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UNIDO has prepared and published over one hundred publications, papers, manuals and guidelines, primarily aimed at technical experts and policy makers in developing countries, though many are used by sector-related institutions and development organizations elsewhere.

The website www.leatherpanel.org is intended to provide an easy access to information sources on the leather, footwear and leather products industry, as well as to UNIDO publications related to the leather sector in one place, including earlier publications that were previously only available in hard copy.

This survey prepared and presented during the 17th UNIDO Leather Panel is a follow-up to Worldwide Study of the Leather and Leather Products Industry, which was the outcome of an exhaustive survey carried out by UNIDO in the 1970s. It is intended to assist the Organization in the formulation of future assistance programmes and in detecting areas where further study of various kinds may be useful. This report assesses the worldwide prospects of the leather and leather products industry in the coming decade. It examines the major underlying trends of recent years and how they are expected to evolve in the short to medium term. In its attempt to provide a thorough picture of the leather sector, the report covers its various aspects: the availability of raw material, the tanning industry, and the manufacture of footwear and other leather products. The basic intention is to help discern prevailing trends in global trade and to support efforts to design an effective role for organizations in the industrial development arena. The findings and forecasts published here are meant to be indicative rather than definitive and to form a basis for further surveys and studies. The need to compile this report arose out of the 16th session of the UNIDO Leather and Leather Products Industry Panel held in Brazil in May 2007. The panel recommended that UNIDO undertake a comprehensive study on the future development of the world leather and leather products industry, a study that would cover demand, technology, production, and trade. Consequently, the UNIDO study provides an analysis of the contemporary demand for leather products (footwear, leather goods, gloves, leather garments, sports goods, upholstery, etc.) vis-à-vis the availability of resources (raw hides and skins, manufacturing capacities, skilled labour, knowledge, support industries, and services). It also contains information on other important aspects of the leather industry: trade statistics, the geographic distribution of production, technology developments, physical infrastructure, environmental conditions, and social aspects involved in the production of leather.

Based on new data and requests from interested users, the revised second edition of the paper Pollutants in tannery effluents was prepared drawing on technical inputs by J. Buljan, I. Král, M. Bosnić, R. Daniels. This training material is primarily intended to meet the needs of tanners and people of different profiles associated with environmental protection in the leather industry in developing countries.

The environment is under increasing pressures from solid and liquid wastes as by-products from leather manufacture and tannery effluent create significant pollution unless there has been a form of treatment before discharge.  The industry has gained a negative image in the society with respect to its pollution potential and therefore the leather processing activity is facing a serious challenge.

The paper presents the main sources of pollution and typical pollution loads generated by tanning processes adopted by the tanneries in developing countries, volume(s) of wastewater discharged, the corresponding concentrations of main pollutants as well as the the table of widely prevailing discharge standards.

In this edition the main pollutants' parameters are elaborated in great detail, together with descriptions of their negative environmental impact. Air pollution and toxicity aspects are expanded and a concise chapter on Substances of Very High Concern, SVHC ( carcinogenic, mutagenic, bioaccumulative, persistent etc.) introduced. One can also find photos of equipment used for laboratory analysis.

For the country-wise overview of discharge standards (admittedly somewhat obsolete) please refer to Part II of the first edition.

Chrome tanning is the most common type of tanning in the world. Chrome tanned leathers are characterised by top handling quality, high hydro-thermal stability, user-specific properties and versatile applicability. Waste chrome from leather manufacturing, however, poses a significant disposal problem. Throughout the world, chrome discharge from tanneries is subject to strict regulations. That notwithstanding, chrome is a component that has to be strictly monitored. The environmental impact of chrome discharged from tanneries has been a subject of extensive scientific and technical dispute. Although the legislative limits on the disposal of solid chrome-containing waste have been relaxed in some countries, liquid emissions remain strictly regulated throughout the world. Given the close link between chrome tanning and the environmental impact of leather manufacturing, chrome management is of primary importance in tanning operations. This paper provides information on chrome management and those techniques most frequently used to reduce the amount of chrome in tannery wastewater. By providing information and citing practical experience, the paper aims at contributing to sustainable development of leather manufacture without avoidable harm to environment.

This short paper presented during the 14th UNIDO Leather Panel in Zlin/Czech Republic reports on the general situation, issues and methodology adopted as well as practical experience in implementation of occupational safety and health standards (OSH)  at work in tanneries under UNIDO’s Regional Programme for Pollution Control in the Tanning Industry in South East Asia in late 90-ies involving .international and local experts. For a practical OSH manual see the document Occupational Safety and Health Aspects of Leather Manufacture.

This study is primarily focused on the pollution load discharged in effluents and the scope for decreasing that load. In addition to knowing how to produce and sell high quality leather, tanners must also be familiar with techniques for decreasing the pollution load discharged in effluents from individual processing operations. The study aims at heightening tanners’ awareness of those techniques. It calculates the decreases possible in a well-managed tannery processing bovine hides into chrome tanned leathers and describes how pollution load can be reduced by introducing advanced technologies based on low-waste processing methods that have been proven on an industrial scale will be taken into account. The study does not consider industrially unproven and purely experimental methods.

Conventional treatment of tannery effluents does not affect the TDS content (colloquially: salinity); they remain unsuitable for lifestock watering or irrigation which, especially in arid areas, represents a great loss of natural resource. This paper reports on successful irrigation trials with treated effluent from a CETP servicing a cluster of tanneries processing wet blue and crust leather into finished leather and with TDS not exceeding 5000 mg/l and chlorides not exceeding 900 mg/l. Eventually a plot of barren land was converted into a pleasant park-like area.This paper, based on the project implemented by a women-only team, provides information on saline resistant plants and assess their growth properties; and the impact that the continuous application of treated effluent had on the soil and ground water.

Processing of one tonne of raw hides results in approximately 100 kg of wetblue shavings, the utilization and/or safe disposal of which is globally a serious challenge. Currently a part of the chrome shavings is used in the manufacture of leather board by combining with shavings of vegetable tanned leather. There have been also other methods tested and used to convert shavings into sellable product, e.g. application in paper, wood and other industries.

The method described in this report is enzymatic digestion.

Conversion of chrome shavings into usable products employing the technique of enzymatic digestion as developed in the United States of America and already implemented in a 3 tonnes/day commercial plant in the Czech Republic. Three products, namely, gelatable protein, protein hydrolyzate and filter cake are obtained from enzymatic digestion of chrome shavings. While the products obtained find use in construction and plywood industry and also as nitrogenous fertilizer, the chrome-containing filter cake can be used as a reducing agent in the preparation of basic chromium sulphate.

The method was successfully demonstrated at pilot scale in India using wooden tanning drums.

Generally 35-60% of the total solids in tannery sludge is organic matter. A number of solutions for utilization and/or safe disposal of tannery sludge have been proposed, practiced, tested and applied at pilot and industrial scale. Composting is one of these options and this report describes results of tests and application of sludge composting on low, non-mechanized scale together with its utilization as soil conditioner for nonedible plants.

The globalization of the leather industry means that all tanners face the same problems of minimizing the environmental impact of processing and selling into the global market. Regulatory pressures oblige tanners to make continuous improvements in the processing operations. The authorities concerned and consumers look more closely whether hazardous substances such as certain preservatives, some azo dyes and Cr(VI) are present in leather and leather products. The presence of potentially harmful substances attract attention of public media with the risk of developing unfavorable perception about health safety of leather products. In that context materials imported from developing countries are especially critically judged in some reports. Closer monitoring of this aspect has revealed that leather and leather products sometimes contain some hazardous substances like Cr(VI) although only chromium compounds in the form of Cr(III) were used in the tanning process. It has been concluded that this might be result of some undesired reactions in leather itself but the cause was unclear. In this paper, in a very brief form, some results of the investigations about conditions conducive to or inhibiting generation of Cr(VI) in leather are summarized. Also, the results of a series of tests carried out on leathers received from several countries included in UNIDO Regional Programme of Pollution Control in the Tanning Industry in South-East Asia are presented.

Utilization or safe disposal of sludge generated by tannery effluent treatment plants poses a challenge worldwide; landfill disposal should be considered only in case when no other viable option is possible.  Unfortunately, in some areas and/or developing countries properly designed and constructed landfills are not available either.
With the technical assistance of UNIDO, CETP-Ranitec in Ranipet, Tamil Nadu, India, established a low cost pilot scale demonstration landfill in October 1997, the first of its kind in the region. The report describes requirements for a safe landfill disposal and practical recommendations for replication.

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