Leather industry needs an eco-technology (r)evolution11 January 2010
A critical assessment in respect to the status quo and conclusions for a long-term sustainability. By Dr Dietrich Tegtmeyer, vice president for product development and application, Leather business unit, LANXESS Deutschland GmbH
Since the industrial revolution the world population has continuously increased, while natural resources such as forests, fish stocks, wetlands, mineral oil and gas have continuously declined. The balance of the earth’s resources in comparison to consumption and population growth has become a major challenge during the last 30 years with consequences for many products and applications. This applies also to the leather industry. Eco or green and sustainable technologies have played an important role in our industry for a long time. Hence, it can be taken for granted that the implementation of further and even stronger measures with positive impact on the environment will become one of the dominating factors for the survival of our industry and its product ‘leather’ in the near future.
Status quo of leather manufacturing
Unfortunately the image of leather and the leather industry has suffered in recent years for various reasons. On one hand we have to face the fact that there are still tanneries in existence which operate with little regard to environmental protection. On the other hand misleading or even incorrect reporting by certain media and lobbies concerning the killing of animals, the application of toxic chemistry and other irresponsible acts within the industry have not contributed to place our industry in the correct light.
Even though we object to this false information and despite the great efforts the industry has already undertaken over the years there is still a lot of room for improvement regarding the reduction of waste, pollution, energy and the consumption of fresh water.
This becomes obvious when looking at various more recent studies1,2,3 which reveal that an average tannery generates 5kg of organic waste, consumes approximately 160l of fresh water and emits around 0.8kg of CO2 in order to produce 1 kg of grain leather. See figure 1.
Although other substrate industries, for example textiles, consume even more process water (for the production of 1kg cotton approximately 500l water is used just for the bleaching, dyeing, printing and finishing of one pair of Jeans) we must not neglect the fact that leather is still an article which calls for a more efficient and advanced chemistry, technology and operation. This becomes clear when we look at the fact that in total two thirds of the chemicals applied from raw hide to finished leather in an average shoe upper leather production are still process or excess chemicals which do not eventually end up in the final leather. When taking into account the waste in terms of trimmings, shavings etc, only some fifteen percent of the originally applied chemicals do end up in the final product, the grain- and split leather3. This cannot be the end of a process development story.
You may be wondering about this statement, coming from a representative of one of the leading tannery chemical suppliers, but it is my personal and LANXESS’ firm conviction that the leather making process has to be further restructured in order to avoid our industry being subjected to forced restructuring and potentially have its substrate replaced by ones which are considered more ecologically sound in terms of their environmental impact.
Process improvements – efforts and opportunities
A number of environmentally friendly chemicals and more efficient machines have been developed by the leading suppliers and external R&D institutes in the recent decade in order to succeed old technologies and applications. The vast majority of tannery owners and managers are fully committed to an environmentally friendly production and invested significantly in their operations in order to raise their eco standards to a very high level. When travelling around the world, we have come across many tanneries with excellent environmental infrastructures, intelligent recycling systems and modern dosing technologies for the responsible utilisation of their chemicals.
The ecological evolution process is running even in our leather sector, but we have to speed it up further. Then, more products and technologies will soon follow. In accordance with the standards of the Leather Working Group audit protocol1 a reduction of 45% in water consumption and 60% in energy is possible compared to average standard conditions. These process optimisations don’t necessarily add additional cost; there are lots of examples known, where a green technology pays back in a very short time due to significant cost savings. See figure 2.
Best practice waste management – difficult to generalise
When thinking of waste reduction and effluent recycling it is difficult to set general standards for a true, environmentally sound process or something like key performance indicators for the environmental impact (eco KPIs). The importance of water consumption differs very much, for example, from the geographical location of an operation. There are regions like northern Europe, where the amount of fresh water used plays not such an important role, if the treatment of the
discharged water is efficient. This is very much different in other parts of the world, especially in developing countries, where
adequate fresh water access is often a
question of survival for the population. So what is a good performance in regard to the right water consumption? This depends very much on the geography and the infrastructure of a single production.
If it comes to the environmental impact of the waste, we have to distinguish between the organic part and the inorganic salt load. Some very promising technologies are already established for reusing the organic part in the wastewater, such as turning the separated fat into steam5. In a tannery producing 1,000 hides a day from raw to wet-blue/white such a technology could lead to yearly reduction of 850t CO2, which counts roughly for 0.7 kg CO2 per sq m produced of wet-blue/white. In such operations many negative and positive impacts should level each other out, so that the overall final environmental impact result is significantly reduced.
The environmental impact of the salt load also differs very much depending on regional aspects. Consider a tannery that has an efficient chrome management – either a high exhaustion chrome tanning process or a chrome recycling technology – and this tannery has access to water which is not fresh but already has a certain salt content, the residual inorganic salt load consisting mainly of sodium chloride and sulphate should not have a negative impact on the immediate environment. This, of course is, a completely different story if a tannery has to discharge its treated wastewater into fresh water rivers, which are used for drinking water. In such a case, concepts of separating and regaining the salt6 need to be considered.
As a conclusion to this, the true environmental impact of a leather production is difficult to determine in general terms, and has to be looked at case by case. However, based on all that has been mentioned before, there is no need to be pessimistic about the future of our product leather. Many successful examples do show that overall a huge potential of waste and energy reduction can be realised already today following the four ‘R’ principles in the priority: 1. Reduction; 2. Reuse; 3. Recycle; and 4. Recover as much of the resources as possible. The industry needs to be willing to implement the already existing process optimisations and costs have to be covered somehow by all shareholders of the manufacturing chain.
Eco leather – what is it?
Thinking about eco-leather, first of all you should ask yourself: What makes your leather eco? How exactly should an eco-leather look, how it should be produced and what kind of chemicals should be permitted? To the best of our knowledge today there is no clear definition of ‘eco’. Nevertheless so called ‘eco leather articles’ can be easily found in the market which implies that the term ‘eco’ is widely misused. In order to consider a serious sustainable production of a green leather article, which rightly deserves the suffix ‘eco’, the entire manufacturing chain must be evaluated starting from the farm and the production of chemicals up to the end of the working life span of a leather article. This process is called Life Cycle Assessment (LCA)7. When looking at such LCA studies interesting aspects occur: At first glance everyone would for example, tend to believe that vegetable tanned leather would be the first to deserve the prefix ‘eco’.
Considering, however, that the production of a vegetable tanning material requires a much higher amount of water compared to a chrome tanning salt and double the amount of water is requires for the tanning process compared to chrome tannage, things have to be seen in a different light. Furthermore, a vegetable tanning process also requires double the energy compared to a standard chrome tannage. Therefore, one can imagine that the LCA of a vegetable tanned leather article is different and has no ecological advantage compared to a standard chrome leather.
An LCA benchmark delivers a similar result for a standard wet-white and a chrome tannage; even here the conclusion is that both tanning systems are comparable and there is no environmentally preferred option8. Therefore, it is also important that leather experts actively participate and drive these eco studies, otherwise more misleading information is reported, which needs to be clarified or corrected.
Mindset – time for a change
From my point of view the leather business is traditionally a conservative industry, which is not always eager or open for innovative ideas. Of course, everyone wants to have the latest information about products. However, as soon as the first teething problems occur with a new technology, tanners can be reluctant to change. This is not a criticism from someone who has no or only a minor interest in the leather business, it is an observation from someone who entered the leather business seven years ago after having spent 15 years of their working life in other industrial sectors.
In the case of implementation of innovative technologies this resistance to change, although prevalent in many industries, is often a barrier in the more conservative tanning industry. In this respect I believe some ‘leather people’ should become a bit more open minded. A culture of change would open more doors for innovative processes.
Rethinking of traditional ways and the courage to tread new paths should be promoted more and supported by good science and technology. New ideas have to be brought to the table for discussion, thinking ‘out of the box’ should be encouraged everywhere, leather standards and specifications should be questioned and re-evaluated, if they are linked to environmentally critical process steps or products.
This is the reason, why the Leather business unit of LANXESS has dedicated virtually all innovation resources to the improvement of application technologies and the development of more environmentally friendly, sustainable chemistry. LANXESS have also put a stringent policy and product stewardship initiatives in place in order to ensure that all products are in accordance with environmental regulations as well as to help the leather industry get through the jungle of restricted substances lists (RSLs) and reaching the multiple targets of set specifications. In addition, LANXESS voluntarily does not promote or support technologies and products, which are environmentally questionable compared to available alternatives, irrespectively of commercial interests. We are taking a proactive stance.
Outlook – no need to be pessimistic
From my perspective there is one other important and positive argument which keeps us optimistic in the battle of leather with alternative materials. In contradiction to most alternative substitutes, the raw material for leather is not mineral oil based, but from a renewable resource, the hide or skin. Around 50% of the collagen is transferred into the sustainable substrate leather and most of the other 50% could be used for energy production5. This should have a very positive impact in Life Cycle Assessment benchmarks with substitutes. As the current president of the IULTCS, Elton Hurlow pointed out: ‘Leather is a sustainable environmental solution to the very real disposal problem of a large volume of hides and skins that originate from the meat industry. The technical process of leather-making effectively transforms this waste product to a highly valued component of leading world brands.’ The environmental impact of disposing of all the hides as waste would be significantly larger than adding up all current tannery pollution in the world.
We have to make sure that green technologies and products are not applied just due to simple cost reasons. I believe it is of utmost importance, that additional cost and investments can’t be the reason to prohibit or even stop this eco-technological (r)evolution and the implementation of eco-innovations in production.
Continuation with old technologies just for cost saving reasons would be a huge mistake; here all stakeholders of the leather manufacturing process, slaughterhouses, tannery owners, chemical suppliers, machinery manufacturers, and definitely including the brands, have to co-operate, stay together and follow the same goal of an ecological innovation of the leather making process; in this regard we all are sitting in the same boat and must row in the same direction. Then the leather industry will be able to recover its good image, get away from a defensive justification stand point in public communication, and will maintain its place as a highly valued component of leading brands.
The author would like to thank Frank Paus, Michael Franken and Chris Tysoe for revising this paper at short notice. Comments to: [email protected]