Strategic Design for Leather Tannery Industries

The province of Tungurahua in Ecuador has a participation of 76% at the national level within the leather production chain with the production of raw materials, these are used in the manufacture of 80% of footwear in the country. These production processes generate environmental problems, the greatest impact being on the water, due to the dumping of liquid waste with chemical contents in rivers, this generates bad odors, gases, smoke and polluting solid waste from this process. According to data from tanneries, approximately 88% of the raw material is transformed, while the remaining 12% is considered as waste (leather trimmings), which are used in other manufacturing processes (footwear, textile industry, leather goods and others), the chip obtained from the process is compressed and discarded. As a preventive action, a process is proposed to generate new products through the use of waste obtained from leather processing. The design methodology is the Double Diamond: discover, define, develop and deliver a new product that reuses this waste, a block of dimensions 150 x 75 x 5 mm and 300 grams of weight was obtained, which can be applied in the sector of construction and allow the transition from a linear production process to a circular process.

A Review on Utilization Routes of the Leather Industry Biomass

The use of biomass to produce bioenergy and biomaterials is considered a sustainable alternative to depleting fossil fuel resources. The world tanneries consume 8–9 MT of skin and hide every year producing 1.4 MT of solid waste. Most of the solid biomass generated from tanneries is disposed of as waste in the environment using either landfilling or thermal incineration. Disposal of this waste into the environment affects the ecosystem, causing bad odor (air pollution) and has an antagonistic impact on the environment. Due to this, European Union legislation bans the landfilling of biomass. This study aims to comprehensively review the possible valorization routes of leather processing industry biomass into high-value biomaterials. Leather biomass (trimmings, shaving, splitting, and buffing dust) mainly contain 30%–35% collagen protein, which is produced by acid or alkali hydrolysis. The biopolymers obtained from leather industry biomass can be utilized in the production of several high-value materials. In addition, leather processing industry biomass also contains fat, which can be converted into a bio-surfactant, and other useful biomaterials. Keratin protein can also be extracted from the hair waste of hides and skins. The increased demand for biomaterials makes the using of leather industry biomass very attractive. From this study, it can be concluded that the conversions of leather processing industry waste to valuable biomaterial can protect the environment, generate additional income for leather industries, and pave way for sustainable and renewable biomaterials production.

Identification of Keratinophilic Fungi in Urban Waste and Cattle Field Soil of Kanpur, India for Environmental Pollution Management

Kanpur is a city which has huge number of leather product units and leather processing plants. These units are one of major contributors of keratinous waste and produces keratinous material as waste in the form of hairs, hides, dermis. During the present study 83 keratinophilic fungi were isolated from 40 soil samples of urban waste and cattle field habitat of various localities. From 20 samples of urban waste, 44 keratinophilic fungi were isolated, 39 fungi recorded from Cattle field. The frequency of genera Chrysosporium was recorded in urban waste (29.54%) and cattle field soil (20.51%). Maximum (13.83%) frequency was recorded in the case of Chrysosporium indicum in urban waste.

Changes to the Collagen Structure using Vibrational Spectroscopy and Chemometrics: A Comparison between Chemical and Sulfide-Free Leather Process

Chemical and physical changes take place when hides and skins are processed to leather that affect the quality and strength of the material. Understanding the structure at each leather-making stage is the basis of this study but also intend to improve the process through a biochemical approach, employing a proteolytic enzyme for processing leather more cleanly with reduced environmental impact. Raman and ATR-FTIR spectroscopy in conjunction with chemometrics was used to investigate each leather-making stage from fresh green cattle hide to dry crust leather. The changes in proteins, lipids, nucleic acids and other biomolecules with leather processing was measured and reported using three novel Raman ratiometric markers, 920/1476, 1345/1259 and 1605/1476 cm-1, to discriminate the structural changes in collagen of hide using standard chemical and enzymatic method. Amide I band was deconvoluted to investigate thecollagen secondary structures using curve fitting by Gaussians function. The results of Principal Component Analysis are well-corroborated with the ratiometric markers of structural changes.

Role of Anionic Chromium Species in Leather Tanning

Chrome tanned leathers are definitely unique in comparison with leather made from any other known tanning agents, especially in terms of thermal stability, cost and its reactive mechanism with collagen fibers. In our current studies, self basifying chrome tanning materials masked with different percentages of organic acid were prepared and applied after the de-liming stage of leather processing. This eliminated the need for pickling and basification steps. Tanned leathers resisted shrinkage up to 103 and 105±2°C while conventional chrome tanned leathers resisted up to 108±2°C. Also, interaction of anionic chrome species in tanning was studied. It was observed that the percentage of anionic species in the experimental chrome tanning material was higher than conventional chrome tanning material and the shrinkage temperature achieved by application of experimental tanning material proves that anionic species do involve in tanning. Tanned leathers were crusted and analysed for strength and organoleptic properties.

Eco-friendly Chrome Tanning of Leather using Ultrasound Technique

This article describes the development of an environment friendly chrome tanning of leather using ultrasound. Most of the leathers are tanned by the conventional method using basic chromium sulphate. It is one of the most polluting and time-consuming steps in leather processing. In this study, investigations were carried out on ultrasound assisted eco-friendly tanning process so that the chrome tanning agent could provide better quality leather without creating any environmental problem. Effects of using ultrasound in chrome tanning process were studied at different pH, tanning time, tanning agent dosage, and then compared with that of conventional method. Tanned leathers were characterized by scanning electron microscopy (SEM), photomicrographic analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy dispersive X-ray (EDX), etc. SEM analyses of the surface and cross-section of the tanned leather showed that fibre structures were not affected by ultrasound. It was also found that the shrinkage temperature of leather tanned with ultrasound was increased by about 5–29°C. Chrome uptake and content were found to increase by 30–50% and 1–7%, respectively. Tanning time was shortened from 6 hours to 2 hours and the quantity of leachable chromium in the leather was also decreased significantly. The noteworthy enhancing effects have been attributed largely because of the increased penetration of tanning agents into pickled leather. Photomicrographic analysis of the cross-section of the tanned leather also showed a higher penetration of tanning agents in presence of ultrasound.

Geochemical State of Wilga River Environment in Kraków (Poland)—Historical Aspects and Existing Issues

Aquatic systems are a very important part of the environment, which requires special attention due to the constant deterioration of the quality and quantity of water globally. Aquatic environments in Poland are mostly affected by the mining and smelting industry, which is especially visible in the south of the country, and one of such anthropogenically affected rivers is the Wilga—a small tributary of the Vistula River (the biggest river in Poland). For many years, the catchment area of the Wilga River accommodated a functioning industry that was based on the use of metals (fur, leather processing, foundry and galvanizing plants), as well as the “Solvay” Kraków Soda Works, which have left behind soda waste piles, and currently, along the course of the river, there are ongoing works connected with the construction of the “Łagiewnicka Route”, which required the relocation of a section of the Wilga river bed, among other things. To determine the general condition of the river, selected physico-chemical parameters were analysed in the water (pH, conductivity, anions: Cl−, N-NO3, P-PO4 and SO4 and cations: Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr and Zn), suspended particulate matter and sediment (Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr and Zn). Samples were taken before the relocation of the river bed (2019) and after its relocation (2021). The obtained data were compared with recorded historical data and this revealed that over the years, the condition of the Wilga environment has improved significantly, especially in terms of the contamination of sediments with metals, the concentrations of which fell several ten-fold. This is attributed to the closure of most industrial plants located within the river’s catchment area and to the modernization and legal regulation of the functioning of the remaining plants. An effect of leachates from the soda waste piles on the waters of Wilga has been observed (in the form of higher pH, mineralization and concentration of chlorides), which has however gradually decreased over time. However, no visible impact of road transport on the river’s environment has been observed, or any impact of the construction works or the related relocation of the river bed for that matter. The river should still be classified as polluted, but the level of this pollution has decreased significantly and the qualitative composition of the pollution has also changed.

Prospects and Challenges of Chrome Tanning: Approach a Greener Technology in Leather Industry

The leather industry is one of the heavy-polluting and hazardous industries that is creating toxic and harmful effects on the environment and human health by producing waste chemicals, tannery effluents, and various pollutants. Moreover, Tanning is the required stage to convert raw skin to durable and sustainable skin but most of the chemicals, salts, organic and inorganic toxic pollutants are produced. In commercial practices, Chrome tanning is the highly employed approach that uses a large number of basic chromium salts that becomes the major source of chromium pollutant in the environment. Chromium salt is not only harmful to the environment and ecology but also harms the human body such as causing respiratory problems, infertility and birth defects, skin and lung cancer of the workers. This article has presented two alternatives eco-friendly greener approaches of chrome tanning and waste management technique to reduce the toxic effect on the environment and human health. Firstly, to get rid of these harmful effects, the possible remedy of environmental and human health problems may be considered the vegetable tanning process. Vegetable tanning uses tannins (a class of polyphenol astringent chemicals), which occur naturally in the bark and leaves of many plants. Secondly, chrome tanning associate with ultrasound having a frequency range of 20–100 kHz is commonly employed for enhancing the physical processes and for performing chemical reactions. The basic principle associated with the process is an ultrasonic cavitation in dissolved media. Ultrasound decreases the consumption of conventional water and chemicals because it can also function as a physical activator resulting reduction in environmental pollution which is a prime concern nowadays to approach greener leather technology and eco-friendly leather processing. Furthermore, the possible waste management technique of chrome tanning helps to prevent pollution and ensure eco-friendly green technology of leather processing. Therefore, vegetable tanning and chrome tanning associated with ultrasound having proper waste management will be the viable and sustainable options for the tanners in the forthcoming future.