Intensive farming risk assessment for your environmental permit

You must follow this guide if you’re applying for a permit or to change (vary) a permit for intensive farming under the Environmental Permitting Regulations.

As part of your risk assessment you must assess the following emissions and check if they are likely to affect ‘receptors’ (people or parts of the environment that could be harmed by emissions from your farm):

• odour
• noise
• dust and bioaerosols (airborne particles that contain living organisms)
• ammonia

Pre-application discussion

Complete and submit the environmental permit pre-application advice form to arrange a pre-application discussion.

Contact the Environment Agency and ask to speak to your local office to arrange a pre-application discussion.

At the pre-application discussion the Environment Agency will tell you about the application process and identify nature conservation sites and neighbours close to your farm who will need to be considered in the environmental risk assessment. The Environment Agency will also tell you what should and should not be included in the permit, for example relevant buildings, fuel storage, carcass incinerators and slurry storage.

Odour and noise from the farm may affect receptors such as local residents, schools, hospitals, parks or businesses. You’ll need to submit written odour and noise management plans as part of your application if there are receptors within 400 metres of the site boundary or if it’s been the cause of odour or noise complaints in the past.

Read the emissions guide to find out what you must do to prevent odour and noise pollution.

Ammonia emissions

You must submit a risk assessment of the impact of ammonia emissions from your site if either of the following apply:

• you’re applying for a new bespoke permit
• you’re applying to change (vary) an existing environmental permit in a way that will cause an increase of ammonia emissions to air from your farm

Factors that could cause an increase of ammonia emissions include:

• an increase in the number of, or change in the type of animals you keep on the farm
• an increase in the amount of manure or slurry you store
• a change to the design of your site, or ventilation, that could lead to higher ammonia concentrations, or to ammonia settling on a nearby receptor, such as residential housing, or a nature conservation site

Ammonia screening

The Environment Agency do a ‘distance screening’ on every application. They will use your address and Ordnance Survey grid details to work out whether your farm is close to nature conservation sites.

At the pre-application discussion the Environment Agency will ask you for information so they can do a simple screening assessment of expected ammonia emissions and the potential effects on nearby nature conservation sites. The simple screening will determine whether you’ll need to employ a consultant to produce a detailed modelling assessment of ammonia emissions to support your application.

You generally cannot get a permit for activities that result in releasing ammonia into water. Contact the Environment Agency before beginning your application if you expect to release ammonia to water.

You will need to provide the following to the Environment Agency so they can do the screening:

• name, address and Ordnance Survey grid reference for your farm
• what type of ventilation system you use, for example fan or natural ventilation
• location of your ventilation, for example roof or side mounted, if roof mounted you must also provide the height of the vents above the ground and the fan efflux velocity in metres per second
• the quantity of manure (in tonnes) stored on your farm at any one time
• the surface area in square metres of any slurry storage facility on your site (including lagoons) and the type of cover used
• a breakdown of animal numbers by type and by type of housing, for example the number of sows, growers and finishers on fully slatted floorings and the number on partly slatted flooring
• the most appropriate ammonia emission factors for the housing type

You’ll also have to provide a site plan if you’re applying for a new application or for a variation which includes changes to the site layout.

If you’re applying to vary your permit, you will also have to describe the proposed change.

At your pre-application discussion the Environment Agency will work out the most appropriate emission factors for the livestock reared on your site and the type of housing you use. Check the standard ammonia emissions factors that the Environment Agency will check your ammonia emissions factors against.

There are 3 standards the Environment Agency will assess your ammonia emissions against to check the risk of air pollution:

• ammonia critical level
• nutrient nitrogen critical load
• acidity critical load

Visit the Air Pollution Information System website to find out what critical levels and loads are.

Ammonia screening thresholds

The Environment Agency will check whether there are any nature conservation sites close to your farm. They will do a simple screening if your farm is within the distances shown in the following table.

Nature conservation site designation	Distance from site in km	Lower threshold %	Upper threshold %
Special protection areas (SPAs), special areas of conservation (SACs), Ramsar sites	5km	4%	20%
Sites of special scientific interest (SSSIs)	5km	20%	50%
National nature reserves (NNRs), local nature reserves (LNRs), local wildlife sites (LWS), ancient woodland (AW)	2km	100%	100%

If the simple screening predicts that emissions from your farm will be less than the lower threshold of the relevant critical level or load you will not need to do detailed modelling.

If the simple screening predicts that ammonia emissions from your farm will be more than the upper threshold of the relevant critical level or load you’ll need to do detailed modelling.

If the simple screening predicts that the ammonia concentrations from your farm will be more than the lower threshold but less than the upper threshold of the relevant critical level or load at a SAC, SPA, Ramsar site or SSSI, the Environment Agency will check if there are other farms in the area whose emissions yours may combine with. If the combined emissions are less than the upper threshold you will not need to do a detailed modelling assessment. If they’re more, you will need to do detailed modelling.

Detailed modelling

Once your simple screening has been completed the Environment Agency will tell you if you need to find a consultant to do detailed modelling for you.

You will need to carry out detailed modelling if:

• the original permit for your installation contained instructions on how you must reduce ammonia emissions - an ‘improvement condition’
• your proposed activities are within 250 metres of any nature conservation sites, for example SPAs, SACs, SSSIs, NNRs, Ramsar sites and local wildlife sites
• the simple screening assessment suggests emissions could affect conservation sites - you will be told if that’s the case

Consultants must follow the guidance for detailed modelling.

Air emissions: biomass boilers

You need to assess the environmental impact of nitrogen dioxide and particulate emissions if you:

• add a biomass boiler to an existing permitted site
• propose a biomass boiler in plans for a new site

Contact the Environment Agency and ask to speak to your local officer to discuss how to do the assessment.

Poultry farms: when you do not need to do an air emissions assessment for your biomass boiler

You do not need to do an assessment of air emissions if the following apply:

• the fuel comes from virgin timber (whole trees and woody parts of trees), clean non-virgin timber (any timber or timber product that has not been treated), straw or miscanthus (also called elephant grass)
• the biomass boiler appliance and its installation are eligible for the Renewable Heat Incentive

In addition, the aggregate boiler net rated thermal input must be less than 0.5 MWth, or it must meet all of the following:

• the aggregate boiler net rated thermal input is less than or equal to 4 MWth
• no individual boiler has a net thermal input greater than 1 MWth
• the stack height is at least 5 metres above the ground and may need to be higher if there are buildings within 25 metres - the stack must extend above the roof level of any building by at least 1 metre
• there are no receptors within 50 metres of the emission points

If your proposed biomass boiler installation does not meet this criteria, then use the criteria for the pig farm. You will not need to do an air emissions assessment if it meets the pig farm criteria.

Pig farms: when you do not need to do an air emissions assessment for your biomass boiler

You do not need to do an assessment of air emissions if the following apply:

• the fuel comes from virgin timber (whole trees and woody parts of trees), clean non-virgin timber (any timber or timber product that has not been treated), straw or miscanthus (also called elephant grass)
• the biomass boiler appliance and its installation are eligible for the Renewable Heat Incentive

In addition, the aggregate boiler net rated thermal input must be less than 0.5 MWth, or it must meet all of the following:

• the aggregate boiler net rated thermal input is less than 1 MWth
• the stack height is greater than 1 metre above the roof level of buildings within 25 metres (where there are no buildings within 25 metres, the stack height must be a minimum of 3 metres above ground)
• there are no SACs, SPAs, Ramsar sites or SSSIs within 500 metres of the emission points
• there are no NNRs, LNRs, AW or LWS within 100 metres of the emission points

Where the aggregate boiler net rated thermal input is greater than 1 MWth but less than 2 MWth you do not need to do an assessment of air emissions if, in addition to meeting all of the above criteria (including fuel type and eligibility for the Renewable Heat Incentive), there are no receptors within 150 metres of the emission points.

Net rated thermal input definition

Net rated thermal input means the rate at which fuel can be burned at the maximum continuous rating of the appliance, multiplied by the net calorific value of the fuel. It’s expressed in MWth. Ask the manufacturer of the biomass boiler for this information.

Air emissions: dust and bioaerosols

You will need to produce and submit a dust and bioaerosol management plan with your application if there are relevant receptors within 100 metres of your farm, such as the farmhouse or farm worker’s houses.

In your dust and bioaerosol management plan, you must give details of control measures you will use to manage the risks from dust and bioaerosols from your farm. Tables 1 and 2 and checklist 1 and 2 in ‘assessing dust control measures on intensive poultry installations’ explain the methods you should use.

The format of your dust and bioaerosol manangement plan should be similar to your odour and noise management plan.

Submit your application

Submit your application within 6 months of your ammonia screening to make sure the data remains current.

If your application requires detailed modelling you must show that your emissions are at the acceptable levels in the screening thresholds table and provide plans to show how you will reduce them if they’re not.

If you’re unable to propose ways to reduce your emissions below these levels, the Environment Agency will do a detailed assessment of your proposal. For SACs, SPAs, Ramsar sites and SSSIs the Environment Agency will consult with Natural England before they decide whether to approve your permit.

Contact

Contact the Environment Agency if you have queries.