A Cleaner Process for Short-Term Preservation of Hides using Wheat Bran

Salting is the most common method to preserve hides and skins. However, this preservation system requires the generation of large amounts of contaminated salt, approximately three million tons per year. In recent years several researchers have suggested different methods for the short-term preservation of hides using plant-based formulations, which either minimize or even completely eliminate the use of salt in the process. In this work, the possibility of using wheat bran for this purpose was studied. Two methods of application (dry and aqueous solution) have been developed. They enable the preservation of hides for one month, reducing by half the salt used in the preservation stage without undermining the quality of the final leather. These two methods contribute to the improvement of the overall sustainability of the tanning process. With dry application, the use of salt is avoided and preservation occurs because the hide is dried. The application in aqueous solution (10% wheat bran) requires its previous hydrolysis and a minimum amount of salt (10ºBé). The preservation occurs because the acidity of the hide is increased.

Effect of using fresh palm oil and used palm oil as a fat liquoring agent to the chemical quality of leather from tilapia fish skin

Tilapia skin has a high value in the form of tanned tilapia skin. One of the factors that play an important role in the tanning process is the using of tanning agents. This research was carried out by vegetable tanning to the tilapia fish skin using selected concentration of fresh palm oil and used palm oil. The study aims to find out the chemical quality of leather through the using of fresh and used palm oil as fat liquoring agent in the vegetable tannery process. The same concentration of fresh palm oil (10%), and used palm oil (10%) were used in this study. The parameter of fat content, and water content as chemical quality was observed in triplicates. Based on the results, the fat content of the leather using fresh palm oil (19.265%) was significantly increased (p<0.05) compared to used palm oil (15.825%), while the water content was also significantly different (p<0.05). In conclusion, the addition of palm oil improved the moisture of tilapia fish skin and become softer that can be used for commercial products, and it became the alternative material that could be use in vegetable tannery processing.

Yield results obtained in maize crop following the foliar fertilization with new biostimulators based on keratin and collagen hydrolysates of animal origin

The aim of the paper is to show the reaction of maize crop to the foliar application of new biofertilizers, obtained from the residues left after the wool tanning process and which are based on protein hydrolysates of keratin and collagen. The tests have been performed in microplots (10 sqm) and macroplots (1000 sqm), in three repetitions, in southern Romania. All data obtained as a result of the 2020 autumn harvest have been centralized in tables and statistically processed, in order to establish the influence of each product, compared to the control. The bifactorial analyses show that, in climatic stress conditions (prolonged drought – Calarasi), very significant increases in yield have been obtained with K4 (2.5 and 5.0 l/ha), K5 (5.0 l/ha) and C (5.0 l/ha), with increases between 700 and 1300 kg/ha, ie up to +24%. In macroplots, subject to a moderate drought (Teleorman), product C (5.0 l/ha) brought a yield increase of 1537 kg/ha (+26%), noting that in this location almost all tested biostimulators offer very significant yield growth (except KC). Based on the 2020 yields, it was possible to identify which the foliar biostimulators that will continue to be tested in 2021.

Biological Desulfurization of Tannery Effluent Using Hybrid Linear Flow Channel Reactors

The tanning process generates a saline effluent with high residual organics, sulfate and sulfide concentrations. The transition from a linear to circular economy requires reimagining of waste streams as potential resources. The organics in tannery effluent have the potential to be converted to renewable energy in the form of biogas if inhibitors to anaerobic digestion are removed. Hybrid linear flow channel reactors inoculated with culture-enriched halophilic sulfate reducing bacteria from saline environments were evaluated as a novel pretreatment step prior to anaerobic digestion for the concurrent removal of sulfur species and resource recovery (elemental sulfur and biogas). During continuous operation of a 4-day hydraulic retention time, the reactors were capable of near-complete sulfide oxidation (>97%) and a sulfate reduction efficiency of 60–80% with the formation of a floating sulfur biofilm containing elemental sulfur. Batch anaerobic digestion tests showed no activity on untreated tannery effluent, while the pretreated effluent yielded 130 mL methane per gram COD consumed.

Water reuse in the post-tanning process: minimizing environmental impact of leather production

The 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.

Composite Polymers from Leather Waste to Produce Smart Fertilizers

The leather industry is facing important environmental issues related to waste disposal. The waste generated during the tanning process is an important resource of protein (mainly collagen) which can be extracted and reused in different applications (e.g., medical, agricultural, leather industry). On the other side, the utilization of chemical fertilizers must be decreased because of the negative effects associated to an extensive use of conventional chemical fertilizers. This review presents current research trends, challenges and future perspectives with respect to the use of hide waste to produce composite polymers that are further transformed in smart fertilizers. Hide waste contains mostly protein (collagen that is a natural polymer), that is extracted to be used in the cross-linking with water soluble copolymers to obtain the hydrogels which are further valorised as smart fertilizers. Smart fertilizers are a new class of fertilizers which allow the controlled release of the nutrients in synchronization with the plant’s demands. Characteristics of hide and leather wastes are pointed out. The fabrication methods of smart fertilizers and the mechanisms for the nutrients release are extensively discussed. This novel method is in agreement with the circular economy concepts and solves, on one side, the problem of hide waste disposal, and on the other side produces smart fertilizers that can successfully replace conventional chemical fertilizers.

Overview of the Leather Industry and Pollution Impact

The growing awareness of the human and environmental vulnerability, to the pollution resulting from industrial activity, highlights the urgent need for control and mitigate the degradation of the world as we know it. The leather industry, considered as one of the industries with a significant environmental impact, applies several chemicals, some of them considered as hazardous chemicals, such as chromium, in leather production. The restricted EU environmental regulations have driven the search for a process that ensures regulatory compliance and a final product that fulfills society’s requirements. The present review describes alternative options, applied in the leather tanning process in the last five years, to overcome some of the industry barriers, without compromising the final characteristics of leather.

Evaluation of Antifungal Activity of Carbonate Solvent – Part:1

Antimicrobial agents have been used in leather manufacturing to prevent leather products from microbial contamination. In this work, the antifungal activity of green solvent such as propylene carbonate was investigated against the mixed culture of fungi isolated from wet-blue using broth dilution/well diffusion. A concentration of 5% and above (propylene carbonate) showed effective antifungal activity against the mixed culture of fungi and the efficiency of propylene carbonate on the mixed culture increased with increasing concentration/volume. Propylene carbonate exhibited fungistatic activity against the mixed culture of fungi but it lost its activity after a certain period and fungal growth was observed again. It was also found that 2% propylene carbonate in chrome tanning process effectively inhibited the fungal growth and the wet-blue can be preserved up to 30 days without any fungal attack.

The Use of Pineapple Fruit in Batting Process on the Chemical Properties of Sheepskin Using Shorfloat Tanning

Batting is the process of removing globular and non-collagen proteins. Bromelain can be found in all parts of the pineapple plant (Ananas comosus L.) with different amounts and properties. Bromelain can be used as a batting agent in the tanning process. The purpose of this study was to determine the effect of the bromelain enzyme concentration used during the protein removal process on the quality of sheepskin. This research used 30 sheets of sheepskin obtained from abattoir in Yogyakarta City and pineapple fruit’s flesh. The experimental design used was a completely randomized design. The research uses different concentrations of pineapples fruit’s flesh (T1 0,5%, T2 1%, T3 1,5% and T4 2% w/w) with feliderm (T0). Statistical analysis using one-way analysis of variance and in accordance with the statistical model. The results of this study showed in dissolved protein content was T0 0.83%, T1 0.77%, T2 0.68%, T3 0.82% and T4 0.85%, protein content of batting skin was T0 19.17%, T1 17.90%, T2 18.37%, T3 21.35% and T4 21.50%, protein content of leather was T0 59.69%, T1 59.27%, T2 60.34%, T3 61.59% and T4 63.25%, fat content was T0 15.31%, T1 14.61%, T2 15.19%, T3 15.36% and T4 16.25%, chromium content was T0 2.60%, T1 2.67%, T2 2.78%, T3 2.82% and T4 3.00% and shrinkage temperature was T0 92.330C, T1 95.670C, T2 93.670C, T3 96.330C and T4 97.330C. The results for pineapple juice showed potency to be used as batting agent for sheepskin. The minimum amount of pineapple juice added for batting the sheepskin is 1% (w/w).