Guidance

T21: recovering waste at waste water treatment works

T21 exemption allows you to recover wastes such as sewage grits, screenings and sewage sludge at a waste water treatment works.

Applies to England

There’s a charge for most waste exemptions

This exemption is in band 1. Read waste exemption charges to find out what the charges and charging bands are.

Types of activity you can carry out

Storing and treating listed wastes on the premises of a waste water treatment works for waste recovery.

Types of activity you cannot carry out

You cannot use this exemption to:

  • treat waste at locations other than at a waste water treatment works
  • treat hazardous waste
  • treat wastes through the waste water treatment process
  • store wastes that will be disposed of through the waste water treatment process
  • store wastes that you will not treat

Type of waste you can treat

The waste codes are listed in the following table. You need to make sure your waste fits within the relevant waste code and description.

Waste code Type of waste
19 08 01 Screenings
19 08 02 Sewage grit (waste from de-sanding) only
19 08 05 Sludge from treating urban waste water
19 08 99 Centrate liquor only
19 09 02 Sludge from water clarification
19 09 03 Sludge from decarbonation
19 09 06 Solutions and sludge from regeneration of ion exchangers
20 03 04 Septic tank sludge
20 03 06 Waste from sewage cleaning
20 03 99 Cesspool waste and other sewage sludge only

You should classify cesspool waste as ‘16 10 02 cesspool waste only’ rather than using the 20 03 99 code. You can further treat partially treated sewage sludges under this exemption. For more information see Waste codes for sewage sludge and sludge containing other materials: RPS 231.

Quantity of waste you can treat

You can treat up to 100,000 cubic metres of imported waste over any 12-month period in addition to any listed wastes you produce on site.

Main conditions

The waste must be stored and treated in a secure location with sealed drainage.

None.

Register this exemption

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

Definitions

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 through the system
  • except where they may be lawfully discharged, all liquids entering the system are collected in a sealed sump

Secure – a container, lagoon or other place is secure in relation to waste kept in it if:

  • all reasonable precautions are taken to make sure the waste cannot escape
  • members of the public cannot gain access to the waste

Updates to this page

Published 28 April 2014
Last updated 1 July 2025 show all updates
  1. Updated with a link to new information about charges and charging bands for waste exemptions.

  2. We have clarified the types of activities you can and cannot carry out, and the types of waste you can treat.

  3. First published.

Sign up for emails or print this page