Waste exemption: T32 treatment of waste in a biobed or biofilter
This exemption allows you to treat non-hazardous pesticide washings in a biobed or biofilter.
The treated washings can be re-used and the biobed material (biomix) can then be spread on land (under an exemption) for agricultural or ecological benefit.
Types of activity you can carry out
You can treat non-hazardous washings in a lined biobed or above-ground biofilter.
Types of activity you can’t carry out
- treat pesticide washings that are hazardous waste
- allow others to bring their pesticide washings to be treated in your biobed or biofilter
- allow agricultural contractors to bring back pesticide washings they have produced while working on other farms
Types 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|
|020109, 160509||Non-hazardous pesticide washings only|
Quantity of waste you can treat
You can store or treat up to 15,000 litres of dilute pesticide washings in a 12-month period.
The treatment can only take place where the pesticide is used and the washings are produced.
You must site the lined biobed or biofilter in a secure place and it must have an impermeable lining.
The biobed or biofilter must be located at least:
- 10 metres from a watercourse
- 50 metres from a spring, well or borehole not used to supply water for producing domestic food
- 250 metres from a borehole used to supply water for producing domestic food
You must not site the lined biobed or biofilter in an area that is designated as a groundwater Source Protection Zone 1. If you are located within a Source Protection Zone 1, email the Environment Agency at to see if you can agree site specific circumstances:
Using the treated washings
Biobeds and biofilters are classed as waste recovery systems. This means that where possible, the treated water should be re-used. Possible re-use options include irrigation, sprayer washing or as the carrier for pre-crop total herbicide applications.
If the treated water is used for irrigation, it must be applied:
- to a vegetated area
- to ground that is not frozen or water logged
- at least 10 metres away from any surface water
- at least 50 metres from any spring, well or borehole not used for domestic or food production
- at least 250 metres from a borehole used to supply domestic or food production
You can treat dilute pesticide washings in a sentinel unit if you register and comply with exemption T29 – treating non-hazardous pesticide washings by carbon filtration for disposal.
You can spread the biofilter and biobed material to land under exemption U10 – spreading waste to benefit agricultural land.
You can also spread the biofilter and biobed material to land under exemption U11 – spreading waste to benefit non-agricultural land.
Registering this exemption
You must register this exemption with the Environment Agency if you will meet the requirements:
Secure place – members of the public and farm animals cannot get access to it and the waste cannot leak from the biofilter/biobed.
Impermeable lining – a containment system that is constructed and maintained so that liquids are fully contained and cannot leak through it.