Code of Good Agricultural Practice for the Protection

Code of GoodAgricultural Practicefor the Protectionof Air

MINISTRY OF AGRICULTURE,FISHERIES AND FOOD

WELSH OFFICEAGRICULTURE DEPARTMENT

OCTOBER 1998

A

ii

Summary

A summary of the key messages in this Code isset out below. You will be able to reduce airpollution from odours, ammonia, smoke andgreenhouse gases by adopting these practices.Read the Code for further guidance.

REDUCING ODOUR ANDAMMONIA EMISSIONS

Slurry and manure spreading

● Wherever possible, use a band spreader orinjector to apply slurry. Paragraph 148, seealso paragraphs 42 and 50.

● Where a band spreader or injector is not used,a slurry spreader which gives a low trajectoryand large droplets will produce less odouremission. Paragraph 44.

● After surface application of slurry and manureto bare land, incorporate the material into thesoil as soon as possible. Paragraphs 39 and150.

● Avoid applying more than 50 m3 per hectare(4,500 gallons per acre) or 50 tonnes perhectare (20 tons per acre) at one time if odourcould be a nuisance; reduce these rates, asnecessary, so that the amount of total nitrogenapplied does not exceed 250 kg per hectare peryear. Only spread downwind of nearby housesand avoid spreading at weekends, bankholidays or in the evening. Consider if there aresome fields where spreading should not takeplace. Paragraphs 34-40.

Livestock housing

● Wherever possible, collect and transfer slurryevery day to a suitable store. Paragraph 59

● Where bedding is required, use enough to keeplivestock clean and keep all manure as dry aspossible. Manage drinking systems to avoidoverflow and spillage. Paragraph 59.

● Keep concrete areas around buildings clean andfree from any build-up of manure and slurry.Paragraph 63.

Slurry and manure storage

● Only mix slurry when the store is going to beemptied. Mixing should only be necessary tobreak up a surface crust or to remove sediment.Paragraphs 92 and 144.

● Do not add waste milk, whey or silage effluentto slurry or dirty water stores if there is a riskof causing odour nuisance from the store orwhen the store contents are applied to land.Paragraphs 79, 80, 82 and 91.

● If poultry manure and broiler litter is stored inthe open, construct narrow A-shaped heaps toshed rainwater. Paragraph 97.

Siting of livestock buildings, slurry& manure stores

● Take into account the risk of causing odourand noise nuisance when planning the locationof new structures or when considering theextension or refurbishment of existingstructures. Paragraph 126.

SMOKE POLLUTION

● Minimise the need to burn waste materials byfirst reducing the use of such materialswherever possible, then recycling materialswhere appropriate and, finally, by usingalternative environmentally acceptablemethods of disposal wherever practicable.Paragraph 154.

iii

● If burning in the open is the only practicablemethod of disposal, do not burn plastics,rubber or other materials known to producedark smoke. Make sure that all burning iscarried out carefully with precautions tominimise fire hazard. Paragraphs 155, 214and 215.

GREENHOUSE GASES

● Seek opportunities to use energy moreefficiently and to exploit non-fossil fuels assources of energy. Improvements in energyefficiency reduce carbon dioxide (a greenhousegas) emission and can reduce farm runningcosts. Paragraphs 220-222.

Summary

v

Contents

Paragraphs

PART A: GENERAL INFORMATION

1. Introduction About this Code 1–2Air pollution problems 3–5Advice 6

2. Legislation Air pollution: general 7–10Planning consents 11–13Dark smoke 14–16Smoke control areas 17Prescribed processes 18Waste management licensing 19

PART B: ODOURS3. General Introduction 20

principles Causes of odour problems 21–25Minimising odours by good agricultural practice 26–29

4. Minimising Introduction 30–33odours from Precautions when spreading manure and slurry 34–40land spreading Precautions when spreading sewage sludge 41of livestock Choosing slurry spreading equipment 42–50wastes Irrigation of liquid wastes 51–53

Spreading solid manures 54–56

5. Minimising Introduction 57–58odours from Livestock buildingshoused Management 59–60livestock Ventilation 61–62systems Open concrete areas 63

Carcases 64Cattle 65–67Pigs 68–69Solid manure systems 70–71Slurry systems 72–73Poultry 74Caged laying birds 75–76Deep litter systems 77Feeding and food stores 78–79Swill 80Silage 81–84

vi

Paragraphs

6. Minimising Introduction 85–86odours from Solid manure storage 87–89stored slurry Storage of slurry and dilute effluents 90–94and manure Storage of poultry manure 95–97

7. Treating Introduction 98–99livestock Mechanical slurry separation 100–104wastes to Biological treatment of slurryreduce odour General principles 105–106

Aerobic treatment (aeration) 107–110Anaerobic digestion 111–112Biological Treatment of ManureComposting 113–115Biological Treatment of Odorous AirExhaust air from livestock buildings 116Treating Odours by Additives and Other Methods 117–119

8. Producing Introduction 120compost for Laws 121mushrooms Good practice 122–125

9. Siting of Introduction 126livestock Factors affecting odour problems 127–130buildings, Siting of existing livestock units 131manure and Siting new livestock units 132slurry stores

PART C: AMMONIA10. Ammonia Introduction 133–134

Ammonia emission 135–137Reducing ammonia losses from manures and slurriesAnimal diets 138–140Housing 141–142Stores 143–144Application of manures and slurries to land 145–146Slurries 147–149Solid manures 150

Contents

vii

Paragraphs

PART D: SMOKE POLLUTION11. General

principles 151–156

12. Reducing the Reducing waste 157volumes of Recycling 158–159waste materials Ease of disposal 160–162for disposal

13. Plastic Introduction 163–164materials Repeated use of plastics 165–166

Alternative uses 167Recycling 168–169Choosing materials 170–172Containers contaminated by pesticides 173

14. Tyres and Dark smoke risk 174–175rubber Disposal off the farm 176

15. Waste oils Sources 177Recycling 178Waste oil burners 179

16. Animal Introduction 180–182carcases Notifiable diseases 183

Incineration 184–185Open burning 186–187

17. Fuels produced Introduction 188on the farm Straw and wood as fuels 189

Choosing equipment 190–191Using and maintaining equipment 192–196Using litter from poultry and other animals as a fuel 197–201

18. Other waste Introduction 202–203materials Crop residues 204–206

Wood waste 207–210Paper sacks and other packaging 211Litter from poultry and other animals 212

19. Burning in Good practice 213–214the open Safety precautions 215

Contents

viii

Paragraphs

PART E: GREENHOUSE GASES20. Greenhouse Introduction 216–217

gases The greenhouse gases 218Reducing emissions 219Carbon dioxide 220-222Methane 223-224Nitrous oxide 225Chlorofluorocarbons (CFCs) 226-227Halons 228

AppendicesPages

Appendix 1 Environment Agency: contact details 72

Appendix II 73Sources of information

Legislation: general and odoursLegislation: smoke pollutionCodes of PracticeWelfare CodesGreenhouse gasesOther publications

Index 77

Contents

1

PART A:GENERAL INFORMATION

2

Introduction

About this Code

1 This Code of Good Agricultural Practice forthe Protection of Air (Air Code) is a practicalguide to help farmers and growers avoidcausing air pollution from odours, ammoniaand smoke, or from greenhouse gases whichcause global warming. It will help you tominimise and dispose of your wastes in wayswhich reduce the risk of causing nuisance orannoyance from air pollution.

It is not a statutory code. Following this Codewill not provide a defence such as ‘bestpracticable means’ (paragraph 10) if you causeair pollution. Nor will it protect you from legalaction, although it should lessen the chancethat this will happen. If you are in any doubtabout what the law requires contact the localauthority Environmental Health Department.

The Code describes the main causes of airpollution from different agricultural activities.In each Section, good agricultural practice is setdown in a way which takes account of the needto avoid causing pollution or nuisance whileallowing economic farming to continue. TheCode was written using the latest informationavailable. Any new practices not coveredshould follow the general principles laid downin this Code.

2 This Code does not give advice on noise or airpollution caused by dust. Advice on spray driftfrom pesticides is contained in the Code ofPractice for the Safe Use of Pesticides on Farmsand Holdings. The Air Code complementsadvice given in the Code of Good AgriculturalPractice for the Protection of Water (WaterCode) and the Code of Good AgriculturalPractice for the Protection of Soil (Soil Code).Copies of all these Codes are available free of charge from MAFF Publications, telephone 0645 556000.

1

1

3

Introduction

This Code is a revised version of the one issuedin 1992.

Air pollution problems

3 Agricultural activities which involve housedlivestock, storing wastes or spreading livestockwastes are those most likely to cause odourproblems. Advice on minimising odournuisance is given in Sections 3 to 9.

4 Agricultural activities can give off various gaseswhich help to cause atmospheric problems.Advice on how to minimise the amount ofgases given off is given in this Code. Ammonia,which contributes to making soils acid and candisrupt sensitive ecosystems is covered inSection 10. Section 20 covers greenhouse gaseswhich contribute to global warming: carbondioxide, methane, nitrous oxide andchlorofluorocarbons (CFCs).

5 Dark smoke or smoke nuisance fromagriculture and horticulture can be caused bythe burning of crop residues, packaging,plastics, tyres, waste oil or animal carcases inthe open or in unsuitable equipment. Advice onhow to minimise the need to burn thesematerials and on how to avoid producing darksmoke or causing smoke nuisance whenburning is given in Sections 11 to 19.

Advice

6 You can get advice and information from localauthority Environmental Health Departments andfrom the Environment Agency. Detailed designand planning services are available fromindependent consultants and equipment suppliers.

4

Legislation

Air pollution: general

7 The local authority Environmental HealthDepartment is responsible for enforcinglegislation on odour nuisance and smoke.Under Part III, Section 79, of theEnvironmental Protection Act 1990, localauthorities have a duty to inspect their areas to detect any statutory nuisances and to takereasonably practicable steps to investigatecomplaints of statutory nuisance which aremade to them.

8 Section 79 of the Act defines statutorynuisances as including:

● any premises in such a state as to be prejudicialto health or a nuisance;

● smoke emitted from premises so as to beprejudicial to health or a nuisance;

● any dust, steam, smell or other effluvia arisingon industrial, trade or business premises andbeing prejudicial to health or a nuisance;

● fumes or gases so as to be prejudicial to healthor a nuisance;

● any accumulation or deposit which isprejudicial to health or a nuisance;

● noise emitted from premises so as to beprejudicial to health or a nuisance;

● any animal kept in such a place or manner asto be prejudicial to health or a nuisance; and

● any other matter declared by any enactment tobe a statutory nuisance.

9 Where a local authority Environmental HealthDepartment is satisfied that a statutorynuisance exists, or is likely to occur or recur, it

2

5

Legislation

has a duty to serve an abatement notice underPart III, Section 80 of the Act requiring:

● the abatement of the nuisance or prohibiting orrestricting its occurrence or recurrence; and

● the execution of such works and the taking ofsuch other steps as may be necessary for any ofthose purposes.

A person served with an abatement notice mayappeal to a Magistrates’ Court within 21 daysof being served with the notice.

Apart from action taken by a local authority,any person aggrieved by a statutory nuisancecan take proceedings in a Magistrates’ Court.

10 It is an offence to contravene or fail to complywith an abatement notice without reasonableexcuse. You could be fined up to £20,000 in aMagistrates’ Court if you commit an offenceunder this part of the Act. It is usually adefence to show that you have used the ‘bestpracticable means’ (which is defined to haveregard amongst other things to local conditionsand circumstances, to the current state oftechnical knowledge and to the financialimplications) to prevent or counteract thenuisance. Since the law relating to statutorynuisances is not straightforward, you wouldbe well advised to consult a suitablyexperienced lawyer if difficulties arise, andshould certainly do so if you are served withan abatement notice.

Planning consents

11 Legislation governing planning consent fordevelopments also includes provisions whichrelate to the avoidance of nuisances.

The Town and Country Planning (GeneralPermitted Development) Order 1995 (the

GPDO) sets out certain types of developmentwhich may be carried out on agricultural landwithout planning permission. However, youwill need planning permission for certain newfacilities (such as livestock buildings, slurrystorage and sewage sludge facilities) and forextensions or alterations to similar structures,where these will be within a distance of 400metres from the boundary of any protectedbuildings (such as houses or schools). This rulehas been introduced to reduce the number ofpotential odour problems coming from newlivestock buildings or waste storage facilitiesbeing built close to housing developments.

12 For livestock buildings, slurry stores andsewage sludge facilities which do not requireplanning permission under the GPDO, a priornotification system is now in force. You mustnotify the local planning authority of yourintention to construct such facilities. The localplanning authority must then decide within 28days whether it wishes to approve details of thesiting, design and external appearance of theproposed development. Where prior approvalis required, the development must not beginuntil such approval has been obtained.

13 The Town and Country Planning (Assessmentof Environmental Effects) Regulations 1988require an environmental assessment to becarried out for certain types of major projectwhich are likely to have significant effects onthe environment.

In the case of agriculture, environmentalassessments are likely to be required for newpig units (more than 400 sows or 5000fattening pigs) and new poultry units (morethan 100,000 broilers or 50,000 layers or otherpoultry including turkeys). These thresholdsmay be amended. Under current planningregulations, new units of this size will almostcertainly need planning permission. You should

2

6

Legislation

talk to the local planning authority about theneed for an environmental assessment beforeyou send in a planning application. This mayinvolve preparing an environmental statementcovering the possible environmental effects of a project, e.g. emissions of offensive odours,and the measures to be taken to reduce these effects.

Dark smoke

14 The Clean Air Act 1993 prohibits the emissionof dark smoke from chimneys of buildings orfrom trade premises. Land on which anagricultural or a horticultural business iscarried on is considered to be trade premises.

15 The Clean Air (Emission of Dark Smoke)(Exemption) Regulations 1969, provide for theexemption of the burning of certain matterfrom Section 2 of the Clean Air Act 1993,which applies to trade premises. In certaincircumstances, the Regulations allow theburning of carcases of animals or poultry andcontainers contaminated by any pesticide,provided, amongst other things, there is noother reasonably safe and practicable methodof disposing of the matter other than burning(paragraphs 173, 187 and 210).

16 Under the Clean Air Act 1993 (subject to theexemptions given in paragraph 15) the occupierof the premises and any person who causes orpermits the emission of dark smoke at any timeis guilty of an offence. Everyone who isinvolved in agriculture and horticulture shouldtake all practicable steps to prevent theemission of dark smoke.

Smoke control areas

17 In some cases a farm may fall within a ‘smokecontrol area’ as declared by local authoritiesunder the Clean Air Act 1993. It is an offence

to emit smoke from the chimney of anybuilding caused by the burning of anunauthorised fuel in these areas. You shouldask your local authority about any local smokecontrol areas.

Prescribed processes

18 Part I of the Environmental Protection Act1990 establishes a pollution control system forcertain ‘prescribed processes’. TheEnvironmental Protection (Prescribed Processesand Substances) Regulations 1991(as amended)set out the processes which pose a particularrisk of air pollution and are subject to specialcontrols. Those prescribed processes ofparticular interest to farmers are given in thetinted box. Under the Act, the EnvironmentAgency and local authorities have powers tocontrol pollution over a range of processes.Those activities which are affected need anauthorisation. This would normally be fromthe local authority for farm scale processes.

The requirements for the local authority airpollution control system mean that:

● You must not operate a prescribed processdesignated for local authority control withouttheir authorisation. The process must beoperated using BATNEEC (best availabletechniques (including technology) not entailingexcessive cost).

The Secretary of State’s Process GuidanceNotes (available from HMSO) for all the mainprocesses include detailed descriptions of thetechniques to be applied in order to meet theBATNEEC objective (see Appendix II); and

● If you operate a prescribed process you mustsubmit a detailed application to the localauthority, for authorisation. You have to pay afee with the application for authorisation as

2

7

Legislation

well as an annual charge for that authorisationto continue in effect.

If you carry out a prescribed process which isexempted from local authority control becauseof size or volume, you should aim whereverpracticable to meet the standards set out in theappropriate Process Guidance Note, to reducethe possibility of nuisance.

Waste management licensing

19 The management of ‘controlled waste’ issubject to the waste management licensingsystem established under Part II of theEnvironmental Protection Act 1990 and theWaste Management Licensing Regulations1994 and to other statutory controls. Wasteproduced on premises used for agriculture isnot currently ‘controlled waste’ but certainagricultural wastes will be brought within thesystem in future regulations. The existingWaste Management Licensing Regulations1994 control the disposal of non-agriculturalwaste to land: see Section 2 of the Soil Code.

Prescribed processes

Prescribed processes include many of interest to farmers

such as:

● general waste incineration processes under

1 tonne per hour;

● waste oil burners below 3 MW net rated thermal input;

● straw combustion processes between 0.4 and

3 MW net rated thermal input;

● wood combustion processes between 0.4 and

3 MW net rated thermal input;

● poultry litter combustion processes between

0.4 and 3 MW net rated thermal input;

● animal carcase incineration under 1 tonne

per hour;

● treatment and processing of animal or vegetable matter

including:

● fur breeding;

● animal feed compounding; and

● production of compost for mushrooms.

Some processes covered in the Process Guidance Notes,

for example, any process under the heading of

‘treatment and processing of animal or vegetable

matter’, are exempt from controls when carried out on a

farm and when they do not involve the manufacture of

goods for sale. Others may be exempt below a certain

size of operation, for example animal carcase

incineration below 50 kg/hour.

2

9

PART B:ODOURS

11

General Principles

Introduction

20 This section describes the main causes ofcomplaints about odours, outlines the sourcesof odours and how they can be measured.It also describes good agricultural practice tominimise odour problems.

Causes of odour problems

21 Complaints from the public about odourscaused by agriculture and industry are reportedby local authorities and recorded every year bythe Chartered Institute of EnvironmentalHealth. There were about 9,000 complaints inEngland & Wales caused by agriculture in1995/96, involving an estimated 3,646 farmpremises.

22 A survey of 212 local authorities in 1995/96showed that pig units are responsible foraround 50% of the livestock premises causingjustifiable complaints, followed by poultryunits (30%) and cattle farms (20%).

23 The application of slurry or manure to landwas associated with 64% of the pig units in thesurvey causing odour complaints while 36%of the pig units caused complaints aboutfarmyard odours from slurry and manurestorage, livestock buildings, and livestock feedpreparation and storage. For poultry units,40% caused odour complaints from the fieldapplication of manure while 60% causedcomplaints about farmyard odours. For cattlefarms, 74% caused odour complaints from thefield application of slurry or manure while 26%caused complaints about farmyard odours.

24 Most farm odours come from several sources.For example, odours from buildings are mainlycaused by the breakdown of faeces and urine.Other sources of odour are from waste foodspilt onto floors, the scent glands of animals,and the animals’ feed.

3

12

General Principles

25 When slurries, silage effluent and solid manuresare spread on land, they may also be a sourceof odour, either during or after the spreadingtakes place.

Minimising odours by good agricultural practice

26 It is not possible to avoid all odours fromagriculture, because often the right techniquesdo not exist. Even where there is a solution, thecost may sometimes be too high. This isrecognised by the legislation which refers to‘best practicable means’, which takes financialimplications into account.

27 However, by using good agricultural practiceand appropriate control systems, you canminimise odour problems from both new andexisting installations. The aim is to minimisethe escape of odours beyond the farmboundary and, where practicable, stop itentirely. This is done by firstly paying attentionto when, where and how you spread manureand slurry onto land and then, if necessary,reducing the amount of odour coming fromother sources. Air movement and distance willreduce any problem, by diluting the odour.

28 You should carry out good agriculturalpractice as described in the following sectionsof this Code.

● Section 4 describes good agricultural practiceto minimise odour nuisance from the spreadingof livestock wastes on agricultural land.

● Section 5 describes good agricultural practiceto minimise odour nuisance from housed cattle,pigs and poultry.

● Section 6 describes good agricultural practiceto minimise odour nuisance during the storingand handling of slurry or manure.

In situations that could be particularlysensitive, you may need to go beyond goodagricultural practice and use more rigoroustreatment and control measures. Section 7describes methods of treating livestock wastesto give further odour reductions during storageand spreading. Before investing in any of theseyou should take professional advice.

29 If an odour complaint has been made to thelocal authority Environmental HealthDepartment and the complaint proves tobe justifiable, then you should take thefollowing steps.

First, discuss the matter with the Environ-mental Health Officer and find out the causeand source of the odour causing the complaint.

Second, compare the management practicesand systems which you use for spreadinglivestock wastes, housing livestock andhandling and storing manure or slurry, withthose set out in Sections 4, 5 and 6. Make anychanges that are needed.

Third, evaluate the improvements. At thisstage, the amount of odour given off may havereduced enough to solve the problem.

If the improvement has not been enough, getadvice on the techniques you need to use toreduce odour still further. Keep the localauthority Environmental Health Departmentinformed of proposals at all stages ofthe process.

3

3

13

Odour measurements

Agricultural odours are caused by a large number of

chemical compounds. No single compound has been

identified which can be measured and used to assess

odour.

‘Olfactometry’ is the method used to measure smells.

It normally relies on using the human nose as a

detector. It is based on the assessments of a trained

panel under controlled laboratory conditions.

Samples of odorous air are collected on site and

transported to the laboratory.

Odour threshold value is most commonly used to

measure an odour. It is the number of volumes of

odour-free air needed to dilute an odour until it is

smelt by only 50% of the panel members. The odour

threshold value is commonly expressed as an odour

concentration in odour units per cubic metre of air

(units/m3).

Background odour concentrations measured in rural

areas are typically 30 odour units per m3. There are

few if any situations where farm odour

concentrations at source are more than 5,000

units/m3 air, whereas industrial odours may have to

be diluted over a million times to reach the odour

threshold value.

General Principles

14

Minimising Odours From Land-Spreading Of Livestock Wastes

Introduction

30 This section describes good agriculturalpractice and the precautions you should takewhen spreading manure and slurry on land tominimise odour nuisance. It also discusses thechoice of spreading machinery which affectsthe concentration of the odour emitted.

31 A number of factors affect the concentration ofthe odour emitted during and after spreadingslurry or manure. These include the type oflivestock (pig slurry tends to be most odorous),whether the waste contains waste milk or silageeffluent (these increase the amount of odourreleased) and the method and length of storage.The type of spreading equipment used and rateof application to land are also very important.

32 Generally, the highest odour emissions occurwhile spreading of waste is actually takingplace. With conventional splash-platespreaders, the odour concentration can beseven to 15 times greater during spreading thanimmediately afterwards. Odour emissionduring the next eight to 12 hours may also behigh enough to cause a nuisance. Odouremissions can be minimised by keeping contacttime with air as short as possible.

33 Odours released during spreading of livestockwastes to land cause about half of allcomplaints of odours from agriculture. Odoursfrom spreading manures and slurries can besmelt a long distance from the field, dependingon the type of waste, the weather and themethod of spreading.

Precautions when spreading manure and slurry

34 Use a weather forecast to help choose suitableconditions for spreading. The best conditionsare where air mixes to a great height above theground, which are typically sunny, windy days,

4

15


followed by cloudy, windy nights. Theseconditions cause odours to be diluted quickly.Check wind direction in relation to nearbyhouses before spreading.

35 Avoid spreading in fields close to and upwindof houses unless slurry is band spread, injectedor has been treated to effectively reduce itsodour. The location of the fields where theslurry or manure will be applied, the directionand strength of the wind, and the distance fromhouses are all extremely important to getenough dilution and dispersal of the odour andso avoid problems.

36 Avoid spreading at weekends, bank holidays orin the evening unless it is absolutely necessary,and then only if slurry is band-spread, injectedor has been treated to effectively reduce itsodour.

37 Use tankers and spreaders which give a lowtrajectory and large droplets.

38 Avoid applying more than 50 m3/ha (4500gallons per acre), or 50 tonnes/ha (20 tonnesper acre) at one time if odour could be aproblem; reduce these rates as necessary so thatthe amount of total nitrogen applied does notexceed 250 kg per hectare per year. Alwaysapply slurry and manure in a way that avoidsthe risk of causing water pollution. See Section3 of the Water Code for detailed informationon assessing the risk of causing water pollutionand the land area needed for different classes of stock.

39 On bare land, lightly cultivate the land aftersurface spreading to mix in the material assoon as possible (see paragraph 150).

40 Avoid over-filling tankers or spreaders. Do notspill manure or slurry on roads; this may be anoffence under the Highways Act, 1980. Cleanthe outside of spreading machinery regularly.

Precautions when spreading sewage sludge

41 Spreading of sewage sludge is controlled by theSludge (Use in Agriculture) Regulations 1989(as amended). Follow the Code of Practice forAgricultural Use of Sewage Sludge. Care shouldbe taken to choose application sites so thatodour nuisance is not caused. In general, thefactors which affect odour nuisance are thesame as those for slurry and manure.

Choosing slurry spreading equipment

42 Choosing suitable slurry-spreading equipmentis, in many cases, the most important decisionto be made when planning a waste-handlingsystem to minimise odour problems.

43 Volatile odorous compounds in slurries arereleased when the slurry is directed onto asplash plate or similar device. This causes thejet of slurry to shatter into very small dropsand releases odorous compounds directly intothe air.

Often, it is this concentrated release of odourwhich causes problems. One tanker may spreadthree or four loads an hour, causing a series ofsuch events.

44 Choose the type of slurry spreader that issuitable for the fields it will be used in. If thefields which the slurry will be spread on areaway from houses, then you can use a tankerwith a conventional splash-plate spreadingdevice (see Figure 1). Tankers which give a lowtrajectory and large droplets are best.

4

4

16


45 When the fields are close to and upwind ofhouses, choose a machine for which there isreliable information on its ability to control theamount of odour which is emitted.

The band spreaders and injectors described inparagraphs 46-49 provide a series of choicesfor controlling odour. Spreaders with boomsand curtains can also control odour. The costsof buying and running equipment vary inrelation to the amount of control achieved. It may be necessary to separate slurrymechanically, or to remove coarse solids andstones to reduce the risk of blockages.

46 Band spreaders discharge slurry at ground levelthrough a series of trailing pipes (see Figure 2).Measurements of odour show a reduction of55 to 60% compared with conventional splash-plate spreaders.

47 Open-slot shallow injection allows slurry to beplaced in shallow grooves in the soil, 50-60millimetres (mm) deep, 200-300 mm apart. Aswith band spreaders the odour can be reducedby 55 to 60% compared with conventionalspreaders.

48 Closed-slot shallow injection applies slurry at adepth of 50-80 mm in grooves 250-300 mmapart. The groove is then closed again by presswheels or discs. The amount of odour emittedis commonly 85% less than from conventionalspreaders.

49 Closed-slot deep injection equipment appliesslurry at a depth of 120-300 mm in the soilusing injector tines, spaced about 500 mmapart (Figure 3). The amount of odouremitted is commonly 85% less than fromconventional spreaders.

Figure 1: Conventional ‘Splash Plate’ SlurrySpreading Mechanism

See paragraph 44 for situations where using thistype of spreading mechanism is likely to beacceptable. Machines giving a low trajectory andlarge droplets are best.

Figure 2: Band Spreader for Slurry

This type of mechanism can reduce odouremissions by 55 to 60% as compared with aconventional splash plate spreader.

4

17


50 The following points should help you chooseslurry spreading machines to reduce odouremissions. Manufacturers should be able toprovide such information. Look for:

● a reduction in the amount of odour emittedduring spreading of at least 50% comparedwith a conventional splash-plate distributiondevice; and

● good control of application rate, so that themachine can give rates ranging from 20 m3/ha(1800 gallons per acre) to 50 m3/ha (4500gallons per acre), when operating at a suitablespeed.

Irrigation of liquid wastes

51 Dilute effluents and separated slurry are usuallyapplied using sprinklers or travelling irrigators.A detailed description of such systems is givenin Section 5 of the Water Code.

Band spreaders

Slurry is pumped to a manifold distributor, often in a

rapid succession of pulses to make sure that all pipes

are supplied at the same rate. The trailing pipes may

hang loosely or can be more rigid with a small metal

shoe which rides along on the surface, parting the

crop and making sure that slurry is applied directly

onto the surface of the soil.

Closed-slot deep injection

A winged tine may be used to loosen the soil over a

strip about 20 centimetres wide so that slurry is

mixed into the soil. However, as with all injection

systems the method has limitations: it may not be

usable when the soil is heavy, dry, frozen or stony,

particularly in grassland, and where there are steep

slopes. Deep injection generally requires a more

powerful tractor compared with other systems.

Injection can reduce odour by 85% compared witha conventional splash plate spreader.

Figure 3: Slurry Injector

4

18

52 Odour risks can increase when silage effluent,waste milk or the liquid from weeping-wallstores or manure stores is added to dirty wateror separated slurry.

There will be some situations when storage willbe needed for the dirty water or separatedslurry to avoid causing water pollution.However, storing them for long periods willencourage odours to develop and extra careshould be taken to avoid nuisance when suchliquids are spread.

53 Application systems should be designed forthe particular site. Where there is a risk ofcausing an odour nuisance, choose sprinklersor irrigators providing a low trajectory andoperating at a low pressure to producelarge droplets.

Spreading solid manures

54 Spreading solid manures, including mixtures ofbedding and manure, poultry manure, solidsfrom weeping-wall stores, and the solids frommechanical separators, can sometimes produceas much odour as spreading slurry.

55 Wherever possible, store manure in a way thatwill encourage natural composting. Thisprocess, when carried out correctly, asoutlined in Section 6, reduces theconcentration and offensiveness of odourreleased during spreading.

56 When odorous or partly composted manurehas to be applied to land, do not spread it closeto houses. Where practicable, you shouldspread it onto arable land and bury itimmediately by ploughing.


19

Minimising Odours From HousedLivestock Systems

Introduction

57 This Section describes good agriculturalpractice to avoid odour nuisance from housedcattle, pigs and poultry. It also covers feedingand food stores, including silage making.

58 It is essential to maintain a high standard ofhygiene and cleanliness. If you don’t, all othermeasures to control odours are likely to fail.

LIVESTOCK BUILDINGS

Management

59 These points relate to most livestock buildings on farms. Additional points relatingto cattle, pigs and poultry are given insubsequent sections.

● Whenever possible, collect and transfer slurryevery day to a suitable store. Dung from non-bedded, concreted areas, should also be dealtwith in this way.

● Maintain drains and repair broken or badlylaid concrete to prevent effluents from pondingwithin buildings.

● Where bedding is used, use enough to keepanimals clean. Stock covered in manure canadd to the amount of odours produced. Storebedding materials in a dry condition to avoidmoulds and dust forming and the loss ofcapacity to absorb liquids.

● Manage drinking systems to avoid overflowand spillage.

60 Livestock buildings need to be cleanedregularly.

If livestock are produced in batches, thoroughlyclean and disinfect buildings after each batch of

5

20

Minimising Odours From Housed Livestock Systems

stock is removed. Remove thick deposits ofdust from the surfaces inside the building andin particular from all ledges, ventilation shaftsand cowls.

If livestock are not produced in batches,thoroughly clean and disinfect individual pensas they become empty.

Clean out grit and sediment from slurrychannels, collection systems and stores. Thicksediments encourage micro-organisms to grow.This produces odours.

Ventilation

61 Ventilation systems in livestock buildings havetwo functions: first, to control temperature andhumidity and limit the concentration ofpoisonous gases and, second, to make sure thatclean air is evenly distributed under a widerange of weather conditions.

Poor ventilation can result in humid conditionswhich give rise to the production of unpleasantodours, high levels of ammonia and pooranimal health. Maintain ventilation fans andcheck that they are running at the correctairflow for the numbers and weight of animalsor birds present.

62 The position and design of ventilation outletswill affect the dilution of smells from buildings.For new buildings, you should get advice onthe most favourable ventilator outlet positionfor your site conditions. The higher the outletis, the more the odour will be diluted by airmovement. Ventilation outlets positioned alongthe sides of buildings below a slatted floor andimmediately over a slurry collection channelcan produce very strong odours.

Open concrete areas

63 Keep areas of concrete which livestock use tothe minimum necessary as these areas will befouled by manure. Pipe or channel wastewaterrather than letting it flow across clean concrete.Information on the disposal of dirty waterfrom buildings and yards is given in Section 5of the Water Code.

Keep concrete areas around buildings clean andfree from any build-up of slurry or manure.

Maintain drains and repair broken or badlylaid concrete to prevent effluents from ponding.

Carcases

64 Remove and dispose of all dead animals, birdsand foetal remains as soon as possible. (Forsafe methods of disposal see Section 16 of thisCode and Section 13 of the Water Code).

CATTLE

5

21


65 The space allowances and other provisions forcattle and calves must meet the requirements ofthe Welfare of Livestock Regulations 1994.You should follow advice in the Code ofRecommendations for the Welfare of Cattle.For dairy cows loose-housed in yards, goodmanagement is essential to maintain a balancebetween stocking density and the amount oflitter you use.

66 Providing cubicles of suitable dimensions forthe size of the cows is crucial for maintainingthe cleanliness of the animals. Keep cubicleswell maintained. Unless you use mats, youshould keep bedding clean and topped up daily.

Scrape cubicle passages and other heavily soiledareas regularly, typically twice daily.

67 Dairy and parlour buildings need to be washedand cleaned frequently. Where disinfectants areused, make sure you have the correct type andquantity of disinfectant and the right volume ofwash water. If you use high pressure hoses takecare to avoid splashing manure onto walls,ceilings and milking equipment.

NOTE: COLLECT CONTAMINATEDWASH WATER AND DISPOSE OF IT INA WAY THAT WILL NOT CAUSEWATER POLLUTION.

PIGS

68 The space allowances and other provisionsmade for pigs must meet the Welfare ofLivestock Regulations 1994. You should followadvice in the Code of Recommendations forthe Welfare of Pigs.

69 Odour problems are minimised if pens are keptclean. Dirty pens can be caused by a number offactors including poor management, ventilationand building design. Overstocking or

understocking, poor ventilation design, wrongpen shape, poor floor surfaces, incorrectconstruction of pen divisions, as well as badlysited feeding and watering facilities, can allcontribute to dirty pens.

Solid manure systems

70 Bedded systems often fail to absorb all theeffluent produced. Appropriately placeddrainage and suitably sized and constructedcollection tanks should be part of such systems.

71 Wherever possible you should clean non-bedded, concreted dunging areas every day.

Slurry systems

72 Less odour comes from fresh slurry andtherefore you should remove slurry frombuildings while it is fresh if this is practicable.

73 Clean slats give off less odour. Well designedand installed slats should be self-cleaning andminimise the risk of injury to the pig.

POULTRY

74 Increasing stocking density increases odourproduction. The conditions under whichpoultry must be kept are set out in the Welfareof Livestock Regulations 1994 which makespecific provisions for the welfare of layinghens in battery cages. You should follow advicein the Code of Recommendations for theWelfare of Domestic Fowls. The type of feed,the humidity in the building and the amountof litter, if used, all contribute to the amountof odour produced. To reduce odour, maintainany manure stored within the house in adry condition.

5

22


Caged laying birds

75 Frequently removing the manure which iscollected on belts beneath cages to a store orspreader outside the building helps to reduceodour. How often you need to remove themanure will vary from daily to twice-weeklydepending on the system design. Proprietary in-house systems are available for rapid air-dryingof manure on the belts. Do not add water topoultry manure as this can result in strong,unpleasant odours.

Prevent leaking drinkers spilling water ontomanure belts or into manure stores.

76 If the manure is stored beneath the caged area,rapid air-drying of the manure will reduceodour formation. One way of achieving this isto separate the manure store from the birdswith a slotted floor. The manure is scrapedeach day to fall through the slots into a storagearea beneath the floor. If the ventilation airleaves the building by going through the slottedfloor, this increases air-drying of the storedmanure.

Deep litter systems

77 The drier the litter is in poultry houses forbroilers, growers, breeders or layers, the lowerthe risk of odour from the buildings. In manycases, keeping the litter dry will be enough toavoid problems. Paying attention to one ormore of the following points will help toachieve this.

● Buildings should be adequately ventilated andalso insulated with suitable materials whichhave a vapour barrier to prevent deteriorationof the insulation.

● Direct-fired gas or oil heaters put extramoisture into the house. Indirect heatingsystems avoid this problem.

● Drinkers should be designed to minimisespillage. If suitable for the type of stock, nippleand drip cups (or similar system) are preferableto hanging bowl drinkers, as they minimisewater spillage. The drinking system must bemaintained at the correct height by frequentlyadjusting them to bird eye level to avoidspillage and wet litter.

● Litter should be 10-15 centimetres deep whichshould be enough to absorb the manure load.

● Feeds which contain certain oils and animalfats which are poorly absorbed by the birds canresult in the manure being greasy, causingcapping of the litter and odour production.Rations should be adjusted to minimise thisproblem if it occurs.

FEEDING AND FOOD STORES

78 Odours can be absorbed by dust particles andthen carried in the air. Finely ground feeds andlong feed drops (into bins or onto floors)increase amounts of dust. Using liquid-feedingsystems or pelleted feed can reduce dust andmay help to reduce odours.

79 Keep foods such as milk by-products (whey,skimmed milk), yeasts and molasses which canproduce strong odours in properly constructedcovered tanks or silos. The delivery area shouldbe concreted and all spillage and wash watershould be piped into the foul-drainage system.

Swill

80 The collection and treatment of swill bycooking is controlled by the Diseases ofAnimals (Waste Food) Order 1973. Premiseshave to be approved and licensed by MAFF.Processing of swill often causes odourcomplaints.

5

5

23

Using automatically controlled systems whichavoid excess steam injection can reduce odoursand save fuel. Enclosed treatment systems stopnearly all escaping steam and greatly reduceodours from cooking. Odours can also bereduced by maintaining the treatmentequipment properly and by avoiding spillingthe feed. Letting swill cool before feeding it tothe pigs may help to reduce odours.

SAFETY NOTE: DO NOT ALLOWEFFLUENT FROM SWILL OR WHEYTANKS AND FROM ENSILEDPRODUCTS TO ENTER SLURRYCHANNELS AS THIS MAY CAUSE LETHALGASES TO BE RELEASED.

Silage

81 Controlling odours from silage clamps, oncethese have been opened for daily use, can bedifficult because of the large surface areaexposed. Well-made silage smells a lot less thansilage which is badly made.

82 You should take the following precautions tocontrol smells from silos and during thehandling and disposal of silage effluent.

● Do not let silage effluent flow across openconcrete; it should be collected in a channeland taken to a suitable storage tank.

● Apply silage effluent with a suitable slurryspreader (see Section 4). Do not spread silageeffluent on fields where it is likely to causeodour problems. Do not apply silage effluent toland where it could cause water pollution (seeSection 8 of the Water Code).

● Do not add silage effluent to slurry stores if thestore or the land the slurry will be spread oncould cause odour problems.

SAFETY NOTE: ADDING SILAGEEFFLUENT TO SLURRY PRODUCESLETHAL GASES VERY QUICKLY. NEVERADD SILAGE EFFLUENT TO SLURRY INCONFINED SPACES OR IN BUILDINGS.

83 The design and construction of new,substantially enlarged or substantiallyreconstructed silos and effluent systems mustcomply with the Control of Pollution (Silage,Slurry and Agricultural Fuel Oil) Regulations1991 (as amended).

84 Consider making baled and wrapped or baggedsilage where silos could cause an odournuisance. Baled silage has the advantage ofbeing enclosed until you use it and only a smallquantity is exposed at any time. Careful use ofthis technique can help to limit the amount ofodour released.


24

Minimising Odours From StoredSlurry And Manure

Introduction

85 This section describes good agriculturalpractice for the design and management ofmanure and slurry stores in order to reducepotential odour nuisance.

86 Storage of manures and slurries is also one ofthe most important ways of avoiding waterpollution at times of the year when spreadingthem to land is likely to cause pollution. A detailed description of the design andmanagement of slurry and manure storagefacilities is given in Sections 4 and 6 of theWater Code.

Solid manure storage

87 To minimise odours from manure stores, youshould encourage natural composting to takeplace within the store by helping air topenetrate the bulk of the manure. Make surethat there is enough bedding in the mix toallow air to penetrate. Thorough composting isunlikely to take place unless you use a propercomposting process (see paragraphs 113-115)

88 The design of the store is also important. If thestore has walls, preferably they should beconstructed so that there is a series of gaps atleast 25 millimetres wide to allow air into themanure. It is also preferable to have low, long,narrow stores, no more than 10-15 metreswide and no taller than 3 metres high. A seriesof stores will mean that one store can be filledand left to compost naturally for a period oftime while a second is filled.

89 You should provide a way of safely collectingand containing any run-off from the store, to avoid causing water pollution(see the Water Code).

6

25

Minimising Odours From Stored Slurry And Manure

Storage of slurry and dilute effluents

90 The design and construction of new,substantially enlarged or substantiallyreconstructed slurry stores must comply withthe Control of Pollution (Silage, Slurry andAgricultural Fuel Oil) Regulations 1991 (asamended). The Water Code gives advice on thedesign, construction and management of storesfor slurry and dirty water. General points ofgood management to avoid odour nuisance aredescribed below. Siting of stores in order toavoid odour nuisance is covered in Section 9 ofthis Code.

91 Do not add feeds such as milk or whey orsilage effluent to slurry or dirty water if there isa high risk of causing odour problems becauseof the location of the slurry store, or fromspreading the waste. Where practicable, youshould contain silage effluent in a separatecollection tank.

SAFETY NOTE: THE ADDITION OFSILAGE EFFLUENT OR WHEY TO SLURRYCAN RELEASE LETHAL GASES. NEVERADD THESE MATERIALS TO SLURRY INCONFINED SPACES OR BUILDINGS.

92 If slurry is frequently agitated in store therewill be a frequent release of odours. If possible,above-ground circular stores located wherethere is a high risk of causing odour problemsshould be equipped with an efficient agitationsystem which can break up any crust or removeany sediment. This will then need to be usedonly when the tank is going to be emptied.

You should choose the best weather conditionswhenever slurry is mixed, if there is a risk ofcausing odour nuisance. These are where airmixes to a great height above the ground,which are typically sunny, windy days,followed by cloudy, windy nights. Check winddirection in relation to nearby houses.

93 If slurry is stored in a lagoon or an above-ground tank, it can be easier to manage if ithas been mechanically separated (see Section7). Mechanical separation removes coarsesolids from the slurry leaving a liquid thatcan be more easily pumped. This liquidcan be stored without having to mix itfrequently which can reduce the amount ofodour released.

94 If cattle slurry contains a lot of straw beddingmaterial, a self-draining, weeping-wall storecan be used.

The contents of the store are removed forspreading once they are dry enough. Usually,these solids are only emptied once a year. Theliquids draining from the store pose a potentialodour problem. They should be spread in aplace and using equipment which will minimisethe risk of odour problems and water pollution(see Section 4).

6

6

26

Storage of poultry manure

95 Poultry excreta has a dry matter content of 20-24%. It is best to handle it as a semi-solid. Itshould not be diluted with water, as this canresult in strong unpleasant odours.

Laying-hen excreta which is collected on beltscan be air-dried in the poultry house, asdescribed in paragraph 75. Where practicable,it should be stored under cover, on a basewhich will not let liquids pass through, untilyou spread it on the land.

96 Broiler litter, when well managed in the house,should have a dry matter content of at least65%. To avoid it becoming wet and causingodour problems you should, where practicable,store it under cover, on a base which will notlet liquids pass through, until you spread it onthe land. Do not burn it under uncontrolledconditions in the open (see Part D of this Code).

97 If you use field heaps, they should be put as faraway as practicable from residential housing,and not within 10 metres of a watercourse,ditch or field drain, and not within 50 metresof a spring, well or borehole that supplieswater for human consumption, or is to be usedin farm dairies. Narrow A-shaped heaps shedrainwater more easily and prevent manurefrom becoming very wet.

Minimising Odours From Stored Slurry And Manure

27

Treating Livestock Wastes ToReduce Odour

Introduction

98 This section describes methods of treatinglivestock wastes to give further reductions inodour emissions during storage and spreading.It also describes the treatment of odorous air.All of these techniques go beyond odourreductions that would result from the goodpractice described in earlier sections of thisCode. However, the use of these techniquesmay be necessary in exceptional situations.

99 Aerobic and anaerobic treatment can beexpensive, as the costs of buying and runningthe treatment systems must be added to thecost of collecting, storing and spreading thewaste. It is important that you get advice tomake sure that the treatment you intend to useworks efficiently and is suitable for the specificproblem, and is cost effective.

The type and degree of treatment that is neededdepends on how serious the odour problemis. In some cases, the source odourconcentration may need to be reduced by asmuch as 95% before the odour problem isreduced enough (see Section 3 for definitionsof odour concentration).

Mechanical slurry separation

100 Mechanical separation can be useful as an aidto improved waste management. There is arange of mechanical separators available forlivestock slurries. It is important that thecorrect machine is chosen for the slurryproduced on a particular farm.

101 The process removes coarse solids from farmslurries. The solid portion, 10-20% of theoriginal slurry volume, can be stacked andstored in a similar way to farmyard manure. If this solid is produced by a separator which

7

7

28

Treating Livestock Wastes To Reduce Odour

gives high dry-matter solids, this portion maycompost readily to produce a relatively mild-smelling material which is unlikely to causea nuisance.

102 The separated liquid portion, which is80-90% of the original volume, flows easilyand can therefore be pumped to a store andhandled by the band spreaders or slurryinjectors described in Section 4, withoutcausing blockage problems. After separation,storing the liquid portion results in less of asurface crust forming and solids settling.Therefore, mixing in store only needs to becarried out occasionally so odours duringstorage are reduced.

103 The separated liquid portion of slurry can beapplied in the spring to arable crops or grassafter silage cuts. This makes good use of thenutrient content. The separated liquid leavesvery little solid residue on crops and avoidsone of the sources of odour associated withwhole slurry.

104 Mechanical separation is usually a necessarytreatment before aerobic treatment (aeration)because it is easier to aerate separated liquidthan a mixture that contains large particleswhich need extra power input to keep themin suspension and more oxygen to giveodour control.

Figure 4: Options for Slurry Treatment – Aeration

7

29


Choice of mechanical separator

For pig slurry of 2-4% dry matter, a wedge wire run-

down screen or vibrating screen will work

satisfactorily. The dry matter content of the

separated solids will be usually 8-12%. These solids

will self-drain if they are held in a suitable store.

For pig and cattle slurries, separators which press

and squeeze the slurry against a fabric belt or

perforated stainless steel screen will produce a solid

with a dry matter ranging from 18-30%. These

solids can be composted.

BIOLOGICAL TREATMENTOF SLURRY

General principles

105 Techniques for treatment of slurries and otherorganic effluents using micro-organisms arewell developed. There is a range of treatmentsfor agricultural slurries and other effluents;examples of these are set out in Figures4 and 5.

106 Any treatment of slurry by micro-organismsrelies on steady flow conditions to encouragetheir rapid continuous growth. Therefore, it isessential that the daily loading rate of slurryshould be kept within the design standards of

Figure 5: Options for Slurry Treatment – Anaerobic Digestion

30


the particular treatment system. Variations inload will alter the retention time; a very largeload may flush out the micro-organisms whichwill lead to treatment failure.

There are two basic methods of treatment:aerobic (with a good supply of oxygen alwayspresent) and anaerobic (without oxygen).

Aerobic treatment (aeration)

107 Treatment of slurries and farm effluents byaerobic biological treatment systems whichare correctly designed and used should becapable of reducing the amount of odouremitted during and after land applicationby up to 90%.

108 Aerobic treatment is usually only suitable forseparated slurry or dilute effluents. Solids inthe waste increase the amount of oxygenneeded and also increase the energy needed formixing. The most efficient oxygen transferoccurs when very small bubbles are used.Successful aerators produce these bubbleseither by blowing compressed air throughporous diffusers with very small outlets, or byentraining air in a fast-moving stream of liquidin submerged ‘venturi’ nozzles or rotatingimpellers. Aerators should supply a minimumof 1 kg of dissolved oxygen for each kilowatthour they use, if they are to be economical.The following conditions should be met:

● a reasonably constant and well mixed volumeof slurry each day to give controlled retention

Retention time:

This is the average time that slurry will stay in the

container that treatment takes place in. For

continuous flow systems, normal retention time in

days is the volume of the treatment vessel divided by

volume loaded every day.

time in the treatment tank of continuous flowsystems;

● a slurry dry matter content of less than 3%;

● bedding material and animal hair should bekept out of the slurry;

● a suitable oxygen concentration throughout thetreatment tank achieved by effective mixing.

109 Most slurries will produce foam when aerated.Extra space should be provided above theslurry in the aeration tank to prevent foamfrom overflowing. Mechanical devices such asspray nozzles or high-speed rotating discs orimpellers can collapse foam and return it tothe liquid.

110 Continuous-flow aeration systems cansuccessfully treat slurries to reduce odournuisance with retention times of as little as oneor two days. In these systems, odour can becontrolled at the treatment tank or storagetank as well as at spreading. Increasing theretention time during treatment will allow youto store the treated slurry for at least a monthor more before the odour returns. If a batchsystem is used, much of the odour will bedriven out into the air above the treatmenttank when treatment starts.

Anaerobic digestion

111 In a properly designed and run system, theodour emitted during and after spreadinganaerobically digested slurry will be reducedby up to 80% and it will be less offensive.The digested slurry can be stored for severalmonths after it has been treated beforeoffensive odours return.

112 Anaerobic digestion of livestock slurriesinvolves using micro-organisms to turn the

7

31


complex organic substances into less complexcompounds. This process is done in the absenceof oxygen and at temperatures normallybetween 30 and 35°C. The end products ofdigestion are biogas (a mixture of 60-70%methane and 30-40% carbon dioxide) and astabilised treated slurry. The biogas may beused for heating or generating electricity. It isnot necessary to separate the slurry beforetreatment. The following conditions should be met:

● a reasonably constant and well-mixed volumeof slurry each day to give controlled retentiontime in the digester;

● a temperature of 30-35°C;

● an optimum dry-matter content of 6-8%;

● an optimum retention time in the digester:12 days for pig slurry and 20 days for cattleand poultry slurry.

BIOLOGICAL TREATMENTOF MANURE

Composting

113 Properly composted manure reducessignificantly both the volume which is spreadto land and the amount of odour released. Butthe process of composting can give rise to siteodours. Practices which minimise odouremissions are described in Section 8.

114 Composting is an aerobic process. Optimumresults are obtained by using well-chopped andmixed ingredients, usually straw and manure inthe right proportions, and by controllingtemperature and moisture content. Control iseasier where heaps are long and narrow (3 to 4 metres), and not too high (1.5 to 2 metres).The amount of aeration to control processtemperature (initially at 55-60ºC) can be

supplied by either a fan and duct system (calledstatic pile) or by physically moving and turningthe heap. The process should be carried out ona concrete yard with proper control of addedwater and run-off (see paragraphs 123-125).

115 Typical farmyard manure heaps do not satisfythe requirements for thorough composting.For this reason, they can give rise to odourswhen the heaps are disturbed and whenmanure is spread to land.

BIOLOGICAL TREATMENTOF ODOROUS AIR

Exhaust air from livestock buildings

116 Odorous air can be treated by passing itthrough an air-cleaning device such as a film ormist of water in an air scrubber. Many systemsuse a material with a large surface area, whichmicro-organisms can become attached to.Many odorous compounds are nutrients for themicro-organisms which clean the liquid, so itcan be recycled. An alternative biofilter systemuses a moist mixture of peat and heather orlightly packed soil.

TREATING ODOURS BY ADDITIVESAND OTHER METHODS

117Several kinds of additives are available that actin different ways and which are claimed tocontrol odours. The main ones are: oxidisingagents, deodorants which react with odorouscompounds, masking agents, biological agents,feed additives and miscellaneous chemicals.

These additives vary in their effectiveness.Current evidence shows that they are notgenerally a long-term solution to reducingodour problems. However, additives maybe useful as a short-term emergency treatmentfor a batch of slurry or a store which is causinga nuisance.

7

7

32

118 Electrolytic methods are also available fortreating slurry. This treatment uses copperelectrodes immersed in a treatment tank, and is claimed to reduce odour nuisance.

119 Ask manufacturers or suppliers of additivesand other methods to provide independentproof of their product’s ability to controlodours when it is used according to themanufacturer’s instructions.


33

Producing Compost For Mushrooms

Introduction

120 Producing compost for mushroom growinginvolves mixing ingredients, mainly straw andmanure, and adding water. The process cangive rise to odours. This section gives advice onthe legislation which applies, and on practiceswhich will minimise odour emission.

Laws

121 Production of compost on which mushroomswill be grown requires an authorisation fromthe local authority Environmental HealthDepartment, under Part I of the EnvironmentalProtection Act 1990. This will be based onthe Secretary of State’s Guidance Note onproduction of compost for mushrooms.This sets out controls and alternativetechnologies for new and existing processes.

However, any process for the manufacture ofcompost other than for sale, carried out on afarm or agricultural holding, is exempt fromthe above legislation. That is to say if compostis produced and used at the same location andby the same grower for growing mushrooms,or produced at one location and transferred toanother location for use by the same grower,the process is exempt.

Processes at locations which are exempt arestill subject to Part III of the EnvironmentalProtection Act 1990 which relates to statutorynuisances (paragraphs 7-10).

Good practice

122 In order to minimise the production of odoursyou should adopt the measures outlined inparagraphs 123-125. A good standard ofgeneral management is important. Keep thecomposting yard and surrounding areas clean

8

8

34

and avoid the ponding of liquids which couldgive rise to odours.

123 If poultry manure and other manure is storedprior to composting, follow the guidelinesgiven in paragraphs 95-97, in order to preventit becoming too wet. If practicable, very wetand potentially odorous material should not beaccepted or stored at a composting site.

124 To avoid producing odours, encourage as muchair as possible to penetrate the material whichis being processed. To do this you may have tolimit the width and height of windrows orheaps and carefully manage the amount ofwater applied. Turn compost frequently tominimise anaerobic conditions which will causeodours to be produced.

125 Run-off and leachate which is containedin storage tanks should be aerated by suitableequipment. Spray heads that are usedto moisten the compost with leachate shouldwork at low pressures and produce largedroplets to reduce drift and possibleodour problems.

NOTE: DO NOT LET LEACHATE ENTERWATERCOURSES. GUIDANCE ON HOWTO AVOID WATER POLLUTION IS GIVENIN THE WATER CODE.

Producing Compost For Mushrooms

35

Siting Of Livestock Buildings,Manure And Slurry Stores

Introduction

126 When you are planning the location of newlivestock buildings or waste storage facilities orextensions or alterations to existing structures,it is essential to consider the risk of odours andnoise causing nuisance (see paragraphs 7-10).By law you need to get planning permission forlivestock buildings and any structures intendedto contain slurry or sewage sludge sited within400 metres of the boundary of protectedbuildings such as houses or schools.

For livestock buildings, slurry stores andsewage sludge facilities which do not requireplanning permission under the Town andCountry Planning (General PermittedDevelopment) Order 1995, a prior notificationsystem is now in force. You must notify thelocal planning authority of your intention toconstruct such facilities. The local planningauthority must then decide within 28 dayswhether it wishes to approve details of thesiting, design and external appearance of theproposed development.

You may need an environmental assessment insupport of a planning application for large pigand poultry units. The legislation on thissubject is described in Part A of this Code(paragraphs 11-13).

Factors affecting odour problems

127 A number of factors strongly influence the riskof odour problems arising from livestockbuildings, manure or slurry stores. Thesefactors include:

● the distance from neighbouring properties andthe local topography;

● the number and type of stock;

9

9

36

● the prevailing wind direction in relation toneighbouring properties;

● the management of the livestock and housingsystem used;

● the type and size of slurry or manure store andthe way in which it is managed;

● the type of feed used.

The distance of a site from a potentialcomplainant is very important as odours arediluted in the atmosphere. The longer thedistance, the more the odour will be dilutedby dispersal. However, distance alone is oftennot enough to avoid odour nuisance andit is important to take the other factorsinto account.

128 Good management of livestock housing andmanure stores which takes account of thefactors outlined in Sections 5 and 6 will reducepotential odour problems.

129 A number of factors have a large effect on theodour concentration downwind and on thedirection of dispersal. Strong wind mixes theair and increases dilution, so exposed sites mayaid odour dispersal. The frequency anddistribution of wind direction and wind speedscan affect the site chosen, so that odours arecarried away from housing. You may needspecific advice on weather influences such aswind direction, atmospheric stability andodour dispersal.

130 Woodlands and shelter belts can act as barriersand help odour dispersal. Shelter belts andplantations must be correctly laid out withtrees spaced to allow 40-50% of the wind topass through them. Get advice on a suitablelayout and the best types of tree to plant.

Siting of existing livestock units

131A large number of existing livestock units andexisting waste storage facilities are situatedclose to houses and similar properties. It isimportant to follow the advice given in thisCode to help reduce potential odour problemsin such cases.

Government guidance to local planningauthorities requires them to consider carefullyapplications for new housing development nearexisting livestock units. Where farmers aremade aware of such proposals, they may wishto draw potential odour problems to the localplanning authority’s attention.

Siting new livestock units

132 Building new livestock units and theirassociated storage facilities in close proximityto housing can cause particular problems.Siting of such new units should take accountof the factors outlined in paragraphs 127-130.Paying attention to these factors may also helpyou to obtain local authority planningapproval, when necessary, for the siting of new units.

Siting Of Livestock Buildings, Manure And Slurry Stores

37

PART C:AMMONIA

39

Ammonia

Introduction

133 Agriculture is by far the largest source ofammonia emissions in the UK, mainly fromslurry and manure. This section describesammonia gas loss from livestock farmingsystems and some steps that can be taken tolimit the amount lost. Some, though not all,techniques to reduce ammonia loss are similarto those for odour reduction. You should readthis section in conjunction with Part B todevelop good practices which minimise bothammonia and odour emissions.

134 Although some of the ammonia emitted will bedeposited locally, it can travel considerabledistances in the atmosphere. Ammonia cancause two major types of environmentaldamage when it is redeposited on land orwater. First, as a source of nitrogen, it candisrupt the balance of some types of vegetationsuch as heathlands or bogs which exist partlybecause of naturally low soil nitrogen. Thiseffect is known as eutrophication and can alsooccur in waters which receive high nutrientlevels. The second effect of ammonia isacidification. Although ammonia itself is not anacid, it results in acidity when it reacts in thesoil. Excess acid in the soil is damaging tocertain types of vegetation.

Trees or other vegetation growing close to asource of high ammonia emissions may sufferdirect toxic effects of the gas, leading todamaged foliage and slower growth.

Ammonia emission

135 Ammonia is formed from the breakdown ofurea in animal manures and slurries or uricacid in poultry manures. Most of the availablenitrogen in manures is in the form ofammonium-nitrogen. If properly assessed andutilised, it can substitute directly for inorganic

10

40

Ammonia

fertilisers. However, ammonia can easily escapeas a gas from manures and slurries and thisrepresents a loss of valuable nitrogen as well ascausing potentially damaging effects to theenvironment.

136 Some ammonia gas is likely to be released frommanures whenever they come into contact withthe air. Sources therefore include, animalhousing where manures accumulate, manureand slurry stores and manures and slurriesapplied to the land (see Figure 6). Ammonia isalso released from urine, and perhaps fromfaeces, in grazed pastures. One of the mostimportant sources of ammonia emissions is theapplication of slurry to land. This is becausespreading is one of the most ‘leaky’ parts of themanure-handling cycle for ammonia and also,because it is the last stage in the cycle, thebenefits of reducing emissions from housing orstores are likely to be lessened if care is nottaken when applying manures to land.Significant amounts are also emitted from usingnitrogenous fertilisers, particularly urea. Thereare also some minor emissions from non-agricultural sources.

* Provided by the Institute of Grassland and EnvironmentalResearch (1996 data).

137 When investing in new or refurbishing existingbuildings and equipment, you may wish to takeinto account the possibility that reducingammonia loss might become a requirement inthe future.

REDUCING AMMONIA LOSSFROM MANURES AND SLURRIES

Animal diets

138 Only about 20-40% of the nitrogen fed tolivestock as protein in forage or feed is actuallyretained in the animal or animal products. Theremainder is excreted as urea (uric acid inpoultry manure) in urine and faeces; much ofit is rapidly converted to ammonia. Increasingthe efficiency with which animals or birdsconvert feed protein into milk, meat and eggsby ensuring that they are not fed more proteinthan that required (for the target level ofproduction) is a first step in reducingammonia losses.

139 Matching pig diets more closely with theparticular requirements of different growthstages (phase-feeding) may reduce nitrogenexcreted. Similar techniques have beendeveloped for the precision feeding of poultry.Low-nitrogen feeds are already available forpigs which may decrease the quantity ofnitrogen excreted in manures whilemaintaining production.

140 Increasing the efficiency of nitrogen use bycattle and sheep is more difficult, but highenergy, lower protein feed such as maize silagemay be beneficial.

Housing

141 Livestock buildings are an important source ofammonia emissions. Measurements have shown

10

Figure 6: Ammonia emissions fromUK agriculture*

41

Ammonia

that ammonia losses are increased if the wallsand floors are constantly covered with urine orlayers of faeces. The depth is less importantthan the surface area. As for odours, the key tolow ammonia emissions from animal andpoultry housing is the maintenance of highstandards of cleanliness.

142 Removing slurry frequently by flushing orscraping and washing floors will help controlammonia emission from cattle and pigbuildings. If you have a scraping and/orflushing system, you should keep it wellmaintained so that the scrapers do not leave alayer of slurry on the floor and ensure thatblocked nozzles do not prevent proper flushing.

For solid manure systems, you should removedung from non-bedded, concrete areas andtransfer it to a store as often as possible.

For poultry, the rapid air-drying of droppingsin laying houses and the maintenance of drycrumbly litter in broiler houses will reduceammonia loss. Managing drinking systems toavoid overflow and spillage will help; forexample, by using nipple drinkers.

Stores

143 Ammonia loss from slurry stores can bereduced by reducing the surface area of wetmaterial exposed to the air. Some steel slurrytanks can be fitted with lids which may preventthe loss of much of the ammonia as well asreducing odours and other gaseous losses.

144 Where fitting a lid is not practicable, allowinga crust to form on the slurry or covering withstraw or some other floating cover such asrapeseed oil, plastic, or light expanded clayaggregate (LECA) may also reduce emissionsfrom tanks, lagoons or weeping-wall stores.The frequency of stirring the store contents

should be minimised. Every time the contentsare stirred ammonia will be lost. Wheneverpossible fill and empty slurry stores frombelow the surface to avoid exposing freshslurry each time.

Application of manures and slurries to land

145 Emissions from land application of slurriesand manures account for a large proportion ofthe total ammonia emissions from agriculture.It is very important to try to minimise losses atthis stage because any ammonia saved duringhousing or storage will be lost if it is notcontrolled by appropriate field applicationtechniques.

146 Reducing ammonia loss from manures andslurries means more nitrogen is potentiallyavailable for grass or crop uptake. You shouldassess the amount of nitrogen in manures andslurries in order to gain maximum benefit fromit. More details on the fertiliser value oforganic manures are given in ‘FertiliserRecommendations for Agricultural andHorticultural Crops’ (RB 209) MAFF, 1994.

Slurries

147 Emissions from slurry applications are stronglyinfluenced by the dry matter content of slurry,the choice of application method and the soiland weather conditions at the time. Infiltrationof slurry into the soil reduces ammoniaemission. The higher the dry matter content thegreater the ammonia emission from slurries, sodilution is a good way of reducing losses,provided you have the storage and spreadingfacilities to handle the extra volume and soilconditions favour rapid infiltration.

148 Application methods such as injection (seeparagraphs 47-49 and Figure 3) or band-spreading, which minimise the surface area

10

10

42

exposed to the air, generally result in loweremissions. Estimates based on recent researchindicate that open-slot injection can reduceammonia emissions by an average of 60%on UK farms compared to conventionalspreaders. Techniques which produce a closed-injection slot are more effective. However, notall land is suited to injection. For example,the technique is not appropriate on steeplysloping, stony or wet soils.

Band spreaders (see paragraph 46 and figure 2)have been shown to be more effective thansplash-plate spreaders but less effective thaninjection for reducing emissions.

149 Rainfall, wind speed and air temperature allinfluence ammonia emissions from slurriesspread to land. The effects of rainfall aredependent on soil type and soil wetness. Ingeneral, emissions will be reduced if slurry isapplied on cool, still days. Application during,or prior to, rainfall may also reduce emissionsprovided the soil is free-draining and there isno risk of causing water pollution.

Solid manures

150 Ammonia emissions from solid manures can bereduced when they are applied to bare soil byincorporating beneath the soil surface. Most ofthe ammonia is emitted within a few hours ofspreading so, to be effective, incorporationshould take place within 24 hours of spreadingand, where practicable, within four hours.

Ammonia

43

PART D:SMOKE POLLUTION

45

General Principles

151 This part of the Code deals with the risk ofcausing air pollution by smoke from theburning on agricultural and horticulturalpremises of carcases and waste materialsarising from agriculture.

In agriculture, dark smoke and smokenuisance are most frequently caused byburning waste materials in the open or inunsuitable equipment.

152 The disposal of waste produced on premisesused for agriculture is not currently subject tocontrol under the waste management licensingsystem, but certain agricultural wastes will bebrought within the licensing system in futureregulations (see paragraph 19). This will leadto some changes in the guidance within thispart of the Code.

153 Under the Clean Air Act 1993 it is an offenceto burn any material which produces darksmoke unless an exemption applies (paragraphs14-16). Part III of the EnvironmentalProtection Act 1990, which relates to statutorynuisances, also applies (paragraphs 7-10).Certain prescribed processes are subject tospecific controls under the EnvironmentalProtection (Prescribed Processes andSubstances) Regulations 1991 (paragraph 18).

154 Minimise the need to burn waste materials onthe farm by:

● First: reducing the use of materials if possible;

● Second: reusing or recycling materials whereappropriate;

● Third: recovering energy or nutrients from thematerials where appropriate;

● Fourth: using alternative environmentallyacceptable methods of disposal wherever this ispracticable, as set out in Sections 13-18.

11

11

46

155 Where burning cannot be avoided, Sections13-19 give advice on methods of burningwhich reduce the risk of producing dark smokeor smoke nuisance.

156 Make regular and frequent assessments of theappearance and odour of smoke producedwhen burning waste materials in the open. Ifdark smoke is emitted at any time, or if thesmoke is likely to cause a nuisance, take actionimmediately to put the problem right.

Measuring dark smoke

The darkness of smoke from chimneys can be

measured by comparing its shade with a graduated

scale. For the purpose of this Code, the Ringelmann

Chart should be used as described in British

Standard 2742: Use of Ringelmann and Miniature

Smoke Charts. This scale starts at 0 and increases up

to a maximum of 5. Dark smoke is defined as 2 or

more on the Ringelmann Chart and represents 40%

obscuration.

Dark smoke

Smoke is finely divided particles of matter suspended

in the air as a visible cloud. Dark smoke can arise

from incomplete combustion of organic compounds.

Dark smoke production will be avoided if the

temperature is high enough for ignition and if

enough oxygen is available to keep the material

burning at this temperature for long enough for

combustion to be completed.

General Principles

47

Reducing The Volumes Of WasteMaterials For Disposal

Reducing waste

157 Using materials, packaging and equipmentcarefully can extend their useful life and reducethe amount of waste produced. Using suitablemachinery and regularly maintaining it willreduce wear and prolong the useful life of itemssuch as tyres.

Take waste disposal into account whenchoosing products to bring on to the holding.Wherever practicable, choose those methods,equipment and husbandry practices which giveextended life and produce relatively lowamounts of waste for disposal.

Recycling

158 You should minimise waste on the holding byreusing materials wherever practicable. Somewastes can also be recycled by specialistoperators. For this, different waste materialsusually need to be sorted out, then stockpiledin good condition for them to be collected ordelivered to the operator. Some localauthorities and commercial companies also runrecycling programmes.

159 Recycling straw by processing it into added-value products can also be considered as goodpractice as long as the processes are controlledto avoid causing water pollution and producingodours and harmful gases.

Ease of disposal

160 If packaging and disposable materials for cropprotection, mulching or crop storage arebrought onto the holding, you should considerhow easy it is to dispose of the waste. Ifpossible, choose materials which can bedisposed of safely and economically withoutburning them. Consider using materials which biodegrade after they have been used.

12

12

48

161 Only burn materials which cannot practicablybe disposed of in any other way, which burneasily and which do not produce dark smokeor poisonous by-products when burnt undersuitable conditions.

162 Ask the Environment Agency about facilitiesfor the disposal and collection of difficultwastes.

Reducing The Volumes Of Waste Materials For Disposal

49

Plastic Materials

Introduction

163 Do not burn plastics in the open onagricultural holdings because this can causelarge amounts of dark smoke and poisonousby-products which can be extremely harmfulto health.

164 If you burn plastics in an incinerator, theinstallation may require authorisation bythe local authority under Part I of theEnvironmental Protection Act 1990(paragraph 203).

Repeated use of plastics

165 Consider reusing plastic materials on the farmor holding. If an item can be used several timesbefore it becomes unserviceable, the quantity ofmaterial which needs to be disposed of will begreatly reduced.

166 To maximise recycling, take care whenhandling and using plastics. Use suitableequipment and methods of handling to makesure that the plastic item is not damaged.Carefully reclaim and reuse items such as cropcovers for mulching.

Alternative uses

167 If a plastic material cannot be reused for itsoriginal purpose, try hard to make use of it forother things. However, never use containersthat have held agricultural chemicals andpersistent, poisonous or harmful substances forany other purpose. (See the Code of Practicefor the Safe Use of Pesticides on Farmsand Holdings).

13

13

50

Recycling

168 Recycle polythene materials using specialistrecycling companies. Suitable items include:

● silage wrapping, bags and sheets;

● polythene inners from fertiliser ‘big bags’;

● 50 kg fertiliser sacks;

● pallet covers;

● polythene covers from greenhouses.

169 Materials for recycling should be clean and freefrom soil. Keep different types of itemsseparate. Store the material in one safe placeready to be collected.

Choosing materials

170 When choosing plastic materials to use in crophusbandry, if recycling is not practicable,then choose those materials which are bio-degradable. Biodegradable plastic materials arelikely to be unsuitable for recycling.

171 If plastic items such as plant pots or trays arereused, their life can be increased by choosingmore durable products. This reduces waste. Ifreturnable items are thrown away because oftheir appearance, using a more durable type ofplastic, a different colour or different type ofreturnable container may enable each unit tobe used more times.

172 Save plastics which cannot be recycled anddispose of them to licensed landfill sites, orauthorised incinerators.

Containers contaminated by pesticides

173 The Code of Practice for the Safe Use ofPesticides on Farms and Holdings gives detailsof preferred disposal methods and allprecautions to take when disposing of orburning these containers. The Code has astatutory basis under Part III of the Food andEnvironment Protection Act 1985 and shouldbe read by all farmers.

Under the Clean Air (Emission of Dark Smoke)(Exemption) Regulations 1969, dark smokeemitted by the burning of containers which arecontaminated by any pesticide or by any toxicsubstance used for veterinary or agriculturalpurposes is exempt from the prohibition inSection 1 of the Clean Air Act 1993 providedthat the following conditions are satisfied.

● There is no other reasonably safe andpracticable method of disposing of the matter.

● The burning is carried out in such a manner asto minimise the emission of dark smoke.

● The burning is carried out under the direct andcontinuous supervision of the occupier of thepremises concerned or a person authorised toact on his behalf.

There are few circumstances where otherpracticable methods of disposal cannot befound. Many specialist waste contractors nowoffer well-managed disposal services.

Part III of the Environmental Protection Act1990, which relates to statutory nuisances, alsoapplies if you do resort to burning(paragraphs 7-10).

Plastic Materials

51

Tyres And Rubber

Dark smoke risk

174 Rubber tyres produce large amounts of darksmoke and may give off poisonous substanceswhen burnt in the open. Do not burn tyres andother rubber materials on agricultural holdings.

175 Ask tyre suppliers to take away old tyres fromthe premises when new ones are fitted toagricultural machinery.

Disposal off the farm

176 Dispose of large numbers of tyres to specialistwaste removal operators or contractors. Smallquantities of tyres may be accepted by licensedlocal authority sites, but you may need to getspecial permission from the site operator.

14

52

Waste Oils

Sources

177 Waste oil comes from the servicing ofagricultural machinery. The main types ofwaste oil are used lubricating oil from enginesand oil from hydraulic systems.

Recycling

178 Collect used oil drained from machinery duringroutine servicing and store it in suitable leak-proof containers. Store surplus oil in a centralstore, preferably bunded and secure fromvandals, and dispose of it to waste oil dealers.Different types of oil should be kept separate.Do not tip waste oil onto land or vegetation.

NOTE: NEVER DISPOSE OF WASTE OILINTO SOAKAWAYS, WATERCOURSES,DRAINS OR SEWERS AS IT CAN CAUSESERIOUS WATER POLLUTION.

15

53

Waste Oils

Waste oil burners

179 You can burn waste oils for heating on farmsprovided that you obtain approval for theinstallation of the burner to be used from thelocal authority Environmental HealthDepartment. Under Part I of the EnvironmentalProtection Act 1990, such burners must complywith the Secretary of State’s Guidance Note forwaste oil burners less than 0.4 MW and wasteoil or recovered oil burners less than 3 MW netrated thermal input (paragraph 18).

NOTE: The design and construction of new orsubstantially enlarged or reconstructed storagefacilities for storing more than 1500 litres (330gallons) of oil to be burnt for agriculturalpurposes must comply with the Controlof Pollution (Silage, Slurry and AgriculturalFuel Oil) Regulations 1991 (as amended).The Water Code gives further advice.

15

54

Animal Carcases

Introduction

180 There are a number of ways to dispose ofanimals and poultry that die on the farm. Thebest way is to send them to a licensed knacker’syard or hunt kennel, authorised incinerator orrendering plant. If a notifiable disease isinvolved, disposal is subject to the StateVeterinary Service animal health controls.

181 Disposal methods on the farm, such as burial,incineration or burning in the open may causewater or air pollution, particularly if they arenot done correctly.

182 The Water Code gives advice on how to avoidcausing water pollution from burying carcases.Consult the Environment Agency if thereis any doubt over the suitability of a proposedburial site.

Never dispose of carcases in or nearwatercourses, boreholes or springs. Apart frombeing prosecuted for causing water pollution,there is a serious risk of spreading disease toanimals on neighbouring farms.

Notifiable diseases

183 If you think that a notifiable disease has causedill health or death you must report it to theDivisional Veterinary Manager at the localAnimal Health Office of the Ministry ofAgriculture Fisheries and Food or Welsh OfficeAgriculture Department. Carcases should beavailable for post-mortem examination in thesecases. Always consider the possibility ofanthrax if death is sudden or unexplained.

16

55

Animal Carcases

Incineration

184 If animal carcases are burnt on farm it shouldbe done in an incinerator wherever possible.

The incinerator used should be fitted with asecondary combustion chamber so that hightemperatures can be achieved throughoutincineration to give complete combustionof all products. Get advice about siting,choosing, installing and running incinerators,chimneys, associated buildings and carcasestorage facilities.

If you intend to install an incinerator designedfor, or to be operated at, loading rates of morethan 50 kg/hour, you must first get approvalfor the installation of the appliance in questionfrom the local authority Environmental HealthDepartment under Part I of the EnvironmentalProtection Act 1990. It must comply with theSecretary of State’s Guidance Note on animalcarcase incineration processes under one tonneper hour (paragraph 18).

For units with a loading rate of less than 50kg/hour, the Clean Air Act 1993 whichprohibits the emission of dark smoke fromchimneys and Part III of the EnvironmentalProtection Act 1990 which relates to statutorynuisances still apply (paragraphs 7-10and 14-16).

185 Incinerate dead animals as soon as possible. Donot exceed the design loading rate of theincinerator at any time.

16

16

56

Open burning

186 Using suitable on-site incineration equipment isstrongly preferred to open burning.

187 Under the Clean Air (Emission of Dark Smoke)(Exemption) Regulations 1969, emission ofdark smoke, caused by the burning of carcasesof animals or poultry which:

● have died or are reasonably believed to havedied because of disease;

● or have been slaughtered because of disease;

● or have been required to be slaughtered underthe Animal Health Act 1981;

is exempt from the prohibition in Section 1 ofthe Clean Air Act 1993, provided that:

● there is no other reasonably safe andpracticable method of disposing of the matter;

● and the burning is carried out under the directand continuous supervision of the occupier ofthe premises concerned or a person authorisedto act on their behalf.

The Environmental Protection Act 1990, PartIII, which relates to statutory nuisances, stillapplies (paragraphs 7-10).

If burning is essential, follow the generalprecautions on open burning given inparagraph 214. A shallow pit should be dugwith cross trenches to provide a good airsupply to the base of the fire. Use only dryfuels which are not likely to produce darksmoke and which burn easily. Do not use tyresor liquids as a fuel and do not use the fire todispose of other materials not recommendedfor burning. Gas-fired equipment may be usedto start the fire. Place the primary fuel in thebase of the fire and place the carcases on top.Use enough fuel to ensure that the carcases arecompletely burned. Do not overload the firewith carcases. Burning should begin as early inthe day as possible.

Animal Carcases

57

Fuels Produced On The Farm

Introduction

188 Straw and other crop residues can be used asanimal feed, for animal bedding and, wheremarkets exist, for paper pulp and formanufacturing board. Excess amounts of strawcan be sold to other agricultural holdings or tostraw merchants. Residues can be mixed intothe soil. Generally the burning of crop residuesis banned, unless specifically exempted by thelegislation (see paragraph 204).

Straw and wood as fuels

189 Straw is a useful energy source and mayprovide a cost-effective and environmentallyacceptable fuel for furnaces that are designedto burn it. Other crop residues, wood and litterfrom stock can also be used as alternative fuels.

Choosing equipment

190 Straw- or wood-fuelled furnaces should beproperly designed for the purpose and havefacilities to give adequate control overcombustion to prevent the production of darksmoke. If units of over 400 kW (0.4 MW) netrated thermal input are used, you must obtainapproval for the installation of the appliance inquestion from the local authorityEnvironmental Health Department under Part Iof the Environmental Protection Act 1990. Itmust comply with the requirements of theSecretary of State’s Guidance Notes oncombustion of fuel manufactured from, orcomprised of, solid wastes in applicationsbetween 0.4 and 3 MW net rated thermal input(see Appendix II).

Chimney height approval may be requiredunder Section 14 of the Clean Air Act 1993 forfurnaces outside local authority authorisation.

17

58


191 Equipment with a thermal input of less than400 kW (0.4 MW) is still subject to theprovisions of the Clean Air Act 1993 whichprohibits the emission of dark smoke fromchimneys (paragraphs 14-16). Part III of theEnvironmental Protection Act 1990, whichrelates to statutory nuisances, also applies(paragraphs 7-10).

Using and maintaining equipment

192 Efficient burning of fuel will prevent theproduction of dark smoke. It is important tochoose suitable equipment and operate itcorrectly. Automatic fuelling equipment that isproperly set up and maintained can provide themost stable operating conditions and willautomatically provide the heat that is needed atany particular time.

193 Many boilers and heaters have a large chamberand are designed to burn a single charge offuel. These units should be designed so that thesupply of primary and secondary air can becontrolled to give efficient burning of the largecharge of fuel without producing dark smoke.

194 Do not try to prolong the burning of a largecharge of fuel by reducing the air supply. Thiswill give inefficient combustion and cause darksmoke. With large charge boilers, if heat isneeded over a long period, they should be usedin conjunction with water-based thermalstorage systems or the boiler itself should havea large water content so that it stores the heat.

195 To avoid producing dark smoke, only burnfuels that the burner is designed for and whichare recommended by the manufacturer. Do notburn animal carcases, plastics, tyres or otherrubber materials in straw or wood burners.Store fuel for the burner under cover. Alwaysmake sure that the fuel is dry. Adjust theprimary and secondary air supply to give

efficient combustion and minimum darksmoke emission.

196 Get burning equipment cleaned and servicedregularly. Scrape or brush internal heat-transfersurfaces to keep them in a clean condition andfree from char and other deposits. Do not carryout uncontrolled burning of a charge of fuel inthe furnace to remove deposits of char from theinternal surfaces of the boiler, as this is likely toproduce dark smoke.

Using litter from poultry and other animalsas a fuel

197 If litter from poultry or animals is to be used asa fuel in heating appliances for space heating oragricultural processes, specialised equipmentdesigned for this type of fuel should be used.Automatic fuelling should be part of thesystem. Air supply for primary and secondarycombustion should be controlled to give highcombustion efficiency.

17

17

59

198 The plant should be operated in a way whichminimises the emission of dark smoke.Monitoring the appearance and smell of theflue gases should be carried out at least oncea day.

199 If a unit of over 400 kW (0.4 MW) net ratedthermal input is used you must get approval forinstallation of the appliance in question fromthe local authority Environmental HealthDepartment under Part I of the EnvironmentalProtection Act 1990. It must comply with therequirements of the Secretary of State’sGuidance Note on combustion of fuelmanufactured from or comprised of solidwastes in applications between 0.4 and 3 MWnet rated thermal input (see Appendix II).

200 Equipment with a thermal input of less than400 kW (0.4 MW) still comes under theprovisions of the Clean Air Act 1993 whichprohibits the emission of dark smoke fromchimneys (paragraphs 14-16). Part III of theEnvironmental Protection Act 1990, whichrelates to statutory nuisances, also applies(paragraphs 7-10).

201 If you wish to install heating systems fuelled bystraw, wood or animal litter heating systemsyou will normally need professional help todesign such an installation.


60

Other Waste Materials

Introduction

202 Under the Clean Air Act 1993, it is an offenceto burn waste materials if the burning producesdark smoke (paragraphs 14-16). Part III of theEnvironmental Protection Act 1990, whichrelates to statutory nuisances, also applies(paragraphs 7-10).

203 If waste materials are to be burnt in anincinerator which is designed or operated atrates of more than 50 kg/hour, you must getapproval for the appliance in question from thelocal authority Environmental HealthDepartment, under Part I of the EnvironmentalProtection Act 1990. It must comply with theSecretary of State’s Guidance Note on generalwaste incineration processes under one tonneper hour.

Crop residues

204 The burning of cereal straw and stubble, theresidues of oilseed rape, field beans and peasharvested dry is banned by the Crop Residues(Burning) Regulations 1993, except in verylimited circumstances, e.g. for disease controlwhere a plant health order has been served.When crop residues are burnt under anexemption or where linseed residue is burnt,the Regulations set out requirements about:

● the area to be burned;

● firebreaks;

● distances from vulnerable objects such as trees,hedges, buildings;

● days of the week and times for burning;

● supervision and other safety requirements;

18

18

61

● notifying relevant authorities and neighbours;

● incorporating ash after burning.

Guidance Notes on the Regulations were issuedto all farmers in England and all cerealproducers in Wales in 1993.

205 The Clean Air Act 1993, the Health and Safetyat Work etc. Act 1974, the Highways Act 1980and the Environmental Protection Act 1990also apply.

206 Burning of broken straw bales and the residuesof other minor crops are not covered by theRegulations. If you do need to burn theseresidues, you should still follow the guidance inparagraph 204.

Wood waste

207 Wood waste is produced during forestryoperations, orchard pruning, demolition ofbuildings, estate maintenance, and buildingconstruction and maintenance.

208 Larger items of timber and waste wood can beused as firewood. Therefore, it is preferable toprocess these into burnable lengths fordomestic use or dispose of them to specialistdealers in this material. Arrangements withcontractors for forestry work and woodlandclearance should include an agreement for thedisposal of any waste wood that is produced.

209 Trimmings from woodland or orchard pruningmay be converted to wood chips wherepracticable. If they have to be burned, followthe guidance in Section 17.

210 Under the Clean Air (Emission of Dark Smoke)(Exemption) Regulations 1969, emission ofdark smoke caused by the burning of timberand any other waste matter (other than natural

or synthetic rubber, or flock or feathers), whichresults from the demolition of a building orclearance of a site in connection with anybuilding operation or work of engineeringconstruction (within the meaning of Section176 of the Factories Act 1961), is exempt fromthe prohibition in Section 1 of the Clean AirAct 1993, provided that the followingconditions are satisfied:

● there is no other reasonably safe andpracticable method of disposing of the matter;

● and the burning is carried out in such a manneras to minimise the emission of dark smoke;

● and the burning is carried out under the directand continuous supervision of the occupier ofthe premises concerned or a person authorisedto act on his behalf.

If in doubt, get advice from the EnvironmentalHealth Department of the local authoritybefore burning any waste.

Other Waste Materials

62

Other Waste Materials18

Paper sacks and other packaging

211 Where practicable, paper sacks and otherpackaging that are not contaminated bypesticides should be stockpiled and sent forrecycling, for example to a board mill. Ifrecycling is not possible, burn paper sackscarefully in small quantities as long as this doesnot cause a nuisance (paragraphs 7-10).

Litter from poultry and other animal litter

212Because litter from poultry or other animalsvaries in its moisture content and composition,it is difficult to burn except under closelycontrolled conditions. Uncontrolled burningwill produce dark smoke and odour. Therefore,do not burn poultry and animal litter inthe open.

63

Burning In The Open

Good practice

213 Under the Clean Air Act 1993, it is an offenceto burn any material in the open on tradepremises if the burning produces dark smoke(paragraphs 14-16). Part III of theEnvironmental Protection Act 1990, whichrelates to statutory nuisances, also applies(paragraphs 7-10).

214 If burning in the open is the only practicablemethod of disposal, take the followingprecautions to prevent producing dark smokeand causing a nuisance.

● Do not burn plastics, rubber, tyres or othermaterials known to produce dark smoke.

● Avoid burning if it will cause a nuisance tonearby residential areas.

● Materials should be dry and have a lowmoisture content. Do not burn greenvegetation.

● Keep fires small and continually addcombustible material, minimising the depth ofthe combustion area. Do not pile material highon fires.

● Minimise the quantity of incombustiblematerial which is added to the fire. Whereverpossible keep incombustible materials separatefrom the materials to be burnt.

● For better combustion, agitate the base of thefire to improve the air supply.

● If a fire produces dark smoke, don’t add anymore material that burns slowly.

19

64

Burning In The Open

Safety precautions

215 Also take the following precautions tominimise fire hazard.

● Build fires well clear of houses, other buildings,overhead cables or flammable materials such asstacks of straw, trees, hedgerows, ripe cerealsor stubble.

● Fires must not be lit near a public road. If thefire, or smoke from it, causes injury,interruption or dangers to road users, this maybe an offence under the Highways Act 1980.

● Do not burn materials in the open when it isvery windy or in a period of drought.

● Only light fires downwind of public highways,houses, other buildings or inflammablematerials, so that the wind will carry anysparks and smoke away from them.

● Tell the local authority Fire Service beforestarting any substantial burning operations.

● Have a fire extinguisher and a supply of waterfrom a mains supply or bowser on hand in caseof an emergency.

● Burning should be carried out under direct andcontinuous supervision of the occupier of thepremises or a person authorised to act on theirbehalf. The only exception to this should be ifthere is an emergency elsewhere on the farmrequiring immediate attention.

● Put out all fires before you leave them.

19

65

PART E:GREENHOUSE GASES

67

Greenhouse Gases

Introduction

216 This section describes the greenhouse gasesemitted by agricultural systems and some stepswhich can help limit the amount of gases thatare released.

217 Climate change is one of the biggestenvironmental problems now facing the world.The sun is the earth’s source of heat. Some ofthe sun’s energy is absorbed by the surface ofthe earth. In turn, the earth radiates the energyback into space as infra-red radiation. Some ofthe gases in our atmosphere can absorb thisinfra-red radiation, and so prevent it leavingthe earth and its atmosphere. This acts as ablanket and makes the earth warmer. This issimilar to the effect of glass in a greenhouse,which lets the sunlight in but stops some of theradiated heat from escaping. The gases whichcause this effect are therefore called greenhousegases. Most of these occur naturally in theatmosphere, and produce a natural greenhouseeffect which keeps the temperature of the earthabout 30°C higher than it would otherwise be.

The greenhouse gases

218 The most important greenhouse gases are watervapour, carbon dioxide, methane, nitrousoxide, and a group of man-made gases such aschlorofluorocarbons (CFCs). All the majorgases have natural sources, but human activityincreases the amount released. It is believedthat this pollution has added to the naturalgreenhouse effect and will cause thetemperature of the earth’s surface to rise. Thiscould have major effects on the world; forexample, changes in sea level could cover low-lying coasts, and changes in climate andweather could damage agriculture and naturalsystems. Because some of the greenhouse gaseslast for a long time in the atmosphere,it is important that any action to reduce

20

68

Greenhouse Gases

emissions of greenhouse gases is taken as earlyas possible.

The UK has signed an international agreementto return its greenhouse gas emissions to 1990levels by 2000 and international negotiationsare underway to set a series of furtherreduction targets for the years beyond 2000.

Figure 7 shows the relative importance of the three

main greenhouse gases emitted by UK agriculture. In

terms of global warming, methane is 21 times more

powerful than carbon dioxide, and nitrous oxide is

310 times more powerful than carbon dioxide over a

100 year period. The amount of carbon dioxide

produced as a by-product of fertiliser manufacture in

the UK is shown, but this carbon dioxide is not

produced directly by agriculture. Agriculture

produces about 1% of the carbon dioxide released in

the UK (as a result of fossil fuel use), 28% of the

methane and 58% of the nitrous oxide. Agriculture

therefore accounts for about 8% of total UK global

warming emissions.

Reducing emissions

219 As industrial emissions of greenhouse gasesreduce, attention will turn to agriculturalsources. This is particularly the case formethane and nitrous oxide because agriculturecontributes significantly to national emissionsof these gases. There are some methods thatfarmers can use to reduce the amount ofgreenhouse gas emitted, many of which willalso save money.

Carbon dioxide

220 The most effective way of reducing carbondioxide emissions is to use energy moreefficiently and to exploit alternative non-fossilfuels as sources of energy. Improvements inenergy efficiency can reduce farm runningcosts. The following are important.

● Maintain engines by following themanufacturers recommendations. A reductionof 5-15% in fuel consumption can be obtainedby servicing air cleaners and fuel injectorsregularly.

● Choose tractors and machinery that aresuitable for the tasks they will be performing.Use the lowest powered tractor capable ofdoing the required job.

● Do not make unnecessary journeys andcultivation passes.

20

Figure 7: Greenhouse gas emissionsfrom UK

*Contribution of methane (CH4), carbon dioxide (CO2),and nitrous oxide (N2O) to global warming potential.Derived from the National Atmospheric EmissionsInventory 1994.

69

Greenhouse Gases

● Maintain fixed equipment such as grain driers,refrigerated stores and bulk milk tanks in goodcondition and operate them efficiently.

● Reduce heat loss from heated buildings.Unintentional ventilation of buildings canwaste a lot of heat. Effective insulation ofwalls, roofs, and heating pipes can significantlyreduce the amount of heat that is lost.

● Heated glasshouses, mushroom houses andpolythene covered structures are major usersof energy. Economise on fuel by precise controlof the correct temperature regimes, usingthermal screens and correct maintenanceof boilers and burners.

● Consider the use of energy sources which arenot fossil fuels. There are opportunities forusing alternative energy sources, such as solarheating, heat pumps, straw-burning boilers,biogas from manure digestion, wind and waterpower. These techniques may be cost effectiveespecially when the amount of energy needed isconsistent through the year. Each project needsfirstly to be critically assessed for its capital,management and running costs. Further detailsof some of these possibilities are given inSection 17.

There are also potential commercialopportunities to sell the energy from alternativesources. Under the Non-Fossil Fuel Obligation,electricity supply companies are required tobuy a proportion of their electricity fromalternative energy sources.

● Large amounts of fossil fuel are needed tomanufacture nitrogen fertilisers. Fertilisersshould only be used at the rates suitable for thecropping situation. When calculatingapplication rates, take into account any organicmanures or sewage sludge applied to the land.Make sure that fertiliser spreaders are properly

maintained and use suitable settings fordifferent types of fertiliser.

221 As well as by using fossil fuels, agriculture alsocontributes carbon dioxide from thebreakdown of liming materials in the soil.Limestone is composed of calcium carbonatewhich releases fossilised carbon dioxide intothe atmosphere as it neutralises acidity in thesoil. Historic changes in land-use have alsoresulted in the release of carbon dioxide.Further emissions can be minimised byavoiding the cultivation of land that has neverbeen cultivated, by avoiding conversionof pasture to arable land, and by protectingpeat soils from degradation caused by drainageand cultivation.

222 It is important not to confuse the permanentrelease into the atmosphere of fossilised carbonfrom fossil fuels and limestone with the carbondioxide that is recycled within agriculture andthe human and animal food cycle. As cropsgrow, they absorb carbon dioxide from theatmosphere, but a similar amount is released tothe atmosphere when the crop products areused as food for animals or people; this part ofagriculture is not considered a net consumer ofcarbon dioxide.

Methane

223 Methane is emitted by farm animals and theexcreta they produce. Direct losses of methanefrom animals are due to fermentation caused bybacteria in the stomach. Cows produce the mostmethane per animal, followed by horses, sheep,goats and pigs. Emissions from lactating dairycows are particularly high due to their greaterenergy demands. In contrast, poultry do notproduce any methane directly, although a smallamount can be released from their excreta.Research is being carried out on modified dietsfor livestock to reduce emissions, although it is

20

70

Greenhouse Gases

unlikely that these will result in significantreductions in the near future.

224 A small amount of methane from agriculture isreleased by bacteria in slurry and manure. Thisis the natural but much slower equivalent ofthe process which occurs in anaerobic digestion(see paragraph 112). Methane produced fromcontrolled anaerobic digestion should be usedefficiently as an energy source.

SAFETY NOTE: METHANE IS HIGHLY FLAMMABLE

Nitrous oxide

225 Nitrous oxide from agriculture is released fromnitrogen compounds in manures, fertilisers,crops, and soils and watercourses. It is likely tobe produced in oxygen-free conditions. Themost effective ways for farmers to reducereleases of this gas are to use nitrogen fertiliserand manures efficiently so that croprequirement is met while losses of nitrogen areminimised. Nitrogen in animal diets should bematched to animal requirement.

Chlorofluorocarbons (CFCs)

226 Apart from their effect as greenhouse gases,CFCs also damage the ozone layer. This allowsmore of the sun’s ultraviolet-B radiation (UVB)to reach the earth’s surface. This could haveimportant economic and health effects, such asincreasing skin cancer, as well as damagingcrops, farm animals and wildlife.

227 CFCs are used in refrigeration equipment. Keeprefrigeration equipment properly maintained tominimise the risk of leaks of refrigerant.Whenever such equipment is serviced, makesure that no refrigerant is lost. Do not allowunused equipment to deteriorate on site. Get a

specialist contractor to take away theequipment and safely remove the refrigerant, so that it can be recycled or destroyed.

Halons

228 Halons (chemicals similar to CFCs) alsodamage the ozone layer. They are often foundin fire extinguishers for use on electrical fires.Avoid releasing the gas from such extinguishersunnecessarily. When they reach the expiry datemarked on them, or have been partly used,dispose of them through the manufacturer or aspecialist contractor so that the halon can berecycled or destroyed.

20

71

APPENDICES

72

Appendix I

E N V I R O N M E N T A G E N C Y: C O N TA C T D E TA I L S

HEAD OFFICERio HouseWaterside DriveAztec WestAlmondsburyBristol BS12 4UDTel: 01454 624400Fax: 01454 624409

ANGLIANKingfisher HouseGoldhay WayOrton GoldhayPeterborough PE2 5ZRTel: 01733 371811Fax: 01733 231840

NORTH EASTRivers House21 Park Square SouthLeeds LS1 2QGTel: 0113 244 0191Fax: 0113 246 1889

NORTH WESTRichard Fairclough HouseKnutsford RoadWarrington WA4 1HGTel: 01925 653999Fax: 01925 415961

MIDLANDSSapphire East550 Streetsbrook RoadSolihull B91 1QTTel: 0121 711 2324Fax: 0121 711 5824

ENVIRONMENTAGENCY GENERALENQUIRY LINETel: 0645 333 111

ENVIRONMENTAGENCYEMERGENCYHOTLINETel: 0800 807060

SOUTHERNGuildbourne HouseChatsworth RoadWorthingWest Sussex BN11 1LDTel: 01903 832000Fax: 01903 821832

SOUTH WESTManley HouseKestrel WayExeter EX2 7LQTel: 01392 444000Fax: 01392 444238

THAMESKings Meadow HouseKings Meadow RoadReading RG1 8DQTel: 01189 535000Fax: 01189 500388

WELSHRivers House/Plas-yr-AfonSt Mellons Business ParkSt MellonsCardiff CF3 0LTTel: 01222 770088Fax: 01222 798555

73

Appendix II

Sources of information

Legislation: general and odours

Animal Health Act 1981, SI 1981, Chapter 22,HMSO (ISBN 0105422819)

Control of Pollution (Silage, Slurry andAgricultural Fuel Oil) Regulations 1991(amended) SI 1991, No 324, HMSO(ISBN 0-11-013324-2) as amended by theControl of Pollution (Silage, Slurry andAgricultural Fuel Oil (Amendment))Regulations 1997 SI 1997, No 547,The Stationery Office (ISBN 0110640497)

Environment Act 1995, HMSO(ISBN 0105425958)

Environmental Protection Act 1990,Chapter 43, HMSO (ISBN 0 10 544390 5)

Factories Act 1961 Chapter 34, HMSO

Food and Environment Protection Act 1985HMSO (ISBN 0-10-544885-0)

Greenhouse Gases. Refrigeration and airconditioning CFC Phase-out, Advice onAlternatives and Guideline for UsersDepartment of Trade and Industry(DTI/Pub/1147/4K/1194)

Health and Safety at Work etc. Act 1974Chapter 37, HMSO (ISBN 0105437743)

Highways Act 1980 HMSO(ISBN 0105466808)

Landfill Tax Regulations 1996 SI 1996,No 1527 (ISBN 0110443810)

Sludge (Use in Agriculture) Regulations 1989 SI1989, No 1263, HMSO (ISBN 0 11 0972635)

as amended by the Sludge (Use in Agriculture)Regulations 1990 SI 1990, No 880, HMSO(ISBN 0110038800)

Special Waste Regulations 1996 SI 1996/972,as amended by the Special Waste (Amendment)Regulations 1996 SI 1996/2019, The StationeryOffice, (ISBN 0110629418), and the SpecialWaste (Amendment) Regulations 1997 SI1997/251, The Stationery Office(ISBN 0110638816)

Town and Country Planning (Assessment ofEnvironmental Effects) Regulations 1988 SI1988, No 1199, HMSO (ISBN 0110871995) asamended by SI 1990, No 367, HMSO(ISBN 0-10-543-7743)

Town and Country Planning (GeneralPermitted Development) Order 1995 SI 1995,No 418, HMSO (ISBN 011052506x)

Welfare of Livestock Regulations 1994 SI1994, No 2126, (ISBN 0110451260)

Legislation: smoke pollution

The Clean Air Act 1993 HMSO(ISBN 0105411930)

The Clean Air (Emission of Dark Smoke)(Exemption) Regulations 1969 StatutoryInstrument No 1969/1263, HMSO

The Crop Residues (Burning) Regulations 1993SI 1993, No 1366, HMSO (ISBN 0110343662)

The Environmental Protection (PrescribedProcesses and Substances) Regulations 1991Statutory Instrument No 1991/472 asamended, HMSO

74

Appendix II

Secretary of State’s Guidance Notes:

Animal carcase incineration Processes under 1 Tonne per Hour PG 5/3 (95), HMSO(ISBN 0117531545)

Combustion of Fuel Manufactured from orComprised of Solid Waste in Appliances

Between 0.4 and 3 MW Net Rated ThermalInput PG 1/12 (95), HMSO(ISBN 0117531960)

General Waste Incineration Processes under 1 Tonne an Hour PG 5/4 (95), HMSO(ISBN 0117531553)

Poultry litter Combustion Processes between0.4 and 3MW Net Rated Thermal Input PG1/9 (91), HMSO (ISBN 0117523992)

Production of Compost for Mushrooms PG6/30 (92), HMSO (ISBN 0117526118)

Waste Oil Burners, less than 0.4 MW NetRated Thermal Input PG1/1 (95), HMSO(ISBN 0117531944)

Waste Oil or Recovered Oil Burners, less than3MW Net Rated Thermal Input PG 1/2 (95).HMSO (ISBN 0117531952)

Wood Combustion Processes between 0.4 and3 MW Net Rated Thermal Input (PG 1/8 (91),HMSO (ISBN 0117524069)

Codes of Practice

Code of Practice for Agricultural Use ofSewage Sludge Department of Environment,1989, Revised 1996, WQI/96/99. Availablefrom DETR Publications Sales Centre(Tel: 01709 891318 or Fax: 01709 881673)

Water Code (Code of Good AgriculturalPractice for the Protection of Water) (PB 0587)MAFF, 1991, Revised 1998. Available free ofcharge from MAFF Publications, Admail 6000,London SW1A 2XX. Tel: 0645 556000

Soil Code (Code of Good Agricultural Practicefor the Protection of Soil) (PB 0617) MAFF,1993, Revised 1998. Available free of chargefrom MAFF Publications, Admail 6000,London SW1A 2XX. Tel: 0645 556000

Code of Practice for the Safe Use of Pesticideson Farms and Holdings, 1998, (PB 3528).Available free of charge from MAFFPublications, Admail 6000,London SW1A 2XX. Tel: 0645 556000

MAFF Codes of Recommendationsfor the Welfare of Livestock

Cattle 1983, PB0074Domestic Fowls 1987, PB0076Pigs 1983, PB0075Sheep 1989, PB00078Turkeys 1987, PB0077Goats 1989, PB0081

Available free of charge from MAFFPublications, Admail 6000,London SW1A 2XX. Tel: 0645 556000

Greenhouse gases

This Common Inheritance. Britain’sEnvironmental Strategy HMSO, 1990(ISBN 0 10 112002 8)

Climate Change – The IPCC ScientificAssessment edited by J.T. Houghton, G.J.Jenkins & J.J. Ephraums, published for theIntergovernmental Panel on Climate Change byCambridge University Press, Cambridge, 1990.(ISBN 0521407206)

75

Appendix II

Climate Change: The UK Programme. TheUnited Kingdom’s Second Report under theFramework Convention on Climate Change1997, The Stationery Office, (ISBN0101355823)

Review of the Potential Effects of ClimateChange in the United Kingdom. UnitedKingdom Impacts Review Group SecondReport Department of Environment, 1996,HMSO, (ISBN 0117532908)

Refrigeration and Air Conditioning CFC Phase-out. Advice on Alternatives and Guidelines forUsers Department of Trade and Industry(Dti/Pub/1147/4k/11.94)

The Potential Effects of Ozone Depletion in theUnited Kingdom. United Kingdom UVBMeasurements and Impacts Review GroupDepartment of the Environment, 1996 (ISBN0117533130)

Other publications

British Standards 2742: 1969 Notes on the Use of Ringelmann and Miniature SmokeCharts BSI.

British Standard 5502: Buildings and Structuresfor Agriculture Part 50: 1989, Code of Practicefor design, construction and use of receptionpits and storage tanks for slurry; Part 33: 1991,Guide to the control of odour pollution BSI

Control of Pollution (Silage, Slurry andAgricultural Fuel Oil) Regulations 1991 (amended) GUIDANCE NOTES FORFARMERS Department of Environment,WOAD, April 1997. Available from RoomA405, Department of the Environment,Transport and the Regions, Romney House,Marsham Street, London SW1P 3PY

Effluent Storage on Farms. HSE Guidance NoteGS12 (May 81)

Guidance Notes to Farmers When BurningCrop Residues MAFF, 1993, PB1326. Availablefree of charge from MAFF Publications,Admail 6000, London SW1A 2XX.Tel: 0645 556000

Planning Policy Guidance Note 7: TheCountryside – Environmental Quality andEconomic and Social Development (PPG7),revised 1997, HMSO (ISBN 011753370x)

Poultry Litter Management, PB1739, MAFF,1994. Available free of charge from MAFFPublications, Admail 6000,London SW1A 2XX. Tel: 0645 556000

Slurry Storage Systems. Health and SafetyExecutive (Annex to AIC 1986/155)

77

INDEX

78

Index

Numbers in the index refer to paragraph numberse.g., 92 in the text. Definitions and descriptions in panel boxes in the text are denoted by pagenumbers in a box e.g.

A Above-ground circular stores 92

Additives for odour control 117-119

Advice 6

Aerobic treatment 108, 107-110

Ammonia 138-150

Anaerobic treatment 111-112

Animal carcases 180-187

Application of livestock wastes to land 30-56

B Band spreading 36, 46,

Battery manure (see Poultry manures)

Bedding 59, 65-66, 70-71, 77

Best practicable means (BPM) 1, 10

Biological treatment of slurries 105-106

Broiler manure (see Poultry manures)

C Carbon dioxide 220-222

Carcases (see Animal carcases)

Cattle manure (see Solid manures)

Cattle slurry 42-50, 90-94, 98-119

CFCs 226-227

Clean Air Acts 1993 14-17, 173, 187, 202,210, 213

17

17

Consultants (see Professional help)

Cow slurry (see Slurry)

Crop residues 204-206, 213-215

D Dairy farms 65-67

Dark smoke (see Smoke)

Dirty water 63, 67, 51-53, 125

E Environmental assessment 13, 126

Environmental Health Officer (EHO)6, 7-9, 17, 28-29, 121

Environmental Protection Act 19907-10, 18, 121, 153, 173, 179,

184, 190-191, 199-200, 202-203, 213

F Farmyard manure (see Solid manures)

Feeds 78-79

Fines 10

G Greenhouse gases 216-228

H Hedge trimmings 207-210, 213-215

I Incineration 184-185, 189-191

Injection (see Soil injection)

Irrigators 51-53

L Land application(see Application of wastes to land)

Legislation 7-13, 18, 121, 204-206

68

79

Index

Livestock buildings

● siting 126-132

● new 11-13, 132

● odour control 57-84

● cleaning 60-67

● dairy 65-67

● pig 68-73

● poultry 74-77

● ventilation 61-62

M Manures (see Solid manures)

Mechanical separation of slurry 93, 100-104

Methane 223-224

Milk 52, 79, 91

Mushroom compost 120-125

N Nitrous oxide 225

O Odours

● application of livestockwastes to land 30-56

● causes 21-25

● complaints 21-23, 28-29

● concentration

● dairy buildings 65-67

● feeds 78-79

● general control 26-29, 32-33

● housed livestock 59

● measurement

● milk 79

● mushroom compost 120-125

● open concrete 63

13

13

29

● pig units 68-73

● poultry manure storage 95-97, 123

● poultry units 74-77

● silage 81-84

● siting of livestock buildings andstores 126-132

● slurry storage 90-94

● solid manure storage 87-89

● swill 80

● treatment of livestock wastes 98-119

● treatment of odorous air 116

● ventilation of buildings 61-62

Open burning 151-156, 173, 186-187,202-212, 213-215

P Paper waste 211, 213-215

Parlour washings 67

Pig manure (see Solid manures)

Pig slurry 42-50, 72-73, 90-94, 98-119

Pig units 13, 68-73

Planning permission 11-13, 126-132

Plastics materials 163-173

Poultry manures 54-56, 61-62, 76-77,95-97, 191-201, 212

Poultry units 13, 74

● caged laying 75-76

● deep litter 77

Prescribed processes 18, 121, 179, 184-185,190-191, 204,

Professional help 6, 10, 28

7

80

Index

R Recycling 154, 157-162, 165-172, 178

Rubber 174-176

S Separation of slurry (see Mechanical separation)

Sewage sludge 41

Silage 52, 81-84, 91

Siting of livestock buildings/stores 126-132

Slurry (see Cattle slurry or Pig slurry)

Smoke

● animal carcases 180-187

● avoiding 20-29

● burning in the open 213-214

● crop residues 204-206

● definition

● legislation 8, 14-17, 153

● paper waste 211

● plastic materials 163-173

● poultry litter 188-201, 212

● rubber 174-176

● straw (fuel) 188-196

● tyres 174-176

● waste oil 177-179

● wood (fuel) 188-196

● wood wastes 207-210

Smoke control areas 17

Smoke nuisance (see Smoke)

Soil injection 36, 47-49, 17

46

Solid manures 54-56, 70-71, 87-89, 120-125

Spreading machinery 32-34, 42-50

Sprinklers 51-53

Storage/handling

● manures 85-89

● slurry 32, 65-69

● poultry manure 95-97, 123

Straw (fuel) 188-196

Swill 80

T Town and Country Planning General PermittedDevelopment Order 1995 11-12, 126

Travelling irrigators 51-53

Treatment of livestock wastes 98-117

Treatment of odorous air 116

Tyres 174-176

V Ventilation of buildings 61-62

W Waste Disposal Authorities 6, 162

Waste oils 177-179

Weeping-wall slurry stores 94

Whey 79, 91

Wood (fuel) 189-196

Wood waste 207-210, 214-215

Y Yard run-off 63, 125

If you would like further

copies of this brochure, which are available

free of charge, please write to:

MAFF Publications

Admail 6000, London SW1A 2XX

or telephone: 0645 556000

© Crown copyright PB 0618Reprinted February 1999

Printed on an environmentally friendly ECO-CHECK© ★ ★ ★ ★ ★ paper

MA

FF

Co

de of G

oo

d Agricultural P

ractice for the P

rotectio

n of A

ir

A

TheAir CodeR e v i s e d 1 9 9 9

Countryside

Code of Good Agricultural Practice for the Protection

Documents

Transcript of Code of Good Agricultural Practice for the Protection