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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.

The precarious situation with water and soil pollution in the area of tannery clusters along the Palar River prompted the state environmental authorities to press for adherence to TDS discharge limits as well as to impose an approach not practiced in the tanning industry: a Zero Liquid Discharge (ZLD) concept.

Essentially, the ZLD systems concentrate dissolved solids by Reverse Osmosis (RO) and some kind of Multi Effect Evaporation (MEE) until only damp solid waste remains. Solid waste is disposed and nearly all water is reclaimed and reused. Accordingly, some of the existing Common Effluent Treatment Plants (CETPs) have been supplemented by RO and MEE, together with auxiliary steps (tertiary treatment, water softening etc.).

The analysis investigates and relates raw and equalized effluent inflows, RO feed, permeate and reject, evaporator feed and condensate and the yield of recovered, reusable water. Since the energy costs are critical for the viability of the entire concept, data about energy consumption (thermal, electrical main and Diesel) at key stages (RO, multistage evaporation) are consolidated, analysed and correlated. Additional energy needs and costs are compared with those for conventional (CETP) treatment and estimates made of the carbon footprint increase caused by the ZLD operations.

 

Due to different ambient temperatures many would expect that the overall thermal energy consumption in a tannery in a hot climate zone is considerably lower than in a temperate zone. In reality it is somewhat more complex and worth comparing.

In any case, two very important factors,  (i) temperature and (ii) humidity of inlet air are often overlooked in estimation of energy required for the crust and/or leather drying.

Chamber drying in (sub)tropical zone benefits from the higher ambient (air) temperature but at the same time it is negatively affected by high relative humidity and consequently much higher volume of fresh air required. However, the fact that the energy required for water evaporation[1] does not change much with water temperature ultimately prevails over parameters such as ambient (air) temperature and air humidity. Accordingly, energy consumption for chamber drying in (sub)tropical zone with average air temperature of 30oC and relative humidity  in the span of 50-90 % is only about 5 % less than in the temperate zone.

However, if the solar energy is used to support water heating, the conditions in the tropic zone are substantially more favourable, due to two factors:

insolation
efficiency factor (depends on the temperature difference of the final vs. inlet water temperature)

The insolation in the temperate zone (Europe) is approx. 1500 kWh/m2/y (4.1 kWh/m2/d), and in the tropical zone (South India) approx. 2200 kWh/m2/y (6.0 kWh/m2/d), so that the factor of proportionality is 1.5. Since the efficiency ratio case can be estimated as 1.05 it means that the solar based production of thermal energy in a hot climate country is about 1.6 times more favourable than in temperate climate.

 The (latent) heat of vaporization is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas. The enthalpy of vaporization is a function of the pressure at which that transformation takes place.

 

Hydrogen supplied gas present in tanneries and effluent treatment plants (ETPs) has proven fatal to workers exposed to it many times.

It is therefore necessary that the owners and managers of tanneries and effluent treatment plants are fully aware of the dangers posed by this poisonous gas and take all preventive and precautionary measures to protect the workforce from exposure to this gas. In the event of accidental exposure of a worker, they should know how to deal with the situation.

UNIDO’s activities in the leather processing has as one of its important objectives, improvement of occupational safety and health practices in tanneries and effluent treatment plants. Under this objective, the project has been seeking to demonstrate in selected tanneries improvement practices for better occupational health and safety of the workers.

It is hoped that the industry representatives and other concerned with the occupational health and safety of workers in tanneries and effluent treatment plants will find this publication useful.

The Global Leather Coordinating Committee (GLCC) in 2013 sought to identify real and perceived strengths, weaknesses, opportunities and threats of importance to the leather industry. This paper sets down a mosaic of major issues stemming from these considerations.This paper was published in the World Leather (February/March 2014).

Dissolving the hair substance in the course of liming and unhairing entails a high load of organic pollution in wastewater; as the environmental demands have grown acute, it has become necessary to further reduce wastewater pollution load as much as possible. Hair-save technology, using only chemicals traditionally applied in liming, is among simple and good options towards achieving that aim. Hair-save unhairing is far from being a general practice as yet, but in future the increase of environmental costs and external pressures might make it more attractive. In addition to process description, equipment requirements, the scope for utilization of hairs obtained as well as cost considerations are also provided.

For an easy reference older papers are also available.

The objective of the study e-Learning in the leather based industries is to analyze the the use of modern (non-traditional, beyond the textbook and classroom based) training methods and related tools. Special attention is paid to the new UNIDO effort in building a library of electronic training materials for the leather, footwear and other leather products industries. As the first attempt the footwear pattern engineering training kit transferred into e-Learning tools are presented in order to demonstrate capabilities and the potential of this technology. Paper presented during the 18th UNIDO Leather Panel in Shanghai/China September/2012

The study titled Life Cycle Assessment, Carbon Footprint in Leather Processing prepared for and presented by F. Brugnoli during the XVIII Session of UNIDO Leather and Leather Products Industry Panel in Shanghai in 2012 provided detailed explanations, definitions and terminology pertaining to leather’s carbon footprint.

It also contained specific suggestions on how to proceed in addressing this issue. Subsequently, it was not only extensively discussed by eminent international leather specialists, but it has triggered a series of activities involving different regional and global establishments.

The essence of that paper, reactions to it and some other views were reflected in a special chapter in UNIDO’s comprehensive study The Framework for Sustainable Leather  Manufacture, a chapter dealing with carbon footprint aspects of leather processing.

That chapter is now here presented as separate paper for the benefit of readers primarily interested in the carbon footprint considerations. 

In addition to earlier content, the paper also presents the main features of the European Standard EN 16887 (approved in Nov 2016, published in March 2017, applicable not later than Sept 2017) Leather – Environmental footprint – Product Category Rules (PCR) – Carbon footprints. It is quite likely that the European norm will prevail globally.

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.

The paper presents the results of the implementation of solar collectors in three Bangladeshi tanneries as well as of energy audit in four Bangladeshi tanneries to evaluate and improve their electrical performance.

It is well known that tanneries use high amounts of hot water and electricity, and today energy costs are raising very fast all over the world, with energy costs increasing their share in the costs of leather production. Other problem especially in developing countries are frequent power cuts and problems with energy supply. Tannery relocation planned in Bangladesh from Hazaribagh to new Tannery Estate Dhaka is an opportunity to implement measures to reduce energy consumption which should lead to reduced costs for production but also reduced GHG production. Therefore, within the Re-Tie-Bangladesh project (Reduction of Environmental Threats and Increase of Exportability of Bangladeshi Leather Products1) UNIDO has implemented two actions to reduce energy costs in Bangladeshi tanneries: use of solar energy - solar water heating and electrical performance improvement.

In view of ever increasing legal and social pressures, no tanner can afford to be unfamiliar with the main issues and principles of environmental protection pertaining to tannery operations. Among these, preventing pollution and promoting cleaner leather processing, which ultimately leads to lower treatment costs, clearly remain a priority. Through the application of industrially proven low-waste advanced methods - such as using salt-free preserved raw hides and skins, hair-save liming, low-ammonia or ammonia-free deliming and bating, advanced chrome management system, etcetera - it is possible to decrease the pollution load expressed as COD and BOD5 by more than 30%, sulphides by about 60 to 70 %, ammonia nitrogen by 80%, total (Kjeldahl) nitrogen by 50%, chlorides by 70%, sulphates by 65 % and chromium by 90%. Yet, despite all preventive measures, there is still a considerable amount of pollution load to be dealt with by the end-of-pipe methods. The purpose of this booklet is to help a tanner or a tannery manager (possibly a well-trained leather technologist) to get familiarized with basic principles and methods of treatment of tannery effluents. This knowledge should make him better equipped for communications with the factory’s environmental unit, environmental authorities and NGOs. To keep the manual short and concise, there are many simplifications and omissions of details; for in-depth understanding of the complexities of treatment of effluents and solid wastes (sludge) we recommend you to consult extensive literature on this subject. Finally, and contrary to the widespread misperception that vegetable tanning is environmentally harmless (in reality its effluents have very high, difficult-to-treat COD), the manual basically refers to the combined chrome tanning (i.e. chrome tanning supplemented by vegetable and synthetic tanning agents) because it is by far the most prevailing leather tanning method.

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