listed in the List of Wastes (LoW) Regulations. You need to make sure your waste fits within the relevant waste code and description.

Waste code Type of waste
160115 Antifreeze fluids not containing hazardous substances

Quantity of waste you can treat

You can store or treat up to 250 cubic metres of waste over any 7 day period.

Key conditions

The waste must be:

  • treated in a location with sealed drainage
  • stored with secondary containment
  • treated at the airport where it was produced

Other things you need to know

Antifreeze is highly toxic to the water environment. You must keep stringent control on storing and treating waste antifreeze to prevent it being released into the environment.

Register this exemption

You need to register this exemption with us if you meet the requirements.


Hazardous waste – see How to classify different types of waste.

Sealed drainage – a drainage system with an impermeable surface that makes sure that:

  • no liquid will run off the surface apart from via the system
  • except where they may be lawfully discharged, all liquids entering the system are collected in a sealed sump

Secondary containment – a bund or any other system for preventing waste that has leaked from its main container from escaping from the place where it is stored or treated.

Published 28 April 2014
Last updated 5 November 2015 + show all updates
  1. Changed reference of 'dangerous substances' to 'hazardous substances' due to changes in the law.

  2. First published.