|
Technique [^E0042] |
Applicability |
| a |
One of the following techniques using natural or forced ventilation: |
|
| a |
1. Frequent litter addition (in case of solid floor with deep litter or deep litter combined with slatted floor). |
For existing plants with deep litter combined with slatted floor the applicability depends on the design of the existing structure. |
| a |
2. Frequent manure removal (in case of fully slatted floor). |
Only applicable to the rearing of Barbary/Muscovy ducks (Cairina Moschata), for sanitary reasons. |
| b |
Use of an air cleaning system, such as: 1. Wet acid scrubber; 2. Two-stage or three-stage air cleaning system; 3. Bioscrubber (or biotrickling filter). |
May not be generally applicable due to the high implementation cost. Applicable to existing plants only where a centralised ventilation system is used. |
A description of the techniques is given in Sections 4.11 and 4.13.3.
3.1.4. Ammonia emissions from houses for turkeys
- BAT 34. In order to reduce ammonia emissions to air from each animal house for turkeys, BAT is to use one or a combination of the techniques given below.
|
Technique [^E0043] |
Applicability |
| a |
Natural or forced ventilation with a non-leaking drinking system (in case of solid floor with deep litter). |
Natural ventilation is not applicable to plants with a centralised ventilation system. Natural ventilation may not be applicable during the initial stage of rearing or due to extreme climate conditions. |
| b |
Use of an air cleaning system, such as: 1. Wet acid scrubber; 2. Two-stage or three-stage air cleaning system; 3. Bioscrubber (or biotrickling filter). |
May not be generally applicable due to the high implementation cost. Applicable to existing plants only where a centralised ventilation system is used. |
A description of the techniques is given in Sections 4.11 and 4.13.4.
4. DESCRIPTION OF TECHNIQUES
4.1. Techniques for reducing emissions from waste water
| Technique |
Description |
| Minimise use of water. |
The volume of waste water can be reduced by using techniques such as pre-cleaning (e.g. mechanical dry cleaning) and high pressure cleaning. |
| Segregate rainwater from waste water streams that require treatment. |
Segregation is carried out by implementing separate collection in the form of properly designed and maintained drainage systems. |
| Treat waste water. |
Treatment can be performed by sedimentation and/or biological treatment. For waste water with a low pollutant load, treatment can be carried out by means of swales, ponds, constructed wetlands, soakaways, etc. A first flush system can be used for separation before biological treatment. |
| Landspreading of waste water e.g. by using an irrigation system such as sprinkler, travelling irrigator, tanker, umbilical injector. |
Waste water streams can be settled, e.g. in tanks or lagoons, before landspreading. The resulting solid fraction can also be landspread. The water can be pumped from the stores and brought into a pipeline that goes to e.g. a sprinkler or travelling irrigator, which landspreads the water at a low application rate. Irrigation can also be carried out using equipment with controlled application to ensure a low trajectory (low spread pattern) and large droplets. |
4.2. Techniques for efficient use of energy
| Technique |
Description |
| Optimisation of heating/cooling and ventilation systems and management, especially where air cleaning systems are used. |
This takes into account animal welfare requirements (e.g. concentration of air pollutants, appropriate temperatures), and can be obtained through several measures: — automation and minimisation of the air flow, while maintaining thermal comfort zone for the animals; — fans with the lowest possible specific power consumption; — flow resistance is kept as low as possible; — frequency converters and electronically commutated motors; — energy-saving fans controlled according to the CO2 concentration in the housing; — correct distribution of heating/cooling and ventilation equipment, temperature sensors and separate heated areas. |
| Insulation of walls, floors and/or ceilings of housing. |
Insulation material can be naturally impermeable or provided with an impermeable coating. Permeable materials are provided with a vapour barrier installed, as humidity is a major cause of insulation material deterioration. A variant of insulation material for poultry farms can be heat-reflecting membranes, consisting of laminated plastic foils to seal off housing from air leakage and humidity. |
| Use of energy-efficient lighting. |
More energy-efficient lighting can be attained by: i. Replacing conventional tungsten light bulbs or other low efficiency light bulbs with more energy-efficient lights such as fluorescent, sodium, and LED lights; ii. Using devices to adjust the frequency of micro flashes, dimmers to adjust artificial lighting, sensors or room entry switches to control the lighting; iii. Allowing more natural light to enter, e.g. by using vents or roof windows. Natural light has to be balanced with potential heat losses; iv. Applying lighting schemes, using a variable lighting period. |
| Use of heat exchangers. One of the following systems may be used: — air-air; — air-water; — air-ground. |
In an air-air heat exchanger, the incoming air absorbs heat from the exhaust air from the plant. It can be composed of plates of anodised aluminium or PVC tubes. In the air-water heat exchanger, water flows through aluminium fins located in the exhaust ducts and absorbs heat from the exhausted air. In the air-ground heat exchanger, fresh air is circulated through buried pipes (e.g. at a depth of about 2 metres) taking advantage of the low seasonal temperature variation of soil. |
| Use of heat pumps for heat recovery. |
Heat is absorbed from various media (water, slurry, ground, air, etc.) and transferred to another location, via a fluid circulated in a sealed circuit using the reverse refrigeration cycle principle. The heat can be used to produce sanitised water or to feed a heating system or a cooling system. The technique can absorb heat from various circuits, such as slurry cooling systems, geothermal energy, scrubbing water, slurry biological treatment reactors, or biogas engine exhaust gases. |
| Heat recovery with heated and cooled littered floor (combideck system). |
A closed water circuit is installed below the floor and another is built at a deeper level for storing the excess heat or to return it to the poultry house when needed. A heat pump connects the two water circuits. At the beginning of the rearing period, the floor is heated with the stored heat in order to keep the litter dry by avoiding moisture condensation; during the second rearing cycle, birds produce an excess of heat that is preserved in the storing circuit while cooling down the floor which reduces the breakdown of uric acid by reducing microbial activity. |
| Apply natural ventilation. |
Free ventilation in the animal house is caused by thermal effects and/or wind flow. The animal houses can have openings in the ridge and, if necessary, also on the gable sides in addition to controllable openings in the side walls. The openings can be equipped with wind protection nets. Fan assistance can be used during hot weather. |
4.3. Techniques for reducing dust emissions
| Technique |
Description |
| Water fogging |
Water is sprayed by nozzles at high pressure to produce fine droplets that absorb heat and fall by gravity to the floor, moistening dust particles that become heavy enough to drop as well. Wet or moist litter needs to be avoided. |
| Ionisation |
An electrostatic field is created in the house to produce negative ions. Circulating airborne dust particles are charged by free negative ions; particles are collected on the floor and room surfaces by gravitational force and electrostatic field attraction. |
| Oil spraying |
Pure vegetable oil is sprayed by nozzles inside the house. A mixture of water and around 3 % vegetable oil can be also used for spraying. Circulating dust particles are bound to the oil drops and collected in the litter. A thin layer of vegetable oil is also applied on the litter to prevent dust emissions. Wet or moist litter needs to be avoided. |
4.4. Techniques for reducing odour emissions
| Technique |
Description |
| Ensure adequate distances between the plant/farm and the sensitive receptors. |
At the planning stage of the plant/farm, adequate distances between the plant/farm and the sensitive receptors are ensured by applying minimum standard distances or performing dispersion modelling to predict/simulate odour concentration in surrounding areas. |
| Cover slurry or solid manure during storage. |
See description in Section 4.5 for solid manure. See description in Section 4.6 for slurry. |
| Minimise stirring of slurry. |
See description in Section 4.6.1. |
| Aerobic digestion (aeration) of liquid manure/slurry. |
See description in Section 4.7. |
| Compost solid manure. |
See description in Section 4.7. |
| Anaerobic digestion. |
See description in Section 4.7. |
| Band spreader, shallow injector or deep injector for slurry landspreading. |
See descriptions in Section 4.8.1. |
| Incorporate manure as soon as possible. |
See descriptions in BAT 22. |
4.5. Techniques for reducing emissions from the storage of solid manure
| Technique |
Description |
| Store dried solid manure in a barn. |
The barn is usually a simple construction with an impermeable floor and a roof, with sufficient ventilation to avoid anaerobic conditions and an access door for transport. Dried poultry manure (e.g. litter from broilers and laying hens, air-dried laying hen excreta collected on belts) is transported by belts or front-end loaders from the poultry house to the barn where it can be stored for a long period of time without the risk of remoistening. |
| Use a concrete silo for storage. |
A foundation slab of water-impermeable concrete that can be combined with walls on three sides and with a cover e.g. roofing over the manure platform, UV-stabilised plastic, etc. The floor is sloped (e.g. 2 %) towards a front drain gutter. Liquid fractions and any run-off caused by rainfall are collected in a leak-tight concrete pit and handled afterwards. |
| Store solid manure on solid impermeable floor equipped with a drainage system and a collection tank for run-off. |
The storage is equipped with a solid impermeable floor, a drainage system such as drains, and connected to a tank for collection of liquid fractions and any run-off caused by rainfall. |
| Select a storage facility with a sufficient capacity to hold the manure during periods in which landspreading is not possible. |
The periods when manure landspreading is allowed depend on the local climatic conditions and legislation, etc.; thus, requiring a storage area with a suitable capacity. The available capacity also allows the landspreading time to be aligned to the nitrogen requirements of the crops. |
| Store solid manure in field heaps placed away from surface and/or underground watercourses which liquid run-off might enter. |
Solid manure is stacked directly on the soil in the field prior to landspreading over a limited period of time (e.g. for a few days or several weeks). The storage location is changed at least every year and situated as far as possible from surface and groundwater. |
| Reduce the ratio between the emitting surface area and volume of the manure heap. |
Manure can be compacted or a three-sided wall store can be used. |
| Cover solid manure heaps. |
Materials such as UV-stabilised plastic covers, peat, sawdust, or wood chips can be used. Tight covers decrease air exchange and aerobic decomposition in the manure heap, resulting in a reduction of emissions to air. |
4.6. Techniques for reducing emissions from slurry storage
4.6.1. Techniques for reducing ammonia emissions from slurry stores and earth-banked storage
| Technique |
Technique |
Description |
| Reduce the ratio between the emitting surface area and the volume of the slurry store. |
Reduce the ratio between the emitting surface area and the volume of the slurry store. |
For rectangular slurry stores, the proportion of height and surface area is equivalent to 1:30-50. For circular stores, favourable container dimensions are obtained with a height — diameter ratio of 1:3 to 1:4. The side walls of the slurry store may be increased in height. |
| Reduce wind velocity and air exchange on the slurry surface by operating at a lower level of fill. |
Reduce wind velocity and air exchange on the slurry surface by operating at a lower level of fill. |
Increasing the freeboard (the length between the slurry surface and the upper rim of the slurry store) of the uncovered store provides a windshield effect. |
| Minimise stirring of slurry. |
Minimise stirring of slurry. |
Keep the stirring of slurry to a minimum. This practice involves: — filling the store below surface level; — discharging as close as possible to the base of the store; — avoiding unnecessary homogenisation and circulation of slurry (before emptying the slurry store). |
| Rigid cover. |
Rigid cover. |
A roof or a lid which can be made of concrete, fibreglass panels or polyester sheets with a flat deck or conical shape, applied to concrete or steel tanks and silos. It is well-sealed and 'tight' to minimise air exchange and to prevent rain and snow from entering. |
| Flexible covers. |
Flexible covers. |
Tent Cover: a cover with a central supporting pole and spokes radiating from the tip. A fabric membrane is spread over the spokes and tied to a rim brace. Non-covered openings are kept to a minimum. Dome-shaped cover: a cover with a curved structural frame installed over round stores with the use of steel components and bolted joints. Flat cover: a cover consisting of a flexible and self-supporting composite material held by plugs on a metal structure. |
| Floating covers. |
Floating covers. |
Floating covers. |
|
Natural crust. |
A crust layer can be formed on the surface of slurry that has a sufficient dry matter (DM) content (at least 2 %) depending on the nature of the slurry solids. In order to be effective, the crust must be thick, not be disturbed and cover the whole slurry surface. The store is filled from below the surface once the cover is formed to avoid breaking it up. |
|
Straw. |
Chopped straw is added to the slurry and a straw-induced crust is formed. This generally works well for DM higher than 4-5 %. A layer thickness of at least 10 cm is recommended. Air blowing can be reduced by adding straw at the time of slurry addition. Straw layers may need to be partially or completely renewed during the year. The store is filled from below the surface once the cover is formed to avoid breaking it up. |
|
Plastic pellets. |
Polystyrene balls of 20 cm in diameter and 100 g in weight are used to cover the slurry surface. A regular replacement of deteriorated elements and a refill for uncovered spots are necessary. |
|
Light bulk materials. |
Materials such as LECA (Light expanded clay aggregates), LECA based products, perlite or zeolite are added to the slurry surface to form a floating layer. A floating layer of 10-12 cm is recommended. A thinner layer can be effective for smaller LECA particles. |
|
Floating flexible covers. |
Plastic floating covers (e.g. blankets, canvas, films) rest over the slurry surface. Floats and tubes are installed to keep the cover in place, while maintaining a void beneath the cover. This technique can be combined with stabilising elements and structures to allow vertical movements. Venting is needed as well as removal of rainwater that gathers on top. |
|
Geometrical plastic tiles. |
Floating hexagonal plastic bodies are automatically distributed on the slurry surface. About 95 % of the surface can be covered. |
|
Air-inflated cover. |
A cover made of PVC fabric supported by an inflatable pocket that floats over the slurry. The fabric is fixed by guy ropes to a peripheral metal structure. |
|
Flexible plastic sheets. |
Impermeable UV-stabilised plastic sheets (e.g. HDPE) are secured at the bank tops and supported on floats. This prevents the cover from turning during manure mixing and being lifted off by wind. The covers can also be fitted with collection piping for removal of gases, other maintenance openings (e.g. for the use of homogenisation equipment) and a system for rainwater collection and removal. |
4.6.2. Techniques for reducing emissions to soil and water from slurry stores
| Technique |
Description |
| Use stores that are able to withstand mechanical, chemical and thermal influences. |
Appropriate concrete mixtures and, in many cases, lining on concrete walls or impermeable layers on steel sheets can be applied. |
| Select a storage facility with a sufficient capacity to hold the manure during periods in which landspreading is not possible. |
See Section 4.5. |
4.7. Techniques for on farm manure processing
| Technique |
Description |
| Mechanical separation of slurry. |
Separation of liquid and solid fractions with different dry matter content, using e.g. screw press separators, decanter-centrifuge separators, separation by sieves and filter pressing. Separation can be enhanced by coagulation-flocculation of solid particles. |
| Anaerobic digestion of manure in a biogas installation. |
Anaerobic microorganisms decompose the organic matter of manure in a closed reactor in the absence of oxygen. Biogas is produced and collected to serve energy generation i.e. production of heat, combined heat and power, and/or transport fuel. Some of the heat produced is recycled in the process. The stabilised residue (digestate) can be used as fertiliser (with sufficiently solid digestate after composting). Solid manure can be co-digested with slurry and/or other co-substrates, while ensuring a dry matter content lower than 12 %. |
| Use of an external tunnel for manure drying. |
Manure is collected from the laying hen houses and removed by belts that convey it outdoors to a dedicated closed structure, containing a series of perforated overlapping belts that form the tunnel. Warm air is blown through the belts, drying the manure in about two or three days. The tunnel is ventilated with air extracted from the laying hens' house. |
| Aerobic digestion (aeration) of slurry. |
The biological decomposition of organic matter under aerobic conditions. Stored slurry is aerated by means of submerged or floating aerators in a continuous or batch process. Operating variables are controlled to prevent nitrogen removal, such as keeping slurry agitation as low as possible. The residue can be used as fertiliser (composted or not) after concentration. |
| Nitrification-denitrification of slurry. |
Part of the organic nitrogen is transformed into ammonium. Ammonium is oxidised by nitrifying bacteria into nitrite and nitrate. By applying anaerobic periods, the nitrate can be transformed into N2 in the presence of organic carbon. In a secondary basin, the sludge settles, with part of it being reused in the aeration basin. The residue can be used as fertiliser (composted or not) after concentration. |
| Composting of solid manure. |
The controlled aerobic decomposition of solid manure by microorganisms producing a final product (compost) sufficiently stable for transport, storage and landspreading. Odour, microbial pathogens and water content of manure are reduced. The solid fraction of the slurry can also be composted. The supply of oxygen is achieved by mechanical reversal of the windrows or by forced aeration of the heaps. Drums and composting tanks can also be used. Biological inoculum, green residues or other organic wastes (e.g. digestate) can be co-composted with solid manure. |
4.8. Techniques for manure landspreading
4.8.1. Techniques for slurry landspreading
| Technique |
Description |
| Slurry dilution |
Dilution rate of water: slurry is from 1:1 up to 50:1. The dry matter content of diluted slurry is less than 2 %. The clarified liquid fraction from the mechanical separation of slurry and the digestate from anaerobic digestion can be used as well. |
| Low-pressure water irrigation system |
Diluted slurry is injected into the irrigation water pipeline and is pumped under low pressure to the irrigation system (e.g. sprinkler or travelling irrigator). |
| Band spreader (trailing hose) |
A series of flexible hoses hang from a wide bar mounted onto the slurry trailer. The hoses discharge slurry at ground level in wide parallel bands. Application between the rows of a growing arable crop is feasible. |
| Band spreader (trailing shoe) |
Slurry is discharged through rigid pipes which terminate in metal ‘shoes’, designed to apply slurry directly in narrow bands to the soil surface and below the crop canopy. Some types of trailing shoes are designed to cut a shallow slit in the soil to aid infiltration. |
| Shallow injector (open slot) |
Tines or disc harrows are used to cut vertical slots (typically 4-6 cm deep) in the soil, forming grooves into which slurry is deposited. The injected slurry is fully or partially placed below the soil surface and grooves will normally be open after slurry application. |
| Deep injector (closed slot) |
Tines or disc harrows are used to cultivate the soil and deposit slurry into it, before covering the slurry fully by means of press wheels or rollers. The depth of the closed slot ranges between 10 cm and 20 cm. |
| Slurry acidification |
See Section 4.12.3. |
4.9. Techniques for monitoring
4.9.1. Techniques for monitoring N and P excretion
| Technique |
Description |
| Calculation by using a mass balance of nitrogen and phosphorus based on feed intake, crude protein content of the diet, total phosphorus and animal performance. |
The mass balance is calculated for each animal category reared on the farm, coinciding with the end of a rearing cycle, on the basis of the following equations: Nexcreted = Ndiet – Nretention Pexcreted = Pdiet – Pretention Ndiet is based on the amount of feed ingested and on the crude protein content of the diet. Pdiet is based on the amount of feed ingested and on the total phosphorus content of the diet. The crude protein and the total phosphorus contents can be obtained by one of the following methods: — in the case of external feed supply: in the accompanying documentation; — in the case of self-processing of feed: by sampling of feedstuff compounds from the silos or the feeding system for analysing the total content of phosphorus and crude protein or, alternatively, in the accompanying documentation or using standard values of total content of phosphorus and crude protein of the feedstuff compounds. Nretention and Pretention can be estimated by one of the following methods: — statistically derived equations or models; — standard retention factors for the nitrogen and phosphorus contents of the animal (or of eggs, in the case of laying hens); — analysis for nitrogen and phosphorus contents of a representative sample of the animal (or of eggs, in the case of laying hens). The mass balance considers especially any significant changes to the diet commonly applied (e.g. change of a compound feed). |
| Estimation by using manure analysis for total nitrogen and total phosphorus contents. |
The total content of nitrogen and phosphorus of a representative composite sample of manure is measured — and the total excretion of nitrogen and phosphorus is estimated — based on records for the volume (for slurry) or weight (for solid manure) of manure. For solid manure systems, the nitrogen content of litter is also considered. In order for the composite sample to be representative, samples must be taken from at least 10 different places and/or depths to make the composite sample. In the case of poultry litter, the bottom of the litter is sampled. |
4.9.2. Techniques for ammonia and dust monitoring
| Technique |
Description |
| Estimation by using a mass balance based on the excretion and the total (or ammoniacal) nitrogen present at each manure management stage. |
Ammonia emissions are estimated based on the amount of nitrogen excreted by each animal category and using the total nitrogen (or the total ammoniacal nitrogen — TAN) flow and the volatilisation coefficients (VC) over each manure management stage (housing, storage, landspreading). The equations applied for each of the manure management stages are: Ehousing = Nexcreted · VChousing Estorage = Nstorage · VCstorage Espreading = Nspreading · VCspreading where: E is the annual NH3 emission from the animal house, manure storage or landspreading (e.g. in kg NH3/animal place/year). N is the annual total nitrogen or TAN excreted, stored or applied in landspreading (e.g. in kg N/animal place/year). If appropriate, nitrogen additions (e.g. related to litter, recycling of scrubbing liquids) and/or nitrogen losses (e.g. related to manure processing) can be considered. VC is the volatilisation coefficient (dimensionless, related to the housing system, manure storage or landspreading techniques) representing the proportion of TAN or total N emitted to air. VC are derived from measurements designed and performed according to a national or an international protocol (e.g. VERA protocol) and validated for a farm with an identical type of technique and similar climatic conditions. Alternatively, information to derive VC can be taken from European or other internationally recognised guidance. The mass balance considers especially any significant change to the type of livestock reared at the farm and/or to the techniques applied for housing, storage and landspreading. |
| Calculation by measuring the ammonia (or dust) concentration and the ventilation rate using ISO, national or international standard methods or other methods ensuring data of an equivalent scientific quality. |
Ammonia (or dust) samples are taken on six days, as a minimum, distributed over one year. Sampling days are distributed as follows: — For animal categories with a stable emissions pattern (e.g. laying hens), the sampling days are randomly selected in every two-month period. The daily average is calculated as a mean over all sampling days. — For animal categories with a linear increase in emissions during the rearing cycle (e.g. fattening pigs), the sampling days are equally distributed over the growing period. In order to achieve this, half the measurements are performed in the first half of the rearing cycle, and the remainder in the second half of the rearing cycle. The sampling days in the second half of the rearing cycle are equally distributed within the year (same number of measurements per season). The daily average is calculated as a mean over all sampling days. — For animal categories with an exponential increase in emissions (e.g. broilers), the rearing cycle is divided into three periods of equal length (same number of days). One measurement day falls in the first period, two measurements in the second period, and three measurements in the third period. In addition, sampling days in the third period of the rearing cycle are equally distributed within the year (same number of measurements per season). The daily average is calculated as the average of the three periodic means. Sampling is based on 24-hour sampling periods and is performed at the air inlet/outlet. Ammonia (or dust) concentration at the air outlet is then measured, corrected for the concentration of the incoming air, and daily ammonia (or dust) emissions are derived by measuring and multiplying the ventilation rate and the ammonia (or dust) concentration. From the daily average of ammonia (or dust) emissions, the yearly average ammonia (or dust) emissions from an animal house can be calculated, if multiplied by 365 and corrected for any non-occupation periods. The ventilation rate, necessary to determine the emission mass flow, is determined either by calculation (e.g. fan wheel anemometer, records of ventilation control system) in forced ventilated houses, or by means of tracer gases (excluding the use of SF6 and any gas containing CFCs) in naturally ventilated houses which allow a proper mixing of air. For plants with multiple air inlets and outlets, only those sampling points considered representative (in terms of expected mass emissions) of the plant are monitored. |
| Estimation by using emission factors. |
Ammonia (or dust) emissions are estimated on the basis of emission factors derived from measurements designed and performed according to a national or an international protocol (e.g. VERA protocol) in a farm with an identical type of technique (related to the housing system, manure storage and/or landspreading) and similar climatic conditions. Alternatively, emission factors can be taken from European or other internationally recognised guidance. The use of emission factors considers especially any significant change to the type of livestock reared at the farm and/or to the techniques applied for housing, storage, landspreading. |
4.9.3. Techniques for monitoring of air cleaning systems
| Technique |
Description |
| Verification of the air cleaning system performance by measuring ammonia, odour and/or dust under practical farm conditions, according to a prescribed measurement protocol and using EN standard methods or other methods (ISO, national or international) ensuring data of an equivalent scientific quality. |
The verification is done by measurement of ammonia, odour and/or dust in the inlet and outlet air and of all additional parameters relevant for operation (e.g. air flow rate, pressure drop, temperature, pH level, conductivity). Measurements are performed under summer climatic conditions (a period of at least eight weeks with a ventilation rate > 80 % of the maximum ventilation rate) and winter climatic conditions (a period of at least eight weeks with a ventilation rate < 30 % of the maximum ventilation rate), with representative management and full capacity of the housing and only if an adequate time period (e.g. four weeks) has elapsed after the last change of wash water. Different sampling strategies can be applied. |
| Control of the effective function of the air cleaning system (e.g. by continuously recording operational parameters or using alarm systems). |
Operation of an electronic logbook in order to record all measuring and operational data over a period of 1-5 years. Recorded parameters depend on the type of air cleaning system and may include: 1. pH and conductivity of scrubbing liquid; 2. air flow and pressure drop of the abatement system; 3. pump operating time; 4. water and acid consumption. Other parameters can be recorded manually. |
4.10. Nutritional management
4.10.1. Techniques for reducing nitrogen excreted
| Technique |
Description |
| Reduce the crude protein content by using a N-balanced diet based on the energy needs and digestible amino acids. |
Reduce excesses in the crude protein supply by ensuring that it does not exceed feeding recommendations. The diet is balanced to meet the animal requirements of energy and digestible amino acids. |
| Multiphase feeding with a diet formulation adapted to the specific requirements of the production period. |
The feed mix matches the animal requirements more accurately in terms of energy, amino acids and minerals, depending on the animal weight and/or production stage. |
| Addition of controlled amounts of essential amino acids to a low crude protein diet. |
A certain amount of protein-rich feedstuffs is substituted by low-protein feedstuffs, in order to further reduce the crude protein content. The diet is supplemented with synthetic amino acids (e.g. lysine, methionine, threonine, tryptophan, valine) so that there is no deficiency in the amino acid profile. |
| Use of authorised feed additives which reduce total nitrogen excreted. |
Authorised (according to Regulation (EC) No 1831/2003 of the European Parliament and of the Council [^E0044] substances, microorganisms or preparations such as enzymes (e.g. NSP enzymes, proteases) or probiotics are added to feed or water in order to favourably affect feed efficiency e.g. by improving the digestibility of feedstuffs or affecting the gastrointestinal flora. |
Regulation (EC) No 1831/2003 of the European Parliament and of the Council of 22 September 2003 on additives for use in animal nutrition (OJ L 268, 18.10.2003, p. 29).
4.10.2. Techniques for reducing phosphorus excreted
| Technique |
Description |
| Multiphase feeding with a diet formulation adapted to the specific requirements of the production period. |
The feed consists of a mix matching the phosphorus supply to the phosphorus animal requirements more accurately depending on the animal weight and/or production stage. |
| Use of authorised feed additives which reduce total phosphorus excreted (e.g. phytase). |
Authorised (according to Regulation (EC) No 1831/2003) substances, microorganisms or preparations such as enzymes (e.g. phytase) are added to feed or water in order to favourably affect feed efficiency e.g. by improving the digestibility of phytic phosphorus in the feedstuffs or affecting the gastrointestinal flora. |
4.11. Techniques to treat emissions to air from animal housing
| Technique |
Description |
| Biofilter |
The exhaust air is led through a filter bed of organic material, such as root wood or wood chips, coarse bark, compost or peat. The filter material is always kept moist by intermittent sprinkling of the surface. Dust particles and odorous air compounds are absorbed by the wet film and are oxidised or degraded by microorganisms living on the moistened litter material. |
| Bioscrubber (or biotrickling filter) |
A packed tower filter with inert packing material which is normally maintained continuously wet by sprinkling water. Air pollutants are absorbed in the liquid phase and subsequently degraded by microorganisms settling on the filter elements. An ammonia reduction of between 70 % and 95 % can be achieved. |
| Dry filter |
The exhaust air is blown against a screen made of e.g. multi-layered plastic placed in front of the end wall ventilator. The passing air is subject to strong changes of direction causing the separation of particles by centrifugal force. |
| Two-stage or three-stage air cleaning system |
In a two-stage system, the first stage (wet acid scrubber) is usually combined with a bioscrubber (second stage). In a three-stage system, a first stage consisting of a water scrubber is usually combined with a second stage (wet acid scrubber), followed by a biofilter (third stage). An ammonia reduction of between 70 % and 95 % can be achieved. |
| Water scrubber |
The exhaust air is blown through a packed filter medium by transverse flow. Water is continuously sprayed on the packing material. Dust is removed and settles in the water tank, which is emptied before refilling. |
| Water trap |
The exhaust air is directed by ventilation fans down onto a water bath where dust particles get soaked. The flow is then redirected 180 degrees upward. The water level is topped up regularly to compensate for evaporation. |
| Wet acid scrubber |
The exhaust air is forced through a filter (e.g. packed wall) where a circulating acid liquid (e.g. sulphuric acid) is sprayed. An ammonia reduction of between 70 % and 95 % can be achieved. |
4.12. Techniques for pig houses
4.12.1. Description of floor types and techniques for reducing ammonia emissions in pig houses
| Type of floor |
Description |
| Fully slatted floor |
A floor where the whole area is slatted using metal, concrete or plastic floor with openings that allows faeces and urine to drop into a channel or a pit beneath. |
| Partly slatted floor |
A floor that is partly solid and partly slatted using metal, concrete or plastic floor with openings that allows faeces and urine to drop into a channel or a pit beneath. Fouling of the solid floor is prevented by proper management of the indoor climate parameters, especially under hot conditions, and/or by proper design of the housing systems. |
| Solid concrete floor |
A floor where the entire area consists of solid concrete. The floor can be covered with litter (e.g. straw) to varying degrees. The floor is usually sloped to facilitate the drainage of urine. |
The floor types listed above are used in the described housing systems, when appropriate:
| Technique |
Description |
| A deep pit (in case of a fully or partly slatted floor) only if used in combination with an additional mitigation measure, e.g.: — a combination of nutritional management techniques; — air cleaning system; — pH reduction of the slurry; — slurry cooling. |
Pens are equipped with a deep pit below the slatted floor that allows for the storage of the slurry between infrequent removals. For fattening pigs, an overflow manure channel can be used. Removal of slurry for landspreading or to outdoor store takes place as frequent as possible (e.g. at least every two months) unless there are technical restrictions (e.g. storage capacity). |
| A vacuum system for frequent slurry removal (in case of a fully or partly slatted floor). |
Outlets at the bottom of the pit or channel are connected to a discharge pipe underneath which transfers slurry to outdoor storage. Slurry is frequently discharged by opening a valve or a plug in the main slurry pipe, e.g. once or twice every week; a slight vacuum develops and allows the complete emptying of the pit or channel. A certain depth of slurry needs to be obtained before the system can operate properly to allow the vacuum to be effective. |
| Slanted walls in the manure channel (in case of a fully or partly slatted floor). |
The manure channel creates a V section with the point of discharge at the bottom. The slope and the smoothness of the surface facilitate the slurry discharge. Manure removal is carried out at least twice every week. |
| A scraper for frequent slurry removal (in case of a fully or partly slatted floor). |
There is a V-shaped channel with two inclined surfaces on each side of a central gutter, where urine can be drained to a collection pit through a drain in the bottom of the manure channel. From the pit, the solid fraction of the manure is extracted frequently (e.g. daily) by a scraper. The addition of a coating on the scraped floor is recommended in order to achieve a smooth(er) surface. |
| Convex floor and separated manure and water channels (in case of partly slatted pens). |
Manure and water channels are built at opposite sides of the convex and smooth solid concrete floor. The water channel is installed underneath the side of the pen where the pigs tend to eat and drink. Water for cleaning the pens may be used to fill the water channels. The channel is partially filled with at least 10 cm of water. The manure channel can be built with flashed gutters or slanted walls which are normally flushed twice every day for example with water from the other channel or the liquid fraction of the slurry (dry matter content no higher than approximately 5 %). |
| V-shaped manure belts (in case of partly slatted floor). |
V-shaped manure belts roll inside the manure channels covering the whole surface, so that all faeces and urine are dropped on them. Belts are run at least twice every day to separately carry urine and faeces to closed manure storage. Belts are made of plastic (polypropylene or polyethylene). |
| Reduced manure pit (in case of partly slatted floor). |
The pen is equipped with a narrow pit with a width of about 0,6 m. The pit can be placed in an external alley. |
| Frequent slurry removal by flushing (in case of fully or partly slatted floor). |
A very frequent removal (e.g. once or twice per day) of the slurry is performed by flushing the channels with the liquid fraction of the slurry (dry matter content no higher than approximately 5 %) or water. The liquid fraction of the slurry can also be aerated before flushing. This technique can be combined with individual variations of the bottoms of channels or pits, e.g. gutters, tubes or a permanent slurry layer. |
| Kennel/hut housing (in case of partly slatted floor). |
Separate functional areas are organised in the pens of naturally ventilated houses. The lying area (about 50-60 % of the total area) consists of a levelled insulated concrete floor with covered, insulated huts or kennels, with a hinged roof that can be raised or lowered to control temperature and ventilation. The activity and feeding areas lie on a slatted floor with a manure pit underneath and frequent manure removal, e.g. by vacuum. Straw can be used on the solid concrete floor. |
| Full litter system (in case of solid concrete floor). |
A fully concrete floor almost completely covered with a layer of straw or other lignocellulosic material. In the litter-floored system, solid manure is frequently removed (e.g. twice per week). Alternatively in the deep litter system, fresh straw is added on top and the accumulated manure is removed at the end of the rearing cycle. Separate functional areas can be organised into lying, feeding, walking and defecating areas. |
| Littered external alley (in case of solid concrete floor). |
A small door allows the pig to go out to defecate in an external alley with a concrete littered floor. The manure falls into a channel from where it is scraped once every day. |
| Feeding/lying boxes on solid floor (in case of litter-based pens). |
Sows are kept in a pen divided into two functional areas, the main one littered and a series of feeding/lying boxes over a solid floor. Manure is captured in the straw or other lignocellulosic material, which is regularly supplied and replaced. |
| Manure collection in water. |
Manure is collected in the cleaning water that is kept in the manure channel and refilled up to a level of around 120-150 mm. Slanted channel walls are optional. After each rearing cycle, the manure channel is emptied. |
| A combination of water and manure channels (in case of fully slatted floor). |
The sow is kept in a fixed place (by using a farrowing crate) with a specific defecating area. The manure pit is split up into a wide water channel at the front and a small manure channel at the back, with a reduced manure surface. The front channel is partly filled with water. |
| Manure pan (in case of fully or partly slatted floor). |
A prefabricated pan (or pit) is placed under the slatted floor. The pan is deepest at one end with a slope of at least 3° towards a central manure channel; the manure discharges when its level reaches around 12 cm. If a water channel exists, the pan can be subdivided into a water section and a manure section. |
| Straw flow system (in case of solid concrete floor). |
Pigs are reared in pens with solid floors, where a sloped lying area and an excretion area are defined. Straw is provided to the animals daily. Pig activity pushes and distributes the litter down the pen's slope (4-10 %) to the manure collection aisle. The solid fraction can be removed frequently (e.g. daily) with a scraper. |
| Littered pens with combined manure generation (slurry and solid manure). |
Farrowing pens are equipped with separate functional areas: a bedded lying area, walking and dung areas with slatted or perforated floors, and a feeding area on a solid floor. Piglets are provided with a littered and covered nest. Slurry is frequently removed with a scraper. Solid manure is manually removed from the solid floor areas on a daily basis. Litter is regularly provided. A yard can be combined with the system. |
| Use of floating balls in the manure channel. |
Balls half-filled with water and made of special plastic with non-sticky coating, float on the surface of the manure channels. |
4.12.2. Techniques for cooling slurry
| Technique |
Description |
| Slurry cooling pipes |
A reduction of slurry temperature (usually less than 12 °C) is achieved by installing a cooling system placed above the slurry, above the concrete floor or cast into the floor. The applied cooling intensity can be from 10 W/m2 to 50 W/m2 for gestating sows and fattening pigs housed on partly slatted floors. The system consists of pipes in which a refrigerant or water is circulated. The pipes are connected to a heat exchange device to recover energy that may be used for heating other parts of the farm. The pit or the channels need to be frequently emptied due to a relatively small exchanging surface of the pipes. |
4.12.3. Techniques for reducing the pH of slurry
| Technique |
Description |
| Slurry acidification |
Sulphuric acid is added to slurry in order to lower the pH to about 5,5 in the slurry pit. The addition can be carried out in a process tank, followed by aeration and homogenisation. Part of the treated slurry is pumped back to the storage pit under the housing floors. The treatment system is fully automated. Prior to (or after) landspreading on acid soils, lime addition may be required to neutralise the pH of the soil. Alternatively, acidification can be performed directly in the slurry store or continuously during landspreading. |
4.13. Techniques for poultry housing
4.13.1. Techniques for reducing ammonia emissions from houses for laying hens, broiler breeders or pullets
| Housing system |
Description |
| Unenriched cage system |
Broiler breeders are housed in unenriched cage systems fitted with perches, litter area and nest. Pullets should be given appropriate experience of management practices (e.g. particular feeding and watering systems) and environmental conditions (e.g. natural light, perches, litter) to enable them to adapt to the husbandry systems which they will encounter later in life. The cages are usually arranged on three or more tiers. |
| Enriched cage system |
Enriched cages are built with sloping floors, are made of welded wire mesh or plastic slats and are equipped with fixtures and increased space for feeding, drinking, nesting, scratching, perching and egg collection. The capacity of the cages can vary from around 10 to 60 birds. The cages are usually arranged on three or more tiers. |
| Deep litter with manure pit |
At least one-third of the total floor in the housing is covered with litter (e.g. sand, wood shavings, straw). The remaining floor area is slatted, with a manure pit underneath. Feeding and drinking fixtures are located over the slatted area. Additional structures can be present inside or outside the housing, such as verandas and free-range system. |
| Aviaries |
Aviaries are divided into different functional areas for feeding, drinking, egg laying, scratching and resting. The usable area is increased by means of elevated slatted floors combined with tiers. The slatted area ranges between 30 % and 60 % of the total floor area. The remaining floor is typically littered. In plants for laying hens and broiler breeders, the system can be combined with verandas with or without free-range system. |
|
|
| Technique |
Description |
| Manure removal by belts (in case of enriched or unenriched cage systems) with at least: — one removal per week with air drying; or — two removals per week without air drying. |
Belts are placed under the cages for manure removal. The frequency of removal can be once every week (with air drying) or more (without air drying). The collection belt may be ventilated for drying the manure. Whisk-forced air drying in the manure belt can be also used. |
|
|
| Manure belt or scraper (in case of deep litter with a manure pit). |
Manure is removed by scrapers (periodically) or by belts (once every week for dried manure, twice every week without drying). |
| Forced ventilation system and infrequent manure removal (in case of deep litter with a manure pit) only if used in combination with an additional mitigation measure, e.g.: — achieving a high dry matter content of the manure; — an air cleaning system. |
The deep litter system (see above for description) is combined with infrequent manure removal, e.g. at the end of the rearing cycle. A minimum dry matter content of manure of around 50-60 % is ensured. This is achieved by an appropriate forced ventilation system (e.g. fans and air extraction placed at floor level). |
| Forced air drying of manure via tubes (in case of deep litter with a manure pit). |
The deep litter system (see above for description) is combined with manure drying by means of forced ventilation applied through tubes that blow air (e.g. at 17-20 °C and 1,2 m3/bird) over the manure stored under the slatted floor. |
| Forced air drying of manure using perforated floor (in case of deep litter with a manure pit). |
The deep litter system (see above for description) is equipped with a perforated floor placed underneath the manure which allows for forced air blowing from below. The manure is removed at the end of the rearing cycle. |
| Manure belts (in case of aviary). |
Manure is collected on belts under the slatted floor and removed at least once every week by ventilated or not ventilated belts. Littered and solid floors can be combined in aviaries for pullets. |
| Forced drying of litter using indoor air (in case of solid floor with deep litter). |
In a deep litter system without a manure pit, indoor air recirculation systems can be used to dry the litter, while meeting the physiological needs of the birds. To this end, fans, heat exchangers and/or heaters can be used. |
4.13.2. Techniques for reducing ammonia emissions from broiler houses
| Technique |
Description |
| Natural or forced ventilation with a non-leaking drinking system (in case of solid floor with deep litter). |
The building is closed and well-insulated, equipped with natural or forced ventilation, and can be combined with a veranda and/or a free-range system. The solid floor is fully covered with litter which can be added to upon necessity. Floor insulation (e.g. concrete, clay, membrane) prevents water condensation in the litter. Solid manure is removed at the end of the rearing cycle. The design and operation of the drinking water system prevents leakage and spillage of water on the litter. |
| Forced drying system of litter using indoor air (in case of solid floor with deep litter). |
Indoor air recirculation systems can be used to dry the litter, while meeting the physiological needs of the birds. To this end, fans, heat exchangers and/or heaters can be used. |
| Litter on manure belt and forced air drying (in case of tiered floor systems). |
A multi-floor system on tiers equipped with manure belts covered with litter. Corridors for ventilation are left between the rows of tiers. Air enters through one corridor and is directed to the litter material on the manure belt. Litter is removed at the end of the rearing cycle. The system can be used in combination with a separate initial stage where broiler chicks are hatched and grown for a limited time on manure belts with litter on a multi-tiered system. |
| Heated and cooled littered floor (in case of combideck systems). |
See Section 4.2. |
4.13.3. Techniques for reducing ammonia emissions from duck houses
| Technique |
Description |
| Frequent litter addition (in case of solid floor with deep litter or deep litter combined with slatted floor). |
Litter is maintained dry by frequent addition (e.g. daily) of fresh material upon necessity. Solid manure is removed at the end of the rearing cycle. The housing system can be equipped with natural or forced ventilation and combined with a free-range system. In case of deep litter combined with slatted floor, the floor is equipped with slats in the drinker area (about 25 % of the total floor area). |
| Frequent manure removal (in case of fully slatted floor). |
Slats cover the pit where the manure is stored and evacuated to the external store. Frequent manure removal to an external store can be done: 1. by permanent gravity flow; 2. by scraping with variable frequencies. The housing system can be equipped with natural or forced ventilation and combined with a free-range system. |
4.13.4. Techniques for reducing ammonia emissions from turkey houses
| Technique |
Description |
| Natural or forced ventilation with a non-leaking drinking system (in case of solid floor with deep litter). |
The solid floor is fully covered with litter which can be added upon necessity. Floor insulation (by e.g. concrete, clay) prevents water condensation in the litter. Solid manure is removed at the end of the rearing cycle. The design and operation of the drinking water system prevents leakage and spillage of water on the litter. Natural ventilation can be combined with a free-range system. |
[^E0001]: Council Directive 91/676/EEC of 12 December 1991 concerning the protection of waters against pollution caused by nitrates from agricultural sources (OJ L 375, 31.12.1991, p. 1).
[^E0002]: Regulation (EC) No 1069/2009 of the European Parliament and of the Council of 21 October 2009 laying down health rules as regards animal by-products and derived products not intended for human consumption and repealing Regulation (EC) No 1774/2002 (Animal by-products Regulation) (OJ L 300, 14.11.2009, p. 1).
Legalize