Managing sewage sludge, slurry and silage
Regulations, guidelines and codes of practice governing the use of sewage sludge, slurry and silage on agricultural land, and the impact of Cross Compliance and Nitrate Vulnerable Zones.
There are various regulations, guidelines and codes of practice that govern the use of sewage sludge, slurry and silage on agricultural land.
It will also show how Cross Compliance and Nitrate Vulnerable Zones (NVZ) impact on your management of farm waste sewage sludge, slurry and silage.
Sewage sludge is a by-product of the waste-water treatment process that you can use on your farm. Treated sewage sludge - also known as ‘biosolids’ - has several valuable properties. It:
- is a readily available alternative soil-building material
- contains nutrients and valuable trace elements essential to animals and plants
- is a more efficient and sustainable alternative to inorganic fertilisers and mineral fertilisers - such as phosphate
- provides a source of slow-release nitrogen ideal for use in land restoration
- is a good substitute for peat in land-reclamation projects thus conserving valuable natural peatland
However, sewage sludge can contain heavy metals which may be harmful to humans and animals unless it is applied correctly. If you supply or spread sludge on agricultural land you must meet the requirements of the Sludge (Use in Agriculture) Regulations.
The key requirements of the Regulations are:
- sewage sludge must have been tested according to the Sludge Regulations
- you must have tested the soil and checked that the concentration of metals in the soil will not exceed the limit
- you must not spread sludge on a soil with a pH below five
For more information, see the guide on soil use.
You must not use sewage sludge and septic tank sludge:
- when fruit - other than fruit trees - or vegetables are growing or are to be harvested in the soil at the time of use
- without considering plants’ nutrient needs
- if it will damage soil, surface water or groundwater quality
The use of sewage sludge on farms is covered by Statutory Management Requirement (SMR) 3 under Cross Compliance. For more information, see the guides on Cross Compliance: the basics and Statutory Management Requirements (SMR).
If sewage sludge gets into a watercourse you should immediately call the Environment Agency Water Pollution hotline on 0800 80 70 60. For more information, see water pollution on farms.
Bringing sludge on to your farm
When sewage sludge passes from one person to another the Environmental Protection (Duty of Care) Regulations apply.
If you have used a different sewage-sludge producer in the past you must give your current producer details of where, when and how much sludge you used and who supplied it.
You cannot transport sewage sludge unless you are registered as a waste carrier and you must complete duty of care waste-transfer notes.
To find out how to reduce the amount of waste your farm produces see minimising farm waste, composting and recycling.
Different types of sewage sludge
Sewage sludge can be raw or treated and there are different sorts of treatment. There are different rules for each of these types of sewage sludge.
You will have to treat your sewage differently depending on how it is classified. For more information see the guides on non-hazardous waste: treatment and disposal and hazardous waste: treatment and disposal.
Untreated or raw sewage sludge
You cannot apply untreated or raw sewage sludge to land that is used for growing crops, whether they are food crops - including crops for livestock - or non-food crops.
Treated sewage sludge
Treated sewage sludge is also known as ‘biosolids’. There are two different forms of treatment - conventional and enhanced.
In conventionally treated sludge at least 99 per cent of pathogens have been destroyed. If you’re using conventionally treated sewage sludge there are rules that cover its use on:
- grazing land - you cannot surface spread. Instead, you must deep inject the sludge into the soil and leave at least three weeks until it is grazed
- land growing vegetables - there must be at least 12 months between treatment and harvest
You can apply conventionally treated sewage to the surface of grassland - or to forage crops such as maize - which will then be harvested. However, there can be no grazing on any regrowth or aftermath in the season in which you applied the sludge.
Enhanced treatment - also known as Advanced Treatment - virtually eliminates all pathogens which may have been present in the original sludge. When using enhanced treated sludge, you must:
- wait at least three weeks before grazing animals or harvesting forage crops
- wait at least ten months before harvesting fruit and vegetable crops that have been grown in direct contact with the soil and are normally eaten raw
Your local sewerage operator can tell you what treatment has been used. This will affect where and when you can apply the sludge and also the fertiliser and soil conditioning value.
For more information, see the guides on soil use and landspreading.
ADAS is the UK’s largest independent provider of environmental solutions, rural development services and policy advice. You can get ADAS guidance on the minimum acceptable levels of treatment based upon crop types and sewage type.
Sewage sludge and Cross Compliance
To qualify for full payment under the Single Payment Scheme (SPS) and other direct payments - eg the Environmental Stewardship schemes - you must meet all relevant Cross Compliance requirements. These requirements are split into two types:
- Statutory Management Requirements (SMRs)
- requirements to keep your land in Good Agricultural and Environmental Condition (GAECs)
For more information on SMRs and GAECs, see Cross Compliance: the basics, Statutory Management Requirements (SMR) and standards of Good Agricultural and Environmental Condition (GAEC).
The use of sewage sludge on farms is covered by SMR 3 under Cross Compliance. SMR3 aims to ensure that if you use sewage sludge on your land there is no risk to human, animal or plant health and no harmful effects on soil. It also tells you what you should and should not do when using sewage sludge.
Farmers registered with the SPS are restricted in how much sludge they can spread and when they should apply it. For example, you must not spread slurry on waterlogged soil or within two metres of the centre of a hedgerow or watercourse.
You can order the Cross Compliance Handbook for England by calling the Defra Publications Orderline on 08459 556 000, or the Cross Compliance helpline on 0845 345 1302.
Storing or spreading slurries
There is guidance for farmers in England who spread or store livestock slurry or solid manure from agriculture.
You should always spread manure, dirty water and slurry in line with good agricultural practice. This includes:
- drawing up a nutrient management plan
- supervising the work of contractors spreading your slurry
- monitoring the content of metals in pig and poultry manures and in the soil
You should not spread or store slurry or solid manure:
- within 10 metres of a watercourse - including field drains or ditches
- within 50 metres of a source of drinking water for human consumption or of water for farm dairies
- on steeply sloping fields where there is a risk of run-off
- on waterlogged or compacted land
- when fields are frozen or snow-covered
- when the soil is cracked down to field drains, or has been pipe- or mole-drained within the last 12 months
If you let livestock slurry or manure enter rivers, streams or other watercourses, you may be committing a pollution offence.
You can also see the guide on landspreading.
If you are storing slurry, you must:
- Inform your environmental regulator in writing at least 14 days in advance if you plan to install a new silo or alter an existing one.
- Make sure any new, substantially reconstructed or enlarged stores last for at least 20 years with proper maintenance.
- Make sure the slurry storage tank accommodates at least four months’ production - including rainwater. Otherwise, you must prepare a manure management plan. This will help you decide when and where to spread your organic manures. You can download Defra’s draft Manure Management Plan from the ADLib website (PDF, 92K).
- Install two valves in series on any drainage pipe and lock them shut when not in use.
- Follow the Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations 1991 if your storage facilities were constructed or substantially altered after 1 September 1991. Older storage facilities are normally exempt. However, your environmental regulator can stop you using the storage until you’ve carried out improvement work.
- Find out whether you are within a NVZ. If you are, you will need to follow certain rules such as limiting use of organic and inorganic nitrogen fertiliser and keeping records. NVZs are designated areas of land which drain to waters polluted by nitrates from agricultural land. For full information see Nitrate Vulnerable Zones.
Slurry and ammonia
Slurry is likely to release ammonia when it comes into contact with air. Ammonia can damage and disrupt vegetation, soil and foliage. The UK is required to reduce ammonia emissions to meet air quality standards.
You can reduce ammonia emissions by using different:
- storage methods for manure
- handling and spreading methods for slurry
To find out more about how you can reduce ammonia emissions, download Defra’s water, soil and air protection guidance from the ADLib website (PDF, 1.37MB).
Silage effluent is one of the strongest effluents produced on the farm. As a farmer, you need to comply with several legal requirements and codes of good agricultural practice in order to safeguard the farm and the environment.
Those legal requirements include:
- informing the Environment Agency in writing at least 14 days in advance if you plan to install a new silo or alter an existing one - although facilities built before March 1991 are exempt, you should still meet the regulation standards
- ensuring silos and baled, bagged or wrapped silage are more than ten metres away from a watercourse
- having a tank to contain effluent - the tank must have a capacity of 20 litres per cubic metre of silo capacity (up to 1,500 cubic metres), and then an additional 6.7 litres per cubic metre thereafter
Using silage effluent as a soil fertiliser
You should dilute silage effluent with the same amount of water then apply it to land at no more than 50 cubic metres per hectare (4,500 gallons per acre).
For more information, see the guide on landspreading.
For full guidance on the requirements for using silage, download Defra’s water, soil and air protection guidance from Agricultural Document Library (ADLib) website (PDF, 1.37MB).
Further information on sewage sludge, slurry and silage
The Environment Agency’s functions and roles play a central role in delivering the environmental priorities of central government and the Welsh Government. Its principal aims are to protect and improve the environment, and to promote sustainable development.
One of the major roles of Defra is to help the farming industry operate as efficiently as possible. Defra administers European support policies that provide around £3 billion to UK agriculture. It also administers the Whole Farm Approach, which offers a faster, more efficient way for farmers and growers to meet regulatory requirements. Defra oversees a number of agencies that work with arable farmers, imports and exports of crops and implement pest and disease controls. You can call the Defra helpline on 08459 33 55 77.
The Rural Payments Agency (RPA) is responsible for licences and schemes for growers, as well as for running the Single Payment Scheme (SPS). For more information about SPS and how RPA can help your farming business call the RPA helpline on 0845 603 7777.
You can also read the guide on the Single Payment Scheme (SPS).
In England, the Farm Advisory System advises farmers about Cross Compliance. For further information, call the Cross Compliance helpline on 0845 345 1302. Alternatively, find information on Cross Compliance requirement on their website.
You can also read the guides on:
- Cross Compliance: the basics
- Statutory Management Requirements (SMR)
- standards of Good Agricultural and Environmental Condition (GAEC)
- the Single Payments Scheme (SPS)
The National Farmers’ Union (NFU) represents the farmers and growers of England and Wales. It aims to promote successful and socially responsible agriculture and horticulture while ensuring the long-term viability of rural communities. Call the NFU Callfirst helpline on 0870 845 8458, or find out about NFU work and national and regional offices.
Farmers are likely to come into contact with local authorities over a number of farming, land use, food standards and environmental regulations. Your local authority may also be able to provide further information or resources.
NFU Callfirst helpline
0870 845 8458
Environment Agency helpline
03708 506 506
01904 462 000
Environment Agency - Water Pollution hotline
0800 80 70 60
08459 33 55 77
0845 603 7777
Cross Compliance helpline
0845 345 1302
0845 766 0085