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Solid Wastes

The leather processing industry produces large amounts of solid organic wastes in the form of un-tanned  (trimmings , fleshings, splits) and tanned (trimmings, splits and shavings) waste from raw hides and skins, semi-provessed leather, as well as sludge as a result of wastewater treatment. If these solid wastes are not properly treated and disposed of, they can cause environmental damage to soil and groundwater as well as emissions of odour and poisonous greenhouse gases into the atmosphere.

 This website includes various options for different fractions[icm1]  of solid wastes generated by the leather industry. These options have been successfully implemented by UNIDO. Results and lessons learned are included in this part of the Leather Panel website.

Desalting of Raw Hides/Skins and Reuse of Dusted Salt in Pickling Operation

Due to climatic conditions the scope for green processing is limited in many countries, sodium chloride is widely used to preserve raw hides and skins. It contributes to a high volume of total dissolved solids (TDS) in the soak waste liquor. No commercially viable technology for treating effluent has been developed to date. A large amount of the salt sticking to the hide and skin surface can be removed by shaking the hides mechanically or manually.
Within the framework of the UNIDO regional programme for pollution control in the tanning industry in South-East Asia, a pilot demonstration unit was set up to demonstrate different options for

(a) desalting hides and skins prior to soaking and

(b) reusing dusted salt in the pickling operation after purifying the salt recovered.

This report covers the demonstrations carried out during the period January 1997 to February 2001 of desalting of salted raw stock and use of the recovered salt in pickling.

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PDF icon desalting_of_raw_hides_skins_salt_reuse.pdf
PDF icon Fact Sheet: desalting of raw hides and skins

Multiple Stage Evaporation System to Recover Salt from Tannery Effluent

UNIDO through its Regional Programme for Pollution Control in the Tanning Industry in South-East Asia has been actively looking for solutions to tackle saline tannery effluent. The following technologies have been tested at pilot scale demonstration units (PDUs):

  • Mechanical / manual removal of excess salt from wet salted hides and skins
  • Reverse osmosis (RO) of treated tannery effluent
  • Improved (accelerated) solar evaporation
  • Recycling of floats in the beamhouse
  • Use of ultrafiltration in tannery effluent.

This report provides preliminary estimates of costs of setting up a multistage evaporation system for recovery of salt from the concentrate (reject) resulting from the Reverse Osmosis (RO) of treated effluents..

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PDF icon multiple_stage_evaporation_for_salt_recovery_from_effluent_rv_2.pdf

Accelerated Evaporation of Saline Streams in Solar Pans

Total dissolved solids (TDS), specifically chlorides, in effluent are a major concern for its discharge into surface waters and its use for irrigation. Conventional treatment systems do not help reduce TDS in the industrial effluent. Taking advantage of the sunshine available for most part of the year, tanneries in Tamil Nadu, India, were required by the regulatory authority to segregate highly saline effluent (soak and pickle streams)  and evaporate it in solar pans. Due to very dissapointing results of evaporation in solar pans attempts have been made to accelerate the evaporation by simple means like combination of improved warming of the effluent and use of sprinklers. This paper reports on results of these pilot scale tests carried out under UNIDO Regional Programme in India during late 90's.

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PDF icon accelerated_evaporation_of_saline_streams_in_solar_pans.pdf

Environmental Aspects of Footwear and Leather Products Manufacture

The survey is intended to cover the environmental impacts and health issues of the footwear and leather goods industries with particular reference to solid waste, air pollution and chemicals. The review covers quantification of solid wastes, technology available for reducing environmental impact and health risks and legislation. It was presented during th 13th UNIDO Leather Panel, Bologna November 1997.

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PDF icon Environmental Aspects of Footwear and Leather Products Manufacture

Wastes Generated in the Leather Products Industry

The present report provides production ratios of solid wastes in leather, footwear and other leather products manufacture and analyse why such wastes are produced and analyses possible solutions in order to reduce the quantity of waste, or to recycle them. 

The report was prepared by C.T.C. for the 14th UNIDO Leather Panel session.

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PDF icon Wastes Generated in the Leather Products Industry

Benchmarking in the Tanning Industry

This paper attempts to discuss the main, predominantly technical, issues with regard to benchmarking; it is intended to assist those who are willing to admit to the fact that despite all explanations and definitions available, they are not quite sure what it is all about and whether and how it could be applied in the tanning industry. The paper outlines "cock-pit" check lists for ten areas - components: 1. Tannery location, infrastructure 2. Production parameters 3. Cleaner technologies 4. Energy management and consumption 5. Quality assurance, reprocessing, delivery time, failures 6. Product development, strategies 7. Occupational safety and health at work, maintenance 8. Effluent treatment, solid waste, air emissions 9. Financial indicators 10. Human resources and staff welfare, CSR. Some typical production parameters are also provided.

 

 

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PDF icon Benchmarking in the Tanning Industry

Prospects and Problems of Establishing an International ECO-label for the Leather and Leather Products Industries

Presented publications documents UNIDO's involvement in promoting Eco-Labelling in the leather industry. Life-cycle assessments or the evaluation of the potential environmental impact of a product system from cradle to grave are fundamental features of some ecolabelling schemes and environmental management systems. Nowadays rhe environmental auditing protocol and reporting mechanism developed and maintained by the Leather Working Group aims to tackle important topical issues, and reflect improvements or changes of technology within the sector.

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PDF icon eco_labelling_in_the_leather_based_industries.pdf
PDF icon prospects_and_problems_of_establishing_an_international_eco-label_for_the_leather_and_leather_products_industries.pdf
PDF icon ecolabelling_in_the_leather_industry.pdf
PDF icon eco_labelling_wf_1995_lju_workshop.pdf
PDF icon Ecolabelling, Environmental Management and Related Activities - April 2001 including all annexes

Life Cycle Assessment, Carbon Footprint in Leather Processing (Review of methodologies and recommendations for harmonization)

Th report provides an overview of publications, standards and references for the calculation of the Product Carbon Footprint (PCF) of the product Finished Leather together with recommendations for harmonization and the main elements needed to define system boundaries. The inherent complexity and inadequate exactness of carbon footprint analyses contrasts with the need to communicate the results in a simple, clear and unambiguous way. The report was prepared for and presented by Mr. F. Brugnoli  in the 18th  UNIDO Leather Panel in Shanghai/China September/2012

International concern has increased over the years on Climate Change. The ten hottest years on record have all occurred since 1998. Out of the last 21 years 18 are among the 20 warmest years since 1880. Data and findings add weight to the common conclusion that the clear long-term trend is one of global warming. Most of the observed increase in global average temperature since the mid - 20th century is very likely due to the observed rise in anthropogenic greenhouse gas concentrations. Among these, particular attention is paid on CO2 (carbon dioxide). Latest estimates show that global CO2 emissions increased to 30,600 million tonnes in 2010. Industry and manufacturing contribute for 19% of all Greenhouse Gas Emissions. Interest has been developed in estimating the total amount of GHG produced during the various stages in the life cycle of products. The outcome of these calculations, are referred to as Product Carbon Footprints (PCFs). Currently, there is no single methodology and no agreement has been reached internationally on Leather PCF calculation methods.

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PDF icon Life Cycle Assessment, Carbon Footprint in Leather Processing (Review of methodologies and recommendations for harmonization)

Review of EU normative documents and legislation and their relevance for the tanning industry in developing countries

The Regulation of the European Union (EU) on Registration, Evaluation, Authorisation and Restriction of Chemicals, REACH entered into force on 1st June 2007. Its proclaimed aims were to ensure a higher level of protection of human health and the environment as well as free movement of substances, on their own, in preparations and in articles, while enhancing competitiveness and innovation.

This Regulation should also promote the development of alternative methods for the assessment of hazards of substances. REACH was also expected to streamline and improve the former legislative framework on chemicals in order to improve the protection of human health and the environment from the risks that can be posed by chemicals, especially by those listed as Substances of Very High Concern (SVHC) The purpose of this desk study was to give some background information and practical advice to the leather industry so as to maintain or establish business in the EU market.

 

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PDF icon reach_repor_fin.pdf
PDF icon bref_report_.pdf

Solidification and Stabilisation of Tannery Sludge

Utilization and/or safe disposal of sludges generated in the course of effluent treatment still represents a great challenge; worldwide many methods have been explored and proposed. This report describes the attempt made under UNIDO Regional Programme in South-East Asia to test another path. The idea was to convert the hazardous tannery sludge  into an inert, physically stable mass, with very low leachability and sufficient strength to allow making building materials like nonfired bricks for fencing or for landfilling or land reclamation. Solidification  (cementation) was achieved by mixing the sludge with various materials to form a solid product hoping that immobilisation/chemical stabilisation) will also be achieved.

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PDF icon solidification_and_stabilisation_of_tannery_sludge.pdf

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