SR2021 No 10: anaerobic digestion of non-hazardous sludge at a waste water treatment works, including the use of the resultant biogas
Updated 17 May 2022
Applies to England
© Crown copyright 2022
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For a Part A installation with a biological treatment capacity exceeding 100 tonnes each day.
The Environmental Permitting (England & Wales) Regulations 2016 – Chapter 4 Standard rules
SR2021 No 10 incorporates SR2008 No 19, both 75kte and 250kte.
This standard rules permit is for a Part A installation:
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with an anaerobic digestion (treatment) capacity of over 100 tonnes of waste, or a combination of waste and non-waste each day
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accepting no more than 500,000 tonnes each year
Introductory note
This introductory note does not form part of these standard rules.
Under these rules, facilities:
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must have the capacity to treat more than 100 tonnes of waste, or a combination of waste and non-waste in any one day
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can accept no more than 500,000 tonnes of waste, or a combination of waste and non-waste each year
The amount of waste accepted each day must be constrained to the designed treatment capacity of the digesters and available storage.
These rules allow a Part A installation operator to:
- accept, prepare, store, carry out anaerobic digestion of specified biodegradable wastes
- treat and use the resulting gas
- treat the resulting digestate
The operations must comply with Best Available Techniques (BAT) conclusions and BAT Associated Emissions Limits (AEL). These are laid out in the Best Available Techniques Reference Document (BREF) for Waste Treatment; Industrial Emission Directive 2010/75/EU) Integrated Pollution Prevention and Control) 2018. Chapter 6 stipulates the BAT conclusions for waste operations in general and specifically for biological treatment of waste. Sites permitted before August 2018 are required to comply with BAT conclusions and AELs by 17 August 2022.
The site must be a minimum distance from certain types of sensitive sites. It cannot be within:
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200 metres of the nearest receptor as measured from any combustion stack or stacks, unless the stacks are at least 7 metres high and the effective stack height of each stack is greater than 3 metres
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500 metres of a European site (within the meaning of Regulation 8 of the Conservation of Habitats and Species Regulations 2017) or a Site of Special Scientific Interest, including candidate or proposed sites or a Marine Conservation Zone
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a groundwater source protection zone 1 or 2, or if a groundwater source protection zone has not been defined within 50 metres of any well, spring or borehole used for the supply of water for human consumption (including private water supplies)
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250 metres of the presence of great crested newts, where it is linked to the breeding ponds of the newts by good habitat
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10 metres of any watercourse
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50 metres of a Local Nature Reserve, Local Wildlife Site, Ancient Woodland or Scheduled Monument
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50 metres of a site that has species or habitats of principle importance (as listed in Section 41 of the Natural Environment and Rural Communities Act 2006) that the Environment Agency considers at risk to this activity (these are often referred to as priority habitats and species)
-
a specified Air Quality Management Area
These rules do not apply to installations with more than one operator.
End of introductory note.
1. Management
1.1 General management
1.1.1 The operator shall manage and operate the following activities:
(a) in accordance with a written management system that identifies and minimises risks of pollution, so far as is reasonably practicable, including those risks arising from operations, maintenance, accidents, incidents, non-conformances, closure and those drawn to the attention of the operator as a result of complaints
(b) using sufficient competent persons and resources
1.1.2 Records demonstrating compliance with rule 1.1.1 shall be maintained.
1.1.3 Any person having duties that are or may be affected by the matters set out in these standard rules shall have convenient access to a copy of the permit. It must be kept at or near the place where those duties are carried out.
1.1.4 The operator shall comply with the requirements of an approved competence scheme.
1.2 Energy efficiency
1.2.1 The operator shall carry out all of the following:
(a) take appropriate measures to ensure that energy is used efficiently in the activities
(b) review and record at least every 4 years whether there are suitable opportunities to improve the energy efficiency of the activities
(c) take any further appropriate measures identified by a review
1.3 Efficient use of raw materials
1.3.1 The operator shall carry out all of the following:
(a) take appropriate measures to ensure that raw materials and water are used efficiently in the activities
(b) maintain records of raw materials and water used in the activities
(c) review and record at least every 4 years whether there are suitable alternative materials that could reduce environmental impact or opportunities to improve the efficiency of raw material and water use
(d) take any further appropriate measures identified by a review
1.4 Avoidance, recovery and disposal of wastes produced by the activities
1.4.1 The operator shall take appropriate measures to ensure all of the following, that:
(a) the waste hierarchy referred to in Article 4 of the Waste Framework Directive (WFD) is applied to the generation of waste by the activities
(b) any waste generated by the activities is treated in accordance with the waste hierarchy referred to in Article 4 of the WFD
(c) where disposal is necessary, this is undertaken in a manner which minimises its impact on the environment
1.4.2 The operator shall review and record at least every 4 years whether changes to those measures should be made and take any further appropriate measures identified by a review.
2. Operations
2.1 Permitted activities
2.1.1 The operator is only authorised to carry out the activities in rule 2.1.
2.1.2 The activities shall be undertaken in accordance with best available techniques.
2.1.3 All process plant and equipment shall be commissioned, operated and maintained in accordance with the manufacturer’s recommendations and shall be fully documented and recorded.
Activity 1 – biological treatment of waste by anaerobic digestion
Activity 1 is listed in Schedule 1 of the EPR under S5.4 A(1) (b) (i).
It is the recovery or a mix of recovery and disposal of non-hazardous waste with a treatment capacity exceeding 100 tonnes a day involving biological treatment.
Under WFD Annex II operations, activity 1 is R3 – recycling and reclaiming organic substances which are not used as solvents.
The activity is limited to:
(a) treatment of waste by anaerobic digestion
The following activities are directly associated activities and are included as part of ‘the activities.’
Activity 2 – physical and chemical treatment of waste
Under WFD Annex II operations, activity 2 is R3 – recycling and reclaiming organic substances which are not used as solvents.
The activity is limited to:
(a) physical treatment of waste restricted to screening, dewatering, mixing and digestate separation
(b) heat treatment of waste including thermal hydrolysis and pasteurisation
(c) chemical treatment with non-wastes to thicken digestate
(d) drying only of digestate fractions
Activity 3 – gas combustion to produce heat and power
Under WFD Annex II operations, activity 3 is R1 – use principally as a fuel or other means to generate energy.
The activity is limited to:
(a) burning biogas or natural gas in stationary combustion plant
(b) burning of biogas or natural gas in boilers and use in fuel cells
(c) single fuel use only
(d) the total aggregated rated thermal input for appliances must be less than 5 megawatts
Activity 4 – treating biogas and biomethane
Under WFD Annex II operations, activity 4 is R3 – recycling and reclaiming organic substances which are not used as solvents.
The activity is limited to:
(a) gas storage and drying
(b) gas cleaning and upgrading to biomethane by biological or chemical scrubbing
(c) injecting upgraded biomethane to the national grid
Activity 5 – using auxiliary standby flares
Under WFD Annex I operations, activity 5 is D10 – incineration on land.
This activity is limited to using auxiliary standby flares burning surplus biogas in emergency conditions or during maintenance.
Activity 6 – storage
Under WFD Annex II operations, activity 6 is R13 – storage of waste pending any of the operations numbered R1 to R12 (excluding temporary storage, pending collection, on the site where it is produced).
This activity is limited to secure storage of:
(a) compatible waste before anaerobic digestion
(b) liquid waste consisting of dirty water and, or liquor
(c) non-digestible and quarantined waste
(d) finished digestate, whole or liquid fraction of digestate in covered tanks or lagoons
Activity 7 – storage of raw material and waste generated on site
This activity relates to storing waste generated on site and raw materials, including:
(a) chemicals
(b) lubrication oil
(c) antifreeze
(d) diesel
(e) activated carbon and other spent air abatement media
2.2 The site
2.2.1 The activities shall not extend beyond the site, being the land shown edged in green on the site plan attached to the permit.
2.2.2 Only the combustion plant, reported under Appendix A and registered with the Environment Agency are permitted to operate within the site boundary.
2.2.3 New combustion plant must be notified in writing to the Environment Agency prior to start up.
2.2.4 The activities shall not be carried out within:
(a) 200 metres of the nearest receptor as measured from any combustion stack or stacks, unless the stacks are at least 7 metres high and the effective stack height of each stack is greater than 3 metres
(b) 500 metres of a European site (within the meaning of Regulation 8 of the Conservation of Habitats and Species Regulations 2017) or a Site of Special Scientific Interest, including candidate or proposed sites or a marine conservation zone
(c) a groundwater source protection zone 1 or 2, or if a source protection zone has not been defined for the site within 50 metres of any well, spring or borehole used for the supply of water for human consumption (including private water supplies)
(d) 250 metres of the presence of great crested newts, where the site is linked to the breeding ponds of the newts by good habitat
(e) 10 metres of any watercourse
(f) 50 metres of a Local Nature Reserve, Local Wildlife Site, Ancient Woodland or Scheduled Monument
(g) 50 metres of a site that has species or habitats of principle importance (as listed in Section 41 of the Natural Environment and Rural Communities Act 2006) that the Environment Agency considers at risk to this activity, these are also often referred to as priority habitats and species
(h) a specified Air Quality Management Area
2.3 Waste acceptance
2.3.1 Waste shall only be accepted at the site if all the following apply:
(a) it is within the quantities, codes and descriptions specified in this rule 2.3 and is not excluded waste
(b) it conforms to the description in the transfer documentation supplied by the producer and holder
(c) the waste is biodegradable
(d) the facility has sufficient waste capacity to store and treat the waste
2.3.2 Records demonstrating compliance with rules 2.3.1 shall be maintained.
Waste quantities
The total quantity of waste including solids and liquids accepted at the site:
- shall not exceed 500,000 tonnes a year
- shall not exceed the designed storage capacity of the site
Excluded wastes
Wastes having any of the following characteristics shall not be accepted:
- non-biodegradable waste
- hazardous waste
Waste codes and descriptions
19 Wastes from waste management facilities, off-site waste water treatment plants and preparation of water intended for human consumption and, or industrial use
| Waste code | Description |
|---|---|
| 19 02 | Wastes from physico/chemical treatments of waste |
| 19 02 06 | Sludges from physico/chemical treatment other than those mentioned in 19 02 05 (sewage sludge only) |
| 19 06 | Waste from the anaerobic treatment of waste |
| 19 06 06 | Digestate from anaerobic treatment of animal and vegetable waste (sewage sludge only) |
| 19 08 | Wastes from wastewater treatment works |
| 19 08 05 | Sludges from the treatment of urban waste water |
| 19 12 | Wastes from the mechanical treatment of waste (for example sorting, crushing, compacting, pelletising) not otherwise specified |
| 19 12 12 | Other wastes (including mixtures of materials) from mechanical treatment of wastes other than those mentioned in 19 12 11 (sewage sludge only) subjected to mechanical treatment only from a process that treats wastes which are listed in these standard rules only |
20 Municipal wastes (household waste and similar commercial, industrial and institutional wastes) including separately collected fractions
| Waste code | Description |
|---|---|
| 20 03 | Other municipal wastes |
| 20 03 04 | Septic tank sludge |
2.4 Operating techniques
2.4.1 The activities shall, subject to the rules of this permit, be operated using the techniques and in the manner described in this rule 2.4.
For new operations, before starting the activities, the operator shall:
(a) submit a validation report for all critical infrastructure (primary and secondary containment) and ensure that these have been designed and built to CIRIA 736 report recommendations or an equivalent approved standard
(b) submit a commissioning plan to the Environment Agency which details a validated engineer report and the commissioning of any plant including where appropriate any air management and abatement systems. Following commissioning, a scheme of inspection and maintenance shall be incorporated in the management system
(c) undertake a Hazard and Operability Study (HAZOP) or similar risk identification technique and document any actions
(d) produce and submit a schedule of planned maintenance as identified by the HAZOP or risk assessment or suppliers, which shall be documented
All sites permitted after August 2018 and any new operations must be compliant with all relevant BAT conclusions and BAT AELs.
Technique 1
(a) all waste solids, liquids and sludges shall be securely stored
(b) the acceptance, storage and physical treatment of wastes shall take place only on an impermeable surface with sealed drainage system that meets the recommendations of a CIRIA 736 report or an equivalent approved standard
(c) all process and storage tanks shall be regularly inspected and maintained, and a record maintained
(d) all tanks shall be fitted with level sensors
Technique 2
The volume of waste in storage and in digesters must not exceed the design capacity.
Technique 3
(a) waste shall be stored for the minimum time practicable before treatment
(b) quarantined and rejected waste shall be stored in closed containers or covered and removed to a regulated facility within 5 days
Technique 4
(a) digestate shall be stored within covered containers or covered lagoons
(b) for all storage lagoons and tanks the operator shall maintain a freeboard of at least 750mm
Technique 5
The operator shall have a site drainage plan that clearly shows clean and dirty water drainage and detail any discharge points as Technique 6.
Technique 6
Discharges to groundwater or surface watercourses shall consist of clean water only.
Technique 7
The operator shall have an inspection, maintenance and repair schedule of the facility’s critical infrastructure, including the impermeable surfacing and drainage system and shall implement the same.
Technique 8
(a) all storage and process tanks shall be located on an impermeable surface (a hydraulic permeability of not greater than 1x 10-9 m/s) with sealed construction joints within a bunded area (secondary containment). The bunded area or secondary containment shall have a capacity at least 110% of the largest vessel or 25% of the total tankage volume, whichever is the greater
(b) the bund or secondary containment area shall be regularly inspected to ensure they are regularly emptied of rainwater
(c) connections and fill points shall be within the bund or secondary containment
(d) no pipework should penetrate the bund wall or secondary containment unless the construction is compliant with CIRIA 736 report
Technique 9
(a) underground tanks shall have 100% secondary containment capacity and appropriate leak detection. 95% of that capacity must be maintained at all times
(b) for new operations all tanks and containers shall have secondary containment that complies with a CIRIA 736 report or an equivalent approved standard
Technique 10
(a) all air extraction and abatement systems shall be designed and built specifically for the facility by a suitably qualified engineer. These shall be inspected and maintained, and a record kept
Technique 11
(a) all tankers loading and discharging shall be supervised
(b) transfer areas shall be monitored to ensure valves are sealed when not transferring
Technique 12
(a) an auxiliary standby flare shall be available to combust unburnt surplus biogas or bio methane
(b) the operator shall only use the auxiliary standby flare in the event of an emergency and during maintenance to protect the integrity of the plant
(c) flare operation shall be recorded
Technique 13
(a) pressure systems shall be designed to accommodate the routine variation in gas flow, production and pressure events
(b) gas pressures shall be monitored and recorded
(c) the pressure relief and vacuum systems shall be inspected to ensure they are correctly seated
(d) the operator shall document and undertake a written scheme of inspection and maintenance in line with an industry standard
(e) emissions of unburnt biogas shall be minimised
Technique 14
(a) each combustion plant shall be operated and maintained in accordance with its manufacturer’s instructions
(b) records shall be made and retained to demonstrate this
(c) periods of start-up and shut-down must be kept as short as possible
(d) there shall be no persistent emission of ‘dark smoke’ as defined in section 3(1) of the Clean Air Act 1993
Technique 15
All combustion stacks are at least 7 metres high with an effective stack height of greater than 3 metres and shall be vertical and unimpeded by cowls or caps.
Technique 16
All biogas condensate shall be discharged into a sealed drainage system or recirculated back to the digester.
Technique 17
Drying separated digestate fibre can only be undertaken in a suitably designed closed system from which all emissions shall be extracted and treated in a suitably engineered and maintained abatement system.
Technique 18
(a) operators shall have procedures and contingency measures in place for when gas grid demand is reduced. Venting and flaring of gas for disposal purposes is not permitted
(b) operators shall have procedures and contingency plans in place for digestate management when the ability to move their digestate or the demand for the digestate by end users is reduced
Technique 19
Methane leak detection and programmed routine maintenance inspections and repair shall be carried out and a record maintained.
Technique 20
Sludges can be diluted using final effluent from the wastewater treatment works where this is done to aid the pre-treatment and digestion process.
Improvement conditions
Operators of existing facilities (permits issued before 20 December 2021) shall by the 1 October 2022:
1. Undertake an inspection and works programme to ensure that all primary and secondary containment is fit for purpose and shall include:
(a) an assessment and inspection of all primary containment, using a Written Scheme of Examination devised and undertaken by an appropriately qualified certified engineer
(b) an assessment and inspection of all secondary containment against the standards set out in CIRIA 736 by a chartered structural engineer
(c) written reports of the findings of a) and b) (improvement condition 1) shall be submitted to the Environment Agency. Where the reports do not demonstrate that critical primary and secondary containment is fit for purpose, the reports shall contain detailed proposals to bring the containment up to the required standards including timescales for the implementation of individual measures (‘the measures’), or shall propose alternative appropriate measures to ensure all polluting materials will be contained on site
(d) where it contains proposals for works, the report recommendations shall be implemented by the operator in accordance with the Environment Agency’s written approval
2. Produce and submit a schedule of planned improvement and maintenance as identified by a HAZOP or risk assessment and, or suppliers.
3. Submit to the Environment Agency a register of all combustion plant on-site in the format detailed in Appendix A to these rules.
4. Operators at existing facilities shall on or before 31 March 2022 submit a report setting out progress to achieving the BAT conclusions and BAT-AEL’s where BAT is currently not achieved but will be achieved by the 17 August 2022.
The report shall include, but not be limited to, the following:
(a) current performance against the BAT conclusions and BAT-AELs
(b) associated targets and timelines for reaching compliance by 17 August 2022
3. Emissions and monitoring
3.1 Emissions to air, water or land
3.1.1 There shall be no point source emissions to air, water or land, except from the sources and emission points listed under ‘Point source emissions to air – emission limits and monitoring requirements.’
3.1.2 Point source emissions shall be identified on a site plan.
3.1.3 The limits given under ‘Point source emissions to air – emission limits and monitoring requirements’ in this rule shall not be exceeded.
3.1.4 Periodic monitoring shall be carried out at least once every 5 years for groundwater and 10 years for soil, unless such monitoring is based on a systematic appraisal of the risk of contamination.
3.1.5 Point source emission to air - emission limits and monitoring requirements
(a) Monitoring stacks on combustion plant burning biogas
The reference period is periodic over a minimum 1-hour period.
The monitoring frequency is annual.
Monitoring is undertaken in accordance with Monitoring stack emissions: environmental permits (formerly M2)
Monitoring equipment, techniques, personnel and organisations employed for the emissions monitoring programme and the environmental or other monitoring specified in this rule shall have either MCERTS certification or MCERTS accreditation (as appropriate), where available, unless otherwise agreed in writing by the Environment Agency
| Parameter | Limit | Monitoring standard or method |
|---|---|---|
| Oxides of nitrogen (NO and NO₂ expressed as NO₂) | 500 mg/m³ | EN 14792 |
| Carbon monoxide | 1400 mg/m³ | EN 15058 |
| Sulphur dioxide - existing combustion plant until 31 December 2029 | 350 mg/m³ | EN 14791 |
| Sulphur dioxide - existing combustion plant from the 1st January 2030 | 162mg/m³ | EN 14791 |
| Sulphur dioxide new medium combustion plant | 107 mg/m³ | EN 14791 |
| Total volatile organic compounds, including methane | 1000 mg/m³ | EN 12619 |
(b) Monitoring boilers burning gas operational before 20 December 2018
The reference period is periodic over a minimum 1-hour period.
The monitoring frequency is annual.
Monitoring is undertaken in accordance with guidance ‘Monitoring Stack emissions: low risk MCPs and specified generators (formerly M5)’
| Parameter | Limit | Monitoring standard or method |
|---|---|---|
| Oxides of nitrogen (NO and NO₂ expressed as NO₂) more than 1MWth aggregated | 250 mg/m³ if burning biogas or natural gas | EN 14792 |
| Oxides of nitrogen (NO and NO₂ expressed as NO₂) less than 1MWth aggregated | No limit | EN 14792 |
| Sulphur dioxide more than 1MWth aggregated | 200 mg/m³ if burning biogas | EN 14791 |
| Sulphur dioxide less than 1MWth aggregated | No limit | EN 14791 |
| Carbon monoxide | No limit | EN 15058 |
(c) Monitoring boilers burning gas that are new MCP operational after 20th December 2018
The reference period is periodic over minimum 1-hour period.
The first monitoring measurements shall be carried out within 4 months of the issue date of the permit or the date when the MCP is first put into operation, whichever is later following which the monitoring frequency is annual.
Monitoring is undertaken in accordance with guidance ‘Monitoring Stack emissions: low risk MCPs and specified generators (formerly M5)’
| Parameter | Limit | Monitoring standard or method |
|---|---|---|
| Oxides of nitrogen (NO and NO₂ expressed as NO₂) – burning biogas | 200 mg/m³ | EN 14792 |
| Oxides of nitrogen (NO and NO₂ expressed as NO₂) – burning natural gas | 100 mg/m³ | EN 14792 |
| Sulphur dioxide – burning biogas | 100 mg/m³ | BS EN 14791 |
| Sulphur dioxide – burning natural gas | No limit set | BS EN 14791 |
| Carbon monoxide | No limit set | EN 15058 |
(d) Stacks on engines and boilers
The following applies:
(i) uncertainty allowance as stated in Environment Agency guidance ‘Monitoring stack emissions: maximum uncertainty values for periodic monitoring ‘
(ii) the gas exit temperature shall be no less than 200°C
(iii) all limits are defined at a temperature of 273.15 K, a pressure of 101.3 kPa and after correction for the water vapour content of the waste gases at a standardised O2 content of 5% for gas engines and 3% for boilers
(e) Monitoring channelled emissions to air
Either the BAT Associated Emission Limit (AEL) for ammonia (NH3) or odour concentration applies.
The reference period is periodic over minimum 1-hour period.
The monitoring frequency is once every 6 months.
| Parameter | Limit | Monitoring standard or method |
|---|---|---|
| Ammonia (NH₃) | 20 mg/Nm3 | - Emissions of pollutants into the environment through any kind of duct, pipe or stack – includes emissions from open top biofilters - EN ISO 21877 to be used for stacks - Open biofilters methodology as agreed with the Environment Agency in the odour management plan |
| Odour concentration | 1,000 ouE/Nm3 | BS EN 13725 |
3.2 Emissions of substances not controlled by emission limits
3.2.1 Emissions of substances not controlled by emission limits (excluding odour) shall not cause pollution. The operator shall not be taken to have breached this rule if appropriate measures, including, but not limited to, those specified in any approved emissions management plan, have been taken to prevent or where that is not practicable, to minimise, those emissions.
3.2.2 The operator shall:
(a) if notified by the Environment Agency that the activities are giving rise to pollution or are likely to do so, submit to the Environment Agency for approval within the period specified, an emissions management plan which identifies, prevents and minimises the risks of pollution from emissions of substances not controlled by emission limits
(b) implement the approved emissions management plan, from the date of approval, unless otherwise agreed in writing by the Environment Agency
3.2.3 Where not already subject to a specific rule all liquids in containers, whose emission to water or land could cause pollution, shall be provided with secondary containment.
3.2.4 The operator will implement a leak detection and repair (LDAR) programme to detect and mitigate release of volatile organic compounds, including methane. The operator shall undertake a minimum of annual inspections and provide a summary report as set out in rule 4.2.1.
3.3 Odour
3.3.1 Emissions from the activities shall be free from odour at levels likely to cause pollution outside the site, as perceived by an authorised officer of the Environment Agency, unless the operator has used appropriate measures, including, but not limited to, those specified in any approved odour management plan, to prevent or where that is not practicable to minimise the odour.
3.3.2 The operator shall:
a) if notified by the Environment Agency that the activities are giving rise to pollution outside the site due to odour, submit to the Environment Agency for approval within the period specified, a revised odour management plan which identifies and minimises the risks of pollution from odour
b) implement the approved revised odour management plan, from the date of approval, unless otherwise agreed in writing by the Environment Agency
3.4 Noise and vibration
3.4.1 Emissions from the activities shall be free from noise and vibration at levels likely to cause pollution outside the site, as perceived by an authorised officer of the Environment Agency, unless the operator has used appropriate measures, including, but not limited to, those specified in any approved noise and vibration management plan to prevent or where that is not practicable to minimise the noise and vibration.
3.4.2 The operator shall:
a) if notified by the Environment Agency that the activities are giving rise to pollution outside the site due to noise and vibration, submit to the Environment Agency for approval within the period specified, a noise and vibration management plan which identifies and minimises the risks of pollution from noise and vibration
b) implement the approved noise and vibration management plan, from the date of approval, unless otherwise agreed in writing by the Environment Agency
3.5 Monitoring
3.5.1 The operator shall, unless otherwise agreed in writing by the Environment Agency, undertake the monitoring specified in rule 3.1.5.
3.5.2 The operator shall maintain records of all monitoring required by these standard rules including records of the taking and analysis of samples, instrument measurements (periodic and continual), calibrations, examinations, tests and surveys and any assessment or evaluation made on the basis of such data.
3.5.3 Permanent means of access shall be provided to enable sampling and monitoring to be carried out in relation to the emission points specified in rules 3.1 and 3.5 and unless otherwise agreed in writing by the Environment Agency.
3.5.4 Process monitoring requirements
(a) Monitoring meteorological conditions
The operator shall monitor these parameters continuously and keep a record of:
(i) wind speed
(ii) air temperature
(iii) wind direction
(b) Monitoring digester process and gas production
The operator shall monitor these parameters continuously:
(i) digester stability
(ii) gas volume and quality
(iii) gas pressure
The operator shall:
(iv) record to a supervisory control and data acquisition (SCADA) system
(v) carry out digester process and gas production measurements within 4 months of the date the permit is issued, or the date when the medium combustion plant or grid injection is first put into operation, whichever is later
(c) Monitoring primary containment and tank integrity
The operator shall:
(i) maintain daily operational records of capacity and storage
(ii) inspect tank integrity in accordance with the design specification
(iii) assess sediment build up and remove sediment as appropriate
(iv) from the date of commission inspect the tank and carry out a non-destructive pressure testing integrity assessment 5 yearly or as specified by the manufacturers technical specification, whichever is more frequent
(d) process monitoring air abatement and gas upgrade abatement systems
| Parameter | Limit | Monitoring standard or method | Other specifications |
|---|---|---|---|
| Surface conditions (signs of vegetation and channelling or bypass) | Daily | Visual assessment | In accordance with Odour Management Plan |
| Inlet and outlet temperature | Continuous | Temperature probe | Requirements as for surface conditions |
| Gas flow rate inlet and outlet | Continuous | Gas flow meter | Requirements as for surface conditions |
| Moisture | Daily | Grab test or oven drying | Requirements as for surface conditions |
| Thatching and compaction | Weekly | Back pressure | Requirements as for surface conditions |
| pH | Weekly | pH meter or litmus paper | Requirements as for surface conditions |
| Efficiency assessment | Annually | Emission removal efficiency | Annual report detailing the removal efficiency of all abatement systems and planned maintenance |
The operator shall meet these other specifications:
(i) air abatement system shall be monitored in accordance with its design specifications and records will be made available on request
(ii) emission assessment may be more frequent to ensure optimum emission abatement
(iii) monitoring equipment, techniques, personnel and organisations employed for the emissions monitoring programme (including the measurement of exhaust gas temperature) shall be UKAS accredited
(e) Monitoring fugitive emissions
| Parameter | Limit | Monitoring standard or method | Other specifications |
|---|---|---|---|
| Volatile organic compounds, including methane | As agreed with the Environment Agency | Leak detection and repair | EN 15446 - Monitoring points as specified in a DSEAR risk assessment and LDAR programme - Limit as agreed with the Environment Agency as a percentage of the overall gas production |
| Auxiliary flare usage | Continuous | SCADA | Operational record including date, time and duration of use shall be recorded |
| Pressure relief valves and vacuum systems - gas pressure | Continuous | SCADA | Continuous gas pressure shall be monitored |
| Reseating | Minimum weekly | Visual | Ensure that valves are re-seated after release in accordance with the manufacturers design |
| Inspection, maintenance, calibration, repair and validation | Following foaming or over topping or at 3 yearly intervals whichever is sooner | Written scheme of examination | - After a foaming event or sticking, build-up of debris, obstructions or damage - Operators must ensure that PRV function remains within designed operation gas pressure in accordance with the manufacturer’s design by suitably trained and qualified personnel |
| Inspection, calibration and validation report | In accordance with design and construction specifications or after over topping or foaming event | Written scheme of examination | Requirements as for maintenance |
(f) Monitoring lagoons and storage tanks
The operator shall monitor and record the volume stored daily using a visual or flow meter measurement and maintain a record.
3.6 Pests
3.6.1 The activities shall not give rise to the presence of pests which are likely to cause pollution, hazard or annoyance outside the boundary of the site. The operator shall not be taken to have breached this rule if appropriate measures, including, but not limited to, those specified in any approved pests management plan, have been taken to prevent or where that is not practicable, to minimise the presence of pests on the site.
3.6.2 The operator shall:
(a) only use approved products for pest control
(b) treat pest infestations promptly
(c) if notified by the Environment Agency, submit to the Environment Agency for approval within the period specified, a pests management plan which identifies and minimises risks of pollution, hazard or annoyance from pests
(d) implement the pests management plan, from the date of approval, unless otherwise agreed in writing by the Environment Agency
3.7 Fire prevention
3.7.1 The operator shall take all appropriate measures to prevent fires and accidents on site and minimise the risk of pollution from them including, but not limited to, those specified in any approved fire prevention plan.
3.7.2 The operator will undertake a DSEAR assessment and maintain an accident management plan in accordance with rule 1.1.1.
4. Information
4.1 Records
4.1.1 All records required to be made by these standard rules shall:
(a) be legible
(b) be made as soon as reasonably practicable
(c) if amended, be amended in such a way that the original and any subsequent amendments remain legible, or are capable of retrieval, and
(d) be retained, unless otherwise agreed in writing by the Environment Agency, for at least 6 years from the date when the records were made, or in the case of the following records until permit surrender:
(i) off-site environmental effects
(ii) matters which affect the condition of the land and groundwater
4.1.2 The operator shall maintain convenient access, in either electronic or hard copy, to the records, plans and management system required to be maintained by this permit.
4.1.3 The operator shall maintain a record of the type and quantity of fuel used and the total annual hours of operation for each combustion plant.
4.2 Reporting
4.2.1 The operator shall send all reports and notifications required by these standard rules to the Environment Agency using the contact details supplied in writing by the Environment Agency in accordance with table 4.2.
4.2.2 Within one month of the end of each quarter, the operator shall submit to the Environment Agency using the form made available for the purpose, the information specified on the form relating to the site and the waste accepted and removed from it during the previous quarter.
4.2.3 The operator shall keep records of the material exported from the site as non-waste including the type of material, the tonnage of material, the batch number and the date of export. This information shall be reported to the Environment Agency within one month of the end of each quarter and the records shall be maintained for at least 2 years.
Table 4.2 Reporting requirements
| Parameter | Emission or monitoring point (reference) | Report frequency |
|---|---|---|
| Energy and resource use | Consumption of water, energy and raw materials | By 31 January each year |
| Emissions to air | As specified | On 31 January and the 31 July each year or as requested by the Environment Agency |
| Emissions from combustion plant | In accordance with rule 3.1 | By 31 January of each year |
| Efficiency of biofilters and other abatement systems | In accordance with rule 3.5 | By 31 January each year detailing the removal efficiency of all abatement systems and planned maintenance, in accordance with rule 3.3.1 |
| Digester process and gas production process monitoring | In accordance with rule 3.5 | Summary reports quarterly during the first year then yearly thereafter or as agreed with the Environment Agency |
| Digester tank integrity | In accordance with rule 3.5 | 5 yearly from date of commission or, as the manufactures recommendation whichever is sooner, by 31 January |
| Under and over pressure relief systems | in accordance with rule 3.5 | Yearly summary report of over pressure and under pressure events detailing mass balance release by 31 January |
| Leak Detection and repair | Inspection calibration and maintenance | Yearly summary report by 31 January |
| Use of auxiliary flare burning surplus biogas | In accordance with rule 3.5 | Submit a report of flare usage annually by the 31 January. Note - a report is not required for routine maintenance testing of flares for short periods but should be clearly documented |
| Waste returns | In accordance with 4.2.2 | Within one month of the end of each quarter |
| Recovered outputs | In accordance with 4.2.3 | Within one month of the end of each quarter |
| Medium combustion plant engines | In accordance with 4.3.7 | Each year on 31 January detailing date commissioned location, serial number and thermal input for each unit as detailed in Appendix A. New plant must be notified in accordance with rule 4.3.7 |
4.3 Notifications
4.3.1 In the event:
(a) that the operation of the activities gives rise to an incident or accident which significantly affects or may significantly affect the environment, the operator must immediately:
(i) inform the Environment Agency
(ii) take the measures necessary to limit the environmental consequences of such an incident or accident, and
(iii) take the measures necessary to prevent further possible incidents or accidents
(b) of a breach of any permit condition the operator must immediately:
(i) inform the Environment Agency, and
(ii) take the measures necessary to ensure that compliance is restored within the shortest possible time
(c) of a breach of permit condition which poses an immediate danger to human health or threatens to cause an immediate significant adverse effect on the environment, the operator must immediately suspend the operation of the activities or the relevant part of it until compliance with the permit conditions has been restored
4.3.2 Written confirmation of actual or potential pollution incidents and breaches of emissions shall be submitted within 24 hours.
4.3.3 Where the Environment Agency has requested in writing that it shall be notified when the operator is to undertake monitoring and, or spot sampling, the operator shall inform the Environment Agency when the relevant monitoring and, or spot sampling is to take place. The operator shall provide this information to the Environment Agency at least 14 days before the date the monitoring is to be undertaken.
4.3.4 Following the detection of an issue listed in 4.2.1, the operator shall review and revise the management system, and implement any changes as necessary to minimise the risk of reoccurrence of the issue.
4.3.5 The Environment Agency shall be notified at least 14 days in advance of any planned change to the Medium Combustion Plant which could affect compliance with applicable emission limits.
4.3.6 The Environment Agency shall be notified within 14 days of the occurrence of the following matters except where such disclosure is prohibited by Stock Exchange rules:
(a) Where the operator is a registered company:
(i) any change in the operator’s trading name, registered name or registered office address, and
(ii) any steps taken with a view to the operator going into administration, entering into a company voluntary arrangement or being wound up
(b) Where the operator is a corporate body other than a registered company:
(i) any change in the operator’s name or address, and
(ii) any steps taken with a view to the dissolution of the operator
(c) In any other case:
(i) the death of any of the named operators (where the operator consists of more than one named individual)
(ii) any change in the operator’s name(s) or address(es), and
(iii) any steps taken with a view to the operator, or any one of them, going into bankruptcy, entering into a composition or arrangement with creditors, or, in the case of them being in a partnership, dissolving the partnership
4.3.7 The operator shall notify the Environment Agency, as soon as is practicable, in writing of any change of new combustion plant or generator at the site.
4.4 Interpretation
4.4.1 In these standard rules the expressions listed in this section shall have the meaning given.
4.4.2 In these standard rules references to reports and notifications mean written reports and notifications, except where reference is made to notification being made ‘immediately’, in which case it may be provided by telephone.
‘accident’ means an accident that may result in pollution
‘accident management plan’ means a plan that identifies risks and failures which can have an impact on the environment or have environmental consequences. The plan must minimise the potential causes and consequences and identify clearly, the roles, responsibilities and action to be taken to minimise the consequences of accidents. This includes measures to prevent and control fires on site (see fire prevention plan). This must take into account any raw material stored on site and include clearly marked zoning as identified in the DSEAR risk assessment or plan
‘Air Quality Management Area’ means that defined in the Environment Act 1995, Part VI, 83(1) as amended
‘anaerobic digestion’ means a process of controlled decomposition of biodegradable materials under managed conditions where free oxygen is absent, at temperatures suitable for naturally occurring mesophilic or thermophilic anaerobe and facultative anaerobe bacteria species, which convert the inputs to a methane-rich biogas and whole digestate
‘associated emission levels (AELs)’ is the emission limit associated with the best available techniques as set out in the Best Available Techniques Reference Document (BREF) for Waste Treatment
‘authorised officer’ means any person authorised by the Environment Agency under section 108(1) of The Environment Act 1995 to exercise, in accordance with the terms of any such authorisation, any power specified in Section 108(4) of that Act
‘auxiliary flares’ means flares that are able to burn biogas in the event of emergency or maintenance of the plant and that achieve complete destruction of all volatile compounds. These are also referred to as surplus gas burners
‘best available techniques’ means the most effective and advanced stage in the development of activities and their methods of operation which indicates the practical suitability of particular techniques for providing the basis for emission limit values and other permit conditions designed to prevent and, where that is not practicable, to reduce emissions and the impact on the environment as a whole:
(a) ‘techniques’ includes both the technology used and the way in which the installation is designed, built, maintained, operated and decommissioned
(b) ‘available techniques’ means those developed on a scale which allows implementation in the relevant industrial sector, under economically and technically viable conditions, taking into consideration the costs and advantages, whether or not the techniques are used or produced inside the Member State in question, as long as they are reasonably accessible to the operator
(c) ‘best’ means most effective in achieving a high general level of protection of the environment as a whole
‘biodegradable’ means a material is capable of undergoing biological anaerobic or aerobic degradation leading to the production of CO2, H2O, methane, biomass, and mineral salts, depending on the environmental conditions of the process
‘capacity’ means the potential capacity and not historical or actual production levels or throughput. This means that the designed capacity is the maximum rate at which the site can operate. Biological treatment of waste usually takes place over more than one day, so the physical daily capacity can be calculated by dividing the maximum quantity of waste that could be subject to biological treatment at any one time by the minimum residence time. Further guidance ‘RGN2: Understanding the meaning of regulated facility Definition of regulated facility’ is available
‘channelled emissions’ means the emissions of pollutants into the environment through any kind of duct, pipe, stack, etc. This also includes emissions from open top biofilters
‘combustion plant’ means medium combustion plant, specified generator or boiler used in the production of heat or power and burning biogas, biomethane or natural gas
‘competent persons and resources’ means that a technically competent person accredited to a relevant scheme must attend site and record their attendance, and that all roles and responsibilities are clearly stated in the management systems along with records of operatives’ training. See the guidance on the level of competence and duration of attendance
‘D’ means a disposal operation provided for in Annex II to Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on Waste
‘digestate’ means material resulting from an anaerobic digestion process
‘DSEAR’ means the Dangerous Substances and Explosive Atmospheres Regulations 2002
‘effective stack height’ means:
a) if away from buildings actual stack height is no less than 3 metres
b) if attached to or on top of a building the stack tip must be no less than 3 metres above roof ridge
c) if there are other buildings within a distance of 5L from the point of discharge, the top of the stack must be no less than 3 metres above the roof ridge of the highest building. L is the lesser of the two measurements of building height and maximum width of the building, measured in metres
‘emissions of substances not controlled by emission limits’ means emissions of substances to air, water or land from the activities, either from emission points specified in these standard rules or from other localised or diffuse sources, which are not controlled by an emission limit
‘emissions to land’ include emissions to groundwater
‘fire prevention plan’ means a written document setting out procedures to prevent and minimise fires and the spread of fires.
‘first put into operation means’ the date when the fuel is first combusted in the combustion plant
‘fuel cell’ means a device that converts the energy of a fuel directly to electricity and heat without combustion
‘generator’ means any combustion plant which is used to generate electricity, excluding mobile, unless it is connected to the national grid
‘good habitat’ means rough (especially tussocky) grassland, scrub and woodland
‘groundwater’ means all water, which is below the surface of the ground in the saturation zone and in direct contact with the ground or subsoil
‘groundwater source protection zone’ means as defined in the document titled Protect groundwater and prevent groundwater pollution published by the Environment Agency in 2017
‘hazardous waste’ has the meaning given in the Hazardous Waste (England and Wales) Regulations 2005 (as amended)
’leak detection and repair (LDAR) programme’ means a structured approach to reduce fugitive emissions of organic compounds by detection and subsequent repair or replacement of leaking components. Currently, sniffing (described by EN 15446) and optical gas imaging methods are available for the identification of leaks. As set out in BAT conclusions 14 and 6.6.2 Diffuse emissions of organic compounds to air
‘MCERTS’ means the Environment Agency’s Monitoring Certification Scheme
‘medium combustion plant (MCP)’ means a combustion plant with a rated thermal input equal or greater than1 megawatt but less than 50 megawatts
‘nearest sensitive receptor’ means the nearest place to the permitted activities where people are likely to be for prolonged periods. This term would therefore apply to dwellings (including any associated gardens) and to many types of workplaces. We would not normally regard a place where people are likely to be present for less than 6 hours at one time as being a sensitive receptor. The term does not apply to those controlling the permitted facility, their staff when they are at work or to visitors to the facility, as their health is covered by Health and Safety at Work legislation, but would apply to dwellings occupied by the family of those controlling the anaerobic digestion facility
‘new medium combustion plant’ means one that is not existing in accordance with the definition in the Environmental Permitting (England & Wales) Regulations 2016, that is one which was put into operation after 20 December 2018. This includes replacement Medium Combustion Plant Directive MCPs and generators
‘operator’ means in relation to a regulated facility, means:
(a) the person who has control over the operation of the regulated facility
(b) if the regulated facility has not yet been put into operation, the person who will have control over the regulated facility when it is put into operation, or
(c) if a regulated facility authorised by an environmental permit ceases to be in operation, the person who holds the environmental permit
‘pest’ means birds, vermin and insects
‘pollution’ means emissions as a result of human activity which may:
(a) be harmful to human health or the quality of the environment
(b) cause offence to a human sense
(c) result in damage to material property, or
(d) impair or interfere with amenities and other legitimate uses of the environment
‘quarter’ means a calendar year quarter commencing on 1 January, 1 April, 1 July or 1 October
‘R’ means a recovery operation provided for in Annex II to Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on Waste
‘sealed drainage system’ in relation to an impermeable surface, means a drainage system with impermeable components which does not leak and which will ensure that:
(a) no liquid will run off the surface otherwise than via the system
(b) except where they may lawfully be discharged to foul sewer, all liquids entering the system are collected in a sealed sump
‘secondary containment’ means a system that is capable of containing loss from all above ground and underground storage tanks and that complies with CIRIA standard 736 or an equivalent standard of design and construction
‘secure storage’ means storage where waste cannot escape and members of the public do not have access to it
‘specified generator’ means a group of generators, other than excluded, between 1 and 50 megawatts or less than 50 megawatts as defined in Schedule 25B(2) of SI 2018 No.110 of the EPR
‘year’ means calendar year commencing on 1 January
End of standard rules
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