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Adopted 15 March 1995, having regard to Article 13, paragraph b) of the Helsinki Convention




RECALLING Article 5 of the Convention on the Protection of the Marine Environment of the Baltic Sea Area, 1974 (Helsinki Convention), in which the Contracting Parties undertake to counteract the introduction of certain hazardous substances, as specified in Annex I of the Convention, into the Baltic Sea Area,

RECALLING ALSO that according to Article 6 of the Helsinki Convention all appropriate measures to control and strictly limit pollution by noxious substances listed in Annex II of the Convention, shall be taken, and that according to Annex III of the Convention the pollution load of industrial wastes shall be minimized,

RECALLING FURTHER that the Ministerial Declaration of the ninth meeting of the Helsinki Commission calls for a considerable reduction of land-based pollution,

RECOGNIZING that the leather industry is responsible for a part of the discharges of hazardous substances, especially chromium, into the Baltic Sea,

RECOGNIZING ALSO that many leather industry plants discharge to municipal sewerage systems where HELCOM Recommendation 13/2 should be applied,

RECOMMENDS to the Governments of the Contracting Parties that they apply to leather industry plants discharging into water bodies or municipal sewerage systems, the following basic principles:


a)to reduce pollution loads from the leather industry Best Available Technologies as per examples listed in Appendix 1, should be selectively applied. It is essential to reduce the volume of waste water discharges through, i.a., a specific water consumption reduction to a maximum rate of 50 m3/t input hide;


b)waste water discharges into either water bodies or municipal sewerage systems should be treated using optional waste water treatment processes, examples of which are listed in Appendix 2;


c)the limit values for waste water discharges from the leather industry into water bodies or municipal sewerage systems should not exceed the following values:

Crtot -0.075 kg/t input hide as annual mean and 1.5 mg/l Cr as 24 h-value or shorter sampling period

CODCr -20 kg/t input hide as annual mean for discharges to water bodies and for discharges into sewerage systems which are not connected to municipal treatment plants

tot-N -8 kg /t input hide as annual mean for discharges to water bodies and for discharges into sewerage systems which are not connected to municipal treatment plants

Internationally accepted standardized sampling, analysing and quality assurance methods (e.g. CEN-standards, ISO-standards and OECD-Guidelines) should be used whenever available;


d)the tanning odour influence should be taken into account in siting of a new production unit as well as in a sludge dumping location,


RECOMMENDS ALSO that the above limit values should be implemented for production units newly constructed or reconstructed by 1 January 1996, and for existing units by 1 January 2000,

DECIDES that the above limit values  be re-examined in 1998,

RECOMMENDS FURTHER that the Contracting Parties report to the Commission every three years starting in 1997.






Appendix 1

                                                          BEST AVAILABLE TECHNOLOGY

Examples of preventive technologies in leather industry reducing the amounts of pollutants



Examples of preventive                            Potential                        Manufacturing         Reduction 

technologies                                            pollutants                       process                  



General good house                                   Water consumption           All wet                       Water consumption

keeping, short floats,                                  general                            processes

modern tannery vessels,

spring valves, recycling



Hide chilling                                               Salt                                Hide preserve               No salt


Hair recovery                                             High COD and BOD          Unhairing                      Reduced COD

                                                                                                   and BOD


Reduced sulphide unhairing                         Sulphide                          Unhairing                    Reduced sulphide


Low-lime unhairing                                     Lime                               Unhairing                    Reduced SS (lime)


Ammonium free deliming                            Ammonium                       Deliming                     No use of ammonia

                                                              compounds                      bating                        Reduced BOD and N


Aqueous degreasing                                  Solvents                           Degreasing                 No solvent



Improved chromium                                   Chromium                        Chrome tanning          Reduced chromium

exhaustion/fixation                                                                                                          effluent


Chromium recovery/                                   Chromium                        Chrome tanning          Reduced chromium

recycling                                                                                                                        effluent


Chromium replacement                               Chromium                        Chrome tanning         Reduced or no chromium

partial or complete                                                                                                         effluent and solid waste


Wet white pretanning                                Chromium                        Chrome tanning         Reduced chromium

                                                                                                    solid waste


Appendix 2

Examples of waste water treatment processes for leather industry



Examples of treatment                            Potential                           Reduction

processes                                                pollutants


1. Pretreatment


Screening                                                 large fragments                   up to 30-40% of total SS


Settling                                                    COD                                  up to 30%


Flow equalization                                                                                neutralization agent and possibility

(balancing)                                                                                        of mutual precipitation in certain cases


2. Primary treatment


Catalytic oxidation or direct                        sulphides

precipitation of sulphides                                                                     lower pH


Precipitation/Flocculation                           chromium                             up to 0.5 mg/l



Physical-chemical treatment                       BOD                                    up to 95% of SS around 70% of BOD

for BOD and solids removal                        SS                                      


3. Secondary treatment                                                                                                                   


 Biological treatment                                 BOD

- biological filters                                       COD

- activated sludge                                                                               below 20 mg/l

(oxidation ditch)                                                                                 of BOD5 and

- activated sludge                                                                               250 mg/l of COD


- anaerobic process                                                                             up to 85% of BOD5



4. Tertiary treatment


 Nitrification/denitrification                          N                                       eutrophication reduction

Sedimentation/filtration                             SS                                      up to 95% efficiency










2.Plant and location


3.Actual production (tonnes of input hides/a and/or m2/a)


4.Water consumption, sewage discharge and pollution loads


Water consumpton


                                                                  Sewage dischaged into:   

               municipal sewerage                                                                            water  bodies

                     systems m3/a                                                                                      m3/a



 Load t/a         Specific load  (kg/t) or max                                                  Load t/a  

                        concentration for Crtot only                     

Specific load (kg/t) or max

concentration (mg/l) for Crtot only 

   CODCr *)      
   *)    For Contracting Parties who are measuring TOC the conversion factor should be indiccated   


 5.Description of technological processes, chemicals in use, preventive and waste water treatment processes


6.Actions undertaken for reducing discharges in the last three years.