The T21 exemption allows you to recover waste, such as sludge from a septic tank or cesspool, which needs further treatment at a waste water treatment works.
Types of activity you can carry out
Includes storing and treating septic tank sludge at a sewage treatment works.
Types of activity you cannot carry out
- use this exemption to treat waste at locations other than at a water treatment works
- 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|
|190802||Sewage grit (waste from de-sanding) only|
|190805||Sludge from treating urban waste water|
|190899||Centrate liquor only|
|190902||Sludge from water clarification|
|190903||Sludge from decarbonation|
|190906||Solutions and sludge from regeneration of ion exchangers|
|200304||Septic tank sludge|
|200306||Waste from sewage cleaning|
|200399||Cesspool waste and other sewage sludge only|
Quantity of waste you can treat
You can treat up to 100,000 cubic metres of waste over any 12-month period.
The waste must be stored and treated in a secure location with sealed drainage.
Register this exemption
You must register this exemption with the Environment Agency 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
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