COMMISSION IMPLEMENTING DECISION
of 11 February 2013
establishing the best available techniques (BAT) conclusions under Directive 2010/75/EU of the European Parliament and of the Council on industrial emissions for the tanning of hides and skins
(notified under document C(2013) 618)
(Text with EEA relevance)
(2013/84/EU)
Article 1
Article 2
ANNEX
BAT CONCLUSIONS FOR THE TANNING OF HIDES AND SKINS
SCOPE
Reference document |
Subject |
Energy Efficiency (ENE) |
General energy efficiency |
Economics and Cross-Media Effects (ECM) |
Economics and cross-media effects of techniques |
General Principles of Monitoring (MON) |
Emissions and consumption monitoring |
Emissions from storage (EFS) |
Emissions from tanks, pipework and stored chemicals |
Waste Incineration (WI) |
Waste incineration |
Waste Treatments Industries (WT) |
Waste treatment |
DEFINITIONS
Beamhouse/Limeyard |
That portion of the tannery where the hides are soaked, limed, fleshed, and unhaired, when necessary, prior to the tanning process. |
By-product |
Object or substance meeting the requirements of Article 5 of Directive 2008/98/EC of the European Parliament and of the Council(2). |
Existing plant |
A plant that is not a new plant. |
Existing processing vessel |
A processing vessel that is not a new processing vessel. |
New plant |
A plant first operated at the installation following the publication of these BAT conclusions or a complete replacement of a plant on the existing foundations of the installation following the publication of these BAT conclusions. |
New processing vessel |
A processing vessel first operated at the plant following the publication of these BAT conclusions or a complete rebuild of a processing vessel following the publication of these BAT conclusions. |
Tannery |
An installation that carries out the activity ‘Tanning of hides and skins where the treatment capacity exceeds 12 tonnes of finished products per day’ (Activity 6.3 of Annex I to Directive 2010/75/EU). |
Tanyard |
The part of the tannery where the processes of pickling and tanning are carried out. |
Urban waste water treatment plant |
A plant subject to Directive 91/271/EEC. |
1.1.
General BAT conclusions for the tanning of hides and skins
1.1.1.
Environmental management systems
Applicability
1.1.2.
Good housekeeping
1.2.
Monitoring
Parameter |
Frequency |
Applicability |
|
a |
Measurement of water consumption in the two process stages: up to tanning and post-tanning, and recording of production in the same period. |
At least monthly. |
Applicable to plants carrying out wet processing. |
b |
Recording of the quantities of process chemicals used in each process step and recording of production in the same period. |
At least yearly. |
Generally applicable. |
c |
Monitoring of the sulphide concentration and total chromium concentration in the final effluent after treatment for direct discharge to receiving water, by using flow proportional 24-hour composite samples. Monitoring of the sulphide concentration and total chromium concentration after chromium precipitation for indirect discharge, by using flow proportional 24-hour composite samples. |
On a weekly or monthly basis. |
The monitoring of chromium concentration is applicable to on-site or off-site plants which undertake chromium precipitation. Where economically viable, the monitoring of sulphide concentration is applicable to plants carrying out some part of effluent treatment on site or off site for treating waste waters from tanneries. |
d |
Monitoring of chemical oxygen demand (COD), biochemical oxygen demand (BOD) and ammoniacal nitrogen after on-site or off-site effluent treatment for direct discharges to receiving water, by using flow-proportional 24-hour composite samples. Monitoring of total suspended solids after on-site or off-site effluent treatment for direct discharges to receiving water. |
On a weekly or monthly basis. More frequent measurements in case process changes are needed. |
Applicable to plants carrying out some part of effluent treatment on-site or off-site for treating waste waters from tanneries. |
e |
Monitoring of halogenated organic compounds after on-site or off-site effluent treatment for direct discharges to receiving water. |
On a regular basis. |
Applicable to plants where halogenated organic compounds are used in the production process and are susceptible to being released into receiving water. |
f |
Measurement of pH or redox potential at the liquid outlet of wet scrubbers. |
Continuously. |
Applicable to plants using wet scrubbing to abate hydrogen sulphide or ammonia emissions to the air. |
g |
The keeping of a solvent inventory on an annual basis, and recording of production in the same period. |
On an annual basis. |
Applicable to plants carrying out finishing using solvents and using water-borne coatings or similar materials to limit the solvent input. |
h |
Monitoring of volatile organic compound emissions at the outlet of abatement equipment, and recording of production. |
Continuously or periodically. |
Applicable to plants carrying out finishing using solvents and employing abatement. |
i |
Indicative monitoring of the pressure drop across bag filters. |
On a regular basis. |
Applicable to plants using bag filters to abate particulate matter emissions, where there is a direct discharge to the atmosphere. |
j |
Testing of the capture efficiency of wet scrubbing systems. |
Annually. |
Applicable to plants using wet scrubbing to abate particulate matter emissions, where there is a direct discharge to the atmosphere. |
k |
Recording of the quantities of process residues sent for recovery, reuse, recycling, and disposal. |
On a regular basis. |
Generally applicable. |
l |
Recording of all forms of energy use and of production in the same period. |
On a regular basis. |
Generally applicable. |
1.3.
Minimising water consumption
Technique |
Description |
Applicability |
|||||
a |
The optimisation of water use in all wet process steps, including the use of batch washing instead of running water washes |
Optimisation of water use is achieved by determining the optimum quantity required for each process step and introducing the correct quantity using measuring equipment. Batch washing involves washing of hides and skins during processing by introducing the required quantity of clean water into the processing vessel and using the action of the vessel to achieve the required agitation, as opposed to running water washes which use the inflow and outflow of large quantities of water. |
Applies to all plants carrying out wet processing. |
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b |
The use of short floats |
Short floats are reduced amounts of process water in proportion to the amount of hides or skins being processed as compared to traditional practices. There is a lower limit to this reduction because the water also functions as a lubricant and coolant for the hides or skins during processing. The rotation of process vessels containing a limited amount of water requires more robust geared drives because the mass being rotated is uneven. |
This technique cannot be applied in the dyeing process step and for the processing of calfskins. Applicability is also limited to:
|
The BAT-associated consumption levels for water
Process stages |
Water consumption per tonne of raw hide(3) (m3/t) |
|
Unsalted hides |
Salted hides |
|
Raw to wet blue/white |
10 to 15 |
13 to 18 |
Post-tanning processes and finishing |
6 to 10 |
6 to 10 |
Total consumption. |
16 to 25 |
19 to 28 |
Process stages |
Specific water consumption(4) |
litres per skin |
|
Raw to pickle |
65 to 80 |
Pickle to wet blue |
30 to 55 |
Post-tanning processes and finishing |
15 to 45 |
Total |
110 to 180 |
1.4.
Reduction of emissions in waste water
1.4.1.
Reduction of emissions in waste water from beamhouse process steps
Technique |
Description |
Applicability |
|||||
a |
The use of short floats |
Short floats are reduced amounts of process water. When less water is present, the quantity of process chemicals which are discarded unreacted, is reduced. |
The technique cannot be applied for the processing of calfskins. Applicability is also limited to:
|
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b |
The use of clean hides or skins |
Use of hides or skins which have less manure adhering to the exterior, possibly through a formal ‘clean hides scheme’. |
Applicable subject to the constraints of the availability of clean hides. |
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c |
Processing fresh hides or skins |
Unsalted hides or skins are used. Rapid post-mortem cooling combined with either short delivery times or temperature-controlled transport and storage are used to prevent their deterioration. |
Applicability is limited by the availability of fresh hides or skins. Cannot be applied when a supply chain longer than two days is involved. |
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d |
Shaking off loose salt from hides by mechanical means |
Salted hides are opened out for processing in a manner which shakes or tumbles them, so that loose salt crystals fall off and are not taken into the soaking process. |
Applicability is limited to tanneries processing salted hides. |
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e |
Hair-save unhairing |
Unhairing is carried out by dissolving the hair root rather than the whole hair. The remaining hair is filtered out of the effluent. The concentration of hair breakdown products in the effluent is reduced. |
The technique is not applicable where facilities for the processing of hair for use are not available within a reasonable transport distance or when the hair use is not possible. Applicability is also limited to:
|
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f |
Using organic sulphur compounds or enzymes in the unhairing of bovine hides |
The amount of inorganic sulphide used in unhairing is reduced by partially replacing it by organic sulphur compounds or by additional use of appropriate enzymes. |
Additional use of enzymes is not applicable to tanneries producing leather with a visible grain (e.g. aniline leather). |
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g |
Reduced ammonium use during deliming |
The use of ammonium compounds in deliming is partially or completely replaced by the injection of carbon dioxide gas and/or the use of other substitute deliming agents. |
The complete replacement of ammonium compounds by CO2 during deliming cannot be applied to the processing of materials whose thickness is over 1,5 mm. The applicability of partial or complete replacement of ammonium compounds by CO2 during deliming is also limited to:
|
1.4.2.
Reduction of emissions in waste water from tanyard process steps
Technique |
Description |
Applicability |
|||||
a |
The use of short floats |
Short floats are reduced amounts of process water. When less water is present, the quantity of process chemicals which is discarded unreacted is reduced. |
This technique cannot be applied for the processing of calfskins. Applicability is also limited to:
|
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b |
Maximising the uptake of chromium tanning agents |
Optimisation of the operating parameters (e.g. pH, float, temperature, time, and drum speed) and the use of chemicals to increase the proportion of the chromium-tanning agent taken up by the hides or skins. |
Generally applicable. |
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c |
Optimised vegetable-tanning methods |
Use of drum tanning for part of the process. Use of pretanning agents to aid penetration of vegetable tannins. |
Cannot be applied in the production of vegetable-tanned sole leather. |
1.4.3.
Reduction of emissions in waste water from post-tanning process steps
Technique |
Description |
Applicability |
|||||
a |
The use of short floats |
Short floats are reduced amounts of process water. When less water is present, the quantity of process chemicals which is discarded unreacted is reduced. |
This technique cannot be applied in the dyeing process step and for the processing of calfskins. Applicability is also limited to:
|
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b |
Optimisation of retanning, dyeing, and fatliquoring |
Optimisation of process parameters to ensure the maximum uptake of process chemicals. |
Generally applicable. |
1.4.4.
Other reductions of emissions in waste water
Description
Applicability
1.5.
Treatment of emissions to water
Description
Technique |
Description |
Applicability |
|
a |
Mechanical treatment |
Screening of gross solids, skimming of fats, oils, and greases and removal of solids by sedimentation. |
Generally applicable for on-site and/or off-site treatment. |
b |
Physico-chemical treatment |
Sulphide oxidation and/or precipitation, COD and suspended solids removal by, e.g., coagulation and flocculation. Chromium precipitation by increasing pH to 8 or above using an alkali (e.g. calcium hydroxide, magnesium oxide, sodium carbonate, sodium hydroxide, sodium aluminate). |
Generally applicable for on-site and/or off-site treatment. |
c |
Biological treatment |
Aerobic biological waste water treatment using aeration, including the removal of suspended solids by, e.g., sedimentation, secondary flotation. |
Generally applicable for on-site and/or off-site treatment. |
d |
Biological nitrogen elimination |
Nitrification of ammoniacal nitrogen compounds to nitrates, followed by the reduction of nitrates to gaseous nitrogen. |
Applicable to plants with direct discharge to receiving water. Difficult implementation into existing plants where there are space limitations. |
BAT-associated emission levels
Parameter |
BAT-AELs |
mg/l (monthly average values based on the average of the 24-hour representative composite samples taken over a month) |
|
COD |
200-500(9) |
BOD5 |
15-25 |
Suspended solids |
< 35 |
Ammoniacal nitrogen NH4-N (as N) |
< 10 |
Total chromium (as Cr) |
< 0,3-1 |
Sulphide (as S) |
< 1 |
Description
Applicability
BAT-associated emission levels
Description
Applicability
BAT-associated emissions levels
Parameter |
BAT-AELs |
mg/l (monthly average values based on the average of the 24-hour representative composite samples taken over a month) |
|
Total chromium (as Cr) |
< 0,3-1 |
Sulphide (as S) |
< 1 |
1.6.
Airborne emissions
1.6.1.
Odour
Applicability
Description
Description
Applicability
Description
Applicability
1.6.2.
Volatile organic compounds
Description
Applicability
Technique |
Description |
|
a |
The use of water-borne coatings in combination with an efficient application system |
Limiting emissions of volatile organic compounds by the use of water-borne coatings, with each coat applied by one of the following: curtain coating or roller coating or improved spraying techniques. |
b |
The use of extraction ventilation and an abatement system |
Treating the exhaust air by the use of an extraction system fitted with one or more of the following: wet scrubbing, adsorption, bio-filtration or incineration. |
BAT-associated solvent use levels and BAT-associated emission levels for VOC
Parameter |
Type of production |
BAT-associated levels |
|
g/m2 (annual average values per unit of finished leather) |
|||
Solvent use levels |
Where water-borne coatings are used in combination with an efficient application system |
Upholstery and automotive leather |
10-25 |
Footwear, garment, and leathergoods leathers |
40-85 |
||
Coated leathers (coating thickness > 0,15 mm) |
115-150 |
||
VOC emissions |
Where an extraction ventilation and abatement system is used as an alternative to the use of water-borne finishing materials |
9-23(10) |
1.6.3.
Particulate matter
BAT-associated emission levels
1.7.
Waste management
Process residue |
Uses as a by-product |
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Hair and wool |
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Limed trimmings |
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Untanned splits |
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Tanned splits and trimmings |
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Waste |
Reuse after preparation |
Recycling as |
Other recovery |
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Hair and Wool |
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Raw trimmings |
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Limed trimmings |
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Fleshings |
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Untanned splits |
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Tanned splits and trimmings |
|
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Tanned shavings |
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Sludges from waste water treatment |
|
|
|
Description
Applicability
Technique |
Description |
Applicability |
|
a |
Recovery of chromium for reuse in the tannery |
Re-solution of the chromium precipitated from the tanning float, using sulphuric acid for use as a partial substitute for fresh chromium salts. |
Applicability is restricted by the need to produce leather properties which meet customers specification, in particular related to dyeing (reduced fastness and less brightness of colours) and fogging. |
b |
Recovery of chromium for reuse in another industry |
Use of the chromium sludge as a raw material by another industry. |
Applies only where an industrial user for the recovered waste can be found. |
Applicability
1.8.
Energy
Description
Applicability
BAT-associated energy consumption rates
Activity stages |
Specific energy consumption per unit of raw material(11) |
GJ/t |
|
Processing bovine hides from raw to wet blue or wet white |
< 3 |
Processing bovine hides from raw to finished leather |
< 14 |
Processing sheepskins from raw to finished leather |
< 6 |