Anaerobic digestion of waste up to 100 tonnes
This activity applies to the anaerobic digestion of less than, or equal to, 100 tonnes of waste per day. You can find the Appendix for your waste data return at the bottom of this web page.
‘Treatment’, for the purposes of this activity, is defined as: chipping, shredding, cutting, pulverising, blending, screening and anaerobically digesting.
The treatment of non-waste feedstocks by anaerobic digestion was introduced by EASR in 2025. However, sites do not require to have an authorisation until 1 April 2028. We are currently working on the forms, guidance and authorisation conditions and these will be made available as soon as possible.
Authorisation level
Registration
Fit and Proper Person tests
Fit and Proper Person tests apply to this activity. You will be asked in your application if you have any relevant convictions held by you or any additional persons.
Read more about Fit and Proper Person tests
Fees and charges
An application fee applies to the application of a new authorisation for this activity.
| Band | Threshold/Description | Fee |
|---|---|---|
| 7 | </=100 tonnes/day | £707.47 |
An annual activity fee applies to this activity.
For detailed information on application, annual activity fees, and fees related to transferring, varying, or surrendering an authorisation, please refer to our charging information.
Standard conditions
The set of Standard Conditions for this activity has the following reference EASR-SC-016.
Your registration application will only be granted if you can confirm you are able to comply with the standard conditions set out below.
If you carry out an activity under a registration authorisation you must comply with the standard conditions. It is an offence if you do not comply with the conditions.
SEPA will not authorise this activity if it poses an unacceptable risk to the environment.
If you cannot comply with these standard conditions, but still want to carry out anaerobic digestion of biowaste, you may be authorised to do so with a permit.
The Authorised Person must regularly carry out a review of the management system and its effectiveness in terms of achieving compliance with the conditions of the authorisation.
The Authorised Person must have a written management system in place to ensure compliance with the conditions of this authorisation.
Only the waste types listed in Table 1 can be accepted at the Authorised Place.
Table 1. Waste codes for anaerobic digestion
Waste Code Authorised Wastes 02 01 01 Sludges from washing and cleaning – vegetables, fruit and other crops 02 01 02 Animal tissue waste 02 01 03 Plant-tissue waste 02 01 06 Animal faeces, urine and manure (including spoiled straw) 02 01 07 Wastes from forestry 02 01 99 Straw, wood or paper–based bedding waste, slurry or dirty water from stables, zoos, animal parks or livestock markets 02 02 01 Sludges from washing and cleaning, peeling, centrifuging and separation 02 02 02 Animal-tissue waste 02 02 03 Materials unsuitable for consumption or processing 02 02 04 Sludges from on-site effluent treatment 02 03 01 Sludges from washing, cleaning, peeling, centrifuging and separation 02 03 04 Materials unsuitable for consumption or processing 02 03 05 Sludges from on-site effluent treatment 02 04 01 Soils from washing and cleaning beet 02 04 03 Sludges from on-site effluent treatment 02 05 01 Materials unsuitable for consumption or processing 02 05 02 Sludges from on-site effluent treatment 02 06 01 Materials unsuitable for consumption or processing 02 06 03 Sludges from on-site effluent treatment 02 07 01 Wastes from washing, cleaning and mechanical reduction or raw materials used in the production of beverages (except coffee, tea and cocoa) 02 07 02 Wastes from spirits distillation 02 07 04 Materials unsuitable for consumption or processing 02 07 05 Sludges from on-site effluent treatment 03 01 01 Waste bark and cork 03 01 05 Sawdust, shavings, cuttings, wood 03 03 01 Waste bark and wood 04 02 10 Organic matter from natural products (e.g. grease, wax) 07 01 08 Glycerol waste from bio-diesel manufacture from non-waste vegetable oils 15 01 01 Paper and cardboard packaging 15 01 02 Compostable or digestible plastics only 15 01 03 Wooden packaging 15 01 05 Compostable or digestible composite packaging only 15 02 03 Absorbents, filter materials and cloths made from compostable material only 16 10 02 Untreated wash waters from cleaning fruit and vegetables on farm only 16 10 02 Milk and dairy waste milk from agricultural premises only 16 10 02 Liquor and leachate from a composting process 19 01 18 Biochar produced from the pyrolysis of the following waste codes:
02 01 03 - untreated plant tissue waste from agriculture, horticulture and forestry activities
02 01 07 - untreated wood waste from forestry activities
02 03 04 - vegetable waste unsuitable for consumption or processing
03 01 01 - untreated waste bark and cork
03 01 05 - untreated sawdust, wood shavings and wood cuttings
03 03 01 - untreated waste bark and wood
19 02 06 Sludge from waste types within this table which have been previously heat treated only
19 02 10 Non-hazardous Glycerol 19 06 03 Liquor from anaerobic treatment of municipal waste (from a process that treats wastes listed in this table) 19 06 04 Digestate from anaerobic treatment of municipal waste (from a process that treats wastes listed in this table) 19 06 05 Liquor from anaerobic treatment of animal and vegetable wastes 19 06 06 Digestate from anaerobic treatment of animal and vegetable wastes 19 08 05 Sewage sludge 19 08 09 Grease and oil mixture from oil and water separation containing only edible oils and fats 19 08 12 Sludges from the biological treatment of industrial waste water (from a process that treats wastes listed in this table) 20 01 01 Paper and cardboard 20 01 08 Biodegradable kitchen and canteen waste 20 01 25 Edible oils and fats 20 02 01 Biodegradable waste 20 03 01 Separately collected biodegradable wastes 20 03 02 Biodegradable waste from markets All waste accepted at the Authorised Place must be inspected to ensure it meets the types and quantities authorised.
Wastes with the following characteristics must not be accepted at the Authorised Place:
- waste significantly contaminated with non-compostable or digestible materials.
- waste containing post-consumer wood, treated wood, wood-preserving agents or other biocides.
- waste containing Japanese Knotweed or any other invasive non-native plant species.
- pest infested waste.
All potentially odorous materials must be stored within suitable closed containers or covered to prevent odour.
All storage and processing of feedstock, digestate and effluent must take place on an area with a sealed drainage system.
All liquid feedstock, digestate and effluent must be kept within a liquid storage and management system.
The liquid storage and management system must be designed, constructed, maintained, managed and of sufficient capacity to prevent any emissions.
The liquid storage and management system must be constructed as detailed in the liquid storage and management system engineering plans.
Liquid digestate storage lagoons with walls made of earth must not be filled to a level that results in less than 750 millimetres of freeboard.
Liquid feedstock, digestate and effluent storage lagoons with walls made of earth must:
- be lined with an impermeable sheet material; and
- have suitable leak detection
The impermeable liner at the mixing and filling zones of any earth-banked liquid feedstock, digestate or effluent storage lagoons must be protected with a layer of concrete.
Liquid digestate storage tank(s) must not be filled to a level that results in less than 300 millimetres of freeboard.
Non-liquid feedstock must not overtop the height of the vessel it is stored in.
Any gas engine and/or combined heat and power (CHP) plant stack height associated with the authorised activities must be:
- greater than or equal to 3 metres above the roof ridge height of the building on which it is located; or
- greater than or equal to 3 metres above the ground if it is located separate to any building; and
- greater than or equal to the height of any part of a building which is located within a distance of 5 times the uncorrected stack height.
All biogas condensate must be:
- collected and contained; or
- recirculated back to the digester.
Pressure, temperature and flowrate in the pressure system must be monitored and recorded via telemetry 24 hours a day.
The pressure relief and vacuum systems must be:
- Inspected to ensure they are correctly seated; and
- Linked to an alarm system(s) which is connected to 24 hour telemetry.
All reasonable steps must be taken to minimise:
- Emissions of unburned biogas;
- Any activation of a pressure relief valve; and
- The operation of the auxiliary flare.
Any activation of the flare must be recorded and reported as an environmental event.
All releases to the air from the authorised activities during normal operation, other than condensed water vapour, must be free from visible emissions.
Point source emissions to air from the authorised activities must only be made from the gas engine and/or the combined heat and power (CHP) plant stack(s).
Emissions of substance(s) to the air from the gas engine and/or CHP plant stack(s) must not exceed the specified emission limit value specified in Table 2.
Air must not be added to dilute emissions in order to achieve emission limit values specified in Table 2.
The emission of any substance, not specified in Table 2, from the authorised activities must not cause environmental harm.
Table 2. Emissions to air from gas engine and/or CHP
Substance Emission Limit Value Dust 50 mg/m3 Oxides of Nitrogen (NOx) 190 mg/m3 Sulphur Dioxide 15 mg/m3 Total Volatile Organic Compounds 20 mg/m3 Carbon Monoxide 1,000mg/m3 Monitoring of emissions of substances to air must be undertaken at the gas engine and/or CHP plant stack(s) at the sample port, frequency and using the monitoring standard specified in Table 3.
Sample points must be installed, maintained and appropriately identified so that representative samples may be safely obtained.
Monitoring must be undertaken:
- during normal operation;
- under stable conditions; and
- at a representative, even load.
The first monitoring of emissions must be undertaken within four months of the start of operations.
Table 3. Monitoring requirements for emissions to air from gas engine and/or CHP
Parameter Emission Point Reference Monitoring Frequency Monitoring Standard Dust Sample port determined in accordance with BS EN 15259 Manufacturer’s guarantee or annually BS EN 13284-1 Oxides of Nitrogen (NOx) Sample port determined in accordance with BS EN 15259 Annually BS EN 14792 Sulphur Dioxide Sample port determined in accordance with BS EN 15259 On commissioning of new plant OR a new feedstock is introduced to the process BS EN 14791 Total Volatile Organic Compounds Sample port determined in accordance with BS EN 15259 Annually BS EN 12619 Carbon Monoxide Sample port determined in accordance with BS EN 15259 Annually BS EN 15058 Measures must be taken to prevent, or where that is not practicable, minimise:
- odour;
- noise;
- dust;
- litter; and
- the presence of vermin;
arising from the authorised activities.
Offensive odours from the authorised activities as perceived by a SEPA Officer must not be emitted beyond the boundary of the Authorised Place.
Noise from the authorised activities, which has a significant impact on the environment, people or property, must not be emitted beyond the boundary of the Authorised Place.
Dust from the authorised activities, which has a significant impact on the environment, people or property, must not be emitted beyond the boundary of the Authorised Place.
Litter from the authorised activities, which has a significant impact on the environment, people or property, must not be emitted beyond the boundary of the Authorised Place.
Waste must not be burned at the Authorised Place.
SEPA must be notified via its pollution hotline contact telephone number as soon as reasonably practicable, and in any case within 24 hours of identification of an event, of any of the following:
- an event that has caused or could cause adverse impact to the environment or harm to human health;
- an event that results, or could result, in an emission to the environment that is not authorised;
- an event that has caused a breach of a condition of this authorisation.
In this condition, the meaning of ‘event’ is as defined in the Interpretation of Terms of this authorisation.
All measures that are reasonably practicable must be taken to stop an event and to minimise its effect on the environment.
Within 14 days of an event a report must be submitted to SEPA detailing:
- The reason(s) for the event;
- the action(s) taken to stop the event and minimise the impacts; and
- the action(s) taken to prevent the event from recurring.
All information recorded, kept or submitted to SEPA in accordance with a condition of this authorisation must be:
- true and accurate;
- kept for a minimum of six years; and
- provided to SEPA upon request.
For each calendar year the information detailed in Appendix 1 must be submitted to SEPA on or before 28 January the following year.
The information detailed in Appendix 1 must be submitted to SEPA via email, in the excel spreadsheet supplied by SEPA, to waste.data@sepa.org.uk
The results of the monitoring of emissions, as described in condition 27, must be submitted to SEPA within eight weeks of the date the monitoring took place via email to registry@sepa.org.uk
Bioaerosols
Particles that contain living organisms, such as bacteria, fungi and viruses or parts of living organisms, such as plant pollen, spores and endotoxins from bacterial cells or mycotoxins from fungi.
Digestate
Material remaining after anaerobic digestion of biodegradable feedstock including whole digestate (mixture of liquor and fibre), liquor, and separated fibre.
Effluent
A mixture consisting wholly of or containing liquid produced from the storage of any forage crop or other feedstock, the storage of digestate, and rainwater or groundwater emanating from an effluent collection system or drain.
Emission
The direct or indirect release of substances or heat from individual or diffuse sources in the authorised activities into air, water or land.
Emission limit value
The mass, expressed in terms of specific parameters, concentrated or level of an emission, which may or may not be exceeded during one or more periods of time.
All emission limit values are defined at:
- a temperature of 273.1K;
- a pressure of 101.3kPa:
without correction for water vapour content.
Environmental harm
- harm to the health of human beings or living organisms,
- harm to the quality of the environment, including:
- harm to the quality of the environment taken as a whole,
- harm to the quality of air, water or land, and
- other impairment of, or interference with, ecosystems,
- offence to the senses of human beings,
- damage to property, or
- impairment of, or any interference with, amenities or other legitimate uses of the environment.
Event
- any accident which has caused or could cause environmental harm; or
- any malfunction, breakdown or failure of plant, infrastructure or techniques which has caused or could cause environmental harm; or
- force majeure or action taken to save human life or limb.
Feedstock
The non-waste materials to be treated in anaerobic digestion plant.
Freeboard
The vertical distance between the crest of a tank, container or lagoon and the digestate surface.
Gas engine
An internal combustion engine which operates according to the Otto cycle and uses spark ignition to burn fuel.
Impermeable surface
A surface constructed of impermeable material to a standard sufficient to prevent the transmission of liquids beyond the surface. Should be read in conjunction with the term ‘sealed drainage system’.
Impermeable sheet material
- synthetic rubbers, EPDM (ethylene propylene diene monomer rubber) and butyl,
- plastics, including polyvinyl chloride, low density polyethylene and high density polyethylene, and
- reinforced geomembranes.
Invasive non-native plant species
Has the same meaning as in the Wildlife and Countryside Act 1981 for “invasive species of plant outwith its native range”.
Leak-proof
To be constructed of impermeable material of sufficient strength and structural integrity such that it is unlikely to burst or leak in its ordinary use.
List of waste
The list of waste established by Commission Decision 2000/532/EC replacing Decision 94/3/EC establishing a list of wastes pursuant to Article 1(a) of Council Directive 75/442/EEC on waste and Council Decision 94/904/EC establishing a list of hazardous waste pursuant to Article 1(4) of Council Directive 91/689/EEC on hazardous waste, as amended from time to time.
Liquid
Any aqueous material but excluding sludge.
Liquid storage and management system engineering plans
The liquid storage and management system engineering plans submitted as part of the application.
Liquid storage and management system
An impermeable system designed to contain liquid, comprising the base(s) and walls of liquid feedstock, digestate or effluent storage tank(s), lagoon(s), pit(s), vessel(s), tower(s) plus any connected channels, pipes and valves which:
- has sufficient capacity to accommodate contaminated run-off (including any rainfall) that directly or indirectly enters the liquid storage and management system and the volume of digestate produced during periods when application is not authorised under activity 18 of column 1 of Schedule 9 of the Regulations or would not comply with the requirements of the Action Programme for Nitrate Vulnerable Zones (Scotland) Regulations.
- has an effluent tank which is at least:
- for a feedstock storage tank, lagoon, pit, vessel or tower with a capacity of less than 1,500m³, 20 litres for every 1m³ of silo capacity; or
- for a feedstock storage tank, lagoon, pit, vessel or tower with a capacity of 1,500m3 or greater, 30,000 litres plus 6.7 litres for every 1m3 of silo capacity over 1,500m3;
- is protected against corrosion in accordance with paragraph 7.2 of the Code of Practice on Buildings and Structures for Agriculture published by the British Standards Institution and numbered BS 5502-50:1993+A2:2010;
- is capable of withstanding characteristic loads calculated on the assumptions and in the manner as set out in paragraph 5 of the Code of Practice on Buildings and Structures for Agriculture published by the British Standards Institution and numbered BS 5502-50:1993+A2:2010;
- where the system incorporates a system of pumps and sumps, it must be fitted with an automatic overfill prevention device with a dedicated electrical supply and an alarm;
- if new, reconstructed or enlarged on or after 1 January 2022, has a life expectancy of at least 20 years, with proper maintenance, from its construction, reconstruction or enlargement;
- Where the liquid digestate storage tank is fitted with a drainage pipe—
- There must be two valves in series on the pipe and each valve must be capable of stopping the flow of liquid digestate through the pipe and must be kept shut and locked in that position when not in use;
- Sub-paragraph (g)(i) does not apply in relation to a liquid digestate storage tank which drains through the pipe into another liquid digestate storage tank of equal or greater capacity or where the tops of the tanks are at the same level.
Normal operation
Operation of authorised activities excluding start-up and shut-down periods.
Oxides of nitrogen
Nitric oxide expressed as nitrogen dioxide (NO2) and nitrogen dioxide, expressed as nitrogen dioxide (NO2).
Point source emission
Single, identifiable source of emission.
Sealed drainage system
A drainage system with impermeable components and surfaces which does not leak and which will ensure that:
- no liquid will run off the surfaces otherwise than via the system; and
- except where they may be lawfully discharged, all liquids entering the system are collected in a sealed sump.
SEPA Officer
Any person who is authorised in writing by SEPA under section 108 of the Environment Act 1995.
Shut-down
The permanent or temporary cessation of all or part of a process.
Sludge
A by-product of the anaerobic digestion process with a suspension having a high solids content.
Start-up
The starting or re-starting of all or part of a process either for the first time or following shutdown.
Storage
Storage, in relation to waste, includes the keeping, managing, and depositing of waste.
Storage tank
Includes a lagoon, pit (other than a reception pit), vessel or tower used for the storage of feedstock, digestate and effluent.
Sump
In relation to a sealed drainage system, the container in which all liquid collects which must:
- hold at least:
- for a single container, 110% of its capacity;
- or for two or more containers, the greater of:
- 110% of the capacity of the largest container; or
- 25% of the capacity of all containers together.
- catch all spills from the container(s) and related parts;
- be leak-proof;
- be located, and/or protected, to prevent damage as far as reasonably practicable; and
- have any spills and/or rainwater removed as soon as reasonably practicable.
Treatment
Chipping, shredding, cutting, pulverising, blending, screening and anaerobically digesting.
Uncorrected stack height
The stack height before any required increases in height are made to account for any nearby buildings.
Waste
Has the same meaning as in section 75 of the Environmental Protection Act 1990.
Waste code
The six-digit code referable to a type of waste in accordance with the List of Waste and in relation to hazardous waste, includes the asterisk.
How to apply
In this section you can find out how to apply for a new authorisation and how to apply for a variation, transfer and surrender of an existing authorisation.
New applications
You can apply for a new registration for this activity using our digital application service.
Step 1: Download your activity form
You will need to download and complete the following activity form. The completed form will be submitted as part of your application:
Step 2: Provide supporting information
For a new registration, you will also need to provide the following supporting information:
- Location plan(s)
- Information on the previous and current use of the area
- Infrastructure plan
- Information on your proposed waste acceptance process
- Information on your waste storage
- Information on your process(es) for waste treatment
- Information on your proposed pollution control measures
Step 3: Submit using our digital application service
You can submit your completed application using our digital application service.
Make an application for a new authorisation
Help and guidance
- Interpretation and glossary of terms
- Appendix 1 – Registration data return requirements
- WAS-G-DEF-07: End of waste criteria for digestate
- WAS-G-EASR-03: Waste storage and treatment