Treatment Of Tannery Wastewater Research Articles

Destabilization and Removal of Mixed Organic-Chromium Complexes from Leather Wastewater by Ultrasonic-Assisted Precipitation

During the leather tanning process, chromium (Cr) can interact with different macromolecular organics to generate mixed ligand complexes. The removal of organochromium complexes is one of the main difficulties in the treatment of tannery wastewater. In this study, a gelatin-gallic ac-id-Cr(III) (G-GA-Cr) mixed ligand complex was used to examine the effects of ultrasonic on chromium destabilization and removal from the dissolved complexes. To investigate organic destruction and chromium liberation, alkali precipitation or chelating precipitation assisted with ultrasound were conducted, respectively. The findings demonstrate that ultrasonic-assisted alkali precipitation and chelating precipitation, respectively, removed over 50% and 93% of Cr from the complexes. According to the data, ultrasonication weakened the bonds that bound macromolecular ligands together, and depolymerization took place to the point where Cr could interact directly with hydroxide ions or chelating agents. In addition, by applying ultrasonic-assisted chelating precipitation, the chromium concentration could meet the discharge standard and the amount of precipitation was also noticeably decreased.

Reducing the pollution load of tannery wastewater and the atmospheric emission of hydrogen sulfide using modified tannin.

Industrial wastewater causes several environmental and health issues due to its composition, and hydrogen sulfide is one of the main contaminants from various industrial activities, including tannery wastewater treatment plants. This study aimed to evaluate the application of a modified tannin to remove hydrogen sulfide, chemical oxygen demand, total nitrogen, color, and turbidity from tannery wastewater and to reduce the atmospheric emission of sulfides. The wastewater was treated using modified tannin, aluminum sulfate, and a combination of both. Gaseous sulfide emissions were analyzed qualitatively using paper soaked in lead acetate. The qualitative methodology of hydrogen sulfide in the atmosphere was efficient to identify the most critical areas in the tannery. The wastewater treatment tests showed that the best option was the combination of both coagulants, in a 50:50 ratio, resulting in a total coagulant dosage of 3,000 mg/L. The removal efficiencies achieved were 13.8% sulfides, 23.3% chemical oxygen demand, 9.1% total nitrogen, 97.3% turbidity, and 96.4% color. This treatment technique promotes the replacement of 50% of the aluminum sulfate currently used in the tannery by a non-toxic coagulant and does not require chemicals to adjust the pH of the wastewater.

Preparation and Characterization of a Clay-Based Ceramic Membrane for Tannery Wastewater Treatment

In this work, a porous clay-based ceramic membrane was developed from locally sourced clay from Nigeria. The clay was ground and sieved through 100 μm size. The chemical, mineralogical, thermal and particle size properties of the clay were determined using XRF, XRD, TGA/DTA and PSD respectively. Starch composition from 10-25 wt% was added to the clay and thoroughly mixed with water. The dough was cast on a potter’s wheel. The produced membranes were fired at a temperature of 900 °C. The maturation properties of the fired clay were determined using bulk density and apparent porosity. Multi-point BET was used to determine the pore characteristics of the membranes. The flexural strength of the produced membrane was determined using a three-point bending test. The microstructure of the fired clay was recorded using FESEM. Membranes produced from the clay were used for the treatment of tannery wastewater. The XRF result shows that the clay contains high silica and alumina. Also, the XRD results show the clay contains many peaks of montmorillonite and other peaks of feldspar and quartz. The BET shows that the pore size of the membranes produced was in the mesoporous range. From water quality test, it shows that the locally sourced clay can be used to produce ceramic membranes for filtration and separation applications.

Parametric study for the treatment of tannery dye wastewater by electro-oxidation

Degradation of tannery effluents is a difficult operation because of their intricate chemical structures. Most of the conventional approaches are becoming ineffective because of the wide variation in the composition of tannery effluent. Dyes from the wastewater is also dangerous, as the wastewater has negative impact on the health of human being, plants and aquatic animals. For the first time once through continuous approach was employed for the removal of Acid yellow 110 tannery dye in electro-oxidation process on Mix Metal Oxide of ruthenium and iridium on titanium sheet electrode. The effects of pH, time (t) and current (i) on % color removal and energy consumed were investigated in a batch setup and found the optimum condition with the help of RSM design. The values of the responses Y1 and Y2 were found to be 93.08% and 1.07 kWh/m3 respectively at the optimum condition. Toxicity Bioassay analysis, GC-MS analysis and the kinetic study were performed at optimum condition. At the flow rates of 10–40 ml/min once through continuous experiments was conducted to found the feasibility of the process at pilot scale or industrial scale application.

Mathematical Modelling and Statistical Approach in Tannery Wastewater Treatment.

The present work investigated the feasibility of photo oxidation process for removal of oil and chemical oxygen demand (COD) in Indian tannery wastewater with a support of mathematical modelling and statistical approach. The influence of process variables such as nano-catalyst dose and reaction time was analysed on removal of oil/grease and COD. The obtained results are discussed using response surface methodology (RSM) design in detail. Zinc oxide nanoparticles prepared from Eclipta Prostrata plant leaves and characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), Scanning electron microscopy (SEM) with Energy dispersive X-ray analysis (EDX) and Transmission electron microscopy (TEM). Chemical oxygen demand (COD) removal of 93.6% and oil & grease removal of 90 % in 35 minutes using 3mg/L nanoparticle dosage were recommended as an optimum condition in photo oxidation process.

Mechanism of Chromium Separation and Concentration from Tannery Wastewater by Membrane Methods

The article specifies conditions for a nanofiltration process employing a diafiltration method with a constant volume diafiltration (NF-CVD) for exhausted chromium tannery wastewater treatment and describes a mechanism of the examined process carried out for model wastewater. The authors prove that a decrease in salt concentration in the NF-CVD process is an important factor that enables effective concentration of chromium. Based on the proposed chromium separation and concentration mechanisms, it was found that this effect may be achieved by (1) limiting the formation of an ionic adsorption-polarization layer and (2) reducing the increase in the osmotic pressure caused by a change in the separation properties of the membrane. The article shows that in the analyzed system a higher amount of the solvent introduced at the diafiltration stage and a lower process pressure that ensures a reduction in salt retention translate to a high level of salt removal. In regenerates, after the NF-CVD processes in which at least the same volume of a washing diluent as the volume of the retentate after the pre-concentration step was used, salt concentration below 10 g L-1 and chromium concentration about three times higher than in the case of the feed solution were obtained. Therefore, the proposed solution implements the circular economy strategy in the tannery.

Treatment of real tannery wastewater using facile synthesized magnesium oxide nanoparticles: Experimental results and geochemical modeling

Tannery wastewater (TWW) is a toxic and hazardous effluent that causes great harm to receiving ecosystems if released untreated. Here, magnesium oxide nanoparticles (MgO-NPs), synthesized from low-cost and readily available magnesite, were used for the treatment of real TWW under batch laboratory conditions. The optimum treatment conditions were 90 min contact time and 10 g MgO-NPs dosage per L of real TWW, under ambient pH and temperature. Results were underpinned by state-of-the-art analytical techniques, including ICP-OES, XRD, XRF, and FIB/EDS-SEM, along with geochemical modelling (PHREEQC). The removal efficiency for the main contaminants that are typically found in TWW was, from higher to lower score, Fe ≥ U ≥ Cr ≥ Mn ≥ Al ≥ Sb ≥ Cu ≥ Ni ≥ TOC ≥ COD≥ SO42−. The removal percentages for these contaminants were ≥99%, aside from Ni (97%), TOC (71%), COD (69%) and particularly SO42− (21%). The underlying mechanism for contaminants removal is linked to the scavenging of metals by the MgO-NPs, forming complexes, in combination with alkalinity addition (through MgO dissolution) that lead to contaminants precipitation. The PHREEQC geochemical model confirmed the existence of divalent, trivalent, oxyanions, and multivalent chemical species in MgO-NPs/TWW solution, including complexes. Contaminants attenuation was achieved through precipitation, co-precipitation, adsorption, and co-adsorption, while these were removed as hydroxides, sulfides, carbonates, oxide, and oxyhydrosulfates. Overall, results highlight the great potential of MgO-NPs for the sustainable management of real TWW.

Efficacy of marigold (Tagetes erecta L.) for the treatment of tannery and surgical industry wastewater under citric acid amendment: a lab scale study.

Contamination of land and aquatic ecosystems with heavy metals (HMs) is a global issue having the persistent potential to damage the quality of food and water. In the present study, Tagetes erecta L. plants were used to assess their potential to uptake HMs from wastewater. Plants were grown in soil for 20days and then transplanted in hydroponic system containing Hoagland nutrient solution. After more than 15days of growth, plants were then subjected to wastewater from tannery and surgical industries in different concentrations ranging from 25 to 100% in combination of citric acid (5 and 10mM). After 6weeks of treatment, plants were collected and segmented into roots, stem, and leaves for characterizing the morphological properties including plant height, roots length, fresh and dry mass of roots, stem, and leaves. For evaluation of the effect of wastewater on the plants, photosynthetic pigments; soluble proteins; reactive oxygen species (ROS); antioxidant enzymes SOD, POD, CAT, and APX; and metal accumulation were analyzed. Application of industrial wastewater revealed a significant effect on plant morphology under wastewater treatments. Overall growth and physiological attributes of plant decreased, and metal accumulation enhanced with increasing concentration of wastewater. Similarly, the production of ROS and antioxidant enzymes were also increased. Chlorophyll, protein content, and enzyme production enhanced with CA (5 and 10mM) mediation; however, ROS production and EL were reduced. Metals analysis showed that the maximum accumulation of Pb was in roots, while Cr and Ni in the stem which further increased under CA mediation. Overall, the metal accumulation ability was in the order of Pb > Ni > Cr under CA.

Sustainable leather making — An amphoteric organic chrome-free tanning agents based on recycling waste leather

Currently, globally, 90 % of the tannery is still tanned by using chrome, resulting in chromium-containing wastewater and chromium-containing solid waste that will cause serious harm to the environment. Under the pressure of environmental protection, on the one hand, the leather manufacturing industry should to dispose the current problem of chromium pollution, especially chromium-containing solid waste (chromium-containing waste leather (CCWL)), on the other hand, to popularize chrome-free tanning agent. Organic chrome-free tanning agents are the way forward for chrome-free tanning agents. However, organic chrome-free tanning agents exhibit several limitations with respect to their preparation and applications: The preparation process is not eco-friendly, and physicochemical properties of tanned crust leather are poor. More importantly, the leather tanned by an organic chrome-free tanning agent has low absorptivity of traditional anionic wet finishing materials, resulting in high total dissolved solids in tannery wastewater, which increased the difficulty of tannery wastewater treatment, and posed a potential threat to the environment. In this study, collagen polypeptide (CP) was extracted by using in situ dechromization and industrial trypsin from CCWL, followed by modification with ethylene glycol diglycidyl ether (EGDE) to obtain an epoxy-terminated, biomass-based, amphoteric organic, chrome-free tanning agent (CP-EGDE) with a high isoelectric point of 5.16, and an epoxy value of 0.316 mol/100 g. CP-EGDE can be applied in the pickling-free and salt-free tanning processes to prepare wet white leather and the tannery wastewater with good degradability. The shrinkage temperature (Ts = 84.9 °C), grain flatness, fullness, softness, yellowing resistance, mechanical properties, absorptivity of traditional anionic fatliquor (88.4 %) and dyes (95.3 %) of CP-EGDE tanned leather exceeded those of commercial organic chrome-free tanning agents. This research considered both environmental protection and leather quality, especially greatly improving the absorptivity of traditional anionic wet finishing materials. CP-EGDE is expected to replace chrome tanning agents and has good application prospects.

Ammonium-free and grain-protection deliming technology with the combination of aromatic sulfonic acid and sodium dihydrogen phosphate in leather manufacture

Ammonia-nitrogen, a grave environmental concern, is a typical pollutant in deliming process due to the inclusion of ammonium salts as deliming agents in leather manufacture. In order to reduce the emission of ammonia-nitrogen and improve the biological treatment of mixed tannery wastewater, an ammonium-free deliming method was designed and optimized based on the synergistic effects of aromatic sulfonic acids and sodium dihydrogen phosphate. The results indicated that, the penetrating and buffering performance of the mixtures of p-Hydroxybenzene sulfonic acid (pHBSA) and sodium dihydrogen phosphate (SDHP) at weight ratio of 2:1 was good enough to fulfill the requirement of deliming. The organoleptic and mechanical properties of the crust leather produced by pHBSA-SDHP mixtures deliming were similar with the conventional ammonium sulfate deliming, and the grain pattern was found to be protected against the damage caused by enzymes during bating. The concentrations of ammonia-nitrogen and total nitrogen in pHBSA-SDHP deliming effluent were dramatically cut down by 99% and 94%. It is anticipated that the mixed tannery wastewater could be disposed of more easily by means of adjusting the total organic ratios of C:N:P to their natural ratio by introducing an additional carbon and phosphorus source to the tannery wastewater. This investigation provides an improved method of leather making with significant reduction of ammonia nitrogen emission in deliming operation and fulfills the integral requirements of the modern sustainable leather industry.

Assessment of physicochemical parameters and trace elements in tannery wastewater treatment facility and associated health risks

Assessment of physicochemical parameters and trace elements in tannery wastewater treatment facility and associated health risks

Resource recovery from tannery wastewater using an integrated biological system: Towards a circular bioeconomy and net positive tannery operations

Anaerobic digestion (AD) of tannery effluents generated by beamhouse processes is limited by ammonia and sulfur species. High sulfate concentrations in beamhouse effluents (BHE) promote sulfidogenesis during AD, and the hydrogen sulfide that is generated inhibits methanogenesis. The feasibility of using a novel integrated biological system that comprised of hybrid linear flow channel reactor/s (HLFCR/s) and an anaerobic sequential batch reactor (AnSBR) connected in series mainly for the pre-treatment and recovery of elemental sulfur (S0) and methane (CH4) was investigated. The application of single-stage and two-stage HLFCR topology operating at 8 and 4 days’ hydraulic retention times (HRT), respectively, produced effluents that were ideal for AD. Single-stage HLFCR (8-days HRT) recovered 21% of the inlet sulfur and the downstream effluent treatment in continuously mixed AnSBR at 50 rpm achieved 238 mL CH4/gCODadded). The full-scale application of the system at a local medium sized tannery treating 2258 m3 of BHE would produce a floating sulfur biofilm with 33% S0, 3420 m3 of CH4, 50 m3 of irrigation water and 31 tonnes of biofertiliser. The sale of recovered resources and potential savings from a 72% reduction in electricity demand and 62% in sludge disposal had a potential revenue of US$5559. This study demonstrated the feasibility of a circular bioeconomy and net positive tannery operations through the conversion of tannery wastewater treatment plants into bio-refineries.

A comparative analysis of degradation efficiencies using alum and orange peel waste for the treatment of tannery wastewater

The tannery wastewater effluent consists of complex compounds requiring a series of treatment processes to meet the desirable effluent discharge standards. The current study deals with the comparison of degradation efficiencies obtained in terms of turbidity, total suspended solids (TSS) and chemical oxygen demand (COD) removal by using alum as a chemical coagulant, orange peel powder (OPP) and activated orange peel powder (AOPP) as naturally obtained adsorbents respectively. The experimental analysis showed that the maximum COD reduction of 49 % approx. was obtained using AOPP at optimum coagulant dosage of 2 g/L, at pH 4 and flocculation time of 30 min. Scanning Electron Microscope (SEM) showed that the AOPP consists of porous structure that leads to adsorption of pollutants over the surface. Brunauer–Emmett–Teller (BET) analysis resulted in surface area reduction of AOPP from 11.663 m2/g to 1.289 m2/g before and after adsorption correlating the experimental results of the study. Moreover, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Total organic carbon (TOC) proved that the chemical properties also play an important role in degrading the pollutants present in TWE. It can be concluded that the AOPP can be used as a cost-efficient alternative for pre-treatment of TWE.

Sono-chemical extraction of silica from rice husk for uptake of chromium species from tannery wastewater: Effect of aging time on porous structure

• Silica powder was produced from rice husk residue after pyrolysis of biomass. • The produced powder was explored for tannery wastewater treatment. • The obtained adsorbent displayed a unimodal mesoporous structure 17 nm. • The sono-chemically prepared silica is efficient for the removal of chromium. • Suitability of present pathway was proven for large-scale treatment of wastewater. The silica powders extracted from rice husk through the normal, and sono-chemical precipitation were explored for the treatment of tannery wastewater. The effect of aging time on adsorptive performance of silica was evaluated via the studying the morphological, and textural characteristics. The uptake of chromium species seems to be dependent of aging time due to unimodal distribution of mesopores in the interval of 2.4–38.2 nm. The sono-chemically prepared silica exhibited a good affinity for the decontamination of tannery wastewater, 98 %, with adsorption capacity ∼185 mg g −1 .

Quantitative Analysis of the Research Development Status and Trends of Tannery Wastewater Treatment Technology

In order to better grasp the development and trends of tannery wastewater (TWW) treatment research, this paper provides a review of the TWW treatment research dynamics based on the Web of Science (WoS) database and using CiteSpace software. The research dynamics, hot topics, evolutionary history and research trends in this field are revealed. The results showed that research related to TWW treatment has shown a high growth trend in the number of articles in recent years, and India was outstanding in terms of influence in this area. The keyword clustering analysis showed that the main research hotspots in the field of TWW treatment were biological treatment processes (phytoremediation, constructed wetlands, anaerobic treatment and biofilm reactors) and chemical treatment processes (coagulation and flocculation, and advanced oxidation processes). The analysis of new research frontiers showed that the bioremediation and the application of biofuel cells in TWW will become important research directions in the future.

Treatment of Industrial Wastewater in a Floating Treatment Wetland: A Case Study of Sialkot Tannery

The city of Sialkot in Pakistan is a hub of leather tanneries, with approximately 260 tanneries in operation and, while producing millions of leather products per day, the city discharges millions of gallons of untreated effluent into drains each day. In order to devise a cost-effective system for the treatment of tannery wastewater, a floating treatment wetland (FTW) was established to treat the effluent using local plant species through phytoremediation. The efficiency of the FTW was tested with three different plant species, each grown separately and operating for three months in the FTW tank. Two of the plant species introduced, water hyacinth and water lettuce, were floating and vascular; the third plant species Typha latifolia was vegetated on a floating mat of styrofoam while the roots extended down to the contaminated water. Wastewater from a tannery drain was pumped into the FTW tank with a flow of 0.5 L per minute and was given a retention time of six days. The influent and effluent from the FTW were periodically tested to determine the percentage removal of contaminants, primarily the total suspended solids, biochemical oxygen demand, chemical oxygen demand, and chromium. After two months with each species, a significant change in the quality of wastewater was measured: chromium was removed by up to 95 percent by the water hyacinth and water lettuce and 33 percent by the Typha latifolia. The pilot model indicates that FTWs are an effective system to treat effluent from tanneries in a cost-effective way as an alternative to establishing an expensive treatment system with high associated operational costs. It can help in achieving the circular economy concept of conventional wastewater schemes towards more sustainable ones. Moreover, to achieve the principles of circular economy and environmentally friendly development, it is crucial that the substances used for a wetland foundation have the capacity to be recycled, are available at a cheap price, and are locally available.

Solar photo-assisted electrochemical peroxidation process for the sustainable treatment of tannery industry wastewater

Abstract Tannery wastewater is a complex mixture of organic and inorganic components from various processes with high concentrations of Cr, BOD, COD, TDS, strong colour and pH. The goal of the present work was to determine the optimal solar photo-assisted electrochemical peroxidation process (SPECP) experimental conditions for the treatment of tannery wastewater. Experiments were conducted in a bench-scale stirred tank SPECP reactor of 5 L with iron plates as anode and cathode in a contact effective area of 218 cm2. In the stirred tank reactor at optimal conditions, the SPECP yielded 97% COD, 98% of colour and 92% of chromium (III) removal after 60 min at 15 mA/cm2. SPECP improved the biodegradability (BOD5/COD) of tannery wastewater from 0.4 to 0.6 in 15 min. These results showed that wastewater from tannery industries could be treated up to the level of the minimal national standards of India for waste disposal; COD=90 mg/L, BOD=30 mg/L and chromium (III)=1.2 mg/L at a treatment time of 60 min. The operating cost of the best economic condition with maximum degradation was $8.2/m3.

Treatment of tannery wastewater by silica nanoparticles produced from rice husk ash via a green route.

Rice husk, which is one of the abundant agricultural biomasses in nature, contains organic and inorganic elements, spastically silica. This waste is frequently managed via incineration, resulting in the contamination of soil, water, and air due to emission of greenhouse gasses and ash. In the present investigation, the potential of silica powder obtained from the rice husk was demonstrated by the removal of Cr(III) from the tannery wastewater. Different combinations of sulfuric, hydrochloric, and acetic acids were used as precipitation agents to produce silica through the conventional and ultrasound-assisted techniques. The mesoporous silica fabricated via the sonication indicated the larger pores, 22 nm, compared to that produced via the conventional method by the employment of sulfuric acid, 10 nm, leading to achieve an adsorption capacity ~385 mg g-1. Although both of applied techniques could develop mesoporous structure, precipitation should be carried out under sonication in the presence of acetic acid for the green production of silica with the appropriate adsorption performance. The conversion of rice husk into silica powder with specific surface area ~62 m2 g-1 could prevent the environmental pollution due to employment of acetic acid in the precipitation stage.

Chromium adsorption on surface activated biochar made from tannery liming sludge: A waste-to-wealth approach

In a beamhouse, liming plays a key role in the removal of hair/wool and epidermis, but problems are created when waste liming sludge is discharged to the environment. The treatment of tannery wastewater is another major challenge to the industry. In this study, thermally-activated biochars derived from liming sludge were studied for their effective adsorption of chromium (Cr) from the tannery wastewater. The thermally activated biochars (B500, B550, B600, and B650) were prepared at different temperatures from the liming sludge. Their characteristics before and after the treatment were investigated using Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy analyses. The related functional groups (C–H, O–H, C–N, and =C–O) and chromium adsorption capacity were determined according to the surface morphology, element contents (C, O, Ca, Na, Al, Mg, and Si), surface area (5.8–9.2 m2/g), pore size (5.22–5.53 nm), and particle size (652–1 034 nm) of the experimental biochars. The biochar originated at 600°C from the tannery liming sludge (B600) had a greater surface area with a chromium adsorption capacity of 99.8% in comparison to B500, B550, and B650 biochars. This study developed an innovative way of utilizing liming sludge waste to minimize the pollution load and wastewater treatment cost in the tannery industry.

Removal of Tannic acid and COD from synthetic Tannery wastewater

Tanning industries generate tannery wastewater having high amounts of tannic acid and high COD. Tannery wastewater is difficult to treat as it is having low biodegradability. Tannic acids or tannins are recalcitrant molecules that are toxic to a wide range of microorganisms. In this study, synthetic tannery wastewater treatment was performed by Electrocoagulation (EC) process. To extract the polyphenolic components of tannins, aluminum was employed as an anode electrode and stainless-steel as cathode electrode. Analysis of removal efficiencies was done by determining tannic acid concentration and COD. The effects of functional parameters such as current density, pH, and initial concentration of tannic acid were examined on the efficiency of electrocoagulation. At a current density of 30 A/m2 with an initial concentration of tannic acid of 1,000 mg/L, 94% of tannic acid removal and 94.92% of COD removal were observed. While tannic acid removal was fast, at 60 min, COD removal took a long duration of 120 min. The removal efficiency was observed for three various pH;4.11 (initial pH of the sample), 6, and 8. The maximal COD elimination was found to be accomplished at pH 4.11, which was the sample’s natural pH, whereas tannic acid removal was better at pH 6 and 8. Experiments with a varying initial concentration of tannic acid at 500 mgl−1, 800 mgl−1, and 1000 mgl−1 showed that as concentration was increased, the removal was difficult. The present study found the EC process effective in reducing COD and tannic acid concentration in synthetic tannery wastewater.