Forum Program

FORUM INTERNAZIONALEI N T E R N AT I O N A L FO R U M

20Ottobre / October

2011Fiera di Bologna

ASSOMAC SERVIZI srlP.O. Box 73 PTB - Via Matteotti, 4/a - 27029 VIGEVANO - PV - ITALYTel.: +39 0381 78883 - Fax: +39 0381 88602 - [email protected]

Technology Sustainability

for

the challenge in leather manufacturing

INNOTECH

PROGRAM

9,30 Registration

9.40 Welcome Address

10.00 UNIC Environmental Report 2011 Presentation

(Salvatore MERCOGLIANO - UNIC Director)

10.10 INTRODUCTION (Sergio DULIO – ASSOMAC)

KEYNOTE SPEECH

Sustainable Leather Prospective:

Realistic Objectives and Future Opportunities

(Heinz-Peter GERMANN - Lederinstitut Gerberschule Reutlingen Director)

10.50 Coffee Break

11.00 EXPERTS’S SPEECHES (moderator Sergio DULIO - ASSOMAC)

13.00 CONCLUSION

Ananthakrishna SAHASRANAMAN - Environmental Management Company of Tanners

The Indian Experiences in Environmental Management

Zhongbai GAO – China Leather & Footwear Industry Research Institute Director

Prospect of Clean Technology in Process of Leather China Production

Daniele REFOSCO – Techical Director Cluster Waste Water Treatment Implant

Acque del Chiampo, Italian Cluster Experience in Integrated Waste Water Treatment

Angelo Borrini- Consorzio Cuoio-Depur S.p.A.

Solid Waste Treatment, FERTILAND Project

Sandra VITOLO - University of Pisa

Evaluation of Environmental Impact of Leather Process Using LCA Methodology

KEYNOTE SPEECH Sustainable Leather Prospective:

Realistic Objectives and Future Opportunities Dr. Ing. Heinz‐Peter GERMANN PROFESSIONAL HISTORY:

Study of chemistry and Doctoral thesis in the field of collagen and peptide chemistry at the Technical University of Darmstadt (supervisor: Prof. Dr. Eckhart Heidemann)

1987 – Research scientist and lecturer at Westdeutsche Gerberschule Reutlingen (West

German Tanners’ School, Reutlingen – ‘WGR’)

1990 – Head of Research & Development department at WGR

1993‐2011 – Director of the Institute “Lederinstitut Gerberschule Reutlingen, LGR” (formerly WGR) – the German Training, Testing & Research Centre for the leather industry

MEMBERSHIPS AND HONORARY OFFICES:

Since 1992 – Member of the Scientific Council of AiF (union of industrial research associations) 1993‐1994 – President of GERIC (group of the European leather research institutes) Since the 1990’s – Member of the Board of VGCT (The German society of leather chemists and

technologists) 1994‐1997 – President of VGCT 2000‐2011 – Treasurer of VGCT 1997‐2011 – Chairman of the VGCT Prize Committee

Since 1994 – Sworn Expert in the field of leather industry (appointed by the Chamber of Commerce and Industry)

Since 1995 – Deputy member of the board of control of the Steinbeis‐Stiftung, Baden‐Wuerttemberg (public foundation for the stimulation of economics)

1998‐2010 – Central European representative in the Executive Committee of the International Union of Leather Technologists’ and Chemists’ Societies (IULTCS)

“John Arthur Wilson Memorial Lecture” (American Leather Chemists Association (ALCA) – delivered in 1997

“Procter Memorial Lecture” (Society of Leather Technologists and Chemists (SLTC), UK) – delivered in 2008

“B.M. Das Memorial Lecture” (Central Leather Research Institute (CLRI), Chennai, India) – delivered in 2010

“Heidemann Lecture” (International Union of Leather Technologists’ and Chemists’ Societies (IULTCS) – to be delivered in September 2011, Valencia/Spain

Program and Documentation

2

Sustainable Leather Manufacture: Realistic Objectives and Future Opportunities

Dr.-Ing. Heinz-Peter Germann N-Zyme BioTec GmbH, Innovation Center Leather & Collagen, Reutlingen/Germany

Sustainable development is a pattern of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for future generations. Practical approaches to realizing the idea of sustainable development in manufacturing companies are mainly followed up by cleaner production which includes reduction of energy use, use of renewable resources, minimization of water consumption and reduction of waste generation. In leather manufacturing e.g. increased use of fresh uncured or chilled hides for processing, application of ecological liming systems and proper selection / intelligent use of tanning agents have been important steps towards environmentally compatible production. However, the ‘destination’ of sustainability is not a fixed place in the normal sense that we understand destination. Instead, it is a set of wishful characteristics of a future system as pointed out earlier. So, what are the future challenges for sustainable leather manufacture? o In principle, leather manufacturing is in itself ‘recycling’ – i.e. it is a sustainable solution to the disposal problem of a by-product that originates from the meat industry.

o The concept of ‘globalization’ in leather production has to be adjusted by taking more into account additional factors like e.g. raw material sourcing that is also relevant to the subject of sustainability.

o Sustainability of leather manufacture can be further increased by using resources (i.e. water, fossil fuels and other natural resources) sparingly, which includes controlling the production processes and improving the systematic re-use of by-products whenever possible, and giving priority to the use of renewable resources.

3

The Indian Experience in Environmental Management

Dr. Ing. Ananthakrishna SAHASRANAMAN:

Vice Chairman,CEMCOT ‐ Chennai, India A post graduate in Economics, Mr. Sahasranaman has published numerous papers on various aspects of leather industry in India and globally too. He has authored one book titled ‘Environment Management – A study of the Tanning Industry in India’ As a retired officer of the Indian government, Mr. A. Sahasranaman had held many important positions in the region of Jammu and Kashmir and in the Government of India, mainly in the field of industrial development, between 1973 and 1996. Mr. Sahasranaman’s association with the Indian leather industry started in 1985 when he became the Executive Director of the Indian Council for Leather Exports in Chennai. After playing a significant role in transformation of Indian leather industry from one of raw material exporter to a major exporter of value added leather products, Mr. Sahasranaman joined United Nations Development Programme, India, to implement a large scale development project for the Indian leather sector. This programme contributed to strengthening existing institutions for human resources development in the country by forging collaborations with like institutions in Europe and Australia. An innovative marketing campaign in the USA and improving environment management in the leather industry were other major components of this project. As the Programme Coordinator of UNIDO’s (United Nations Industrial Development Organization, Vienna) ‘Regional Programme for Pollution Control in The Tanning Industry in South East Asia’ covering Bangladesh, China, India, Indonesia, Nepal and Sri Lanka, Mr. Sahasranaman contributed significantly to introducing new cleaner and end of pipe technologies for tackling solid and liquid wastes of the leather industry in all these countries. For the past three years, Mr. Sahasranaman has been closely involved with Chennai Environmental Management Company of Tanners (CEMCOT) at Chennai, India, first as its Managing Director and later as the Vice Chairman of the Board of Directors. CEMCOT is engaged in setting up six large ‘Zero Liquid Discharge’ common waste treatment plants, at an estimated cost of Euro 30 million.


4

CHENNAI ENVIRONMENTAL MANAGEMENT COMPANY OF TANNERS http://www.cemcot.com/ Chennai Environmental Management Company of Tanners (CEMCOT) is a Special Purpose Vehicle (SPV), incorporated as a not‐for‐profit company, registered under the Indian Companies Act 1956, formed by the six common effluent treatment plants in Tamil Nadu, to implement certain infrastructure projects, namely establishment, operation and maintenance of zero liquid discharge (ZLD) systems for seven common effluent treatment plants in the state of Tamil Nadu under the Indian Leather Development Programme (ILDP) Scheme of Department of Industrial Policy and Promotion (DIPP), Government of India (GoI) and Government of Tamil Nadu (GoTN). The company was incorporated on 15 July 08 in Chennai.

5

Sustainable Development of China Leather Industry

Prof. Dr. Zongbai GAO:

Professor of China Leather & Footwear Industry Research Institute (CLFI), Deputy Director of CLFI‐ member of CLIA, Beijing China

Degree in Chemical Engineering at the University of Padua in 1981. Responsible of Clean Technologies and Environmental Technologies in CLFI Working Backgrounds: From 1986 until now CLFI Research Institute Professor From 2006 until now Tianjin Science & Technology University Visiting Professor From 2002 until now Shanxi Science & Technology University Visiting Professor

2000 British Leather Technology Centre Visiting scholar 1999 TNO‐MEP, Environmental Sciences, Energy

Research and Process Innovation, The Netherlands Visiting scholar

1999 Environmental Department, Wageningen University, The Netherlands

Visiting scholar

1995 British Leather Technology Centre Leather Department, Northampton University, UK

Trained

2004, Specialists who enjoy the special government allowance granted by the state council. 2007, Application China National Patent for an Invention”Recycle Method of the Leather

Waste”CN:200710099422.9. 1995‐1999, Take charge of the UNIDO Project, （US/CPR/92/120）. 1999‐ 2004, Take charge of the Netherlands Government Project（CN012502）and Extension

Project（No. 10554）


6

The China Leather and Footwear Website WWW.LEATHER365.com and China Leather and Footwear International Industrial. Subcontracting And Exchange Network (www.clfpx.com) are built by the Centre

7

Leather Cluster Experience in Integrated Waste Water Treatment

Dr. Ing. Daniele REFOSCO:

1998‐2011 – Technical Director of the Wastewater treatment implant Acque del Chiampo S.p.A. of Arzignano leather cluster district , Italy

Degree in Chemical Engineering at the University of Padua in 1981.

From 1982 he worked in industry, with experience in production of chemical,

pharmaceutical industry and in the environmental field, both as a designer in a

major study of civil and environmental engineering and as a technical manager in a

companies design, construction and management, particularly of sewage treatment

plants Civil and industrial waste and waste disposal.


8

http://www.acquedelchiampospa.it

Arzignano wastewater treatment implant

160 tanneries directly connected to the system 40,000 residents of seven of the ten municipalities of the valley of Chiampo

9

Solid Waste Treatment, FERTILANDIA Project Dr. Ing. Angelo BORRINI:

Director of Consozio CUOIO‐DEPUR, San Miniato‐ Pisa Italy The Fertilandia project is co‐financed by the Eco‐innovation programme of the European Commission. The Eco‐innovation programme supports innovative solutions protecting the environment, supporting market replication projects of products, processes or eco‐innovative practices, already technically proven, but needing incentives to have success in the market.


10

http://www.cuoiodepur.it/

Utilization of tannery working by‐products

• Cuoio Depur, through new society CCT specially born, intents to collect solid by‐products come from tanning process and treating, in according with the rule CE 1774/02, to obtain leather‐meal mixed with stabilized proteic sludges, for the production of the fertilizers line derived from “Pellicino Integrato”. For this purpose a technology system globally costing € 1,400,000 is being realized. The project will make possible closing cycle of tannery working solid by‐products.

11

Evaluation of Environmental Impact of Leather Process Using LCA Methodology

Prof. Ing. Sandra VITOLO:

Since 1995 professor of Chemetry and Industrial Chemestry in Chemical Engineering degree course and in Industrial Engineering degree courses. Actually Director of Environmental Department ‐ University of Pisa Italy

Sandra Vitolo graduated with maximum votes in Chemical Engineering at the University

of Pisa in 1989. After experience in the process industry, she entered the Department of

Chemical Engineering, Industrial Chemistry and Materials Science in the University of Pisa

as a Research Assistant in 1992 in the Industrial Chemistry and Technology sector. From

september 2000 up to December 2004 she is Associate Professor in the same sector and,

from January 2005 she is full professor. Her research is performed in the field of the

industrial chemistry of liquid effluent treatments, gas treatment, thermo‐chemical

conversion of bio‐masses and sustainability of the leather industry.


12

Tannery Industry

Guidelines for a more sustainable BEAMHOUSE & TANNING PROCESSES

Reduction in tannery wastewater: Chloride, Sulphate, Chrome Tanning

2

Published in 2007 A.T.O. Valle del Chiampo A.A.T.O. Bacchiglione Guidelines published in 2007. This work was the result of the impact assessment of tanning process in the Arzignano district, specifically drawn to indicate the need for a better control of wastewater entering in the treatment plant and meet parameters in the output according to the Italian Regulation. A special thanks is due to Mr. Hans George Hoerter, Dr. Raoul Sartori and the late Dr. Umberto Sammarco for their availability in the drafting of the Guidelines by courtesy of Acque del Chiampo SPA Translation and Reprint by ASSOMAC SERVIZI S.r.l.

3

Summary

1. GUIDELINES FOR THE CHLORIDE REDUCTION in Tannery wastewater..........................4

1.1.CHLORIDE from CONSERVATION of RAW HIDES.....................................................4

1.1.1. Skins whisking...............................................................................................4

1.1.2. Using fresh raw hides ...................................................................................4

1.2.CHLORIDE REDUCTION IN PICKEL............................................................................5

2. GUIDELINES FOR THE SULPHATES REDUCTION in Tannery wastewater.........................6

2.1. REDUCTION OF SULPHATES ORIGINATED FROM OXIDATION OF SULPHITE..........6

2.2. REDUCTION OF SULPHATES IN DELIMING..............................................................7

2.3. REDUCTION OF SULPHATES IN PICKEL ...................................................................7

2.4. REDUCTION OF SULPHATES IN TANNING...............................................................8

2.5. REDUCTION OF SULPHATES FROM DYES and RETANNING AGENTS .....................8

3. GUIDELINES FOR THE TANNING CHROME REDUCTION in Tannery wastewater ...........9

3.1. CHROME RECOVERY ...............................................................................................9

3.2. OPTIMIZATION OF THE CHROME FIXATION .........................................................10

Amount of chromium salt (in Cr2O3) ...................................................................10

Float, long ..............................................................................................................11

Final temperature of tanning ................................................................................11

Duration of tanning ...............................................................................................11

pH of the end tanning............................................................................................11

Masking..................................................................................................................11

CONCLUSION ........................................................................................................................12


4

1. GUIDELINES FOR THE CHLORIDE REDUCTION in Tannery wastewater

Sodium chloride is mainly used in the tanning process preservation of raw hides and during pickling to suppress the acid swelling. The environmental impact of chlorides, respect to the two phases mentioned above, has a different incidence.

1.1. CHLORIDE from CONSERVATION of RAW HIDES

The amount of salt needed to ensure a long‐term safe storage amounts to about 30% by weight of raw hides. It is estimated that over 70% of chlorides present in wastewater of the entire production process comes from salt used for leather conservation. The methods of treatment for this pollutant are very expensive even for high investments and for the requested high energy contribution. At this time the replacement of salt with other products and/or alternative non‐polluting methods is still not yet feasible at large scale, therefore the reduction of sodium chloride used when salting can be done by implementing the following Best Available Techniques.

1.1.1. Raw hides beating

The salt quantity that can be eliminated through this approach is related to the raw hides provenience and approximately can be calculated on the weight of raw hides. The amount of salt removed by this operation varies depending on the origin of the raw between 6 and 12% calculated on the weight of the raw hide. To increase the efficiency of the operation it is recommended to increase the beating time and decrease the inclination of the drum. A system for verifying the effectiveness of beating is to run an occasional re‐whisking of lower rates of skins. The weight difference found between the first and second the operation should not exceed 1%.

1.1.2. Using fresh raw hides

The contribution in reduction of chlorides into waste water processing fresh raw hides is evaluated at least 40%. In a mixed production (50% and 50% of freshly salty) you can get a reduction of over 20%. Many European countries use fresh skin for a long time in significant quantities. On the other hand, for the processing of fresh hides must be taken into consideration a few things: • Italian tanneries may have fresh supplies of hides only from Europe; • Substantial supplies are not in case of substantial price fluctuations.

5

• The skin should be kept at a temperature of 2° C during transport and storage

in the tannery; • Storage can not be continued for longer than 7‐8 days; • The need to keep your skin at low temperatures is really expensive related to the

energy consumption.

The limitations related to the process of fresh raw hides may be muffled with a rigorous organization. Beyond the limits listed above first, however, be solved with proper business organization, processing of hides presents fresh following advantages: o the stock does not present fairly common defects due to salting (spots, damage the grain); o the authenticity of origin can be identified more easily; o the elimination of row hides beating and manage of the salt waste.

1.2. CHLORIDE REDUCTION IN PICKEL

The bath density, compared with common average in use (8‐9 °Bé), can be reduced significantly anyway avoiding the acid swelling. A density of 6.0‐6.5 °Bé ensures proper execution of this operation. This parameter will be checked each time, after a rotation of 20 minutes by the addition of salt. To further reduce the amount of salt it is necessary to work in a fairly short float. The 20‐35% on the pelt weight (depending on whether you use liquid chrome or powder) is more than enough, since the substantial increase in volume resulting from the addition of diluted acid. For safe operation it is advisable to recheck the density even after the addition of acids. It must not be less than 5.5 °Bé, this value still guarantees maximum operational safety. Moreover, it is known that non high density values produce a better quality leather. Another benefit from the short float is an increased speed of the acids in crossing of the leather section, resulting in time savings that can be conveniently used in the later stage of tanning. These measures allow a drastic reduction of the salt used in pickling (30%), which can be quantified in a decrease of about 10% of the total chloride discharge ¹.

¹ Calculated assuming the use for each kilogram of raw skin of 25 liters of water for a complete processing cycle, an average content of 3000 mg/l of sulfates of 7000 mg/l of chloride and 200 mg/l Cr in the effluent at the end of the process.


6

2. GUIDELINES FOR THE SULPHATES REDUCTION in Tannery wastewater

The predominant amount of sulphates present in wastewater comes from the deliming, pickling, tanning phases as well as from sulfur present in the effluent at the end of liming, which turns into sulphates during depuration phases. Less significant contributions of sulphate, especially when the complete cycle is carried out, are due to the dyes and retanning used.

2.1. REDUCTION OF SULPHATES ORIGINATED FROM OXIDATION OF SULPHITE

It is known that sulfide from wastewater by liming may be oxidized to sulphate during water purification. Assuming that oxidation is complete, the reduction of 1% of the sulfur offer in liming phase would determine a reduction of sulphate in wastewater of about 300 mg/l ¹. The main systems, which allow the reduction of the sulfur supply, are based on the following measures:

Simultaneous use of assisting substances. They enable an efficient hair removal using a total amount of sulfur and hydrogen sulphate equal to 2‐2.5%;

Reintroduction of the hair recovery. This technique allows a liming with a total offer of sulfur and hydrogen sulphate equivalent to 1.5‐2.0% compared to the traditional 3.0‐3.5% used for liming with hair destruction. Swelling and turgescence can be adjusted by adding dilute caustic soda. The hair recovery also helps the not inconsiderable advantage of a load reduction of COD, TKN and suspended solids;

IMPACT OF CHLORIDE IN THE DRAINAGE

4.835

2.165

7.000

3.398

1.456

4.855

0

1.000

2.000

3.000

4.000

5.000

6.000

7.000

Conservation salt Pickel salt Total

Chloride reduction

mg/l of drainage.

Traditional Innovative

7

Recovery and reuse of the bath at the end of liming appropriately reintegrated with lime and sulfur. Obviously, in this case the emissions of sulfur and consequently of sulphate will be reduced to a minimum. This system saves a vital resource like water and about 20% of sulfur and lime. Spending on plant recovery could be depreciated quickly enough due to less consumption of agents liming. The lower use of sulfur allows a reduction of the reagents used for the abatement of emissions during the deliming and pickel phases.

2.2. REDUCTION OF SULPHATES IN DELIMING

At this stage sulphates come from ammonium sulfate, which is the most widely used deliming for reasons of price, better speed cross section and for his buffering effect. Really, the pH of the bath never drops below the safety threshold when this product is used as deliming agent. Unfortunately, it also helps to raise the effluent TKN values. On the other hand, the deliming of full thickness heavy hides using products free of ammonium salts is hardly feasible, as the lead times of the process would be too long. It’s realistic, and industrially feasible, the partial replacement of this salt, at least 50%, with products based on alternative mixtures of dicarboxylic acids and / or organic esters. This measure would lead to a reduction of over 10% of sulphates present in the effluent in the entire processing cycle. It should be stressed that the new generation deliming allows to make a full thickness skin deliming with a supply of ammonium sulphate of about 0.5% versus 2.5% medium used. This means to reduce the contribution of sulphates in the effluent of 580 mg / l, a value corresponding to about 20% of total ¹. The use of these products also offers the advantage of obtaining better items in quality compared to those obtained by making deliming with ammonium sulfate used alone.

2.3. REDUCTION OF SULPHATES IN PICKEL

Unfortunately there isn’t now a viable alternative for replacing sulfuric acid during pickling. On the other hand, the contribution of sulfate due to the use of this acid has been estimated about 500 mg / l in wastewater, ¹. The use of precise instruments (pH meters) to control the degree of acidity of the pickling solution avoids an excessive unwanted use of sulfuric acid. Even a very well done deliming and a washing very efficient at the end of maceration allow the attainment of pH desired end pickel with and the cross section of the skin, without unnecessary waste of sulfuric acid.

¹ Calculated assuming the use for each kilogram of raw skin of 25 liters of water for a complete processing cycle, an average content of 3000 mg/l of sulfates of 7000 mg/l of chloride and 200 mg/l Cr in the effluent at the end of the process


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2.4. REDUCTION OF SULPHATES IN TANNING

The improvement of the chrome exhaustion in the tanning allows the reduction of supply. This eventuality offers a considerable economic advantage. By reducing the supply of chrome, respectively 1% as powder or 2% as liquid (13%), the contribution of sulphates in wastewater is reduced to about 200 mg/l, which represents a decrease of over 6% of the total amount of sulphate in the effluent end of pipe. In fact, it’s known that every kilogram of chrome powder (25% of Cr2O3) contains 540 g of basic chromium sulphate and at least 300 g of sodium sulphate, corresponding to 314 g and 203 g of sulphate ion. This means that reducing the supply of chromium by 1% of chromium a total decrease of 517 g of sulphate is obtained, equivalent to about 200 mg/l of sulphate in the effluent of the complete working cycle ¹.

2.5. REDUCTION OF SULPHATES FROM DYES and RETANNING AGENTS

It’s not possible to quantify, in a reliable way, the contribution of sulphates of the dyes and retanning agents used during post‐tanning, because the applied formulations change within wide limits depending on the tannery and the final product. Generally dyes can contain sodium sulphate (Na2SO4) and sodium chloride (NaCl) in quantities between 10 and 30%, although in certain cases higher levels have been found. Assuming to use a dye containing 30% by weight of sulphate and dosing that in 4% on the weight of shaved cattle hides to mm. 1.2/1.4, the amount of sulphate in wastewater would amount to a total of about 100 mg/l1,2.

Some products used in re‐tanning such as resins, synthetic tannins, re‐tannings and dispersants often contain significant amounts of sulphate. It's therefore preferable to use high concentration products and therefore with a low content of sulphates and chlorides.

¹ Calculated assuming the use for each kilogram of raw skin of 25 liters of water for a complete processing cycle, an average content of 3000 mg/l of sulfates of 7000 mg/l of chloride and 200 mg/l Cr in the effluent at the end of the process. ² Calculated considering the dyeing of 1 kg of wet‐blue, shaved 1.3/1.4 mm. corresponding to 4 kg. raw hides

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IMPACT OF SULPHATE IN THE DRAINAGE

1.051

730500

2.500

100

4.881

751

365500

2.300

30

3.946

0

500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

5.000

Liming Deliming Pickel Tanning Dyeing Total

Sulphate reduction

mg/

l of dr

aina

gTraditional

Innovative

3.GUIDELINES FOR THE TANNING CHROME REDUCTION in Tannery wastewater

The reduction of chrome in water at the end of tanning may be primarily done in 2 ways: chrome recovery by precipitation with alkali and redissolution in sulfuric acid.

Chrome regenerated with new fresh tanning agent is used in the subsequent chrome tanning phase.

optimization of the efficiency of chrome fixation to leather and exhaustion of the tanning baths.

3.1. CHROME RECOVERY

This system has some limits: wastewater spill of significant quantities of chromium, physically not cross‐linked into

the skin; the need to have a recovery plant; the not economically advantageous applicability for small and medium‐sized

productions; the need to carry out continuous analytical monitorings of chrome obtained; the inapplicability in the production of certain types of articles of high quality range.

The first point limits ecological performances of this method. In fact, we must point out that using this system, at the end of tanning chrome not chemically bound is contained in the skin. The amount of chromium adsorbed at a physical level is proportional to the concentration of tanning agent left in the bath at the end of tanning. The highest the concentration is, the highest the amount of spilled chrome is in waste water through the setting out operation after washing and shaving.


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While the squeezing bath may be sent to the recovery of chrome, the same can not be implemented, for obvious reasons, with the washing baths for large volumes to process. Therefore, significant amounts of chrome escape from recovery founding in wastewater and then in sewage sludge. Moreover, recovery would result an economically disadvantageous operation and difficult to carry out for end tanning baths with a limited concentration of chrome.

3.2. OPTIMIZATION OF THE CHROME FIXATION

The improvement, within certain limits, of fixation and exhaustion of chrome, is the system of more easily applicable reduction of chrome in wastewater. Unlike the methods with a too forced exhaustion, the systems that are based on this concept, do not interfere with the quality of some high level items. The optimization of the chrome fixation does not require additional equipment and can be obtained without being different from the normal processing methods. In addition, the articles produced have a quality comparable to that obtained with the standard methods for chrome tanning.

Any tanning optimization system must ensure to leather the same amount of Cr2O3 of the standard working, ranging from a minimum of 3.5 to a maximum of 4.2% (at 0% of humidity) and a shrinkage temperature above 100 °C. The main parameters that influence the efficiency of fixation are as follows:

Amount of chromium salt (in Cr2O3)

A smaller amount of chrome is adequate if upholstery leather are produced, while the higher one is required when leather for shoes is made. The use of excessive amounts of chromium is not recommended, since it would only increase the concentration of tanning agents and of suspended solids in water discharged. At the same time the quality of the article is not improved, while the costs of production increase and sometimes the mechanical strength of the skin gets worse.

Float, long

The efficiency of the pickel bath changes depending on the fact that chrome is liquid, or in powder, because during tanning process it’s necessary to have more or less the same volume of bath. In the first case, the pickel is made with 20‐25% water, in the second case with 30‐35%. The short float ensures a faster penetration of chrome, a rapid rise in temperature, which allows to take advantage of the thermal effect for a longer period of time.

Final temperature of tanning

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This parameter is very important for the performance of fixation. It’s obvious that a final temperature of 40°C ensures a good return on fixation without modifying the characteristics of grain and mechanical strength.

Duration of tanning

The fixed quantity of chrome increases according to the duration of the process. It is therefore recommended, as an indication, that the duration is not less than 10 hours from the time of chrome addition.

pH of the end tanning

The pH of the end tanning should be between 3.8 and 4.0 for upholstery leather. For footwear articles it’s recommended not to exceed a value of 3.9. The size of pH should be made by reliable and accurate instruments. To have a pH value of the end tanning constant, deliming and pickel phases should be standardized. As for temperature, if the desired pH value is reached in a reasonable timescale, chromium can unfold its optimum responsiveness for a longer duration and, consequently, increase the efficiency of fixation.

Masking

Masking agents, besides facilitating the penetration of chromium, making it more stable to precipitation with alkali and giving leather blue‐tinted shades and a finer grain, can swell the molecule of tanning. This means that the reticular complex of chromium can more easily and consequently improve the efficiency of fixation and of exhaustion of the float.

CONCLUSION By optimizing the above listed parameters according to the recommended guidelines the overall depletion of chrome can be greatly improved. Furthermore, they could reduce the concentration of tanning agent in wastewater of the whole cycle of over 80 mg/l ¹ ¹ Calculated assuming the use for each kilogram of raw skin of 25 liters of water for a complete processing cycle, an average content of 3000 mg/l of sulfates of 7000 mg/l of chloride and 200 mg/l Cr in the effluent at the end of the process.


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Courtesy

ACQUE DEL CHIAMPO SPA Via Ferraretta, 20 36071 Arzignano (VI) tel. +39‐0444 159 111 fax +39‐0444 459 222 www.acquedelchiampospa.it [email protected]

MEDIO CHIAMPO SPA Via Gen. Vaccari, 18 36054 Montebello Vic.no (VI)tel. +39‐0444 648 398 fax +39‐0444 440 131 www.mediochiampo.it [email protected]

AVS Alto Vicentino servizi spa Via San Giovanni Bosco, 77/b 36016 Thiene (VI) [email protected]

Translation and Reprint by ASSOMAC SERVIZI S.r.l.

www.fertilandia.eu

ENGLISH VERSION

fertilandia

The main Objective of the project FERTILANDIA is to commercialize an Organic Nitrogenous Fertilizer named “pellicino integrato” (integrated leather meal) constituted of a mix of leather meal and dewatered sludge rising from tannery wastewater treatment plant. The specific object of the action to be carried out is replacing the animal meals component - at present used in the prototype mix, with leather meal to obtain an Organic Nitrogenous Fertilizers, to be used in agriculture

The Fertilandia project is co-financed by the Eco-innovation programme of the European Commission. The Eco-innovation programme supports innovative solutions protecting the environment, supporting market replication projects of products, processes or eco-innovative practices, already technically proven, but needing incentives to have success in the market.

Further information at ec.europa.eu/environment/eco-innovation/

presentationcontactsCONSORZIO CUOIO-DEPUR S.P.A.Via Arginale Ovest, 8156020 San Romano San Miniato (PI) | Italy0571 44871 | 0571 [email protected] www.cuoiodepur.it

CCTVia Chico Mendez 56024 Ponte a Egola San Miniato (PI) | Italy

GOZO COTTAGEGozitano Buildings Mgarr Road Xewkjia Gozo | [email protected] www.gozocottage.com

C.C.T. srl

www.fertilandia.eu

before fertilandia ...Before the Fertilandia project was realised, the leather processing cycle in the tannery district was carried out as follows:

The slaughtering of animals for the preparation of meat results in a by-product made of coat and raw skins, which cannot be used for the food industry, but constituting the raw material for the production of leather in the tannery district of Ponte a Egola. The tanning district located in Tuscany between Florence and Pisa, is characterised by the use of natural agents such as tannins. 100 kg of raw skins result in 30 kg of end product, 70 kg of by-products and 1,500-2,000 litres of waste waters containing portions of organic substance. Such organic substance derives from parts of skins, cuttings, etc. The leather is used by the shoe and leather industry and it supplies 95% of the Italian market for footwear soles and 60% of the European one.

Solid by-products include all the parts of the original skins not used for manufacture and to be sorted.

At the Cuio Depur plant, waste water is collected and treated, resulting in purified water, which is poured into the final receptor (the river Arno), and sludge containing part of the aforementioned by-products.

tanneries

disposalcuoiodepurWASTE

DISPOSAL

www.fertilandia.eu

The slaughtering of animals for the preparation of meat results in a by-product made of coat and raw skins, which cannot be used for the food industry, but constituting the raw material for the production of leather in the tannery district of Ponte a Egola. The tanning district is characterised by the use of natural agents such as tannins. 100 kg of raw skins result in 30 kg of end product, 70 kg of by-products and 1,500-2,000 litres of waste waters containing portions of organic substance.

tanneries

At the Cuio Depur plant, waste water is collected and treated, resulting in purified water, which is poured into the final receptor (the river Arno), and sludge containing part of the aforementioned by-products.

cuoiodepur

With the creation of Consorzio CCT the current by-products of the tanning process will be managed differently. Treated and untreated solid by-products will be sent to the CTT plant to obtain organic flours with fertilising properties to be mixed with the stabilised proteic sludge received from Cuoio Depur. The objective is producing a pelletted nitrogenous organic fertilizer (the integrated leather meal and the products derived from it), and is so doing closing the chain.

c c t

after fertilandia...

The Fertilandia project makes it possible to use by-products that would otherwise be sorted to be transformed into a reusable resource.

www.fertilandia.eu

c c t

The thus-obtained fertilizer, of full organic origin, can easily be used to nourish plants. The balanced composition guarantees that nutrients are properly released, with a conditioning effect.

prodotto

In the framework of the Fertilandia project, the integrated leather meal will be tested in Italy and in Gozo, Malta, by Gozo Cottage.

gozo cottage

functioningintegrated leather meal

integrated leather meal

www.fertilandia.eu

Integrated leather meal is a nitrogenous fertilizer with high content of digestible organic matter. It is designed to replace most common chemical fertilizers as ammonium nitrate, ammonium sulphate and urea.A massive use of chemical fertilizers causes the loss of organic substances in the soil with the increase of erosive phenomena and groundwater pollution of nitrogenous compounds.Organic substances in soil have the role of:

- strengthening soil structure with colloidal and fibrous substances- stabilising the aggregates- increasing cationic exchange capacity- increasing water hold up- being a reserve of nutritious for micro organisms and soil’s fauna It was estimated that over hundred years the utilisation of “compost”, similar in composition with integrated leather meal, will consent to reduce 54 Kg of equivalent CO2 per ton of utilized compost (EC Environment DG, 2003). The use of organic fertilizers in agriculture could therefore contribute in reducing carbon presence and air pollution. The disposal of sludge and bio-waste produces a pollutant leachete and biogas.

The recycling of sludge and solid waste material from tanneries as integrated leather meal will not only contribute in reducing greenhouse emission, but also to return organic substance to the soil.

An amount of 26.000 ton/year of sludge (the total production of Cuoio-Depur wastewater plant) can be reused in the production of integrated leather meal and an amount of 12.000 ton/year of solid waste from tanneries will be processed to obtain the leather meal, allowing a remarkable reduction of greenhouse emission, leachete, soil pollution and increasing organic presence in soil.

productwww.fertilandia.euwww.fertilandia.eu

1

Papers published in the Journal of the American Leather Chemists Association (2008; 103(1): 1-6)

Life Cycle Assessment (LCA) of the oxidative unhairing process by hydrogen

peroxide

Domenico CASTIELLO

(1), Monica PUCCINI

(2), Maurizia SEGGIANI

(2), Sandra VITOLO

(2),

Francesco ZAMMORI(3)

(1) Po.Te.Co. Scrl – Polo Tecnologico Conciario Via Walter Tobagi, 30 - 56022 Castelfranco di Sotto Pisa, Italy

(2) Dipartimento di Ingegneria Chimica, Chimica Industriale e Scienza dei Materiali - Università di Pisa, Largo Lucio

Lazzarino, 1 - 56126 Pisa, Italy

(3) Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione - Università di Pisa, Via Bonanno Pisano, 25/B

56126 Pisa (Italy)

Abstract

The ever increasing attention to the environmental impact of the process industry imposes an

obligation to constantly improve the global sustainability of the tanning process.

Among the numerous phases of the tanning process, the beamhouse accounts for most of the total

polluting charge, due to the use of sodium sulfide and lime during the manufacturing process of

hides. Hence, the authors have recently developed an alternative unhairing process that eliminates

the use of sulfides. The actual reduction of the environmental impact of this process, in relation with

the traditional one, was evaluated performing a Life Cycle Assesment (LCA) using SimaPro 6, one

of the most used software for LCA analysis. Environmental impacts were finally rated using “EDIP

97” assessing methodology. Since impact assessment methodologies were mainly developed for the

manufacturing field, EDIP 97 was slightly modified and adapted to fit with the tannery industry.

Key words: LCA, unhairing process, sulfide, hydrogen peroxide

2

Introduction

The tanning industry generates great amount of wastes and causes several negative effects on the

ecosystem. Considering the ever increasing attention toward environmental themes, it is necessary

to minimize the pollution charge of effluents and to decrease production of wastes.

Among the several phases of the tanning process, the beamhouse is responsible for most of the

overall impact, as it generates 83% of BOD5, 73% of COD, 60% of suspended solids, 68% of

salinity and 76% of total polluting charge produced during the manufacturing process of hides. This

is because the traditional unhairing process requires sodium sulfide, and lime in the beamhouse

phase. Besides, the fleshing operation that follows the unhairing phase, generates a waste (mainly

constituted by collagen) whose reutilization and valorization, as a valuable protein source, may be

precluded by the presence of sulfides. Consequently, the development of an alternative unhairing

process, with an environmental impact lower than the traditional one, represents a priority. To the

scope, a recent research activity has been conducted by the authors (S. Bronco et al., 2005). The

obtained alterative unhairing process is based on the use of hydrogen peroxide and makes it

possible to avoid sulfides utilization. To assess the quality of the finished leather (obtained through

the oxidative unhairing process), several experimental activities have been performed, both on a

laboratory and on an industrial scale. Results have shown that the finished leathers are comparable

to that obtained by the traditional process in terms of physical-mechanical and technical properties.

In addition, the process has proved to be practical and economical to be implemented, for it is

compatible with the existing machineries installed in the plant.

Given the technical and the economical feasibility of the oxidative unhairing process, the objective

of the present work consists in the evaluation of the actual reduction of the environmental impact in

relation with the traditional one. To the scope, a Life Cycle Assesment (LCA) was made.

LCA is a methodology that provides a quantitative basis to assess the environmental performance of

a product and/or a process. The most important applications are: (i) analysis of the contribution of

the life stages to the overall environmental load, and (ii) comparison of products and/or processes

designed to fulfill the same function. First applications of LCA took place in the early nineties and

nowadays, LCA studies are receiving an increasingly deal of attention, especially to compare

products such as: paper/ceramic/plastic cup, polyetilene/cardboard packages, plastic/mirror bottles,

paper/cloth diapers, paper/plastic/durable shopping bags (Matthews et al., 2002). Other typical

applications concern the agri-food industry, and the energy production field. Excellent applications

can be found in: Andersson et al. (1993), Koroneos et al. (2003), Ardente et al. (2005), Finnveded

et al. (2005). On the contrary, fewer applications directly address chemical processes (Munoz et al.,

2006), and the tanning process in particular (Rius et al. 2002).

In the present work, the oxidative unhairing process is compared to the traditional one focusing in

particular on the life cycle stages that account for most of the environmental loads: (i) Na2S

production, (ii) H2S production, (iii) H2S waste treatment, (iv) unhairing. LCA was accomplished

by aim of SimaPro 6, one of the most used software for life cycle analysis in the industrial field.

Environmental impacts were finally rated using EDIP 97 assessing methodology. Since impact

assessment methodologies were mainly developed for the manufacturing field, EDIP 97 was

slightly modified and adapted to fit with the requirements of the tannery industry.

LCA Description

LCA is a quantitative and objective technique for assessing the environmental performance of a

product and/or a process over its life cycle (Werzel et al. 2000). The basic concept is that the impact

an item has on the environment does not depend exclusively on the manufacturing process, but

begins with the design and ends with the final disposal (Zabaniotou, Kassidi, 2002). For this reason,

all the inputs (i.e. energy, material, etc.) and the outputs (i.e. products, waste materials, emissions,

etc.) must be identified and quantified for each life stage of a product. Only in this way it is possible

to objectively evaluate its impact on the environment. According to the definition given in the

international standard ISO 1400, LCA is based on four sequential steps. These are listed below:

Aim and Scope definition (ISO 14040). The aim is a brief description of the reasons for using LCA,

while the scope is a clear definition of the main choices, assumptions and limitation of the analysis.

3

The main issues to be addresses are the following ones. Functional unit that is the reference

quantity used to evaluate, in relative terms, two alternative products. To keep the comparison fair

the functional unit should refer to the function fulfilled by each product. System boundaries that

specify which unit processes (i.e. life stages) are included in the analysis. Three alternative

approaches are possible: (i) first order (i.e. only production and transportation of material are

considered), (ii) second order (i.e. all process are included, but equipments and ancillary goods are

not considered), (iii) third order (i.e. also equipment are taken into account). Allocation rules are

used whenever a process realizes more than an output, or performs more than a function. Under

these circumstance it must be defined how the environmental loads of a process are allocated

among its several outputs.

Life Cycle Inventory (ISO 14041). During LCI, a model is made to represent the technical system

used to produce, transport, use and dispose of a product. This results in a flow diagram containing

all the unit processes of the entire life cycle. Furthermore, for each unit process, all the inflows and

outflows must be quantified (on a volume or mass basis) and listed into different environmental

categories, relevant to resource use, human health and ecological areas.

Life Cycle Impact Assessment (ISO 14042). To determine which flows are significant and how great

is their contribution, data contained in the LCI must be interpreted. To do that, a model of

environmental mechanisms is used to establish a connection between the environmental loading and

known exposure pathways to humans and ecology. Using several environmental mechanisms, LCI

results can be translated in a number of environmental issues of concerns (i.e. impact categories)

such as: acidification, ozone depletion, climate change, eutrophication etc.. The contribution of a

parameter to a certain impact category is then evaluate through an equivalence factor that expresses

its effects in relation with a reference parameter. For example CO2 is the reference parameter for the

“climate change” category and the equivalence factor for CH4 is 42 (i.e. contribution of 1 Nm3 of

CH4 is 42 times as high as the emission of 1 Nm3 of CO2). Clearly, determination of equivalence

factors is the most difficult and controversial step of the process, but can be often overcome

applying standard procedures (CML2, EDIP, ECO-Indicator) purposely developed to the scope.

Results are finally normalized to describes their magnitude in relation to a background impact that

is generally expressed as the average impact per person.

Interpretation and improvements (ISO 14043). The last step mainly consists in the validation of the

obtained results and in the development of feasible solutions intended to reduce the overall impact.

Methodology

Considering that the objective of the present work consists in an environmental comparison of two

alternative processes, LCA have been accomplished in relative terms using a third order approach,

and considering only inputs and outputs that change with the alternative. This is clearly represented

in Figure 1 that shows the main phases considered in the analysis.

Figure 1. Processes flow diagram

4

For what concerns the leather productive process, the main differences can be found in the inputs

required at the unhairing stage. On the contrary, energy flows, required machineries and ancillary

goods remain unchanged. Another major difference is due to the fact that the traditional process

requires a system to eliminate H2S generated during the unhairing process, while this step is

completely eliminated through the adoption of the oxidative process that uses oxygen peroxide

instead of sodium sulfide. Please note that the boundary of the system here considered includes the

production of chemicals used for the unhairing process. In fact, accordingly to the main principles

of LCA, all the environmental impacts occurring during the life cycle of an item must be taken into

account. If this was not made, the comparison would not be made on an equal base because

environmental loads upstream the unhairing process would be neglected.

This is especially true in the present case. In fact, if the boundary was not extended to include the

production of chemicals, the impact of the oxidative process would obviously results lower than the

traditional one, for the absence of sulfides in the wastewater and in the emissions.

Input flows and emissions at the unhairing phase were collected directly on the field, and are listed

in Table I. Please note that the amount of each pollutant is evaluated per kg of salted hides that

represents the functional unit adopted for the present work.

Oxidative Unhairing Traditional Unhairing

Input

Na2S 0 [kg] 0.04 [kg]

Ca(OH)2 0 [kg] 0.04 [kg]

NaOH (50%) 0.096 [kg] 0 [kg]

H2O2 0.09 [kg] 0 [kg]

Output

COD 85.9 [kg] 106 [kg]

suspended solids 58.73 [kg] 59.9 [kg]

Nitrogen (as NH4+) 0.8 [kg] 0.6 [kg]

Sulfides (as S2-) 0 [kg] 0.04 [kg]

Table I. Input – Output of the unhairing processes

Other data were taken from the Buwal and the Ecoinvent Database, both included in the library of

the software SimaPro 6, which has been used to develop the LCA model. This is clearly shown in

Figure 2, which displays the life cycle of the traditional unhairing process, defined in SimaPro 6.

Traditional

process

Traditional

unhairing

H2S

treatment

Ca(OH)2Na2S ElectricityNaOH

H2S ElectricityNaOH Heatcoal

Figure 2. Life cycle of the traditional unhairing

5

In order to evaluate the environmental impact of both processes, taking into account the effect on

the ecosystem and on the human health, the following impact categories have been considered: (i)

global warning, (ii) ozone depletion, (iii) acidification, (iv) eutrophication, (v) photochemical smog,

(vi) eco-toxicity water chronic, (vii) eco-toxicity water acute, (viii) eco-toxicity soil chronic, (ix)

human toxicity air, (x) human toxicity water, (xi) human toxicity soil, (xii) bulk waste, (xiii)

hazardous waste, (xiv) radioactive waste, (xv) slag and ashes, (xvi) non renewable resources.

Next, to evaluate contributions to each environmental issues of concern, EDIP 97 impact

assessment methodology was selected. This choice was motivated by the fact that EDIP 97 is

probably the impact assessment methodology more suitable for an application concerning a

chemical process. In particular there is a perfect matching between the parameters for which EDIP

97 provides an equivalence factor, and the chemicals included in the LCI of the unhairing process.

The only inconvenient was that, unfortunately, EDIP 97 in its standard way, does not take into

account COD as parameters affecting the eutrophication impact category. However, COD is one of

the main parameter used to characterize wastewaters of a chemical process, as the one here

considered. To fulfill these requirements, a specific equivalence factor was computed in order to

express the environmental load of COD in relation to the reference parameter (i.e. nitrates). The

equivalence factor was evaluated in 0.23 point, making an interpolation of all parameters that

characterize the eutrophication impact category in EDIP 97 and CML’96 impact assessment

methodologies.

Results

Results of the impact assessment step are graphically shown in Figure 3 and Figure 4.

The bar chart of Figure 3 shows the relative contribution of the inputs of the traditional unhairing

process for each environmental impact category. It is evident that the life cycle of Na2S accounts for

most of the whole environmental impact. Therefore the elimination of Na2S from the unhairing

process appears to be necessary to reduce the environmental impact. Please note that the

environmental impact of Na2S is due to the sulfides released in the wastewaters and also to its

productive process.

Figure 3. Relative contribution of the inputs of the traditional unhairing process

The analogous evaluation for the oxidative unhairing process is shown in Figure 4, that shows how

the life cycle of H2O2 accounts for most of the whole environmental impact..

6

0%

20%

40%

60%

80%

100%

Oxidative unhairing

Traditional Unhairing

Glo

bal W

arm

ing

Ozon

dep

letion

Acid

ific

ation

Eutr

op

hic

ation

Pho

toch

. sm

og

Ecoto

x. W

ate

r ch.

Ecoto

x. W

ate

r ac.

Eco

tox. S

oil

ch.

Hu

ma

n T

ox.

air

Hum

an

To

x. w

ate

r

Hum

an

To

x. soil

Bu

lk w

aste

Ha

zard

ou

s w

aste

Ra

dio

active

wa

ste

Sla

g -

ashe

s

Non

Re

n.

Re

sou

rc.

Global Warming

Ozon depletion

Acidification

Eutrophication

Photoch. smog

Ecotox. Water ch.

Ecotox. Water ac.

Ecotox. Soil ch.

Human Tox. air

Human Tox. water

Human Tox. soil

Bulk waste

Hazardous waste

Radioactive waste

Slag -ashes

Non Ren. Resourc.

Figure 4. Relative contribution of the inputs of the oxidative unhairing process

Finally, Figure 5 shows, in relative term, which one of the alternative processes has the greatest

impact for each impact category.

Figure 5. Impact assessment results

Take for instance the photochemical smog category. In this case, the oxidative process has an

impact 0.9 times lower than the traditional one. As can be seen from Figure 5, the oxidative

unhairing has an environmental impact greater than the traditional one in several impact categories.

This is due to the production of oxygen peroxide that accounts for more than the 50% of the overall

environmental impact.

As previously noted, for a fair assessment of results, data must be normalized to express their actual

magnitude in relation to a known reference value that is the equivalent impact per person (i.e. the

average annual impact generated by the ordinary activities performed by an individual).

Normalized data are listed in Table II.

As clearly shown in Table II, the impacts categories most significantly affected are “Eco – Toxicity

water chronic” and “Eco Toxicity water acute”. It is also evident that the adoption of the oxidative

process makes it possible to greatly reduce impact in both these environmental impact categories.

7

As far as the other categories are concerned, even if several impacts of the oxidative unhairing are

greater than the traditional one, their normalized magnitudes may be considered not significant in

terms of effects on the ecosystem and on the human health.

Impact Categories Oxidative Unhairing Traditional Unhairing

Global warming 1,96E-05 1,43E-05

Ozone depletion 1,08E-07 3,65E-07

Acidification 9,73E-06 8,80E-06

Eutrophication 9,32E-03 6,90E-03

Photochemical smog 7,12E-06 7,69E-06

Eco-toxicity water chronic 3,73E-04 7,00E+01

Eco-toxicity water acute 3,68E-04 3,36E+02

Eco-toxicity soil chronic 6,11E-05 4,34E-06

Human toxicity air 2,46E-06 1,29E-06

Human toxicity water 3,11E-05 3,49E-04

Human toxicity soil 4,77E-05 2,44E-05

Bulk waste 7,91E-06 3,44E-06

Hazardous waste 1,68E-07 1,43E-09

Radioactive waste 1,27E-04 4,78E-06

Slag/ashes 4,38E-06 7,01E-10

Non Renewable Resources 1,00E-08 1,00E-08

Table II Normalized results per impact category

Conclusions

An alternative oxidative unhairing process has been previously developed by the authors. Given its

technical and economical feasibility, the objective of the present work consists in the evaluation of

the reduction of the environmental load, in relation with the traditional process.

To assess the environmental sustainability, LCA was used to compare the traditional and the

oxidative unhairing process. The life cycle model for both processes has been implemented using the

software SimaPro 6. Results show that “Ecotoxicity water chronic” and “Ecotoxicity water acute”

are the most affected impact categories and that, damages on both these impact categories are greatly

reduced through the adoption or the oxidative unhairing process.

At the moment, the process has been investigated leaving the wastewaters treatment out of the

boundaries of the system. Considering the obtained results, which reveal that the main impact affect

the water’s pollution, it seems desirable to extend the systems boundaries to include in the analysis

the treatment of the wastewaters too. Further researches are intended to the scope.

8

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