Reference Document on Best Available Techniques for the

1,96

MB

Tanning of Hides and Skins (adopted Feb 2003)

246

stron

1149

ID

JRC-IPTS Instituto de Prospectiva Tecnológica (IPTS)

2003

rok

EXECUTIVE SUMMARY I

PREFACE XIX

SCOPEXXIX

1 GENERAL – STRUCTURE OF THE INDUSTRY.1

1.1 Overall production in Europe and world wide 2

1.2 Distribution of the EU tannery industry 4

1.3 Economic situation, investments and employment in the EU tannery industry 6

1.4 Environmental relevance of the tannery industry8

2 APPLIED PROCESSES AND TECHNIQUES13

2.1 Hide and skin storage and beamhouse operations .15

2.1.1 Sorting15

2.1.2 Trimming .15

2.1.3 Curing & storing .15

2.1.4 Soaking 16

2.1.5 Unhairing & liming of bovine hides .16

2.1.6 Painting & liming of sheepskins .16

2.1.7 Fleshing16

2.1.8 Splitting17

2.2 Tanyard operations.17

2.2.1 Deliming 17

2.2.2 Bating.17

2.2.3 Degreasing 17

2.2.4 Pickling 17

2.2.5 Tanning18

2.2.6 Draining, samming and setting .18

2.2.7 Splitting18

2.2.8 Shaving 18

2.3 Post-tanning operations .18

2.3.1 Neutralisation.19

2.3.2 Bleaching .19

2.3.3 Retanning.19

2.3.4 Dyeing19

2.3.5 Fatliquoring19

2.3.6 Drying 19

2.4 Finishing.20

2.4.1 Mechanical finishing processes 20

2.4.2 Applying a surface coat 20

2.5 Abatement of potential releases to the environment21

2.5.1 Waste water streams .21

2.5.2 Waste .22

2.5.3 Air emissions 22

3 CURRENT EMISSION AND CONSUMPTION LEVELS 25

3.1 Chemicals.30

3.1.1 Salt .31

3.1.2 Sulphides32

3.1.3 Nitrogen .32

3.1.4 Tanning agents32

3.1.5 Organic solvents .35

3.1.6 Surfactants 39

3.1.7 Fatliquoring agents . 40

3.1.8 Other post-tanning operation agents. 40

3.1.9 Dyes and dyeing auxiliaries 41

3.1.10 Finishing products 43

3.1.11 Biocides. 44

3.2 Water & waste water. 47

3.3 Waste . 55

3.3.1 Hair / wool. 59

3.3.2 Trimmings / fleshings / splits / shavings / dust. 59

3.3.3 Sludges from waste water treatment. 60

3.3.4 Other waste fractions 62

3.4 Air 63

3.5 Energy 64

3.6 Noise 65

3.7 Typical emission and consumption from process units 65

3.7.1 Trimming. 65

3.7.2 Curing 65

3.7.3 Beamhouse operations 67

3.7.4 Tanyard operations . 72

3.7.5 Post-tanning operations 82

3.7.6 Finishing 85

4 TECHNIQUES TO CONSIDER IN THE DETERMINATION OF "BAT" 89

4.1 Substitution of substances. 90

4.1.1 Substitution of surfactants 91

4.1.2 Substitution of halogenated organic compounds 92

4.1.3 Substitution of binders and cross-linking agents 94

4.1.4 Substitution of organic solvents in the finishing process . 94

4.1.5 Substitution of biocides 95

4.1.6 Substitution of complexing agents . 96

4.2 Beamhouse. 97

4.2.1 Curing and soaking. 98

4.2.2 Green fleshing 104

4.2.3 Unhairing & liming 105

4.2.4 Lime splitting . 112

4.3 Tanyard operations . 113

4.3.1 Deliming and bating . 113

4.3.2 Pickling 116

4.3.3 Degreasing. 117

4.3.4 Tanning 120

4.4 Post-tanning operations. 132

4.4.1 Chrome fixation, neutralisation and retannage. 132

4.4.2 Dyeing . 133

4.4.3 Fatliquoring 135

4.4.4 Drying 135

4.5 Finishing 136

4.5.1 Mechanical finishing operations. 136

4.5.2 Applying a surface coat 137

4.6 Waste water abatement . 139

4.6.1 Reduction of water consumption and process-integrated measures . 140

4.6.2 Waste water treatment plant . 143

4.6.3 Special treatment 149

4.7 Waste management . 150

4.7.1 Organic waste fractions 150

4.7.2 Other residues. 154

4.8 Air abatement. 155

4.9 Energy 157

4.10Noise, vibrations . 160

4.11Monitoring . 160

4.12Decommissioning . 161

5 BEST AVAILABLE TECHNIQUES 165

5.1 Management & good housekeeping 166

5.1.1 Operation and maintenance.166

5.1.2 Accident prevention167

5.2 Substitution of chemicals 167

5.3 Process-integrated BAT measures.169

5.4 Water management and treatment .171

5.5 Waste management and treatment.172

5.6 Air abatement .173

5.7 Energy 173

5.8 Decommissioning.173

6 EMERGING TECHNIQUES 175

6.1 Curing.175

6.1.1 Short-term preservation with flo-ice .175

6.1.2 Curing through irradiation of hides.176

6.2 Unhairing and liming.176

6.2.1 Substitution of sulphides.176

6.3 Degreasing177

6.3.1 Application of supercritical fluids in leather processing.177

6.4 Tanning 178

6.4.1 Thru-blu process .178

6.4.2 Iron tanning178

6.4.3 Organic tanning.179

6.4.4 Vegetable tanning .179

6.5 Finishing.179

6.5.1 Electrostatic spraying179

6.5.2 Organic solvent-free finishing 180

6.5.3 Substituting monomers .180

6.6 Application of membrane techniques in various process steps .181

6.7 Use of enzymes in various process steps.182

6.8 Waste treatment183

6.8.1 Thermal treatment.183

7 CONCLUDING REMARKS .185

7.1 Timing of the work185

7.2 Sources of information 185

7.3 Level of consensus 185

7.4 Recommendations for future work186

7.5 Suggested topics for future R&D projects.187