Chapter

Toxic Waste From Leather Industries

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  • Karpagam Academy of Higher Education (Deemed to be University) India
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... Secondly, although the use of salts for the preservation of raw animal skins and hides is effective, the lipolytic activity of extremely halophilic microorganisms further reduced the quality and commercial viability (Berber and Birbir 2010;Caglavan et al. 2015). In addition, the liquor discharged poses a major threat to aquatic ecosystems leading to environmental pollution (Sivaram and Barik 2019). ...
... Such concentrated effluent profoundly hampers growth of seedlings and other agriculturally important floras, when used for irrigation purpose or normally flown to the fields. Alongside, high production costs, lack of skilled labour, and microbial attacks due to poor storage demand further investigation (Sivaram and Barik 2019). ...
Article
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Leather is the transformed product obtained from processing of raw skins and hides flayed from animals. Proteins, being the main constituent of the raw materials with about 70% moisture, are prone to microbial attack. Preservation of the raw materials is quintessential to retain the protein matrix for successful leather production. Common salt to the extent of 40–50% w/w is a widely practised method of preservation. Although effective, this approach generates huge amount of pollutants in the form of total dissolved solids (TDS) and chlorides demanding alternative curing systems. In this view, gallic acid–capped silver nanoparticles (GA@AgNPs) were evolved to serve as an alternative curing system for broad-spectrum antimicrobial and pollution abatement under optimized conditions. Nanocharacteristics were studied using UV–vis spectroscopy, X-ray diffraction (XRD), and electron microscopic (EM) analysis. Antimicrobial susceptibility testing was performed using an array of microbes isolated (n = 15) from flayed goat skin, and minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) was determined. The preservation efficacy of GA@AgNPs and salt (40%) challenged against goat skin was demonstrated and the leather characteristics validated after 30 days of treatment. Possible mechanism involved in curing process was deciphered using EM studies. GA@AgNPs were prepared under optimized conditions in a rapid fashion that typically revealed surface plasmon resonance with λmax 406 nm, crystalline phase, and spherical and anisotropic particles of size < 40 nm. Significant antimicrobial activity was exhibited upon exposing individual microbe and consortia at 1 mg/mL of GA@AgNPs. Antimicrobial mechanism via membrane damage was clearly elucidated using EM studies. The preservative efficacy of GA@AgNPs at 10% (v/w) was well-established from its water repelling efficacy and broad-spectrum antimicrobial activity owing to their strong zeta potential (− 31.4 mV) conferred by gallic acid. Therefore, GA@AgNPs might find its application in leather industry as an alternative curing system prior to trials and challenging adverse environmental conditions.
... The tannery industry generates substantial waste amounts, about 40% of the hides are lost, generating about 600,000 t of solid waste per year worldwide [8,9]. Residual tanned leather contains Cr(III) as the main Cr species, which is considered harmless [6,7]. ...
... Under uncontrollable conditions, Cr(III) can be oxidized to Cr(VI) that is a mutagenic agent [7,10]. It is important to mention that the tannery process is extremely water consuming, discharging into the environment about 200 L of wastewater for each kg of produced leather [8]. Taking account these aspects, residual tanned leather can be classified as dangerous and requires suitable treatment and disposal in industrial landfill. ...
Article
In this work, the feasibility of microwave (MW) energy and ethylenediaminetetraacetic acid (EDTA) as complexant for Cr removal from residual tanned leather were evaluated. The Cr-EDTA complex was removed from the leather surface applying washing cycles with hot water (50 ºC). The following experimental conditions were evaluated: complexation time (1 to 4 min), washing time (1 to 4 min), number of washing cycles (1 to 5) and complexant recycling (1 to 5 cycles). The morphology of untreated and treated residual tanned leather after microwave-assisted extraction (MAE) was characterized by scanning electron microscopy (SEM). After optimization of MAE process, the following conditions were selected: 3 g of residual tanned leather, 75 mL of complexant solution (3 mol L⁻¹ EDTA), 60 °C and 3 min of complexation time. After extraction, 3 washing cycles (each cycle with 50 mL of water at 50 °C for 3 min) were applied reaching Cr removal of 99%. A green analytical procedure index was used to emphasize the greenness of the proposed treatment comparing with the literature, highlighting the suitability of MW for this purpose. Moreover, the proposed process is energy and reagents saving, taking into account the low extraction time and possibility of complexant recycling.
... Chromium, a naturally occurring heavy metal commonly used in many industrial manufacturing processes is responsible for major industrial and environmental pollution. The main chromium industries include metal plating and finishing, leather and textile manufacturing, electro-painting industries which discharge huge quantities of toxic metal ions to the surrounding environment [1][2][3]. Being non-degradable, chromium gets accumulated and persists in nature for a long time and may enter into the food chain causing remarkable health damage. ...
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In the present study, sequence and structural aspects of five bacterial chromate reductase-related enzymes from Escherichia coli, Pseudomonas putida, Shigella flexneri, and Synechocystis sp. have been investigated. Comparative sequence analyses of different chromate reductase family enzymes showed that Ser13 in E. coli quinone reductase remains conserved among most of the homologous proteins and plays an important role in Flavin mononucleotide (FMN) binding. Comparative protein–ligand binding energy calculation from the docking of all the five modeled complexes of bacterial chromate reductase-related enzymes depicted that quinone reductase from S. flexneri has the highest binding affinity (−7.97 kcal/mol) with FMN. Molecular interactions study suggested that the quinone reductase from P. putida has the highest number of bonded interactions with FMN. In silico mutation design (Y85N) in E. coli ChrR confirmed the significant role of Tyr85 residue in maintaining the network established at the tetramer interface of this enzyme during substrate interaction. Analyses from molecular simulation trajectories also suggested that the mutant E. coli ChrR is much stable than the wild-type form during the interaction with substrate FMN. The present study revealed the interrelationship between the structure and function of bacterial chromate reductase-related enzymes which will help to understand their importance in chromium bioremediation. Graphic abstract
... During leather production, many wastes are generated in solid, liquid and gas form. The characteristics of the waste generated vary depending on the process, raw material and chemicals used [5,6] Many chemicals are used in the processing of leathers. Therefore, some of these chemicals pass into tannery wastewater [4]. ...
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In this study, COD, turbidity, total nitrogen, phosphate, sulphate, oil-grease and chromium removals from wastewaters taken from a local tannery using the electrocoagulation process were examined and the most suitable parameters for the electrocoagulation system were tried to be determined. Soluble iron plate electrodes were used as electrodes in the experiments. As a result of the studies carried out, the most suitable initial pH in uncontrolled pH was determined as pH = 4 and for controlled pH as pH = 5. In studies, the most suitable current density for iron electrodes was determined as 1.2 mA cm−2. Even if the increase in current density increased the amount of dissolved Fe, it negatively affected the removal efficiency. In addition, the turbidity of the wastewater was removed in 30 minutes, phosphate in 20 minutes and chromium in 15 minutes by 100%. During 60 minutes of operation, while 62.91% of TN, 87.8% of oil-grease were removed, sulphate was removed at the rate of 54.78%. In the studies, 1st and 2nd order kinetic equations for COD removal were examined and it was determined that removal kinetic is more suitable for 2nd order kinetics.
... Since leather production is a transformation process, significant amounts of waste are generated in solid, liquid and gaseous form both during and after production. The characteristics of the waste generated vary depending on the raw materials, chemicals used and technologies [5,6]. ...
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In this study, the effects of the pH of tannery wastewater obtained from a local leather processing factory on the removal of COD and turbidity, and cost of theelectrocoagulation process was investigated. Studies were carried out under two different operatingconditions. The highest COD removal efficiency was obtained as 83.5% when the initial pH was set to 3, while the energy consumption at this pH was found to be 3.88 kwh m⁻³. In studies where pH was kept constant, the highest removal efficiency obtained was 83.33% at pH = 5. In this case, the energy consumption was determined as 2.44 kWh m⁻³. The total cost of the system was calculated as 1.0899 $ m⁻³ under controlled pH conditions and 0.8761 $ m⁻³with uncontrolled pH. Studies show that the COD removal kinetics are more suited to 2nd degree kinetics. The highest removal rate for uncontrolled pH was k2 = 0.0791 L g⁻¹ min⁻¹ at pH = 3. The highest rate for controlled pH was k2 = 0.0397 L g⁻¹ min⁻¹ at pH = 5.
... Manufacturing is one of the vital sectors in any society, irrespective of being a high or lowincome economy (Fisher et al., 2018). Leather products are one of the most traded products globally as well as the leather products trade is presently exceeding the US $80 billion per year and which is anticipated to grow as there is an increase in population and urbanization of the countries (Sivaram and Barik 2019). In Asia, leather footwear is the fastest-growing share of the leather industry of China, Bangladesh, India, and Vietnam. ...
Article
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Production of finished leather as well as leather goods create various types of cutting wastage, solid wastes, and effluents which lead to immense environmental and atmospheric pollution along with biological chain destruction. To keep pace with the rapid development of the up-to-date leather industry, various innovative techniques have been developed and these should be cost-effective and eco-friendly. This study aims to identify the methods to utilize the waste generated from the leather products industries as raw material and convert into value added leather products. Seven small market-demand leather products like Headphone Holder, Decorative Skull, Key Rings, Earring-set, Doggy Belt, Bottle Holder, and Bracelets were prepared from leather cutting wastages. The pattern making and cost calculation was evaluated in a systemic way. Small leather goods need to be acceptable in the national or international marketplace. To survive in the marketplace, the designers and manufacturers especially who manufacture small leather goods from leather wastage should know the costing method and also need to know its acceptance by releasing prototype samples of their goods in the marketplace. The whole study is going to give a new business idea to the young entrepreneur as well as it will work as a solution for reducing leather wastage and save the environment.
... To make the environment pollution-free, it is needed to reduce the use of synthetic polymer as well as to reuse the waste materials. Leather industries are rapidly growing industries in the Asia Pacific region and thus these industries are also adding waste materials to the environment causing pollution [1][2][3]. If these waste materials cannot be processed into commercial materials, they will be problematic for the industry. ...
Article
Nowadays, the environment is getting polluted due to different types of manmade pollutants because of the excess use of synthetic materials. Various kinds of waste materials, which are eluted from numerous industries, are also enhancing environmental pollution. So, utilization of waste materials along with reduction of using synthetic materials will definitely subside the environmental pollution. In this research, waste jute fabric and waste leather (cow hides) were used as reinforcing agents and unsaturated polyester resin (UPR) as a matrix to fabricate environmentally friendly composite materials. Hand-lay up technique was conducted to prepare composite materials. Different percentages of waste leather and used jute fabrics were used with the UPR to modify properties. Improved mechanical properties such as tensile strength (TS), tensile modulus (TM), and percentage elongation at break (EB) have been experimented for every percentage of reinforcement addition, and 2% leather along with 10% jute fabrics containing sample revealed the best result (TS=24MPa, TM=907MPa, and EB=0.98%). Composites were also characterized by the scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) to support the results in favor of enhanced mechanical properties.
... The tannery wastewater is characterized by complex mixtures of organic and inorganic chemicals with high concentrations of Cr, BOD, COD, TDS, strong color, and pH (Buljan et al., 2011). The various chemicals in the tannery effluents pollute water bodies, soil, and air, and seriously affect human health and other biological organisms (Sivaram and Barik, 2019). Cr is one of the chemical components in the tannery wastewater which can be oxidized from +III to +VI oxidation states. ...
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Tannery wastewater is composed of a complex mixture of organic and inorganic components from various processes that can critically pollute the environment, especially water bodies if discharged without treatment. In this study, integrated vesicular basalt rock and local plant species were used to establish a horizontal subsurface flow constructed wetland system and to investigate the treatment efficiency of tannery wastewater. Four pilot units were vegetated with P. purpureum, T. domingensis, C. latifolius, and E. pyramidalis, and a fifth unit was left unvegetated (control). The constructed wetland units in horizontal subsurface flow systems were effective in removing total chromium (Cr), chemical oxygen demand (COD), and 5-day biological oxygen demand (BOD 5) from the inflow tannery wastewater. The removal efficiency reached up to 99.38, 84.03, and 80.32% for total Cr, COD, and BOD 5 , respectively, in 6 days of hydraulic retention time (HRT). The removal efficiency of total suspended solid (TSS), total phosphorus (TP), and nitrate (NO 3 −) of the constructed wetland units reached a maximum of 70.59, 62.32, and 71.23%, respectively. This integrated system was effective for treating tannery wastewater, which is below the Ethiopian surface water standard discharge limit set to BOD 5 (200 mg L −1), COD (500 mg L −1), total Cr (2 mg L −1), NO 3 − (20 mg L −1), TSS (50 mg L −1), and TP (10 mg L −1).
... In crusting, certain chemicals and dyes are added to the tanned leather. The sub-processes of crusting include drying, softening, shaving, neutralization, fixation, conditioning, dyeing, etc. Finishing is the final process in leather manufacturing that involves oiling, brushing, spraying, polishing, ironing, etc. [22]. Fig. 1 is showing a process flow diagram of a tannery. ...
Article
The research focuses on implementation of cleaner production techniques and sustainable practices to reduce the environmental footprint in 07 tanneries of Pakistan through the project titled, International Labour and Environmental Standards (ILES) in SEMs of Pakistan by WWF-Pakistan. The baseline data of the industries were collected, and each industrial unit was surveyed for 05 days to cover all the major areas of resource and energy consumption, chemical conservation, reduction in CO2 emission and economic feasibility including payback period and profit. Collected data were analyzed and suitable technological solutions were proposed for the opportunities. After a specific time, post-performance analysis was carried out to ensure the on-ground implementation and to develop strong business cases. Gaps were shared with the examined industries for their internal use and continuous improvements for further reduction in their environmental footprint. It was concluded that by working on the suggested interventions 07 industries, on average, conserved 71,131 m³ water per year, 1643.166 m³ per year compressed air was saved, and 333,791 kW energy was conserved on a yearly basis. Steam management helped industries to save 136,398 kg of steam on a daily basis, and the overall CO2 reduction was 300,842 kg/year. The graphical abstract below indicates the resources conserved by the industries that ultimately save the cost and reduce CO2 emission. Resource Conservation and GHG Reduction by 07 Tanneries.
... Previous studies report that the processing of one metric tonne of hides yields 200 kg of useful leather product. In other words, only 20% of total raw material is suitably processed, and more than 60% (i.e., 600 kg) of the processed raw material becomes waste ( Sivaram & Barik, 2019 ). Such undesirable results question the progress towards two important SDGs: Life on Land (SDG 15) and Life Below Water (SDG 14). ...
Article
Circular economy practices are considered an important initiative in achieving sustainable development goals; however, studies synergizing circular economy and sustainable development goals are limited. The leather industry, widely criticized for its adverse environmental impacts, has the strong potential to implement circular economy practices. Further, the leather industry is considered a foundational source for economically marginalized sectors and it is a major economic contributor to emerging economies. Thus, the leather industry plays a significant role in attaining sustainable development goals. Hence, a study on circular economy practices considering the leather industry is of significant importance. This paper proposes a methodological framework for evaluating the inhibitors to circular economy practices in the leather industry. For identifying the critical inhibitors to circular economy practices, this study uses a systematic literature review and identifies twenty-five inhibitors. A hybrid multi-criteria decision-making method combining the grey-decision making trial and evaluation laboratory with fuzzy complex proportional assessment method is employed for evaluating the inhibitors to circular economy practices. The findings of the study reveal that the uncertainty of consumer demand, lack of social awareness, stakeholders with short-term agendas, a lack of technologies and technical skills, and challenges in the safe return of waste to the biosphere are the five most influential inhibitors in circular economy practices. These findings can assist the industrial community and governmental agencies in formulating the required strategies to implement circular economy practices in the leather industry.
... The absorption of only 50-70% of the Cr during the chromium tanning leads to both, material losses and the creation of ecological imbalances. The posttanning process also leads to changes of total solids dissolved, COD and heavy metal quantity [5]. ...
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The study proposes a treatment process for the wastewater resulting from the technological processing of the skin (leather industry) using a new developed adsorbent material embedded with metal oxide nanoparticles. The paper focused on the influence of the pH in this process and the optimal value of the pH for triggering the mechanism of interaction between material and pollutants. The measured parameters in the water samples resulting after treatment include the chemical oxygen demand, biochemical oxygen demand, total suspended solids, ammonium nitrogen, chlorides, sulphates, organic compounds extractable in organic solvents and the solid residue adsorbed by the material.
... Consequently, the International Agency for Research on Cancer (IARC) has categorized formaldehyde as a human carcinogen (ATSDR, 2008). Furthermore, formaldehyde is a restricted substance, and thus, it may lead to residues of restricted substances in the leather product itself (Sivaram and Barik, 2019). Nevertheless, Rao et al. (2004) have reported a novel polymeric syntan that is free from formaldehyde with high capacity of enhancing chromium uptake while reducing the environmental challenge (Rao et al., 2004). ...
Article
Chrome tanning remains the most favourite technology in the leather industry worldwide due to its ability to produce leather with attributes desirable for high-quality leather such as excellent hydrothermal stability, better dyeing characteristics and softness. Nevertheless, the technology has been censured globally for its severe environmental pollution and adverse effects on human health and other organisms. Developing alternative eco-friendly tanning technologies capable of producing leather of high quality has remained a challenging scientific inquiry. This review article provides an assessment of various eco-friendly tanning attempts geared towards improving or replacing the chrome technology without compromising the quality of the produced leather. The reviewed publications have ascertained that, these attempts have been centred on recycling of spent liquors; chromium exhaustion enhancement and total replacement of chromium salts. The research gaps and levels of key environmental pollutants from the reviewed technologies are presented, and the qualities of the leather produced from these technologies are highlighted. Of all the examined alternative technologies, total replacement of chromium salts sounds ideal to elude adverse effects associated with chrome tanning. Combination tanning, which implies blending two tanning agents that individually cannot impart desired properties to the leather, is anticipated to be an alternative technology to chrome tanning. Apart from being an eco-friendly technology, combination tanning produces leather with similar features to those produced by chrome tanning. In this regard, blending vegetable tannins with aluminium sulphate provides a promising chrome-free tanning technology. However, further studies to optimize combination tanning technologies to suit industrial applications are highly recommended.
... Chemicals employed by tanneries are not completely soaked by hide leaving a large emission load by effluents (Nazer and Siebel 2006;Ramírez et al. 2019). For every metric ton of leather, more than 2.4 tons of solid waste and more than 35 m 3 of wastewater are produced, most of that is related to the unhairing in the beam house operations, which, if not properly controlled, is a threat to the environment (Aravindhan et al. 2007, Sivaram andBarik 2019). ...
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The effluent generated by Merox unit of oil refinery was used instead of freshwater for bovine hide unhairing because of its proper composition and alkalinity. The effect of temperature, treatment period, sodium sulfide (Na2S), and calcium carbonate (CaCO3) dosage was investigated on unhairing efficiency using lutrom (unhairing slurry) prepared from the Merox effluent (effluent-based lutrom). Under similar operating conditions and chemicals’ dosage, the effluent-based lutrom resulted in a higher efficiency (98.6%) than water-based lutrom (67.3%) indicating faster unhairing kinetics for the former lutrom. Moreover, an acceptable swelling (48%) and suitable mechanical properties were also observed. The experimental strategy can save 50 to 67% toxic chemicals and 100% of water consumption in unhairing, which is equivalent to US$ 34 per ton of hide, leading to zero discharge from Merox unit. Recycling of effluent-based lutrom after 3 consecutive runs was associated with a significant reduction in COD (55.6 kg/t hide) and BOD5 (11.6 kg/t hide) load. The effluent-based and conventional lutroms, before and after unhairing, were treated with ozone under moderate conditions. The FTIR results indicated a high-quality and low costly pelt benefits from the integration of wastewater treatment units of both industries in an environment-friendly manner. Graphical abstract
... "Chrome" is one of the major pollutants in tannery waste used in the post tanning process. (Sivaram and Barik, 2019;Doble and Kumar, 2005;China et al., 2020;Yin et al., 2016) Leather industries produce approximately 40 million Chromium (Cr) containing waste throughout the world every year (Asfaw et al., 2017). High Cr concentrations with a range of 1-50 g/kg were reported in tannery surrounding soils of waste disposal sites in India, with hexavalent Cr was present in groundwater at these sites (Saranraj and Sujitha, 2013). ...
Article
Industrial wastes, for instance, tannery wastes are rich soups of resistant and bioremediation-potent bacteria. In the present work, Chromium (Cr) and tannic acid (TA) resistance bacterial strains were isolated from tannery effluent and identified as Bacillus subtilis (MCC 3275) and Bacillus safensis (MCC 3283) based on its 16S Ribo-somal RNA homology. Hexavalent Cr is highly toxic and mutagenic due to its high mobility and reactivity. Whereas, TA is known to inhibit enzyme activity, substrate deprivation, and interaction with membranes and matrix-metal ions. The developed In vitro co-cultured microcosm of B. subtilis and B. safensis was able to remove Cr(VI) up to 95% and TA up to 23%. The bacteria cultures separately were able to degrade Cr(VI) to 88% by B. subtilis and 91% by B. safensis and TA up to 27%. Plackett Burman design (PBD) followed by Response surface methodology (RSM) was applied for the optimization of physio-chemical parameters. The optimized conditions for co-culture development were recorded as K 2 HPO 4 = 0.2 g/L, MgSO 4 = 0.2 g/L, NH 4 Cl = 0.5 g/L, glucose-0.2 g/L, TA-5%, Cr = 200 ppm, incubation period of 96 h, agitation speed of 110 rpm, pH = 5.0, temperature= 30 • C and inoculum size = 3%. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) revealed the thorough mechanism of cellular uptake followed by degradation of Cr(VI) and TA. The efficiency of co-culture for other heavy metals was observed as follows: Zn 65%, Pb 63%, Cd 65%, and Ni 65%. Bioreme-diation using bacteria is an economical and environmentally better alternative to conventional remediation methods. The isolated bacteria are useful in the effluent treatment of tannery or related industries and in metal recovery in mining processes.
... Leather is one kind of natural and durable material that is widely used in the manufacture of daily necessities such as footwear, clothing, upholsteries, gloves and car seat cushions . The leather industry is an important global manufacturing sector that exceeds US$ 80 billion annually (Sivaram & Barik, 2019). However, at present, the leather industry is facing a worldwide concerned survival challenge because of the chrome (Cr) pollution caused by the widespread use of chromic salts in tanning (Guan et al., 2022;Moktadir & Rahman, 2022), and the long-term toxicity of residual formaldehyde (FA) in leather resulting from the massive use of amino resin (AR) in retanning. ...
Article
Dialdehyde sodium alginate (DSA) is an eco-crosslinker attracting extensive interest while undergoing limited large-scale applications. Herein, we employed DSA to react with dicyandiamide (DA) for engineering a biomass-derived retanning agent (BDR) towards addressing the long-term toxicity of residual formaldehyde (FA) in leather caused by amino resins. Results confirmed that BDR reserved the structural features of DSA by grafting DA onto DSA molecules. Owing to the suitable molecular weight (main components, 1424–1462 g/mol) and abundant oxygen-containing groups of BDR endowed by DSA, BDR-treated chrome-free leather showed higher hydrothermal stability (82.4 °C), thickening ratio (13.93 %), mechanical strengths (17.2 N/mm2 for tensile strength and 120 N/mm for tear strength), and fullness compared with industrial dicyandiamide-FA-resin (DFR)-treated leather. The FA-free feature of DSA led to BDR-treated leather containing no FA, while FA in DFR-treated leather reached 591.5 mg/kg. This work provided new insights into broadening the large-scale application scopes of DSA.
... Because of its minimal sludge production and low energy and space requirements, the UASB technique has become well-known for treating wastewater. However, the most significant benefit of this technology is that it can generate energy rather than consume it while treating wastewater [51]. ...
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During the last three decades, environmental challenges related to the chemical and biological pollution of water have become significant as a subject of major concern for society, public agencies, and the industrial sector. Most home and industrial operations generate wastewater that contains harmful and undesirable pollutants. In this context, it is necessary to make continuous efforts to protect water supplies to ensure the availability of potable water. To eliminate insoluble particles and soluble pollutants from wastewaters, treatment technologies can be employed including physical, chemical, biological (bioremediation and anaerobic digestion), and membrane technologies. This chapter focuses on current and emerging technologies that demonstrate outstanding efficacy in removing contaminants from wastewater. The challenges of strengthening treatment procedures for effective wastewater treatment are identified, and future perspectives are presented.
... Heterocomplex iron (Fe) salts are used instead of basic chromium sulfate (BCS) to achieve sufficient waterproofing effect and strengthen the loose fibers through higher exhaustion of tannage within a short tanning span [7]. Furthermore, organometallic salts of different heavy metals such as chromium (Cr) cadmium (Cd), copper (Cu), lead (Pb), etc. are extensively used as coloring agents and mordant during leather dyeing and in other post-tanning and finishing operations to make the leather suitable for making various leather products such as bags, shoes, wallets, upholstery furniture, etc. [8,9]. As a result, a substantial amount of different heavy metals like Cr, Cd, Cu, Ni, Pb, Ba, As, Fe, etc. are discharged with tannery wastewaters [10]. ...
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Accumulation of metals (Cr, Zn, Ni, Cd, and Cu) in leafy vegetables cultivated on tannery effluent contaminated soil and agricultural land soil were determined with an Atomic Absorption Spectrophotometer (AAS). The values of risk factors for the human population were studied, where metals were transferred from tannery effluent to plants via effluent contaminated soil and finally, transmitted to human body through the consumption of these metal accumulated leafy vegetables. Leafy vegetables, namely Stem amaranths (Amaranthus lividus), Spinach (Spinacia oleracea), Red amaranths (Amaranthus gangeticus), Jute mallows (Corchorus capsularis), Water spinach (Ipomoea aquatica), and Malabar spinach (Basella alba) were cultivated on the soils collected from downstream of Hazaribagh tannery area and Keraniganj agricultural land. The study revealed that the metal contents in contaminated soil exceeded the permissible limits recommended by WHO/DoE. Tannery effluent contaminated soil was found more polluted than the agricultural land soil. Metal contents in leafy vegetables cultivated on contaminated soil were higher than that of agricultural soil and exceeded the permissible limit, particularly in the case of Cr (125.50-168.99 mg/kg Dw) and Cd (0.19-0.83 mg/kg Dw). Metal content order was found as Cr>Zn>Ni>Cu>Cd for contaminated soil and Zn>Cr>Cu>Ni>Cd for agricultural land soil. The metal accumulation and translocation were found in vegetables in the order of Spinach>Water spinach>Malabar spi-nach>Jute mallows>Red amaranths>Stem amaranths. The analyses also revealed that the metal translocation rate in the plants of contaminated soil was higher than that of non-contaminated agricultural soil. The values of each risk index exceeded 1 in case of vegetables cultivated in contaminated soil. Therefore, the possible threat of chronic and carcinogenic diseases emerged if those polluted vegetables would be consuming as daily diet.
... "Chrome" is one of the major pollutants in tannery waste used in the post tanning process. (Sivaram and Barik, 2019;Doble and Kumar, 2005;China et al., 2020;Yin et al., 2016) Leather industries produce approximately 40 million Chromium (Cr) containing waste throughout the world every year (Asfaw et al., 2017). High Cr concentrations with a range of 1-50 g/kg were reported in tannery surrounding soils of waste disposal sites in India, with hexavalent Cr was present in groundwater at these sites (Saranraj and Sujitha, 2013). ...
Article
Full-text available
Industrial wastes, for instance, tannery wastes are rich soups of resistant and bioremediation-potent bacteria. In the present work, Chromium (Cr) and tannic acid (TA) resistance bacterial strains were isolated from tannery effluent and identified as Bacillus subtilis (MCC 3275) and Bacillus safensis (MCC 3283) based on its 16S Ribosomal RNA homology. Hexavalent Cr is highly toxic and mutagenic due to its high mobility and reactivity. Whereas, TA is known to inhibit enzyme activity, substrate deprivation, and interaction with membranes and matrix-metal ions. The developed In vitro co-cultured microcosm of B. subtilis and B. safensis was able to remove Cr(VI) up to 95% and TA up to 23%. The bacteria cultures separately were able to degrade Cr(VI) to 88% by B. subtilis and 91% by B. safensis and TA up to 27%. Plackett Burman design (PBD) followed by Response surface methodology (RSM) was applied for the optimization of physio-chemical parameters. The optimized conditions for co-culture development were recorded as K2HPO4 = 0.2 g/L, MgSO4 = 0.2 g/L, NH4Cl = 0.5 g/L, glucose - 0.2 g/L, TA - 5%, Cr = 200 ppm, incubation period of 96 h, agitation speed of 110 rpm, pH = 5.0, temperature= 30 °C and inoculum size = 3%. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) revealed the thorough mechanism of cellular uptake followed by degradation of Cr(VI) and TA. The efficiency of co-culture for other heavy metals was observed as follows: Zn 65%, Pb 63%, Cd 65%, and Ni 65%. Bioremediation using bacteria is an economical and environmentally better alternative to conventional remediation methods. The isolated bacteria are useful in the effluent treatment of tannery or related industries and in metal recovery in mining processes.
... More than 100 tons of organic dyes are produced annually [125,126]. This demand is due to the need for colorants for a broad number of industries, including textile [127], leather [128], food [129], and solar cells [130], with a significant part being wasted in the dyeing process [131]. Organic dyes are, in general, nonbiodegradable, toxic, and carcinogenic contaminants present in water, leading to a significant impact on biotic systems and ecosystems [132,133]. ...
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Chemical pollution of water has raised great concerns among citizens, lawmakers, and nearly all manufacturing industries. As the legislation addressing liquid effluents becomes more stringent, water companies are increasingly scrutinized for their environmental performance. In this context, emergent contaminants represent a major challenge, and the remediation of water bodies and wastewater demands alternative sorbent materials. One of the most promising adsorbing materials for micropolluted water environments involves cyclodextrin (CD) polymers and cyclodextrin-containing polysaccharides. Although cyclodextrins are water-soluble and, thus, unusable as adsorbents in aqueous media, they can be feasibly polymerized by using different crosslinkers such as epichlorohydrin, polycarboxylic acids, and glutaraldehyde. Likewise, with those coupling agents or after substituting hydroxyl groups with more reactive moieties, cyclodextrin units can be covalently attached to a pre-existing polysaccharide. In this direction, the functionalization of chitosan, cellulose, carboxymethyl cellulose, and other carbohydrate polymers with CDs is vastly found in the literature. For the system containing CDs to be used for remediation purposes, there are benefits from a synergy that arises from (i) the ability of CD units to interact selectively with a broad spectrum of molecules, forming inclusion complexes and higher-order supramolecular assemblies, (ii) the functional groups of the crosslinker comonomers, (iii) the three-dimensional structure of the crosslinked network, and/or (iv) the intrinsic characteristics of the polysaccharide backbone. In view of the most recent contributions regarding CD-based copolymers and CD-containing polysaccharides, this review discusses their performance as adsorbents in micropolluted water environments, as well as their interaction patterns, addressing the influence of their structural and physicochemical properties and their functionalization.
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Water pollution is a severe and challenging issue threatening the sustainable development of human civilization. Besides other pollutants, waste fluid streams contain phenolic compounds. These have an adverse effect on the human health and marine ecosystem due to their toxic, mutagenic, and carcinogenic nature. Therefore, it is necessary to remove such phenolic pollutants from waste stream fluids prior to discharging to the environment. Different methods have been proposed to remove phenolic compounds from wastewater, including extraction using ionic liquids (ILs) and deep eutectic solvent (DES), a class of organic salts having melting point below 100 °C and tunable physicochemical properties. The purpose of this review is to present the progress in utilizing ILs and DES for phenolic compound extraction from waste fluid streams. The effects of IL structural characteristics, such as anion type, cation type, alkyl chain length, and functional groups will be discussed. In addition, the impact of key process parameters such as pH, phenol concentration, phase ratio, and temperature will be also described. More importantly, several ideas for addressing the limitations of the treatment process and improving its efficiency and industrial viability will be presented. These ideas may form the basis for future studies on developing more effective IL-based processes for treating wastewaters contaminated with phenolic pollutants, to address a growing worldwide environmental problem.
Article
BACKGROUND Membrane technology is an attractive alternative to conventional water/wastewater treatment technologies as it is sustainable and can be used as independent processes as well as be a part of integrated systems with other treatment technologies. Notwithstanding the abundant benefits that membrane‐based systems offer, their commercial application is overshadowed by the ubiquitous fouling. However, accurate prediction and identification of membrane fouling mechanism can help to open new doors in recognition of appropriate arrangements for developing more effective membrane synthesis methods and fundamental strategies to achieve better performance, especially in large‐scale production. RESULTS Herein, in this study, three fouling models, namely resistance‐in‐series (RIS), Hermia's and combined cake filtration‐pore blockage models were applied to precisely analyse fouling behavior in dead‐end microfiltration (MF) of collagen solution, as model foulant using pure high‐density polyethylene (HDPE) and modified HDPE membranes. RIS model was shown to be not representative of the real fouling mechanism in MF membrane units. Similarly, none of the classical models were able to accurately predict fouling in the entire MF process. However, the combined cake‐intermediate blockage model provided excellent fits for the membranes. CONCLUSION Obtained results also demonstrated that physical cleaning was not enough for organic fouling elimination in MF processes. Finally, computational results were validated with the experimental observation of collagen rejection and FESEM analyses as well. This article is protected by copyright. All rights reserved.
Article
Nowadays, the increasing pollution of natural water effluents with textile dyes is an emerging problem that has not received attention enough. This work presents a study on the preparation of two Ti/IrO2-SnO2-Sb2O5 electrodes so-called E1 and E2 with 0.01 and 0.09 wt.% of Sb dopant, respectively, by the Pechini method. The characteristics of these electrodes were analyzed by scanning electron microscopy-energy dispersive X-ray spectroscopy and X-ray diffraction. The E2 anode possessed a higher electroactivity and produced more largely hydroxyl radicals in electrochemical oxidation (EO). The action of this oxidant, along with active chlorine of textile dyes like Violet RL, Green A and Brown DR was assessed in 50 mM Na2SO4 and 10 mM NaCl at pH 3.0 by EO with the E2 anode. It was found that the discoloration of 80 mg L−1 of each individual solution was enhanced with increasing the current density from 25 to 50 mA cm−2, always obeying a pseudo-first-order kinetics. The process was faster in the sequence: Green A < Brown DR < Violet RL, and at 50 mA cm−2, a loss of color > 86% of color was lost was attained in only 6 min. A mixture with 80 mg L−1 of each dye was treated under analogous EO conditions, giving rise to 100% discoloration in 20 min and about 90% chemical oxygen demand removal in 60 min at 50 mA cm−2. Three carboxylic acids, maleic, oxalic and oxamic, were detected as final byproducts by ion-exclusion high-performance liquid chromatography. The results reported in this work demonstrate the large effectiveness of the synthesized Ti/IrO2-SnO2-Sb2O5 electrodes to remove textile azo dyes, with higher rate constants than usual anodes.
Chapter
Issues related to sustainability are an inevitable factor which always associated with leather products as the raw material is associated with animal slaughtering. At the same time, research agencies predicted that the footwear industry is expected to grow 371.8 billion USD in 2020 with a CAGR of 5.5%. Out of different raw materials used in the industry, leather products are occupying a significant market share as premium goods. The major pollution by the footwear and other leather products not only comes from the disposal but also from the manufacturing stages like machine usage, energy confirmations, chemicals, etc. It is estimated that approximately 50.2 m² of land and 25,000 L of water required to develop leather boots. On average, the production of single boot emits 30 lb of carbon-di-oxide to the environment. The existing leather alternative materials like polyurethane, synthetic textiles, and rubber will take roughly 50 years to decompose totally. Material selection is one of the important solutions for sustainability-related issues and to reduce the negative environmental impacts. Bacterial cellulose is one such material that attracted the footwear industry due to its special properties like unique structure, biodegradability, mechanical strength, and high crystallinity. The chapter discusses various research works performed on leather alternative materials and specifically details the potential nature of bacterial cellulose. The production method, factors influencing the production, material properties, and application scopes will be analyzed with specific concern on the leather and footwear industry. The chapter also details the advantages of bacterial cellulose over other alternative material in terms of wearer comfort, durability, disposability, biodegradability, and cost factors.
Article
The tanning industry generates a large amount of waste, which should be managed following the principles of the circular economy. It is estimated that leather processing produces 200 times more waste than total product output. This paper presents a review of the methods that offer recycling of materials or energy from tannery waste, including chemical, thermal and biological techniques. These processes can recover a number of secondary feedstocks such as chromium, nutrients, collagen hydrolysate, fat, biogas, and anaerobic digestate, which can be used in other industrial processes. The review also covers the current legislative status of waste and its impact on the environment. Smart and sustainable valorization technologies enable a high degree of recycling with no burden on the environment.
Article
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This study was aimed to investigate the chromium removal from the tannery wastewater through electrocoagulation. The zinc and copper plates were used as electrodes for the electrocoagulation process. The effectiveness of the electrocoagulation for chromium removal efficiency was examined investigating various parameters: applied voltage, time, and current density. In batch experiment, 500 mL chromium-containing wastewater was used for electrocoagulation. Chromium content in the raw wastewater and after treatment at optimized conditions was 340.1 and 6.9 mg/L, respectively. The efficiency of chromium removal and reduction of biochemical oxygen demand (BOD) was at 98.0 and 64.6%, accordingly. Although total dissolved solids (TDS) was slightly increased. The increment of current density enhances forming zinc hydroxide which causes the damage of electrodes. Electrocoagulation is an effective technique to remove chromium from the wastewater especially from the tannery wastewater.
Article
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Tannery wastewater is a significant cause of chromium (Cr) contamination in land and water. This study assessed Cr contamination caused by the discharge of tannery wastewater in the Dhaleshwari River and identified possible native plants for phytoremediation of Cr. Water, soil and sediments samples were collected from upstream and downstream of the wastewater discharge channel of Savar tannery industrial estate situated on the bank of the river. Samples of root, stem, leaf and fruit of four selected plants (i.e., Eichhornia crassipes, Xanthium strumarium L., Cynodon dactylon, Croton bonplandianum Baill.) were also collected from those sampling points. The total Cr in acid digested samples were determined by flame atomic absorption spectrometry. High concentrations of Cr were detected in the water, soil and sediment samples collected near the wastewater discharge channel. Of all the plant species, Xanthium strumarium L. exhibited high translocation factors (TF) and bioconcentration factors (BCF) for Cr. Based on the findings of this study Xanthium strumarium L. is preferable as a native species for phytoremediation of Cr.
Article
An increase in urbanization and industrialization has not only contributed to an improvement in the lifestyle of people, but it has also contributed to a surge in the generation of wastewater. To date, conventional physico-chemical and biological treatment methods are widely used for the treatment of wastewater. However, the efficient operation of these systems require substantial operation and maintenance costs, and the application of novel technologies for the treatment and disposal of sludge/residues. This review focuses on the application of different treatment options such as chemical, catalyst-based, thermochemical and biological processes for wastewater or sludge treatment and membrane-based technologies (i.e. pressure-driven and non-pressure driven) for the separation of the recovered products. As evident from the literature, a wide variety of treatment and resource recovery options are possible, both from wastewater and its residues; however, the lack of planning and selecting the most appropriate design (treatment train) to scale up from pilot to the field scale has limited its practical application. The economic feasibility of the selected technologies was critically analyzed and the future research prospects of resource recovery from wastewater have been outlined in this review.
Article
Tamil Nadu leather industry has a strong bearing on the overall leather production of the country. So much so, that fluctuations in Tamil Nadu largely affect the overall performance of the Indian leather industry. Although, the southern region is performing far much better than Northern and Eastern region, there are still some pressing issues which need to be explored, analyzed and solved on a priority basis. Ample research is conducted in analyzing the overall performance of Indian leather industry including the Tamil Nadu cluster, yet the challenges faced by the business especially the small ones have yet not received considerable attention. This paper aims to explore issues prevailing in Tamil Nadu leather industry and understanding their underlying causes. The data has been gathered by conducting indepth interviews with experts in leather industry and crystallized the interview transcript by performing content analysis. Five main themes have been identified including decline in demand for leather products, difficulty in cost reduction, sensitive industrial situation, changing customer orientation and inadequate government support. These themes are then further divided into subthemes which are then analyzed through Analytical Hierarchy Method. Findings reveal that difficulty in cost reduction is the most pressing issue for the industry especially the production and compliance costs. The model proposed by the study highlights the major areas of concern in Tamil Nadu leather industry which need to work out on priority basis. Issues have been assigned respective weights which will make easier for the industrialists, academicians, and government to focus on the critical ones.
Article
Two of the multiple limitations of phytoextraction efficiency (PE %) of TSW polluted soils are: (i) low growth of plant performance, (ii) poor bioavailability of excessive essential and heavy metals (ascribed as Category-I and II metals respectively) The current study reports biostimulant role of allochthonous Trichoderma harzianum (F1) and autochthonous Trichoderma pseudokoningii (F2) in growth of Tagetes patula L. and uptake of Category-I & II metals from TSW-soil (0, 5 & 10%). Significantly higher growth (27.5–47.8% dry wt. than Control) and highly significantly higher uptake of Category-I & II metals (72–80% Ca, 32–69% K, 72–76% Na & 73–86% Cd, 63–100% Cr, 72–77% Cu, 73–78% Fe, 43–77% Mg, 22–33% Ni, 70–73% Zn) was observed in T. patula applied with F1 + F2 treatment. The PE (%) parameters viz.specific extraction yield, tolerance and translocation index of Category-I & II metals were higher in plants cultivated on fungal inoculated TSW:soil. The Trichoderma spp. acted as strong biostimulants for enhancing plant growth and conc. of catalase (CAT, 44-52% than control), superoxide dismutase (SOD, 37–43%), soluble proteins (37-68%) and total chlorophyll (10–26%) in T. patula during metal phytoextraction of TSW:soil. Novelty statement Due to multiple socio-economic constraints for effective management of tannery solid waste (TSW), the heavy metal phytoextraction seems to be one of the promising approaches. However, due to complex composition of TSW, that is, with more than 37 components, high pH, multiple types and high conc. of metals; there lies huge challenge of enhancing phytoextraction efficiency (PE %). This can be done by enhancing growth of hyperaccumulator plants and increasing bioavailable fraction of metals. The current study suggests application of selected fungal biostimulants for increasing growth of T. patula while improving bioavailable fraction of the total metal contents of the TSW: soil.
Article
Leather post-tanning is responsible for producing effluents that are difficult to treat due to several recalcitrant pollutants. Dyes, tannins, and fatliquoring agents are mainly related to this characteristic. This study, as the state-of-the-art, attempts to systematically review treatment technologies applied in recent years to the post-tanning effluents. The Scopus database was used to identify articles related to post-tanning pollutants removal. Through the review, Advanced Oxidation Processes (AOPs) and adsorption proved to be good alternatives to increase the effluent biodegradability when applied before biological treatment. AOPs and adsorption were also efficient for the final polishing of the effluents, to reach the regulation standards for disposal, as well as enzymatic treatment. Furthermore, Membrane Separation Processes demonstrated good applicability when the reuse of the treated effluent is aimed.
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The scientific revolution in omics technologies has paved the way for emerging technologies in wastewater treatment. These approaches have been adopted to investigate the metabolic potential, diversity, and spatiotemporal dynamics of microorganisms in wastewater systems. The prokaryotic, eukaryotic diversity can be utilized in industrial wastewater systems for higher performance. Industrial wastewater contains high concentrations of organic and inorganic pollutants, exerting a huge pressure on the environment. The adverse effects on biodiversity, soil, natural water bodies, and groundwater emphasizes the urgent need for proper wastewater treatment techniques prior to its disposal to the environment. Wastewater treatment via omics technologies offers advantages namely enhanced nutrient removal, cost reduction, wide applicability, the possibility of biofuel/bioenergy production, etc. The availability of diverse microbial communities can be expected in biological wastewater treatment plants, and they possess different metabolic capabilities which could be harnessed in the wastewater treatment process. Microorganisms can play a key role in the performance optimization of wastewater treatment plants. Coupling microalgae and cyanobacteria, production of microbes-based nanomaterials, use of bacterial and algae symbiotic systems for wastewater treatment have been recognized as promising techniques in biological wastewater treatment. The chapter focusses on the important aspects of omics, applications, limitations, challenges, and futuristic approaches in omics technologies related to industrial wastewater treatment.KeywordsAlgaeCyanobacteriaMicrobesOmicsWastewater treatment
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Leather industry has been considered as one of the most highly polluting industries, because of the generation of solid, liquid, and gaseous wastes containing organic and inorganic matters. During leather processing, huge amounts of untanned and tanned solid wastes are discarded. Nearly 800 kg of solid wastes are generated while production of only 200 kg of finished leather. Generally, 90% of water used in leather manufacturing is generating as wastewaters rich in toxic and hazardous compounds. However, these wastes accumulates in nature and contributes to a global pollution over the years. For this reason, the tannery sector needs to implement new greener strategies and solutions to provide a cleaner, more sustainable and more competitive industry. This chapter discusses the possible solutions for utilizing and bioconverting leather industry wastes such as, the bioremediation of dye and chromium contaminated wastewaters, the enzymatic digestion of chrome shavings, and the bioconversion of organic wastes as fleshings and keratin rich wastes to renewable energy and biofuels.
Book
This book comprises a detailed overview on the role of photocatalysts for environmental remediation, hydrogen production and carbon dioxide reduction. Effective ways to enhance the photocatalytic activity of the material via doping, hybrid material, laser light and nanocomposites have been discussed in this book. The book also further elaborates the role of metal nanoparticles, rare earth doping, sensitizers, surface oxygen vacancy, interface engineering and band gap engineering for enhancing the photocatalytic activity. An approach to recover the photocatalytic material via immobilization is also presented. This book brings to light much of the recent research in the development of such semiconductor photocatalytic systems. The book will thus be of relevance to researchers in the field of: material science, environmental science & technology, photocatalytic applications, newer methods of energy generation & conversion and industrial applications.
Article
The ever-increasing consumption of antibiotics in both humans and animals has increased their load in municipal and pharmaceutical industry waste and may cause serious damage to the environment. Impact of antibiotics on the performance of commercially used anaerobic digesters in terms of bioenergy output, antibiotics’ removal and COD removal have been compared critically with a few studies indicating more than 90% removal of antibiotics. AnMBR performed the best in terms of antibiotic removal, COD removal and methane yield. Most of the antibiotics investigated have adverse effects on microbiome associated with different stages and methane generation pathways of AD which has been assessed using high throughput technologies like metatranscriptomics, metaproteomics and flow cytometry. Perspectives have been given for understanding the fate and elimination of antibiotics from AD. The challenge of optimization and process improvement needs to be addressed to increase efficiency of the anaerobic digesters.
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The tannery industry is characterized by the consumption of a large quantity of water, around 30–40 m3 for processing 1000 kg of hide or skin. This amount becomes wastewater, containing about 300 kg of different chemicals, mainly refractory organic compounds, with high chemical oxygen demand (COD), total dissolved salts (TDS), chromium, and evolution of toxic gases, such as ammonia and sulfides, etc. The remaining tanning chemicals are released as effluent having high resistance against biological degradation, becoming a serious environmental issue. Usually, end-of-pipe treatment is not sufficient to meet the concerns of environmental issues. In terms of cleaner production options, the redesigning of the existing effluent treatment procedures with alternate or additional treatment techniques, which “supports resource recovery with no added chemicals”, is expected to give a sustainable solution for the management of toxic effluent. The Zero Liquid Discharge (ZLD) system serves to ensure zero water emission, as well as treatment facilities by recycling, recovery, and reuse of the treated wastewater using advanced cleanup technology. The international scenario shows the implementation of ZLD thanks to pressure from regulatory agencies. The ZLD system consists of a pre-treatment system with conventional physicochemical treatment, tertiary treatment, softening of the treated effluent, reverse osmosis (RO) treatment for desalination, and thermal evaporation of the saline reject from RO to separate the salts. By adopting this system, water consumption is reduced. Moreover, ZLD also becomes effective in disaster mitigation in areas where the tannery industry is a strong economic actor. With this review, we aim to give an outlook of the current framework.
Chapter
The tanning industry includes the process of animal skins and hides to make leather. The tannery process generates a lot of wastewater in almost every step, different processes have different wastewater characteristics. Although many health hazards exist at tanneries, such as acute and chronicmusculoskeletal injury, falls, and skinwounds from trauma, chemical hazards are of great importance. There are several norms decided by regularity authorities for discharge effluents in streams. Traditional wastewater treatment approaches are already available for treating tannery wastewater. But they are not fully successful for the treatment of tannery wastewater, so advanced and integrated processes are now in trend. This chapter provides an insight into the tannery industry and treatment approaches for the wastewater generated from the tannery industry.
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Tannery wastewater is considered one of the most contaminated and problematic wastes since it consists of considerable amounts of organic and inorganic compounds. These contaminants result in high chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS). In this work, the heterogeneous photodegradation of recalcitrant COD in wastewater from the tanning industry was investigated, in particular the recalcitrant COD due to the presence of vegetable tannins extracted from mimosa and chestnut and from synthetic tannins based on 4,4′ dihydroxy phenyl sulfone. TiO2 Aeroxide P-25 was employed to study the photodegradation of model molecules in batch conditions under different parameters, namely initial concentration of COD, temperature, and catalyst dose. The maximum COD abatement reached was 60%. Additionally, preliminary kinetic investigation was conducted to derive the main kinetic parameters that can be useful for process scale-up. It was found to be independent of the temperature value but linearly dependent on both catalyst loading and the initial COD value.
Article
Chromium contamination from tannery waste sludge (TWS) is a significant environmental concern. Vermicomposting is useful for conversion of toxic TWS into sanitized nutrient-enriched product for agricultural application. However, interactions among microbes and heavy metals are yet to be studied in Eisenia fetida incubated TWS-based vermireactors. The prime research hypotheses/objectives were to identify the most favorable feedstock combination for efficient vermiremediation; to generate novel information about the microbe-metal interaction during vermicomposting; and justify the functionality E. fetida by studying the TWS-induced shift in microbial community structure, nutrient dynamics, and metal removal. Earthworm population increased by 2.58–2.67 folds in TWS vermibeds. Water soluble and exchangeable fractions of potentially toxic metals (Cr, Pb, Ni, and Cu) considerably reduced by 48–69%. The alkalinity in TWS-dominated feedstocks [TWS + CD (3:1 and 2:1)] was also significantly neutralized with substantial reduction in organic C and increase in NPK availability. Microbial biomass C and different enzyme activities (fluorescein diacetate hydrolysis, urease, phosphatase, sulphatase, and glucosidase) substantially increased in the TWS-vermibeds. Interestingly, PLFA and species diversity analyses revealed that microbial community structure and fatty acid profiles greatly alter depending on the TWS proportion in the feedstocks and the metal-induced stress on microbial communities was substantially low in TWS + CD (1:1) feedstock. The correlation statistics explained that microbial activity and growth have strongly suppressed heavy metal bioavailability in TWS-vermibeds. Overall, the results indicate that TWS + CD (2:1 and 1:1) mixtures were favorable substrates for Eisenia fetida and microbial proliferation. The study revealed new information on microbial influence on metal remediation during vermicomposting and the results suggests that E. fetida could be utilized as a potential candidate for vermiremediation of toxic TWS.
Article
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Liming and unhairing is the conventional operation in the tannery where raw animal skins are treated with sodium sulphide and calcium hydroxide to remove keratin proteins e.g., hair and wool epidermis and to dissolve nonstructural proteins. The hair dissolving liming process discharges wastewater containing soluble sulphide. In acidification, the sulphide in wastewater generates toxic hydrogen sulphide, which has a negative impact on the environment. In this present study, the efficiency of hydrogen peroxide (H2O2) and sodium chlorite (NaClO2) oxidizers are compared to remove sulphide from the hair dissolving liming wastewater. The soluble sulphide in the raw liming wastewater was 3666 mg/L. At optimized dose and pH for H2O2 and NaClO2 soluble sulphide in the solution were 109.2 and 54.6 mg/L, respectively. The sulphide removal efficiency for H2O2and NaClO2 were 97.0% and 98.5%, respectively at an optimum pH (pH 7). Before and after treatment the physicochemical parameters of the liming wastewater were analysed by observing different water quality parameters viz: pH, TDS, EC and salinity. At optimized condition TDS and salinity removal efficiency was 47.2%, 52.3% and 8.1%, 11.2% for H2O2 and NaClO2, respectively. This simple and easy method would be effective for treating hair dissolving liming wastewater in reducing soluble sulphide discharge from the tanneries. Journal of Engineering Science 12(3), 2021, 67-72
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Post-tanning wastewater is very diversified, as the post-tanning stage should meet the desirable properties of the leather for the final product, with low standardization of the process (compared to beamhouse and tanning). This makes post-tanning effluent reuse less feasible, and reuse in the post-tanning stage still needs to be explored. This work aims to evaluate the reuse of liquid effluents in the post-tanning process. The work methodology consisted of (i) characterization of water streams (groundwater, liquid effluent after primary treatment, and liquid effluent after secondary treatment); (ii) pilot-scale post-tanning tests using groundwater, primary effluent, and secondary effluent; (iii) characterization of the residual baths from pilot-scale tests (pH, conductivity, total solids, chemical oxygen demand, biochemical oxygen demand, chloride, hardness and oil and grease); and (iv) testing the leather obtained for total sulfated ash and organoleptic properties. Results showed that the primary effluent and the secondary effluent could be reused in pilot-scale post-tanning tests. There was an increase in the conductivity of the residual baths when liquid effluents were reused, which confirms the accumulation of salts in the effluents after their reuse. HIGHLIGHTS Treated liquid effluents could be reused in the post-tanning process.; Post-tanning water reuse can reduce the volume of water consumed and effluent generated by tanneries.; Leather produced with reuse water achieved the desired organoleptic characteristics.; Leather sulfated ash increased with water reuse, remaining within the technical limit.;
Article
The major problems encountered in conventional biological treatment are the microbial cultures were insensitive to degrade the refractory organics in wastewater. The biological treatment system must contain robust microbial consortia to adapt the environment and to treat the refractory organics in wastewater. In the present investigation, the efficient microbial consortium was isolated and immobilized onto carbon-silica matrix (CSM) at the density of 3.31 ± 0.2 × 10⁷ cells gm⁻¹ of CSM and the same was used in the fluidized reactor to remove the refractory organics in wastewater. The bacterial cell immobilized fluidized reactor (CIFR) exhibited the performance that CODtot and CODdis were removed by 43 ± 2.8% and 42 ± 3.3% respectively in 24 h under batch mode of operation. The mineralization of refractory organics from wastewater under batch study was confirmed using UV–Visible and FT-IR spectroscopic studies. The CODtot and CODdis were removed by 43 ± 8.4% and 50 ± 8.4% respectively with remaining of CODtot, 625 ± 86 mg/L and CODdis, 502 ± 91 mg/L in the treated post tanning wastewater under continuous mode of operation using CIFR with the organic loading rate of 1.0 ± 0.1 kg COD/m³/d. The phylum Proteobacteria showed the relative abundance by 53.53% in the total bacterial community and played the major role in the degradation of refractory organics in wastewater.
Article
Chrome buffing dust and chrome-containing leather waste (CCLW) are produced from leather industries. In this study, extraction of chromium has been carried out from CCLW. Extracted collagen powder and alumina particles were ball-milled for 100 h. The average density of alumina content and ball-milled collagen was reduced from 3.725 g/cm 3 to 3.68 g/cm 3. The mixture of collagen and alumina content was obtained in a single entity after ball-milling. Agglomeration of collagen powder was found when the mixture of alumina contents and without ball-milled collagen powder was encapsulated in the aluminum (Al) alloy. The microstructure of the ball-milled-reinforced composite had uniform dispersal of the reinforcements. After heat treatment, the grain structure of the alu-minum/collagen/alumina composite material was refined. X-ray diffraction of ball-milled collagen powder and alu-mina-reinforced composite after heat treatment showed the presence of aluminum, alumina, chromium and chromic oxide phases. Comparative mechanical behavior study of aluminum/collagen powder, aluminum/alumina, Al/colla-gen powder/alumina with and without ball-milled and aluminum/collagen powder/alumina after heat treatment was performed to investigate the collagen and alumina addition effect in aluminum alloy.
Chapter
In the world of increasing industrialization and global population, environmental pollution has continued to rise over last few decade. Photocatalysis came forward as capable method in removal of various recalcitrant pollutants from atmosphere. The nano-photocatalytic semiconductors are majorly used in the form of slurry, and removal of these nano-photocatalytic materials turns out to be quite challenging and costly. Therefore, to resolve the problem of recollection of material, voluminous strategies have been executed for immobilising nano-photocatalyst on various substrates including carbon-based compounds, glass, zeolites, polymers, clay and ceramics and various natural fibres. The strategies including sol-gel, dip coating, polymer-assisted hydrothermal discharge, photo-etching, electrophoretic deposition, cold plasma discharge (CPD), RF magnetron sputtering and spray pyrolysis are discussed in this chapter. At last, characterization techniques used for studying various properties of immobilized catalyst are discussed in brief.
Chapter
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Hydrogen has an enormous potential to become the ideal and promising energy source as it is a green, renewable and high energy density resource. It is efficiently storable and highly abundant in nature. Different approaches have been used to produce hydrogen; however, clean hydrogen production is not always green; i.e. only a few of these methods are environment-friendly. The photo-electrochemical water splitting for hydrogen production got great attention to reduce dependency on a non-renewable resource with waste minimization for clean hydrogen generation. This chapter gives a comprehensive view of different production methods and electrode materials for photocatalytic water splitting towards hydrogen production. The covered topics include different metal oxides (MOs), metal chalcogenides (MSs) and different shapes of nanocomposites, which are used for photoelectrocatalytic hydrogen production. Also, the advantages and disadvantages of the selected materials and methods for hydrogen evolution from water splitting are discussed along with their challenges and prospects.
Chapter
This chapter reviews recent advancements in the photocatalytic process, along with other similar green technologies such as nanotechnology, nonthermal plasma treatment, ozone-based technologies, etc., with specific emphasis on reducing the environmental impacts of leather production and processing. Leather industries are among the most polluting industries worldwide, and to address the challenges leather industries are facing with respect to environmental pollution much scientific work has been carried out. Photocatalytical processes have been explored for treatment of wastewater from tanneries and leather dyeing and finishing. Green photocatalytic processes exhibit great potential for chromium removal from tanneries’ wastewater, and degradation of dyes and other hazardous chemical compounds usually found in wastewater from leather industries. Nanomaterials and nanomaterial-based photocatalytic processes also provide leather and leather products with diverse types of surface functionalization and antimicrobial finish which is environmentally affable compared to conventional technology. Other similar technologies are nonthermal plasma and ozone technology which is principally based on nonthermal plasma. Nonthermal plasmas-ionized gases at low temperature have a potential for surface modification of leather which can render applications such as sterilization, improved uptake of dyes, chemicals, and natural products, varieties of finish including antimicrobial finish, etc. Being a dry technology the nonthermal plasma processing can significantly reduce environmental impacts compared to wet chemical processing. The ozone-based technologies are also similar in modes of action with that of the photocatalytic process. The ozone-based technologies are explored by contemporary researchers and are reported to have potential applications such as cleaner dehairing, cleaner preservation, treatment of tanneries’ wastewater, hazardous chemicals used in leather manufacturing, dye degradation, etc. The holistic overview provided in this chapter would be certainly useful to researchers working in these areas.
Article
Policymakers and officials worldwide are making more stringent environmental norms and waste disposal policies to encourage industries to move towards cleaner production. One of the main challenges that industries face moving towards cleaner production is the adoption of different strategies for optimising their resource utilisation and waste reduction economically. This is particularly challenging for large-scale industries or a group of industrial plants located in an industrial region. This paper presents a novel approach to economic resource optimisation focussed mainly on large-scale industries, different industrial plants located in the vicinity of each other, or an industrial symbiosis network. In this work, a clustering algorithm is developed to segregate the given plants into different clusters based on the concept of load deficits and surpluses of each plant. The concept ideally allows only the plants with surpluses to send out their unused sources and plants with deficits to only receive external sources/resources. The clusters are formed based on the distances between plants, which in turn helps in saving transportation and communication costs. The clustered plants are then easy to optimise and manage for resource and cost optimality. The applicability of the proposed clustering algorithm is demonstrated using two case studies from the domain of water recycling networks containing multiple contaminants with detailed network design, highlighting the importance of clustering in an industrial symbiosis network. It is observed that directing the excess flows from one plant to other plants in the same cluster can save a considerable amount of fresh resources. It implies that in the broader aspect, the developed methodology can address the optimisation of economic resources and can aid in the better management of overall resources for a large-scale industrial symbiosis network.
Article
The heavy metal toxicity has the connection with the numerous deadly diseases in human body that includes but is not limited to the diseases related to DNA damage, cancer, hemolysis, gastrointestinal hemorrhage, and pulmonary edema. The metals, Cr, Cu, Ni, Cd and Pb, widely used in the Tannery industries have the potential to show similar toxicity. Therefore, we studied the environmental pollution caused by a recently relocated Hemayetpur Tannery Estate, Dhaka, Bangladesh. A comparative study has been carried out between Tannery Estate soil and nearby non-industrial agricultural area soil. To accomplish this study, laboratory based analytical tools to statistical analysis were used for the assessment of extent of pollution and its health risks indices. The results revealed that the Tannery Estate soil and vegetables contain of a very high concentration of heavy metals (20.15, 19.67, 12.93, 10573.02 and 4.02 mg/kg in soil; 18.13, 12.17, 7.63, 201.63 and 1.60 for B. alba; 15.67, 9.87, 8.03, 16.00 and 1.20 for A. gangeticus of Ni, Pb, Cu, Cr and Cd, respectively) compared to the samples collected from non-industrial agricultural area. The order of all the studied metals posing cancer risk is Cr > Pb > Ni > Cd and non-cancer risks is Pb > Cd > Ni > Cu > Cr which were supported by the statistical analysis (ANOVA, PEARSON Correlation and Principal Component Analysis). The tanning agents and inefficient treatment of the effluent could play the crucial role to contaminate the soil-vegetable system in the Tannery Estate areas. Therefore, this study indicates that the metals pollution in soils can be minimized by translocating the studied metals in non-edible plants (as of Plant Transfer Factors) followed by effective and careful monitoring of the disposal of solid and liquid wastes during the processing of leather and leather products after appropriate treatments.
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Catalytic complexes of photosensitizer Radachlorin® (sodium salts of chlorin e6, chlorin p6, purpurin 5) with polyvinylpyrrolidone (PVP) and detonation nanodiamonds (DND) have been synthesized and studied by optical absorption spectroscopy, luminescence excitation, dynamic light scattering and viscometry methods. Binary complexes PVP-Radachlorin® demonstrated electrostatic and donor–acceptor binding of Radachlorin® with PVP detected by spectrophotometric titration when Q-band (~650 nm) displayed bathochromic shift and enhancement with isosbestic point indicating a single type of binding sites. Similar changes in luminescence emission spectra in binary complexes were observed earlier at higher polymer contents. The yield of singlet oxygen under UV-irradiation (405 nm) of Radachlorin® increased in PVP-Radachlorin® complex. Dynamic light scattering and viscometry confirmed the stability of complexes and no agglomeration. Ternary complexes DND-PVP-Radachlorin® provided a generation of singlet oxygen by UV-irradiation exciting diamonds which do not emit but transfer the energy to surrounding molecules. The results allow develop effective catalysts for chemical and medical applications as well as for disinfection, active filtration and cleaning air, water, surfaces. Novel catalytic complexes based on chemically inert diamonds are resistant to the singlet oxygen and profitable for long-term usage.
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Recent advances have been recorded in the tanning industry with biotechnology in principle playing a very important role through related applied research. This review paper demonstrates that a previously tagged tanning sector as the most hazardous can be resolved through adoption of cleaner technologies, waste management and remedial measures that can be put in place. Pollution is depicted stepwise along the leather processing phases with a selected xenobiotic and contaminants identified such as Sodium chloride, Chromium, Sulphates, Chlorinated phenolics etc. As an interventionist strategy, biological tools using novel techniques of investigation are shown including the aquatic ecosystems. Remedial methods using known threshold in an identified tannery in Kenya is used to comprehend how to scale down the pollutants eventually. However it is recognised that though phytoremediation potential exist, it will require a combination of several other recently developed methods to provide a much firmer basis of controlling pollution loads related to the tanning Industry.
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The leather tanning industry is perceived as responsible of a significant consume of natural resources and output of wastes such as high concentration of organics, salts and heavy metals such as chromium, both in solid and liquid form as a result. Now as ever the future of tanneries strongly depends on the increase of their awareness that a sustainable industry for the future means embracing a forward-looking philosophy of the leather making process through optimal resource management within the tannery. This study reports the characterization of some chemicals used in a large tanning district area in terms of COD, BOD, aromaticity (UV280) and double bond (UV254) absorbance measurements, toxicity on fresh and saline water as well as terrestrial species, GC-MS scanning. The study provides a consistent set of information on tannin-associated concentration-related trends and suggests novel criteria in defining control quality for evaluating environmental impact of leather tanning industry.
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The environmental impact of the tanning industry is generally significant with outputs of wastes, i.e. high concentrations of organics, salts and heavy metals (chromium compounds), both in solid and liquid form, as a result. In order to bring the tanning industry more in line with present environmental thinking, various methods have been devised to reduce impacts.The underlying study proposes a modification of the method for unhairing–liming of hides where the unhairing–liming liquids are reused several times after being recharged by reduced quantities of chemicals. The study, therefore, aims at reducing both the economic and environmental costs of the unhairing–liming process.Experiments were carried out at lab scale with a simulation apparatus designed for the purpose. Life cycle assessment was used to evaluate the net environmental benefits of the modified method. The present value approach was used to evaluate the economic feasibility of the modified method. The quality of the produced leather was assessed by experts from the tanning sector (tanners).On the environmental level, the modified method reduced the environmental impact of the process by 24%, COD was reduced by 50% as well as sulfide which was reduced by 73% when the process water was recycled four times.The modified method requires some investment in new equipment and is a little more labor intensive as compared with the conventional method but does permit for savings in water up to 58% and chemicals up to 28% as well as wastewater treatment cost which was reduced by 58%. The modified method allowed for four times reuse of the unhairing–liming liquor without visibly affecting the quality of the final product of leather.It was concluded that both the economic and the environmental costs of the unhairing–liming process were reduced relative to the same of the conventional method.
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Lead is a ubiquitous toxicant that causes tremor and cerebellar damage. Essential tremor (ET) is a highly prevalent neurologic disease associated with cerebellar involvement. Although environmental toxicants may play a role in ET etiology and their identification is a critical step in disease prevention, these toxicants have received little attention. Our objective was to test the hypothesis that ET is associated with lead exposure. Therefore, blood lead (BPb) concentrations were measured and a lifetime occupational history was assessed in ET patients and in controls. We frequency matched 100 ET patients and 143 controls on age, sex, and ethnicity. BPb concentrations were analyzed using graphite furnace atomic absorption spectrophotometry. A lifetime occupational history was reviewed by an industrial hygienist. BPb concentrations were higher in ET patients than in controls (mean +/- SD, 3.3 +/- 2.4 and 2.6 +/- 1.6 microg/dL, respectively; median, 2.7 and 2.3 microg/dL; p = 0.038). In a logistic regression model, BPb concentration was associated with diagnosis [control vs. ET patient, odds ratio (OR) per unit increase = 1.21; 95% confidence interval (CI), 1.05-1.39; p = 0.007]. BPb concentration was associated with diagnosis (OR per unit increase = 1.19; 95% CI, 1.03-1.37; p = 0.02) after adjusting for potential confounders. Prevalence of lifetime occupational lead exposure was similar in ET patients and controls. We report an association between BPb concentration and ET. Determining whether this association is due to increased exposure to lead or a difference in lead kinetics in ET patients requires further investigation.
Article
This study examines the possibility of using pelletized leather tannery wastes (LTW) in the co-combustion process with hardwood pellets (HP). The experiments were carried out in a small-scale combustion reactor and were followed by thermogravimetric analysis (TGA) of fuels in the nitrogen and air atmosphere. The experimental investigation has indicated that the leather tannery wastes can be an interesting fuel with a relatively high heating value (HHV), at the level of 16 MJ/kg, and the volatile content of about 68%. Thermal decomposition of the leather tannery sample occurs at temperatures ranging between 220 and 420 °C, with the maximum of intensity at 320 °C. The experimental results indicated that the averaged maximum temperatures obtained during the combustion reached similar values for all samples, which indicates that doping wood pellets with leather waste pellets does not have a significant impact on the temperature characteristics of the combustion process. However, decreasing the amount of hardwood pellets in the mixture reduces the bulk density of the fuel bed and the combustion front velocity. The emission of nitrogen oxides for combusting blends is twice as high as for combustion of pure HP, which is related to higher nitrogen content in leather waste as well as higher ash content.
Article
A mixture of aquo complexes of chromium (III) is used for tanning. These complexes vary in their nature and reactivity to the protein. The present investigation deals with the understanding of the nature of the chromium(III) complexes present in spent chrome tanning solutions. An ion exchange chromatography technique has been employed for the isolation of the various complexes from fresh and spent tanning solutions. These studies indicated the presence of low affinity species to the extent of 45% of the total chromium in the spent solution. The low affinity chromium(III) complex was characterised by UV-visible spectroscopy, charge per atom, charge per species, degree of polymerisation and hydroxyl per chromium and has been established to be a cyclic tetrapositive tetrameric species with unusual reactivity.
Article
The idea of "sustainability" has become one of the major topics in industry and politics and probably represents one of the mega-trends of the early 21st Century. Due to outdated processes and methods applied in the leather industry, the waste products and the significant amounts of process water used oppose more and more legislation and the concept of sustainability. Examples are very well known, e.g. organic sludges with sulfides, chrome, salts, residues of surfactants like Nonylphenolethoxylates (NPE), poor biodegradable tannins and fats - the list is long and we are aware that these problems can only be tackled stepwise. Last year we reported about a more "sustainable" surfactant for the substitution of NPE's. Today we want to discuss a whole new concept, which especially addresses new legislation in Europe. It states that by the middle of 2005 chrome shavings and other organic wastes can no longer be dumped in landfill-sites.
Article
Severe restrictions imposed by the pollution control authorities on the disposal of chromium, total dissolved solids and chlorides in tannery effluents have forced the tanners to look for low-waste, high exhaust chrome tanning salts. An improved chrome syntan with more than 90% uptake of chrome has been developed. The new product serves both as tanning and retanning agent and can be applied directly to delimed pelts thus eliminating the conventional pickling stage in the leather processing. This modified process helps to reduce the chemical oxygen demand (COD), total dissolved solids (TDS) and chlorides in the spent tan liquor by 51, 81 and 99%, respectively. The product offers full, soft leathers having shrinkage temperature comparable to conventional chrome tanned skins. Since the developed product is highly reactive, it saves time and reduces the water requirement when compared to the conventional chrome tanning method. Thus the novel product/process developed not only has advantages in reducing pollution loads but also seems to be techno-economically viable.
Article
The occurrence of foam on a transboundary river close to the Austrian-Hungarian border was a constant strain to Austria's political relationship with Hungary. A one-year monitoring programme linked the instream foam mainly to the effluent of three Austrian tanning factories in the catchment of the river. As all tanneries are equipped with wastewater treatment technology in accordance with the best available technique, an amendment of the Austrian Edict on wastewater emissions for tanneries was necessary to implement foam-abatement measures. The changes in the Edict included the introduction of surface tension as an emission parameter for foam causing substances together with appropriate emission standards to reduce the resulting instream foam formation.
Article
An attempt has been made to develop a method for processing leathers in a narrow range of pH viz., 4.0-8.0. A process for dehairing at a pH of around 8.0 has been explored. This has been achieved by employing a commerical enzyme in combination with small quantities of sodium sulphide. A method for applying the dehairing formulation on the grain side was established. Hair removal was shown to be complete using scanning electron microscopy (SEM) and cystine content analysis. Potential grain damage by the enzyme formulation was avoided through process control measures and the effectiveness of such methods was established by investigation by scanning electron micrographs. Strength and bulk properties of the experimental leathers appear to show some improvement as compared to the leathers made using conventional processes. The process enjoys an environmental benefit by significantly reducing the COD load in the effluent. Improved chrome content in the grain surface of the butt region adds an additional benefit to the dehairing process developed.
Article
There is a growing demand for the formaldehyde-free leathers in global leather market due to increasing awareness towards eco-labelling. The first part of this work described the optimisation of formaldehyde-free syntans in their applications as single syntans in making leathers with desired properties. In this work the use of formaldehyde-free syntans in combination to produce leathers with desired properties has been attempted. Three combination-retanning systems have been chosen using formaldehyde-free resin, acrylic and protein syntans. The performance of leathers in terms of bulk and strength properties is shown to be comparable or even better for all the combination-retanning systems chosen compared to the control system. In particular, Experiment “C” (resin syntan 3%, acrylic syntan 4% and protein syntan 2%) provides leathers with improved bulk, strength and colour properties as well as reduced COD and TS loads, besides not having free formaldehyde. Scanning electron microscopic study reveals that the extent of filling in all the three combination-retanning systems is similar.
Article
The problem of water pollution acquires greater relevance in the context of a developing agrarian economy like Pakistan. Even though, the leather industry is a leading economic sector in Pakistan, there is an increasing environmental concern regarding tanneries because they produce large amounts of potentially toxic wastewater containing both trivalent and hexavalent chromium, which are equally hazardous for human population, aquaculture and agricultural activities in the area. Therefore, we defined the scope of the present study as to employ different bioassays to determine the eco-toxic potential of tannery effluent wastewater (TW) and its chromium based components, i.e., potassium dichromate (K2Cr2O7) and chromium sulfate Cr2(SO4)3. Particle-induced X-ray emission (PIXE) analysis of TW was carried out to determine the concentration of chromium in TW and then equal concentrations of hexavalent (K2Cr2O7) and trivalent chromium Cr2(SO4)3 were obtained for this study. Cytotoxicity assay, artemia bioassay and phytotoxicity assay was utilized to investigate the eco-toxicological potential of different concentrations of TW, K2Cr2O7 and Cr2(SO4)3. All the dilutions of TW, K2Cr2O7 and Cr2(SO4)3 presented concentration dependent cytotoxic effects in these assays. The data clearly represents that among all three tested materials, different dilutions of K2Cr2O7 caused significantly more damage (P < 0.001) to vero cell, brine shrimp and germination of maize seeds. Interestingly, the overall toxicity effects of TW treated groups were subsequent to K2Cr2O7 treated group. Based on biological evidences presented in this article, it is concluded that hexavalent chromium (K2Cr2O7) and TW has got significant eco-damaging potential clearly elaborating that environmental burden in district Kasur is numerous and high levels of chromium is posing a considerable risk to the human population, aquaculture and agricultural industry that can obliterate ecosystem surrounding the tanneries.
Article
In the present study, green and sustainable method or eco-friendly approaches to tanning process based on unnatural D-amino acids (D-AA)-aldehyde (Ald) as a substitute for chrome-free tanning has been attempted. The distribution of optically active D-AA in tanned leather, the hydrothermal stability, the mechanical properties and resistance to collagenolytic activity of tanned leather, the evaluation of eco-friendly characteristics were investigated. Scanning electron microscopic (SEM) and Atomic force microscopic (AFM) analyses indicate the surface morphology and roughness, respectively, of the tanned leather collagen matrix. Shrinkage and Differential scanning calorimetric (DSC) analyses shows that the shrinkage temperature (T(s)) and denaturation temperature (T(d)) of tanned leather are related to the content of D-AA+Ald present in the leather matrix. It has been found that the T(s) of D-AA tanned leather is more than that of Ald tanned leather and also more or less equal to chrome tanned leather. Environmental impact assessment (EIA) shows that the developed process results in significant reduction in total solids content (TSC) and improves better biodegradability of organic compound present in the effluent compared to chrome tanning.
Article
Biomethanation is a process by which organic material is microbiologically converted under anaerobic conditions to biogas. Three main physiological groups of microorganisms are involved: fermenting bacteria, organic acid oxidizing bacteria, and methanogenic archaea. Microorganisms degrade organic matter via cascades of biochemical conversions to methane and carbon dioxide. Syntrophic relationships between hydrogen producers (acetogens) and hydrogen scavengers (homoacetogens, hydrogenotrophic methanogens, etc.) are critical to the process. Determination of practical and theoretical methane potential is very important for design for optimal process design, configuration, and effective evaluation of economic feasibility. A wide variety of process applications for biomethanation of wastewaters, slurries, and solid waste have been developed. They utilize different reactor types (fully mixed, plug-flow, biofilm, UASB, etc.) and process conditions (retention times, loading rates, temperatures, etc.) in order to maximize the energy output from the waste and also to decrease retention time and enhance process stability. Biomethanation has strong potential for the production of energy from organic residues and wastes. It will help to reduce the use of fossil fuels and thus reduce CO(2) emission.
Article
Influence of ultrasound (US) on various unit operations in leather processing has been studied with the aim to improve the process efficiency, quality, reduce process time and achieve near-zero discharge levels in effluent streams as a cleaner option. Effect of US on substrate (skin/leather) matrix as well as substances used in different unit operations have been studied and found to be useful in the processing. Absorption of US energy by leather in process vessel at different distances from US source has been measured and found to be significant. Effect of particle-size of different substances due to sonication indicates positive influence on the diffusion through the matrix. Our experimental results suggest that US effect is better realized for the cases with pronounced diffusion hindrance. Influence of US on bioprocessing of leather has been studied and found beneficial. Attempts have also been made to improve the US aided processing using external aids. Operating US in pulse mode operation could be useful in order to reduce the electrical energy consumption. Use of US has also been studied in the preparation of leather auxiliaries involving mass-transfer resistance. Preliminary cost analysis carried out for ultrasound-assisted leather-dyeing process indicates scale-up possibility. Therefore, US application provide improvement in process efficiency as well as making cleaner production methods feasible. Hence, overall results suggest that use of US in leather industry is imminent and potential viable option in near future.
Article
The effects of Metanil yellow, Orange II and their blend on hepatic xenobiotic metabolizing enzymes were compared. Parenteral administration of Metanil yellow and Orange II to rats at a dose of 80 mg/kg body weight for 3 days caused a significant induction of ethoxyresorufin-O-deethylase (40-190%), aniline hydroxylase (27-92%), aryl hydrocarbon hydroxylase (50-62%) and aminopyrine N-demethylase (42-49%) activities. Metanil yellow and Orange II brought about a substantial increase in cytosolic quinone reductase (34-82%) and glutathione S-transferase (23-43%) activities and significant depletion of glutathione levels with a concomitant increase in lipid peroxide formation. A blend (1:1) of Metanil yellow and Orange II showed a synergistic or additive effect on these hepatic parameters, suggesting that the addition of these two prohibited dyes together in foodstuffs may give rise to more toxic effects than are produced by each dye individually.
Article
The interaction of three types of chromium(III) complexes, [Cr(salen) (H2O2]+, [Cr(en)3]3+, and [Cr(EDTA) (H2O)]- with AGP has been investigated. [Cr(salen) (H2O2]+, [Cr(en)3]3+ and [Cr(EDTA) (H2O]- bind to Human alpha1-acid glycoprotein with a protein:metal ratio of 1:8, 1:6, and 1:4, respectively. The binding constant, K(b) was estimated to be 1.37 +/- 0.12 x 10(5) M(-1), 1.089 +/- 0.05 x 10(5) M(-1) and 5.3 +/- 0.05 x 10(4) M(-1) for [Cr(salen) (H2O2]+, [Cr(en)3]3+, and [Cr(EDTA) (H2O)]-, respectively. [Cr(en)3]3+ has been found to induce structural transition of AGP from the native twisted beta sheet to a more compact alpha-helix. The complexes, [Cr(salen) (H2O2]+ and [Cr(EDTA) (H2O]-, in the presence of H2O2, have been found to bring about nonspecific cleavage of AGP, whereas [Cr(en)3]3+ does not bring about any protein damage. Treatment of [Cr(salen) (H2O)2]+-protein adduct with iodosyl benzene on the other hand led to site specific cleavage of the protein. These results clearly demonstrate that protein damage brought about by chromium(III) complexes depends on the nature of the coordinated ligand, nature of the metal complex, and the nature of the oxidant.
Article
This paper describes the derivation of aquatic life water quality criteria for formaldehyde, developed in accordance with United States Environmental Protection Agency's (USEPA's) Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses. The initial step in deriving water quality criteria was to conduct an extensive literature search to assemble available acute and chronic toxicity data for formaldehyde. The literature search identified a large amount of information on acute toxicity of formaldehyde to fish and aquatic invertebrates. These acute data were evaluated with respect to data quality, and poor quality or uncertain data were excluded from the data base. The resulting data base met the USEPA requirements for criteria derivation by having data for at least one species in at least eight different taxonomic families. One shortcoming of the literature-derived data base, however, was that few studies involved analytical confirmation of nominal formaldehyde concentrations and reported toxicity endpoints. Also, there were relatively few data on chronic toxicity. The acute toxicity data set consisted of data for 12 species of fish, 3 species of amphibians, and 11 species of invertebrates. These data were sufficient, according to USEPA guidelines, to calculate a final acute value (FAV) of 9.15 mg/l, and an acute aquatic life water quality criterion (one-half the FAV) of 4.58 mg/l. A final acute-chronic ratio (ACR) was calculated using available chronic toxicity data and USEPA-recommended conservative default assumptions to account for missing data. Using the FAV and the final ACR (5.69), the final chronic aquatic life water quality criterion was determined to be 1.61 mg/l.
Article
A 2-generation reproductive toxicity study of tributyltin chloride (TBTCl) was conducted in male rats using dietary concentrations of 5, 25, and 125 ppm TBTCl to evaluate its effect on sexual development and the reproductive system. F1 males were killed on postnatal day 119 and F2 males were killed on postnatal day 91. TBTCl affected the male reproductive system of rats. The weights of the testis and epididymis were decreased and homogenization-resistant spermatid and sperm count were reduced mainly in the 125 ppm TBTCl group. Histopathologic changes were also observed in the testis of this group and included vacuolization of the seminiferous epithelium, spermatid retention, and delayed spermiation. However, the changes were minimal in nature. The weight of the ventral prostate was decreased to 84% of the control value in the 125 ppm group in the F1 generation and decreased to 84 and 69% of the control value in the 25 ppm and 125 ppm TBTCl groups, respectively, in the F2 generation. The serum 17beta-estradiol concentration was also decreased to 55% of the control value in the 125 ppm group in the F1 generation and decreased to 78 and 57% of the control value in the 25 ppm and 125 ppm TBTCl groups, respectively, in the F2 generation. However, the serum concentrations of luteinizing hormone (LH) and testosterone were not decreased in these groups. These changes corresponded with those caused by aromatase inhibition and therefore TBTCl might be a weak aromatase inhibitor in male rats.
Article
The comparative toxicities of selected phenols to higher plants Cucumis sativus were measured and the negative logarithm molar concentration of the root elongation median inhibition (IRC50) were derived. Quantitative structure-activity relationships (QSARs) were developed to explore the toxicity influencing factors and for predictive purpose. The toxicity data, fell into two classes: polar narcosis and bio-reactive. For polar narcotic phenols, a highly significant two-parameter QSAR based on 1-octanol/water partition coefficient (logKow) and energy of the lowest unoccupied orbital (E(lumo)) was derived (IRC50 = 0.77 log Kow - 0.39E(lumo) + 2.36 n = 22 r2 = 0.89). The five bio-reactive chemicals proved to show elevated toxicity due to their typical substructure involved diverse reactive mechanisms. In an effort to model all chemicals, a robust multiple-variable QSAR combining logKow, E(lumo) and Qmax, the most negative net atomic charge, was developed (IRC50 = 0.65 logKow - 0.72E(lumo) + 0.23Qmax + 2.81 n = 27 r2 = 0.94), indicating that hydrophobicity, electrophilicity and hydrogen bond interaction contribute mainly to the phytotoxicity. The toxicological data was compared with Tetrahymena pyriformis 2-d population growth inhibition toxicity (IGC50) and excellent interspecies correlations were observed both for the polar narcotics and for five reactive chemicals (for polar narcotics: IRC50 = 0.95IGC50 + 1.07 n = 16 r2 = 0.89; for bio-reactive chemicals: IRC50 = 0.98IGC50 + 2.19 n = 5 r2 = 0.97; and for all: IRC50 = 0.93IGC50 + 1.63 n = 21 r2 = 0.87). This suggested that T pyriformis toxicity could serve as a surrogate of C. sativus toxicity for phenols and interspecies correlation also could be established for reactive chemicals.
Article
While attempting to find a suitable crosslinking reagent for biopolymers, a naturally occurring proanthocyanidin (PA) obtained from grape seeds was selected to fix biological tissues. The cytotoxicity and crosslinking rate, reflected by the in vitro and in vivo degradation of fixed matrices has been studied. The shrinkage temperature of the fixed bovine pericardium increased from 66 to 86 degrees C. A cytotoxicity assay using fibroblast cultures revealed that PA is approximately 120 times less toxic than glutaraldehyde (GA), a currently used tissue stabilizer. In vitro degradation studies showed that fixed tissue was resistant to digestion by bacterial collagenase. Crosslinks between PA and tissues can be stabilized by decreasing the dielectric constant of the solution during storage. After subcutaneous implantation for periods ranging between 3 and 6 weeks, we found no apparent degradation of the GA- or PA-fixed tissues, whereas fresh tissue controls rapidly disintegrated. Beyond 6 weeks PA crosslinks began to degrade. More fibroblasts migrated and proliferated inside the PA-fixed implants compared with GA counterparts. Tissues crosslinked with PA manifested an enhanced collagen expression and deposition and did not calcify after implantation. GA, on the other hand, even after thorough rinsing continued to be cytotoxic, inhibited collagen synthesis and encouraged dystrophic calcification. Collagen matrices crosslinked with PA are expected to be of value in the design of matrices that will encourage cell ingrowth and proliferation, which are temporary in nature, and that are intended to regenerate or replace missing tissues, which can delay the biogradation of collagen. As such they should be of significant value in the emerging field of tissue engineering.
Article
Leather processing generates huge amounts of both solid and liquid wastes. The management of solid wastes, especially tanned leather waste, is a challenging problem faced by tanners. Hence, studies on biodegradability of leather become imperative. In this present work, biodegradability of untanned, chrome tanned and vegetable tanned leather under anaerobic conditions has been addressed. Two different sources of anaerobes have been used for this purpose. The effect of detanning as a pretreatment method before subjecting the leather to biodegradation has also been studied. It has been found that vegetable tanned leather leads to more gas production than chrome tanned leather. Mixed anaerobic isolates when employed as an inoculum are able to degrade the soluble organics of vegetable tanned material and thus exhibit an increased level of gas production during the initial days, compared to the results of the treatments that received the anaerobic sludge. With chrome tanned materials, there was not much change in the volume of the gas produced from the two different sources. It has been found that detanning tends to improve the biodegradability of both types of leathers.
Article
Apoptosis is an active process induced by a variety of physiological and external stimuli, in which elimination of damaged cells are effected through a genetically controlled process. In this study, we have examined the mechanism of chromium(III) [Cr(III)]-induced cytotoxicity with respect to its relationship to oxidative stress. Morphology, flow cytometry, and DNA fragmentation studies show that tris-(1,10-phenanthroline)chromium(III) [Cr(III)-phen], tris-(2,2'-bipyridyl)chromium(III) [Cr(III)-bpy], trans-diaqua[1,2-bis(salicylideneamino)ethanechromium(III)] [Cr(III)-salen], and trans-diaqua[1,3-bis(salicylideneamino)propanechromium(III)] [Cr(III)-salprn] induced apoptosis of lymphocytes. Pentaammineaquachromium(III) [Cr(III)-hpa] does not induce apoptosis. Apoptosis induced by these complexes involves the generation of reactive oxygen species (ROS) as seen by increased fluorescence of dichloroflourescein (DCF) observed through flow cytometry. Pretreatment of lymphocytes with antioxidants completely abrogate apoptosis. Cr(III) treatment also increased the expression and activation of Src-family tyrosine kinases viz. p56lck, p59fyn, and p53/56lyn, as seen by immunoblotting and immune complex kinase assay. PP2, a selective Src-family tyrosine kinase inhibitor, abolishes apoptosis, indicating that Src-family tyrosine kinases are directly involved in eliciting apoptosis. Interestingly, a one-to-one correlation between the expression of Src-family tyrosine kinases and ROS is observed, since antioxidants pretreatment inhibits the expression and the activation of these kinases. These results further indicate that Cr(III)-induced apoptosis is mediated through production of ROS, which in turn activates the Src-family tyrosine kinases. The increased activation of Src-family tyrosine kinases may be a mechanism involved in apoptosis of lymphocytes elicited by various other physiological stimuli that exploit ROS as a second messenger.
Article
In this paper, the authors deal with the problem of processing various types of waste generated by leather industry, with special emphasis to chrome-tanned waste. The agent that makes this waste potentially hazardous is hexavalent chromium. Its compounds can have negative effects on human health and some CrVI salts are considered carcinogens. The authors present the risks of spontaneous oxidization of CrIII to CrVI in the open-air dumps as well as the possible risks of wearing bad quality shoes, in which the chromium content is not controlled. There are several ways of handling primary leather waste, but no satisfactory technology has been developed for the secondary waste (manipulation waste, e.g. leather scraps and used leather products). In this contribution, a new three-step hybrid technology of processing manipulation waste is presented and tested under laboratory, pilot-scale and industrial conditions. The filtrate can be used as a good quality NPK fertilizer. The solid product, titanium-chromium sludge, can serve as an inorganic pigment in glass and ceramic industry. Further, the authors propose selective collection of used leather products (e.g. old shoes), the hydrolysable parts of which can be also processed by the new hybrid technology.
Physical chemistry of leather making
  • K J Bienkiewicz
Bienkiewicz KJ. Physical chemistry of leather making. United States: Krieger Publishing Co; 1983.
Fundamentals of leather manufacture. United States: Roether
  • E Heidemann
Heidemann E. Fundamentals of leather manufacture. United States: Roether; 1993.
Centre Technique Du Cuir
  • M Aloy
  • A Folachier
  • B Vulliermet
Aloy M, Folachier A, Vulliermet B. Tannery and pollution. Lyon, France: Centre Technique Du Cuir; 1976.
Effect of sulphide, chromium and phosphate ions on methane production by an anaerobic sludge acclamatised of tannery beamhouse effluent. Proceedings of the 14th industrial waste Mid Atlantic conference
  • D G Bailey
  • M H Tunick
  • M A Kuzma
Bailey DG, Tunick MH, Kuzma MA. In: Effect of sulphide, chromium and phosphate ions on methane production by an anaerobic sludge acclamatised of tannery beamhouse effluent. Proceedings of the 14th industrial waste Mid Atlantic conference; 1982.
In: Environmental aspects of leather processing
  • T Ramasami
  • Bgs Prasad
Ramasami T, Prasad BGS. In: Environmental aspects of leather processing. Proceedings of the LEXPO-XV, Calcutta, India; 1991. p. 43.
Ecotoxicological diagnosis in the tanning industry
  • M Mwinyihija
Mwinyihija M. Ecotoxicological diagnosis in the tanning industry. New York: Springer; 2010.
Development document for effluent limitations guidelines & standards for the Leather Tanning & Finishing Point Source Category
  • Epa
EPA. Development document for effluent limitations guidelines & standards for the Leather Tanning & Finishing Point Source Category. EPA-440/1-82-016, Research Triangle Park, NC: U. S. Environmental Protection Agency; 1982.
  • R Streicher
Streicher R. Entkaelkung mit ammoniumsalzfreien Entkaelkungsmitteln. Leder u Häutemarkt 1987;39:7.
Midwest Research Institute, with F. Rutland. Environmental Consultant, Leather Industries of America
  • A M Telecon
Telecon, A. M. (1996). Midwest Research Institute, with F. Rutland. Environmental Consultant, Leather Industries of America.
Amending for the 26th Time Council Directive 76/769/EEC Relating to Restrictions on the Marketing & Use of Certain Dangerous Substances & Preparations (Nonyl Phenol
EU, 2003. Directive 2003/53/EC of the European Parliament & of the Council of 18 June 2003 Amending for the 26th Time Council Directive 76/769/EEC Relating to Restrictions on the Marketing & Use of Certain Dangerous Substances & Preparations (Nonyl Phenol, Nonyl Phenol Ethoxylate & Cement).
EPA-738-F-98e008. United States Environmental Protection Agency
EPA. Prevention, pesticides & toxic substances. EPA-738-F-98e008. United States Environmental Protection Agency; 1998.
Dietary Exposure Health Assessment Section, Medical Toxicology Branch, Department of Pesticide Regulation
  • Epa
  • Ortho
EPA. Ortho-phenylphenol (OPP) & sodium ortho-phenylphenate (SOPP) risk characterization document; 2007. Dietary Exposure Health Assessment Section, Medical Toxicology Branch, Department of Pesticide Regulation, California, Environmental Protection Agency.
Monographs on the evaluation of carcinogenic risks to humans
IARC. Monographs on the evaluation of carcinogenic risks to humans. Inorganic & organic lead compounds, vol. 87. France: International Agency for Research on Cancer; 2004, p. 10-7.
Compendium of sanitation systems and technologies. second revised ed. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (Eawag)
  • E Tilley
  • L Ulrich
  • C Lüthi
  • P Reymond
  • C Zurbrügg
Tilley E, Ulrich L, Lüthi C, Reymond P, Zurbrügg C. Compendium of sanitation systems and technologies. second revised ed. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (Eawag); 2014, ISBN: 978-3-906484-57-0.
The ArrowBio process for mixed municipal solid waste-Responses to "Requests for Information". 1st UK conference and exhibition on biodegradable and residual waste management
  • M S Finstein
  • Y Zadik
  • A T Marshall
  • D Brody
Finstein MS, Zadik Y, Marshall AT, Brody D. In: The ArrowBio process for mixed municipal solid waste-Responses to "Requests for Information". 1st UK conference and exhibition on biodegradable and residual waste management, February 18-19, 2004, Harrogate, UK. Leeds: CalRecovery Europe Ltd.; 2004. p. 407-13.
Agency for Toxic Substances & Disease Register
  • Atsdr
ATSDR. Toxicological profile for cadmium. Atlanta, GA: Agency for Toxic Substances & Disease Register; 2008.