Intensive pig and poultry farming: how to comply with your permit

3. Emissions and monitoring

How to meet the emissions and monitoring requirements in section 3 of your intensive pig and poultry farming permit.

You must read the guidance on control and monitor emissions for your environmental permit and follow the sections that apply to you. You must also meet all the following standards in this section.

In this section the Environment Agency refers to ‘slurry’, ‘other fouled water’ and ‘clean water’.

Slurry is liquid or semi-liquid matter composed of excreta produced by livestock while in a yard or building. It is also a mixture consisting of livestock excreta, livestock bedding, rainwater and washings from a building or yard used by livestock. It has a consistency that allows it to be pumped or discharged by gravity at any stage in the handling process. Slurry includes duck effluent, seepage from manure and wash water.

Other fouled water is unclean water that is not directly contaminated by livestock excreta. It applies to drainage from farm buildings and yards not accessible to livestock but used for farm activities and by farm vehicles. Other fouled water must be intercepted and treated before it can discharge to ground, surface waters or to soakaways. It includes:

• roof water contaminated with dust from animal housing with medium velocity fans or from natural ventilation with roof outlets
• yard water where yards are adjacent to dust sources such as side or gable end ventilation and feed storage

Clean water is water draining from roofs or other surfaces that is free of contamination. Clean water kept separately from slurry and other fouled water may be discharged to ground, surface waters or soakaways without interception and treatment. It includes:

• roof water from housing with high velocity fans or no roof outlets
• clean yard water in areas where any slurry is diverted by a diverter valve to slurry or wash water tanks

High velocity roof extraction fans have a minimum stack height of 5.5 metres and a minimum ventilation outlet efflux velocity of 7 metres per second.

3.1 Point source emissions to water, air, or land

A point source emission is localised in origin – for example, housing ventilation system outlets, soakaway, or a ‘breather’ vent from an oil storage tank.

Your permit only allows point source emissions listed in the table in schedule 3 of the permit. You must meet any specified limits.

If your site condition report has identified that there is a risk to groundwater from your activities, then you must carry out periodic monitoring at least once every 5 years for groundwater and 10 years for soil.

There must be no untreated point source emissions of other fouled water directly into ground or surface waters. The appropriate treatment method must consider the type of contamination and the water it will affect. You can use methods like a swale, constructed wetland, settlement pond or sediment trap. You may need to consider how the system will cope with high rainfall events.

Slurry must be collected and can be applied to land in line with the Farming Rules for Water and, where applicable, with nitrate vulnerable zones (NVZ) requirements. 

You can discharge clean water direct to ground or surface waters. 

3.2 Emissions of substances not controlled by emission limits

Emissions of substances not controlled by emission limits must not cause pollution.

Pollution means any emission as a result of human activity which may:

• be harmful to human health or the quality of the environment
• cause offense to a human sense
• result in damage to material property
• impair or interfere with amenities and other legitimate uses of the environment

General building and site maintenance

You must:

• maintain buildings in good repair to minimise rainwater leaks into the house which may increase the moisture content of litter and manure
• keep areas around buildings free of any build-up of manure, slurry and spilt feed
• maintain impermeable surfaces and containment kerbs in areas that may be contaminated by potentially polluting substances - for example, concrete areas around buildings must be free from cracks which may pose a risk to groundwater

Drainage systems and run-off management

You must identify all drainage systems in the accident management plan. Your management system must outline how you intend to prevent the contamination of surface water systems.

It is acceptable for drainage from clean yards and from roofs with high velocity fans or no roof outlets to drain to surface waters. However, measures must be in place to ensure that any clean water drainage systems do not become contaminated.

You must minimise the amount of water from yard areas that requires collection using a combination of the following techniques (BAT 6):

• keep contaminated yard areas as small as possible
• minimise use of water
• segregate uncontaminated rainwater from contaminated water streams that require treatment

Diverter valves or similar (such as temporary bunds) must direct flows to storage immediately prior to when yard areas will become contaminated. For poultry farms, this is likely to include any thinning, catching or mucking out activities, in addition to washing down. For pig farms this would include any time animals are being moved across a yard or when housing is being mucked out.

You may also need to consider kerbing or similar along the edge of concrete areas to ensure there are no escapes onto adjacent unmade ground.

You must prevent slurry from entering surface water drains or draining into the ground. Slurry must be collected and fully contained. It must be contained within covered storage that is compliant with silage, slurry and agricultural fuel oil (SSAFO) requirements for removal off site or spreading on land.

Drainage from animal housing and water from cleaning out is slurry and you must collect it in a tank or lagoon before landspreading or removal from the farm.

Roof water from housing where there are no roof outlets from ventilation systems does not require interception and treatment.

Where housing ventilation systems have outlets through side walls or through gable end fans, interception is required before drainage reaches surface water systems. Interception may include grassed areas, swales or collection pits.

Where side-wall outlets are located above grass areas, further interception is not required, provided that the grass cover is sufficient to collect the dust and to impede run-off to surface water systems.

You must remove the dust regularly where side-wall outlets are located above yard areas.

Roof water from housing with low efflux velocity roof fans (2 to 7 metres per second and minimum 3.5 metre stack height) must be intercepted and treated to remove dust before it discharges to surface waters.

Filters or first flush retention tanks under downpipes can retain a significant amount of contaminants from rainfall. This is especially important after prolonged dry periods, when there may be significant accumulations of dust around vents on roofs.

Roof water from systems with high efflux velocity roof fans (more than 7 metres per second and minimum 5.5 metre stack height) does not require interception and treatment provided roofs remain clean with no visible signs of dust.

You must collect condensate from heat exchangers in a specific tank or wash water tank. You must then treat it in the same way as the wash water from the poultry housing at the end of the crop cycle.

Free-range poultry and ranging areas management

The highest risk areas for nitrogen and phosphorus deposition and run-off potential on free range poultry units are immediately outside of the pop-holes (providing access from sheds to the range) and any outdoor areas where birds tend to congregate.

When considering the siting of free-range poultry units, you should consider the following to determine if there are significant risks to ground and surface waters:

• the slope of the land, especially if over 12 degrees
• a lack of grass cover which could increase the risk of run-off
• proximity to surface water
• soil type and condition which has an impact on the permeability of the soil
• the presence of land drains

Mitigation techniques to reduce the risk of ground and surface water contamination could include the following options.

For range areas:

• fence off any streams or surface waters within the ranging area to prevent bird access and direct deposition of manure
• maintain good grass cover across the range
• rotate areas within the range
• remove compaction to improve water infiltration and reduce run-off

For areas outside of pop-holes:

• protect the areas around pop-holes to prevent rain from entering housing
• manage the ground around pop-holes to prevent capping or erosion of the surface
• manage the area under any mesh platforms to prevent manure build up and generation of slurry
• eliminate the production of slurry by roofing over the area immediately outside the pop-holes
• intercept rainwater from the roof in guttering and direct to a sealed clean water drainage system (this can drain directly to a ditch or watercourse)
• use hardstanding immediately outside of pop-holes with barriers or drainage channels to divert any slurry to a slurry system
• line the ground immediately outside of pop-holes to create an impermeable barrier and divert any contaminated run-off to a slurry system

The area outside the pop-holes may be considered a yard if it has been subject to construction work, topsoil removal, or is enclosed by a temporary or permanent fence. Measures such as excluding rainfall and keeping the area clean may reduce the likelihood of slurry being generated from deposited manure.

Where slurry is generated, it must be collected and contained in a SSAFO compliant structure and it must have a minimum of 4 months storage where the slurry is intended to be spread to land.

Disinfectant footbaths and wheel washes

You must design and manage all biosecurity equipment, so it does not pose a risk of pollution to surface water or groundwater through run-off or infiltration into the ground.

Disinfectant footbaths must be large enough to avoid overflow.

You must adjust any vehicle disinfection systems to produce a fine mist and minimise water use, reducing the risk of run-off. You must consider how to capture and dispose of any run-off from wheel wash and misting areas, if there is no built-in collection tank in the system, depending on the proximity to clean water drains and groundwater vulnerability.

Where you use a knapsack sprayer this should use low levels of disinfectant and run-off containment is generally not required, but you must prevent contamination of clean water drains.

Wheel wash pits must be lined with impermeable material to prevent any risk of pollution to surface or groundwater. You must prevent overtopping.

You can add small amounts (approximately 10 litres) of spent disinfectant from wheel washes and footbaths to manure stores or slurry tanks. This can be applied to land in line with the Farming Rules for Water and, where applicable, with NVZ requirements. 

For larger volumes you can:

• drain the spent disinfectant to a foul sewer if you are connected to one - you must get approval from your sewerage undertaker before you add spent disinfectant to a foul sewer
• use a registered waste carrier to export it from the farm

Housing ventilation

You must operate all ventilation systems to achieve the optimum air quality condition levels for the appropriate stage of production in all weather and seasonal conditions.

You must plan the control of minimum ventilation rates to avoid the build-up of moisture, ammonia, hydrogen sulphide, carbon dioxide, carbon monoxide and dust in the house.

Ventilation must be appropriate to the age, weight and health of the animal.

Draughts will influence animals’ behaviour and must be managed to avoid increased emissions.

Poultry litter management

You must take all reasonable steps to ensure that you maintain poultry litter in as dry and friable condition as possible. You must investigate any changes as this could be due to illness, high temperature, a feed problem or increased humidity.

You must choose and manage poultry drinkers to maintain dry and friable litter.

Duck housing is not expected to maintain dry and friable manure due to the ducks’ water requirements. Water use by ducks should be within the normal range for the age of the bird.

Dust management

You must submit a dust and bioaerosol management plan with your permit application if there are relevant receptors within 100 metres of the installation boundary, such as the farmhouse or farm workers’ houses.

You must:

• store dusty or potentially dusty foodstuff in covered containers, purpose-built silos or under cover
• carry out milling, mixing and transfer of foodstuff in a way that prevents or minimises dust emissions to air
• consider extraction and abatement of dust from feed preparation areas

You must use one or a combination of the following techniques to reduce dust emissions (BAT 11):

• use coarse litter material
• apply litter using a low dust littering technique
• apply ad lib feeding
• use moist feed, pelleted feed or add oily raw materials or binders in dry feed systems
• install dust separators for pneumatically fill feed stores
• design and operate the ventilation system with low air speed within the building
• reduce dust concentration in housing using one of the following:
  • water fogging
  • oil spraying
  • ionisation
• treatment of exhaust air by an air cleaning system such as:
  • water trap
  • dry filter
  • water scrubber
  • wet acid scrubber
  • bio-scrubber (or bio-trickling filter)
  • 2 or 3 stage air cleaning system
  • biofilter

More suggested appropriate measures are in the dust, mud and litter section in the guidance control and monitor emissions for your environmental permit. For more information see the AHDB model template for a dust and bioaerosol management plan.

Examples of appropriate measures for your dust and bioaerosol management plan

Feed management:

• fit covers to feed silo pipes and use bags or collection containers on silo exhausts to capture excess feed and dust during feed deliveries
• extract dust from feed mill areas using suitable filtration systems to reduce dust emissions released to the external environment
• cover feed containers and storage areas to minimise dust emissions and reduce the risk of feed contamination by pests
• promptly collect and remove feed spillages
• use pelleted feed to bind fine feed particles together and reduce dust generation
• increase the fat content of feed to help to bind fine particles together and reduce dust generation (this may not be cost-effective or suitable for some livestock types)
• maize can generate less dust than wheat and barley
• hand feeding may generate less dust than screw augers or automatic feeding systems, although it is unlikely to be practicable on larger farms
• feed pans may generate less dust than feed tracks, although animal welfare must be considered when selecting feeding systems
• avoid overfeeding to minimise feed spillages, as feed crushed into fine particles on the floor can become airborne and contribute to dust emissions

Bedding management:

• select less dusty bedding materials to help reduce dust generation such as sawdust and flax straw
• use a deep litter system instead of a shallow litter system where suitable
• use baled bedding, opened within the house, instead of bulk bedding that is blown into the house
• fit catching curtains when unloading and spreading bulk bedding within the house

Environmental conditions and humidity:

• use misting systems at low ventilation rates, but balance this with the risk of increasing ammonia emissions and with impacts on livestock welfare

Ventilation management:

• increase ventilation rates to reduce airborne dust within the house, but this will require dust to be managed outside of the house
• design and operate ventilation systems according to livestock type and age to optimise airflow and dust removal, while maintaining welfare and avoiding excessive draughts

House cleaning and housekeeping:

• remove dust deposits from around exhaust vents regularly to prevent accumulation
• clean exhaust vents in a way that avoids the release of dust to air or water and do not blow dust off-site or wash it into surface water drains
• cover litter before transporting off-site or move it promptly to a suitable store
• in laying hen enriched cage systems, remove dust deposits using vacuum cleaning while birds remain in the house to reduce the amount of dust available for disturbance and release through ventilation systems

Bird characteristics:

• select less active bird genotypes where practicable
• select bird genotypes with feather characteristics with lower dust production where practicable

Livestock numbers and crop cycle length:

• reduce livestock numbers to reduce the overall dust generation within the house where practicable
• rear livestock to a lower final body weight where practicable

At exhaust dust control methods:

• use screens and windbreaks (natural and artificial) to intercept dust
• use dry filters to collect dust on filters fitted to exhaust vents or internal air recirculation units
• use electrostatic precipitation devices that electrically charge and collect dust
• use passive dry air cleaning units that collect dust on filter panels in front of fans (ensure fans can still operate at higher pressure to prevent heat stress)
• use an air cleaning system such as a wet acid scrubber, 2-stage or 3-stage air cleaning system, bio-scrubber or bio-trickling filter

Slurry storage

All slurry store systems must:

• be covered
• conform with the technical measures in SSAFO

You must use a combination of the following techniques alongside appropriate design and management to reduce ammonia emissions to air from a slurry store (BAT 16):

• reduce the ratio between the emitting surface area and the volume of the slurry store
• reduce wind velocity and air exchange on the slurry surface by keeping the slurry level below full
• minimise stirring of slurry
• cover the store using a rigid cover, flexible cover or floating cover such as plastic pellets, light bulk materials, floating flexible covers, geometrical plastic tiles, air inflated cover, natural crust, straw
• slurry acidification (cover not required)

You must use the following techniques to reduce ammonia emissions to air from an earth banked slurry store (BAT 17):

• minimise stirring of the slurry
• cover the store with a flexible or floating cover such as flexible plastic sheets, light bulk materials, natural crust or straw

The containment stores must have appropriate holding capacity. Calculations must include any slurry produced, wash water, contaminated yard water, run-off from manure storage facilities and any rainfall which will enter the store.

Farms must have a minimum of 4 months storage capacity to comply with SSAFO, where the slurry is intended to be spread to land. If you operate a pig or poultry farm in an NVZ you will need to provide 6 months storage capacity. Greater storage may be required to comply with the Farming Rules for Water. In some scenarios up to 9 months storage capacity may be required depending on site-specific factors, for example:

• crops grown
• soil type
• results of soil analyses
• readily available nitrogen content of manures or slurries

Slurry store covers

You must cover slurry stores and lagoons, or have an acidification system, to reduce ammonia emissions.

Slurry stores that are used to store what the best available techniques (BAT) conclusions define as ‘wastewater’ do not need to be covered. Wastewater is rainwater run-off commonly mixed with manure, water derived from the cleaning of surfaces (such as floors) and equipment, and water derived from the operation of air cleaning systems. This includes yard run-off, wash water and heat exchanger condensate.

Wastewater stores do not require covering providing this effluent is not combined with any other slurry. For example, wash water tanks on poultry farms do not need to be covered.

For more information, see the benefits of covering slurry stores or ask your local Environment Agency officer.

Slurry storage management

You must use at least 2 of the following techniques to prevent emissions to soil and water from slurry collection, piping and from a store or earth bank lagoon (BAT 18):

• use stores that can withstand mechanical, chemical and thermal influences
• select a storage facility with sufficient capacity to hold the slurry during periods when landspreading is not possible
• construct leak-proof facilities and equipment for collection and transfer of slurry
• store slurry in earth banked lagoons with an impermeable base and walls
• install a leak detection system
• check structural integrity of stores at least once every year

Manure storage

Where manure is stored in the yard, all new manure storage areas must:

• have an impermeable base
• provide a collection and containment system for liquid run-off (slurry) which meets the requirements of SSAFO

You can reduce run-off by providing a roof or cover.

You must maintain slurry collection channels and tanks to avoid blockages, and empty tanks to ensure they do not overflow.

You can store manure temporarily in a field for a maximum of 12 months before disposal.

You must use one or more of the following techniques to reduce ammonia emissions to air from the storage of solid manure (BAT 14):

• reduce the ratio between the emitting surface area and the volume of the solid manure heap
• cover solid manure heaps
• store dry, solid manure in a barn
• use a concrete silo for the storage of solid manure

You must use one or more of the following techniques to reduce ammonia emissions to soil and water from the storage of solid manure (BAT 15):

• store dried solid manure in a barn
• use a concrete silo for storage of solid manure
• store solid manure on an impermeable floor with a drainage system or collection tank for run-off
• ensure the store has enough capacity to hold the manure during periods when landspreading is not possible
• ensure any field heaps are located away from surface or groundwater sources where liquid run-off could enter

Further restrictions may apply in NVZs.

If you are processing manure on farm, you must use at least one of the following techniques (BAT 19):

• mechanical separation of slurry
• anaerobic digestion of slurry in a biogas installation
• use of external tunnel for manure drying
• aerobic digestion of slurry
• nitrification-denitrification of slurry
• composting of solid manure

This will:

• help reduce emissions of nitrogen, phosphorus, odour, and microbial pathogens to water and air
• help with manure storage management and manure spreading

Carcass management

The regulation of animal by-products is the responsibility of the Animal and Plant Health Agency.

You must dispose of carcasses in line with the animal by-products regulations.

You can dispose of carcasses off-site or on-site.

If off-site, you must dispose of carcasses through:

• the National Fallen Stock Company
• a licensed knacker
• a rendering plant
• a hunt kennel
• a maggot farm
• an authorised incinerator

You must remove carcasses frequently to prevent odour and fly nuisance. You must cover carcasses to prevent access by birds, flies or rodents.

If on-site, you must dispose of carcasses with an authorised incinerator. You will need to have evidence that the incinerator is authorised, such as the Animal and Plant Health Agency (APHA) licence or by inclusion on the animal by-product operating plants: approved premises.

You can spread ash from a pig or poultry carcass incinerator to land that you own under a U15 exemption. Alternatively, you can export ash off site for disposal with other wastes or it can be spread on land under an environmental permit.

Agricultural fuel oil and other chemical storage

You must contain agricultural fuel oil, pesticides, and veterinary medicines in an area capable of retaining any spillage.

Agricultural fuel oil storage facilities must be bunded, regardless of size or age. Oil bunds must meet the requirements of SSAFO.

Bunds must:

• be impermeable and resistant to the stored materials
• have no outlet (drains or taps)
• have pipework routed within bunded areas with no penetration of contained surfaces
• be designed to catch leaks from tanks or fittings
• have a capacity of greater than 110% of the largest tank or 25% of the total tankage, whichever is larger
• be looked at regularly and any contents removed after checking for contamination
• be fitted with a high-level probe and an alarm, where not frequently inspected
• have tanker connection points within the bund where possible. Otherwise, adequate containment should be provided at the connection point
• be regularly inspected for their condition
• pesticides and veterinary medicines must also be kept in a store that is resistant to fire, dry, frost-free and secure against unauthorised access

Feedstuff

You must provide containment for feedstuff to prevent spillages and minimise waste. You must ensure any potential spill is prevented from entering a drainage system. Stores of feedstuff that can flow under the influence of gravity must be bunded and sited away from drainage systems.

Storage vessels must be protected from collision damage. Collision protection can include:

• careful siting, taking into consideration traffic flow
• use of kerbs or markers to stop reversing vehicles
• use of barriers in more vulnerable locations
• use of high visibility markings such as paint or tape on high-risk structures

3.3 Odour

The Environment Agency acknowledges that there is likely to be odour from outside of the installation boundary.

You must prevent, or where that is not practicable, reduce odour emissions from your farm by using appropriate measures. The Environment Agency will decide if the odour is at a level likely to cause pollution, as described in the odour management guidance.

However, even if you are using all appropriate measures, the Environment Agency considers that the residual odour is unreasonable, you must take further measures to reduce odour pollution. Otherwise, you risk having to reduce or cease operations.

There is more information in control and monitor emissions for your environmental permit: odour.

You must submit a written odour management plan as part of your permit application if there are receptors within 400 metres of the site boundary, or the farm has been the source of odour complaints.

You can use the odour management guidance to help you decide what to include in your plan. You must be able to show how you have tried to minimise the odour where it is not possible to prevent odour pollution outside of the site.

Where odour nuisance at sensitive receptors is expected or has been substantiated, you may need to periodically monitor emissions to air. Section 4 of the odour management guidance provides more information on how to do this.

You must use a combination of the following techniques to reduce odour emissions and impact from your farm (BAT 13).

You can ensure there is adequate distance between the farm and sensitive receptors.

You can use a housing system which implements one or more of the following principles:

• keeping animals and surfaces dry and clean
• reducing the emitting surface of manure
• removing manure frequently to an external (covered) manure store
• reducing the temperature of the manure, for example, by slurry cooling, and of the indoor environment
• decreasing the air flow and velocity over the manure surface
• keeping the litter dry and under aerobic conditions

You can optimise the discharge conditions of exhaust air from the animal house by using one or more of the following techniques:

• increase the outlet height
• increase the vertical outlet ventilation velocity
• effective placement of external barriers to create turbulence in the outgoing air flow
• add deflector covers in exhaust apertures located in low parts of walls to divert exhaust air towards the ground
• disperse the exhaust air at the housing side which faces away from the sensitive receptor and aligning the ridge axis of a naturally ventilated building transversally to the prevailing wind direction

You can use an air cleaning system, such as a bio-scrubber (or bio-trickling filter), bio filter or 2 stage or 3 stage cleaning system.

You can use one or more of the following techniques for manure storage:

• cover slurry or solid manure during storage
• consider general wind direction when locating the store and take measures to reduce wind speed around and above the store
• minimise stirring of slurry

You can process manure with one of the following techniques to minimise odour emissions during or before spreading:

• aerobic digestion (aeration) of slurry
• compost solid manure
• anaerobic digestion

You can use one or more of the following techniques for landspreading:

• band spreader
• shallow injector or deep injector for slurry landspreading
• incorporate manure as soon as possible or within 12 hours

For more information see the AHDB model template for an odour management plan and the odour management guidance

Examples of appropriate measures for your odour management plan

Feed management:

• avoid accumulation of waste feed
• clean up spills
• prevent overflows and spills from feed and drinking systems
• avoid the use of finely ground feeds and long feed drops, as these can increase odorous dust emissions
• carry out mixing and milling of dry foodstuffs within closed systems or in environments where you can minimise emissions
• deliver feed to storage areas and transfer feed from storage facilities to feeding systems, using closed systems to minimise dust generation
• cover feed storage areas or use purpose-built silos
• protect storage areas and silos from collision damage
• store and manage the use of odorous by-products, such as whey and fish meal, to minimise odour

Carcass disposal:

• remove carcasses frequently
• cover carcass storage areas to minimise odour and to prevent access by birds, flies or rodents using lidded bins or plastic bags

Ventilation design and management:

• when designing the ventilation system consider roof (apex) vents as they tend to provide better dispersion of odorous emissions than side-wall vents
• increase the height of discharge points above roof level as this may improve dispersion
• ducting ventilation flows to a single, higher-level stack may provide additional improvements in dispersion (this may reduce odour concentrations close to the installation, but it may increase the distance over which odours can be detected)
• operate ventilation systems at optimum rates appropriate for the age, type and number of livestock housed
• regularly clear dust deposits around the ventilation discharge points to prevent excessive build-up

Drainage management

• fit kerbs to concrete aprons to direct slurry into collection tanks
• enclose slurry collection systems
• empty and clean slurry collection systems regularly to prevent anaerobic conditions developing in settled sludge
• maintain drains and concrete areas in good condition
• promptly collect and manage slurry generated during the cleaning out of buildings at the end of each production cycle

Pig housing management:

• maintain a high standard of cleanliness for the pigs, pens, flooring and areas surrounding livestock buildings
• reduce the area of exposed contaminated surfaces
• ensure adequate separation of feeding, lying and dunging areas
• consider the floor design as this is an important measure in reducing odour emissions from slurry-based pig housing, for example, partially slatted floors generally have lower odour emissions than fully slatted floors
• maintain scraped areas to prevent ponding and the accumulation of urine
• repair damaged flooring as soon as practicable
• remove slurry and manure to a suitable store as frequently as practicable
• clean slurry channels and drainage systems regularly to remove deposits
• maintain drinkers and troughs to prevent leaks
• in solid floor housing systems, provide adequate drainage to prevent the accumulation of effluent in areas where it may stagnate and become anaerobic
• repair damaged concrete surfaces and drains to prevent ponding within buildings
• use sufficient bedding material to absorb excreta and help keep animals clean
• thoroughly clean and disinfect housing between production cycles
• store bedding materials in a dry area

Poultry housing management:

• control dust generation within poultry houses by managing litter moisture content and maintaining good air quality
• minimise dust emissions from buildings where practicable
• maintain good litter quality by managing temperature, ventilation, drinkers, feeders, feed formulation, litter material and depth, condensation, stocking density and bird health
• store litter removed at the end of the production cycle in a dry condition and locate storage areas away from nearby receptors
• maintain drinking systems to prevent leaks and water spillage
• use nipple drinkers with drip cups, which operate on demand, in preference to bell drinkers that continuously hold water
• position drinkers at the correct height for the age and size of the birds to minimise water spillage

Manure and slurry storage, handling and landspreading:

• keep roadways and other areas, such as around buildings and yards, free of slurry or manure
• store manure and slurry as far away as possible from residential areas
• maintain a slurry store cover to give maximum coverage, especially when using a floating cover
• minimise the frequency of slurry stirring where practicable
• keep manure under cover in a storage building
• use treatment techniques such as separation, composting, aeration and anaerobic digestion
• when landspreading do not overfill tankers and spreaders to avoid spills
• clean spreading machinery regularly
• avoid spreading during periods of high humidity, very light winds or clear, still nights
• use low emission slurry spreading techniques, such as a band spreader, shallow injector or deep injector - more information is in the code of good agricultural practice for reducing ammonia emissions
• incorporate manure as soon as possible or within 12 hours

3.4 Noise and vibration

The Environment Agency acknowledges that there is likely to be noise outside of the installation boundary.

You must prevent, or where that is not practicable, reduce noise or vibration pollution from your farm by using appropriate measures. The Environment Agency will decide if the noise or vibration is at a level likely to cause pollution.

If there are receptors within 400 metres of the site boundary, or the farm has been the source of noise complaints, you must submit a written noise management plan as part of your permit application.

You should consider the time of day or night when assessing the impact of noise, not just the level itself. For example, noise can have more impact at night or during leisure times. Reasonable times are during the working day, but certain activities may have to be done outside of these hours. For intensive farming we use the following time definitions:

• daytime is 7am to 11pm
• nighttime is 11pm to 7am
• the working week is Monday to Friday and Saturday mornings, not including public and bank holidays

To prevent or reduce noise emissions from your farm, you must use a combination of the following techniques (BAT 10):

• adequate distance between the installation and sensitive receptors
• consider the location of any equipment such as feed bins and feed silos
• use of operational measures such as closure of doors during feed times, avoidance of noisy activities at night or on the weekends, operation of conveyors and augers full of feed if possible, keeping dirty yard areas to a minimum to reduce scraping activity
• low noise equipment such as high efficiency fans, pumps and compressors, feeding systems which reduce the pre-feeding stimulus
• noise control equipment including noise reducers, vibration isolation, enclosure of noisy equipment, sound proofing of buildings
• noise abatement by inserting obstacles between the source and receptors

For more information see the AHDB model template for a noise management plan and the noise and vibration management guidance.

Examples of appropriate measures for your noise management plan

Deliveries and collections:

• locate feed bins so that delivery movements and handling are reduced
• position delivery and collection points for feed, fuel, other materials, livestock, slurry and waste to take advantage of natural barriers provided by buildings and topography
• instruct staff, contractors and visitors to minimise avoidable noise, especially during night-time periods, including raised voices and unnecessary use of audio equipment
• place hard materials, rather than drop, onto hard surfaces
• minimise the drop height of bulk materials
• arrange for deliveries and collections to take place during normal working hours wherever practicable
• drivers should comply with site speed limits and avoid travelling over rough ground where possible

Ventilation fans:

• when designing the ventilation system avoid the use of sheet metal or other similar construction materials that may vibrate
• use fewer, larger fans operating at lower speeds, or variable-speed fans, as these may produce less noise than smaller, high-speed fans (although variable-speed fans may be less effective at odour dispersion)
• minimise resistance at the air inlet and outlet to avoid placing unnecessary load on each fan
• fan outlet cowls and stacks can provide noise reduction (but if they are undersized, they may increase pressure drop by restricting airflow)
• automatically controlled natural ventilation is an alternative method of ventilation, but its use may be restricted by welfare or production factors and may be less effective than fan-assisted ventilation
• orientate noisy equipment so that noise is directed away from noise-sensitive areas
• locate fans at low level, for example on sidewalls rather than at roof level, as any noise emitted is more likely to be screened by surrounding buildings, vegetation, or local topography
• use acoustic barriers to absorb and reduce noise
• use inlet silencers for fan-pressurised ventilation systems
• incorporate rough surfaces, such as straw bales, within the building to help absorb sound
• operate a small number of fans continuously rather than a larger number of fans that repeatedly switch on and off, particularly at night (however this may not provide the required minimum ventilation rates)
• inspect and maintain fans in accordance with the manufacturer’s instructions as worn, damaged, or unbalanced fans can generate elevated noise levels, including undesirable frequencies or tonal noise

Vehicles and machinery:

• reduce the need for scraping by minimising the area of yard contaminated during the removal of manure from buildings
• place pressure washers and compressors inside buildings or within acoustic enclosures during use (check with the manufacturer before enclosing any plant or equipment as suitable ventilation may be required to prevent overheating)
• locate noisy machinery and operations as far as practicable from noise-sensitive areas.
• screen loading and off-loading points using natural barriers, such as buildings and fences, or temporary screens, such as straw bales
• house generators within an acoustic enclosure or positioned behind an acoustic barrier
• minimise unnecessary movements of trailers, loaders and other vehicles
• avoid idling machinery between work periods and unnecessary engine revving
• organise bird catching and loading operations to minimise manoeuvring of forklift trucks and other equipment outside buildings
• carry out cleaning and the removal of manure using powered equipment at reasonable times to minimise disturbance to nearby receptors
• maintain site roads and tracks in a good state of repair to reduce noise generated by vehicle movements
• ensure that loaders, tractors and other machinery are well maintained, particularly exhaust systems and silencers
• minimise noise caused by vibrating machinery with rotating parts through servicing, balancing and regular maintenance
• reduce noise caused by friction in conveyor rollers, trolleys and other equipment through lubrication and regular maintenance
• test emergency generators and alarms during normal daytime working hours, ideally between 9am and 5pm on working days (where alarm systems are linked to monitoring centres, testing may also need to be carried out at weekends to ensure system functionality)
• minimise any disturbance caused by alarm testing by carrying it out at a consistent time and on a consistent day of the week or month
• ensure alarm noise levels do not exceed those necessary to alert staff

Feeding equipment:

• use auger systems as they are generally the quietest and most energy-efficient method of mechanically transporting feed
• avoid operating conveyors and augers when empty where practicable
• keep pipework and conveyor runs as short as practicable to minimise noise
• as pneumatic transfer systems can be a source of high-frequency noise, use a higher-capacity system operating at a lower speed rather than a lower-capacity system operating at a higher speed
• operate feed mills at reasonable times where practicable
• operate hammer mills and pneumatic conveyors in feed mills when background noise levels are highest to minimise their impact on nearby receptors

Manure and slurry handling:

• contain manure conveyors within suitably constructed enclosures designed to reduce noise emissions
• design pneumatic conveyor systems to minimise the length of conveyor runs and the number of bends
• operate equipment and vehicles at reasonable times wherever possible
• maintain equipment to ensure optimum operating performance and minimise noise emissions

Animal noise:

• use passive feeding techniques for pigs, where appropriate, to minimise squealing associated with anticipation of feeding
• directly deliver feed to minimise the period between pigs becoming aware of feeding activities and feed being made available, to reduce noise generated in response to feeding stimuli
• plan and manage the timing and methods used during stocking and destocking of animals to minimise noise

3.5 Monitoring

Your monitoring requirements are specified in schedule 3 of your permit.

You must use one of the following techniques, at the frequency listed, to monitor the total nitrogen and total phosphorus excreted in manure (BAT 24):

• calculation by using a mass balance of nitrogen and phosphorus based on the feed intake, crude protein content of the diet, total phosphorus and animal performance
• estimation by using manure analysis for total nitrogen and total phosphorus content

This should be completed once every year for each animal category required to report. The Environment Agency guidance tells you how to submit nitrogen and phosphorus emissions data from your permitted farm using an online reporting form.

You must use one of the following techniques, once every year for each animal category, to monitor ammonia emissions to air (BAT 25):

• estimation by using a mass balance based on the excretion and the total (or total ammoniacal) nitrogen present at each manure management stage.
• estimation by using emission factors

You must monitor dust emissions from each animal house once every year using one of the following techniques (BAT 27):

• calculation by measuring the dust concentration and the ventilation rate using EN standard methods or other methods ensuring data of an equivalent scientific quality
• estimation by using emission factors

Both ammonia emissions to air and dust reporting are covered by annual pollution inventory reporting. Duplicate reporting of these emissions is not required. Note dust reporting under pollution inventory reporting currently applies to permitted poultry farms only.

Where livestock housing ventilation air can be channelled through an active system of ducts, a reduction in ammonia emissions and odour can be achieved by using an air cleaning system. An air cleaning system is typically installed at the end of the system of ducting, to remove ammonia before the waste air is vented to the atmosphere. The use of an air cleaning system may require emissions monitoring. Monitoring of key operational parameters may also be required, as referenced in the operating techniques in schedule 1, table S1.2 of the permit.

Other monitoring may be included, for example to ensure compliance with medium combustion plant or small waste incinerator plant requirements.

3.6 Pests

A pest management plan may be required if there is a history of substantiated complaints, such as for flies. The Environment Agency will notify you if this is required.

The plan should include a complaints log and describe in detail the extra controls you need to put in place to control any pests identified.

Appropriate measures to prevent or control flies include:

• regular inspections by nominated personnel
• isolation, securing, removing, or covering of manure, slurry, carcasses and wastes that are attracting flies.
• use of physical prevention methods for example traps, electric fly killers.
• use of pesticides
• seeding litter with Carcinops species beetles
• employing professional pest control contractors

See the section on pest management plans in control and monitor emissions for your environmental permit.

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