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The leather industry converts the hide, a byproduct of slaughterhouses, into leather, a value-added product. This old industry generates wastes, causing environmental pollution. However, nanomaterials can help to decrease this problem. These tiny particles (1-100 nm) can replace chemicals in various steps of leather processing. This paper aims at giving an overview of the fundamentals of classical leather process and how nanomaterials can be applied in each step to obtain a more sustainable manufacturing. After a comprehensive literature review of journal articles, six steps were identified for potential for application of nanomaterials: unhairing, tanning, retanning, dyeing, fatliquoring, and finishing. With nano-oxides, polymers, and metals, it is feasible to reduce the amount of chemical products and also improve the properties of leather. Thus, it is possible to reach a more eco-friendly and effective process with the use of nanomaterials to turn hide/skins into finished leather.

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The tannery industry is one of the economic sectors that contributes to the development of different countries. Globally, Europe and Asia are the main producers of this industry, although Latin America and Africa have been growing considerably in recent years. With this growth, the negative environmental impacts towards different ecosystem resources as a result of the discharges of recalcitrated pollutants, have led to different investigations to generate alternative solutions. Worldwide, different technologies have been studied to address this problem, biological and physicochemical processes have been widely studied, presenting drawbacks with some recalcitrant compounds. This review provides a context on the different existing technologies for the treatment of tannery wastewater, analyzing the physicochemical composition of this liquid waste, the impact it generates on human health and ecosystems and the advances in the different existing technologies, focusing on advanced oxidation processes and the use of microalgae. The coupling of advanced oxidation processes with biological processes, mainly microalgae, is seen as a viable biotechnological strategy, not only for the removal of pollutants, but also to obtain value-added products with potential use in the biorefining of the biomass.

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Treatment and safe disposal of tannery saline wastewater, a primary effluent stream that is generated by soaking salt-laden hides and skin is one of the major problems faced by the leather manufacturing industries. Conventional treatment methods like solar evaporation ponds and land composting are not eco-friendly as they deteriorate the ground water quality. Though, this waste stream is comprised of high concentration of dissolved proteins the presence of high salinity (1-6 percent NaCl by wt) makes it non-biodegradable. Enzymatic treatment is one of the positive alternatives for management of such kind of waste streams. A novel salt-tolerant alkaline protease obtained from P.aeruginosa (isolated from tannery saline wastewater) was used for enzymatic degradation studies. The effect of various physical factors including pH, temperature, incubation time, protein source and salinity on the activity of identified protease were investigated. Kinetic parameters (Km , Vmax) were calculated for the identified alkaline protease at varying substrate concentrations. Tannery saline wastewater treated with identified salt tolerant protease showed 75 percent protein removal at 6 h duration and 2 percent (v/v) protease addition was found to be the optimum dosage value.

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RESUMO

Treatment and safe disposal of tannery saline wastewater, a primary effluent stream that is generated by soaking salt-laden hides and skin is one of the major problems faced by the leather manufacturing industries. Conventional treatment methods like solar evaporation ponds and land composting are not eco-friendly as they deteriorate the ground water quality. Though, this waste stream is comprised of high concentration of dissolved proteins the presence of high salinity (1-6 % NaCl by wt) makes it non-biodegradable. Enzymatic treatment is one of the positive alternatives for management of such kind of waste streams. A novel salt-tolerant alkaline protease obtained from P.aeruginosa (isolated from tannery saline wastewater) was used for enzymatic degradation studies. The effect of various physical factors including pH, temperature, incubation time, protein source and salinity on the activity of identified protease were investigated. Kinetic parameters (Km , Vmax) were calculated for the identified alkaline protease at varying substrate concentrations. Tannery saline wastewater treated with identified salt tolerant protease showed 75 % protein removal at 6 h duration and 2 % (v/v) protease addition was found to be the optimum dosage value.

RESUMO

Treatment and safe disposal of tannery saline wastewater, a primary effluent stream that is generated by soaking salt-laden hides and skin is one of the major problems faced by the leather manufacturing industries. Conventional treatment methods like solar evaporation ponds and land composting are not eco-friendly as they deteriorate the ground water quality. Though, this waste stream is comprised of high concentration of dissolved proteins the presence of high salinity (1-6 % NaCl by wt) makes it non-biodegradable. Enzymatic treatment is one of the positive alternatives for management of such kind of waste streams. A novel salt-tolerant alkaline protease obtained from P.aeruginosa (isolated from tannery saline wastewater) was used for enzymatic degradation studies. The effect of various physical factors including pH, temperature, incubation time, protein source and salinity on the activity of identified protease were investigated. Kinetic parameters (Km , Vmax) were calculated for the identified alkaline protease at varying substrate concentrations. Tannery saline wastewater treated with identified salt tolerant protease showed 75 % protein removal at 6 h duration and 2 % (v/v) protease addition was found to be the optimum dosage value.

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Leather manufacturing is a worldwide industry that has been carried out for centuries and has achieved great importance in Turkey. However, the leather industry is associated with the generation of large amounts of waste water and solid wastes that are a threat to the environment. A germination experiment was conducted to determine the effect of different dilutions of pre-tanning effluents on the germination characteristics of broad bean, lentil and common bean. The experiment was designed as a completely randomized block with three replications. Seeds of each species were sown and irrigated with different dilutions of pre-tanning effluents (1:10, 1:40 and 1:80 tap water:effluent), undiluted pre-tanning effluent, and tap water (control). Number of germinated seeds, germination percentage, root length, root weight, shoot length, shoot weight and root+shoot weight were measured at 15days after planting. All germination properties varied considerably, and significant differences among them were determined (P<0.05). Undiluted pre-tanning effluent had adverse effects and no germination occurred for any of the tested plant materials. Except for the undiluted pre-tanning effluent, no significant differences were detected in the number of germinated seeds and germination percentage, whereas some differences among treatments were observed for the remaining characteristics.

La manufactura del cuero ha sido practicada por siglos en el mundo entero y en Turquía reviste gran importancia. No obstante, la industria del cuero se asocia con la generación de grandes cantidades de aguas residuales y residuos sólidos que constituyen una amenaza para el ambiente. Se llevó a cabo un experimento de germinación para determinar los efectos de diferentes diluciones de efluentes del preteñido de una tenería sobre las características germinativas de habas, lentejas y frijol común. El experimento fue diseñado como un bloque completamente al azar con tres réplicas. Las semillas de cada especie fueron sembradas e irrigadas con diferentes diluciones de efluentes (1:10, 1:40 y 1:80 agua corriente:efluente), efluente sin diluir y agua corriente (control). A los 15 días después de la plantación se midieron el número de semillas germinadas, porcentaje de germinación, longitud de la raíz, peso de la parte aérea y peso de la planta entera. Todas las propiedades de germinación variaron considerablemente, determinándose diferencias significativas (P<0,50) entre ellas. El efluente de preteñido sin diluir tuvo efectos adversos y no hubo germinación en ninguna de las plantas ensayadas. Exceptuando el del efluente sin diluir, no hubo diferencias significativas en el número de semillas germinadas y porcentaje de germinación, mientras que se observaron diferencias entre los tratamientos en las demás características.

A manufatura do couro tem sido praticada por séculos no mundo inteiro e na Turquía reveste grande importância. No entanto, a indústria do couro está associada à geração de grandes quantidades de águas residuais e resíduos sólidos que constituem uma ameaça para o ambiente. Realizou-se um experimento de germinação para determinar os efeitos de diferentes diluições de efluentes do pre tingimento de um curtume sobre as características germinativas de feijões de fava, lentilhas e feijão comum. O experimento foi desenhado como um bloco completamente aleatório com três réplicas. As sementes de cada espécie foram plantadas e irrigadas com diferentes diluições de efluentes (1:10, 1:40 e 1:80 água corrente:efluente), efluente sem diluir e água corrente (controle). Aos 15 dias após a plantação foram medidos; o número de sementes germinadas, porcentagem de germinação, longitude da raíz, peso da parte aérea e peso da planta inteira. Todas as propriedades de germinação variaram consideravelmente, determinando-se diferenças significativas (P<0,50) entre elas. O efluente de pre tingimento sem diluir teve efeitos adversos e não houve germinação em nenhuma das plantas ensaiadas. Com excesão do efluente sem diluir, não houve diferenças significativas no número de sementes germinadas e porcentagem de germinação, enquanto que se observaram diferenças entre os tratamentos nas demais características.

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Objetivo Determinar si los niveles de cromo en orina están más altos de los permitidos y contrastarlos con alteraciones de salud en personas del barrio San Benito en Bogotá. Métodos En una muestra de 827 personas, se cuantificó cromo total en orina como biomarcador de exposición y se contrastó con alteraciones de salud atribuibles a exposición a cromo. La exposición se definió, por la "Ocupación actual" relacionada con la labor en curtiembres. Se definieron dos estratos: "Directamente expuestos" 26 por ciento y "Potencial alta exposición" 73 por ciento. Resultados Un 6,3 por ciento presentó niveles de cromo >10 ug/L (intervalo de confianza: 4,64-7,96 por ciento). No se encontraron diferencias estadísticamente significativas entre los dos estratos. El 34,3 por ciento presentó diagnósticos posiblemente atribuibles a la exposición a cromo. El 23,3 por ciento otorrinolaringológico; 6,5 por ciento dermatológico; 2,9 por ciento oftalmológico; 1,6 por ciento cavidad oral y el 65,7 por ciento no relacionados. Se halló asociación entre niveles >10ug/L y residir en la zona (OR 4,94 IC:1,2- 20,7 por ciento). Los resultados sugieren asociación entre ocupación y alteraciones de salud atribuibles a la exposición a compuestos de cromo. Conclusiones Las personas que participan del proceso productivo del cuero tienen un riesgo significativo de presentar hallazgos clínicos posiblemente atribuibles a la exposición a cromo, OR 4,33 (3,12-6,02). La población general se esta viendo expuesta de manera no diferente a aquella con ocupación relacionada con las curtiembres, lo que puede deberse a que los habitantes del sector están en contacto con cromo o compuestos por vías diferentes a la ocupacional, como contaminación ambiental.

Objective Determining whether chromium levels in urine samples were higher than limits and contrasting them with alterations in the health of people living and working in the San Benito neighbourhood of Bogotá. Methods The total amount of chromium in urine was measured as a biological marker of exposure in a sample of 827 people. This was contrasted with health alterations attributed to chromium exposition. Exposure was defined by being whether current economic activity was related to working in a tannery. Two groups were defined: being directly exposed (26 percent) and having potentially high exposure (73 percent). Results 6.3 percent presented >10 ug/L chromium levels (4.64 percent to 7.96 percent confidence interval). No significant statistical differences were found between both groups. 34.3 percent presented a diagnosis of possible attribution to chromium exposure, of whom 23.3 percent were due to otorhinolaryngologic issues, 6.5 percent to dermatological ones, 2.9 percent to ophthalmologic ones and 1.6 percent to oral cavity issues. The remaining 65.7 percent of cases were not related. >10ug/L levels and living in the particular neighbourhood in question were associated (4.94 odds ratio; 1.18 percent-20.69 percent CI). The results suggested a connection between economic activity and health alterations due to chromium components. Conclusions The people involved in producing leather have a significant risk of presenting clinical conditions attributed to chromium exposure (4.33 OR; 3.12-6.02 CI). San Benito´s inhabitants are being exposed to chromium as if they were actually working in a tannery as they are in daily contact with chromium or its components through non work-related activities, such as environmental contamination. Concern at such exposure should lead to further in-depth studies.

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