Treatment Of Tannery Wastewater Research Articles

Tannery Waste Water Treatment through Aggregation of Bio-sorption and Chemical Coagulation Aided by Indigenous Coagulant

Tannery in Bangladesh seems a source of pollution load and waste water to all because there are 270 registered tanneries where approximately 220 MT raw hides and skins are taking for the production of leather in Bangladesh. The leather industry has crossed the record $1-billion mark in exports in 2013-2014. According to the Department of Environment, the tanneries discharge 22,000 cubic meters of untreated liquid toxic waste daily. These pollution load and waste water should need treatment to make environmentally sustainable and living. From this point of view, we worked on tannery waste water processing. The paper highlights the initiation of Algal treatment with chemical coagulation process aided by natural coagulant for waste water processing in Bangladesh. The methodology of this process starts with mixing of waste water from different section of beam house operations at a definite ratio. The mixer takes nearly six hours to settle down. After sedimentation, the turbidity decreases at a reasonable amount i.e. 1428 NTU whereas before sedimentation it was 9050 NTU (2100P Turbid Meter of HACH). Later the supernatant was collected for algal treatment. After algal treatment the turbidity reduced to 530 NTU from 1428 NTU and the DO level increased up to 4.48 mg/L at 33.6 °C (HQ 40d of HACH) where DO level was 0.24 mg/L at 33.6°C in raw mixer. In addition, the amount of alum as chemical coagulant was reduced in tannery waste water treatment by using indigenous snail shell powder as coagulant aid in conjunction with alum. In case of untreated sample after sedimentation required alum dozing was 6 mL/ 40 mL sample. After algal treatment, required alum dozing reduced to 4 mL/ 40 mL sample. By adding 3 mL/ 40mL liquid natural coagulant as coagulant aid, alum dozing was further minimized to 1 mL/ 40mL sample. The odour was more tolerable than raw mixer after algal treatment but after adding alum aided by natural coagulant, the odour was more acceptable than before. The diversified technique can hopefully reduce a reliable chemical cost in treatment process, considerable amount of pollution load and increase DO level and thus make effluent environment friendly to discharge. Finally, the DO level increases up to 6.56 mg/L at 33.7 0C and turbidity reduces to 183 NTU, pH reduces to 7.6, odour turns to be tolerable limit.

Microbial Community of Tannery Wastewater Involved in Nitrification Revealed by Illumina MiSeq Sequencing.

The aim of this study was to investigate the microbial community of three tannery wastewater treatment plants (WWTPs) involved in nitrification by Illumina MiSeq sequencing. The results showed that highly diverse communities were present in tannery wastewater. A total of six phyla, including Proteobacteria (37-41%), Bacteroidetes (6.04-16.80), Planctomycetes (3.65-16.55), Chloroflexi (2.51-11.48), Actinobacteria (1.91-9.21), and Acidobacteria (3.04-6.20), were identified as the main phyla, and Proteobacteria dominated in all the samples. Within Proteobacteria, Beta-proteobacteria was the most abundant class, with the sequence percentages ranging from 9.66% to 17.44%. Analysis of the community at the genus level suggested that Thauera, Gp4, Ignavibacterium, Phycisphaera, and Arenimonas were the core genera shared by at least two tannery WWTPs. A detailed analysis of the abundance of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) indicated that Nitrosospira, Nitrosomonas, and Nitrospira were the main AOB and NOB in tannery wastewater, respectively, which exhibited relatively high abundance in all samples. In addition, real-time quantitative PCR was conducted to validate the results by quantifying the abundance of the AOB and total bacteria, and similar results were obtained. Overall, the results presented in this study may provide new insights into our understanding of key microorganisms and the entire community of tannery wastewater and contribute to improving the nitrogen removal efficiency.

The role of salinity on the changes of the biomass characteristics and on the performance of an OMBR treating tannery wastewater

Tannery wastewaters are difficult to treat biologically due to the high salinity and organic matter concentration. Conventional treatments, like sequential batch reactors (SBR) and membrane bioreactors (MBR), have showed settling problems, in the case of SBR, and ultrafiltration (UF) membrane fouling in the case of MBR, slowing their industrial application. In this work, the treatment of tannery wastewater with an osmotic membrane bioreactor (OMBR) is assessed. Forward osmosis (FO) membranes are characterized by a much lower fouling degree than UF membranes. The permeate passes through the membrane pores (practically only water by the high membrane rejection) from the feed solution to the draw solution, which is also an industrial wastewater (ammonia absorption effluent) in this work. Experiments were carried out at laboratory scale with a FO CTA-NW membrane from Hydration Technology Innovations (HTI). Tannery wastewater was treated by means of an OMBR using as DS an actual industrial wastewater mainly consisting of ammonium sulphate. The monitoring of the biological process was carried out with biological indicators like microbial hydrolytic enzymatic activities, dissolved and total adenosine triphosphate (ATP) in the mixed liquor and microbial population. Results indicated a limiting conductivity in the reactor of 35 mS cm−1 (on the 43th operation day), from which process was deteriorated. This process performance diminution was associated by a high decrease of the dehydrogenase activity and a sudden increase of the protease and lipase activities. The increase of the bacterial stress index also described appropriately the process performance. Regarding the relative abundance of bacterial phylotypes, 37 phyla were identified in the biomass. Proteobacteria were the most abundant (varying the relative abundance between 50.29% and 34.78%) during the first 34 days of operation. From this day on, Bacteroidetes were detected in a greater extent varying the relative abundance of this phylum between 27.20% and 40.45%.

Identification of two low-cost and locally available filter media (pumice and scoria) for removal of hazardous pollutants from tannery wastewater

BackgroundTannery wastewater contains the most hazardous pollutants. Therefore, identifying potentially efficient, low-cost and locally available filter media as an adsorbent for the treatment of tannery wastewater is critical. The aim of this study is to identify and assess the ability of identified adsorbents and compare their efficiency. The volcanic rocks of pumice and scoria were collected from the rift valley area of Oromia region, Ethiopia and their chemical characteristics were determined using X-ray fluorescence analysis. Batch mode experimental study design was carried out. The rocks were crushed and effective size was determined by using a standard sieve. The composite tannery wastewater was collected from Dire tannery, Addis Ababa, Ethiopia and treated with pumice and scoria. Two adsorption kinetics and isotherm models were conducted to predict the removal mechanism and capacity of the adsorbents on the reduction of NO3–N, PO4–P and [Cr]T from tannery wastewater. Analysis of wastewater samples was done before and after different retention time. R statistical software and Originlab pro 2017 was run for data analysis and graphing.ResultsThe untreated tannery wastewater revealed that the mean concentration of BOD5, COD, TSS, orthophosphate, ammonium, nitrite, nitrate, sulfide, sulfate and chromium were beyond the permissible limits. Nitrate removal efficiency of scoria and pumice were 99 and 95% respectively at retention time of 72 h. Phosphate removal was better by scoria on the first 24 and 48 h. The efficiency of pumice to remove sulfate was 83–84%, whereas scoria shows 75–77%. In the first 24 and 48 h retention time, pumice and scoria achieved 76 and 71% in chromium reduction respectively.ConclusionThis study revealed that both scoria and pumice have a potential capacity to treat tannery wastewater. Conversely comparing the average efficiency to reduce hazardous pollutants scoria showed better results than pumice.

Tannery Wastewater Treatment Using Low Cost Coagulants with Simple Coagulation-Filtration Process

Tannery is the oldest industries in the world. It is characterized as pollutants generating industries, which produce wide varieties of high strength toxic residues. This study has been focused on the removal of physicochemical parameters of tannery wastewater through simple coagulation-filtration techniques using low cost coagulants. Standard methods were used for sampling and analysis. Removal efficiency was measured in terms of reduction of COD, BOD5, suspended solids (SS), total dissolved solids (TDS), conductivity and color. Several doses of coagulants e.g. alum, ferric chloride and their combination were used in treatment process. Maximum removal efficiency was obtained with the combination of alum and ferric chloride dosing at 75 mg/L in terms of color, BOD5, COD, TDS, SS and conductivity corresponding to 75%, 78%, 76%, 37%, 94% and 41% respectively and that were increased to92%, 82%, 80%, 48%, 98% and 51% respectively after sand-stone filtration. Ferric chloride and combination of alum and ferric chloride are recommended for the effective primary treatment of tannery wastewater. The filtration with multi-layer sand-stone filter was effective in removing of color, TDS, conductivity and SS.

Enhanced hexavalent chromium removal performance and stabilization by magnetic iron nanoparticles assisted biochar in aqueous solution: Mechanisms and application potential

The superiority of the nanoscale zero valent iron (nZVI) assisted biochar (BC) composites compared to traditional nZVI and its application feasibility are still unclear. This study aimed to provide valuable information for practical application. Firstly, the Fe/BC mass ratio of 2:1 during the preparation of nZVI-BC was proved obtaining the complete Cr6+ removal. Then, results revealed that the initial pH value tuned Cr6+ removal performance via varying existing Cr6+ species, surface charge, and chemical states of iron nanoparticles (NPs). Improvement of colloidal stabilization and positive surface charge attributed to enhancement of Cr6+ removal of nZVI-BC. The Cr6+ removal process was well described using pseudo-second-order kinetic. By Langmuir isotherm model, the maximum removal capacity (58.82 mg g−1) was determined. Moreover, the multiple evidences (XRD, XPS, FTIR, and TEM results) explained the mechanisms of Cr6+ removal (i.e. electrostatic force, complexes, metal reduction, and precipitates on the edges). Little inhibitory effect of coexisting anions (SO42−, PO43−, and NO3−) and well regeneration ability (82.2% removal efficiency after five cycles using acid washing), along with well Cr6+ removal efficiencies of real contaminated water (electroplating wastewater, tannery wastewater and groundwater) treatment, suggested nZVI-BC was considered as a superior and cost-effective choice for Cr6+ included polluted water treatment.

Influence of experimental parameters in the treatment of tannery wastewater by electrocoagulation

ABSTRACTElectrocoagulation (EC) was carried out using a laboratory-scale system for the treatment of tannery wastewater (TWW). Statistical experimental design was applied to investigate the effect of various operating parameters (OP) including initial pH, electrode material (EM), and effluent load (EL). Analysis of variance showed that the proposed models fitted well with the removal of COD and TSS; high coefficient of determination values were obtained (R2 > 0.99). The results show that the EL was an important factor affecting pollutant removal from TWW. COD and TSS removals are principally controlled by EL and initial pH. However, EM has no significant effect on TSS removal and its effect on COD removal is contracted at neutral pH medium. The treatment of TWW with an EL = Eff.am (COD0: 5634 mg l−1, TSS0: 910 mg l−1, and Cr0: 75 mg l−1) at neutral pH allows removal of more than 64%, 96%, and 99% of COD, TSS, and chromium, respectively, as well as a significant color reduction. Working at 68 mA and after 15 min of electrolysis process time, under optimal OP, the EC reactor operational cost is 2.01 US$ m−3. EC technique coupled to an equalization basin could be recommended as an effective process on TWW treatment.

An Effective Use of Anodizing Mud for Treatment of Tannery Wastewater as a Coagulation Agent

An Effective Use of Anodizing Mud for Treatment of Tannery Wastewater as a Coagulation Agent

Desirability function applied to the optimization of the Photoperoxi-Electrocoagulation process conditions in the treatment of tannery industrial wastewater

The aim of this work was to determine the optimal Photoperoxi-Electrocoagulation (PPEC) process experimental conditions for the treatment of a tannery industrial wastewater (TIW). The lab-scale PPEC-reactor comprises a pair of iron-flat plates, resulting in a contact effective area of 58.5 cm2; the PPEC reaction was conducted by electrochemical phenomenon associated to a Fenton’s reaction based on the H2O2 concentrations added, the solar UV–vis light was exposed, as well as iron ion dissolved original plate deterioration, resulting in a production of an efficient hydroxyl radical (OH). An optimising analysis using a response surface methodology was performed; the optimum conditions of the PPEC process were attained at a solution pH of 4, current density of 34.2 mA cm−2, 6 g H2O2 L−1 and an electrolysis time of 120 min. The effects on the removal of chromium and COD were evaluated, suggesting satisfactory results for the PPEC reaction. Based on the low calculated median lethal dose (LD50) values from a lettuce-seed-based ecotoxicity test, untreated TIW samples were completely lethal for doses with 100%, except for samples taken after 90 and 120 min. The PPEC process could be applied as an efficient low-cost alternative treatment for the removal of pollutants from TIW with a low environmental impact.

Fungi from industrial tannins: potential application in biotransformation and bioremediation of tannery wastewaters.

Tannins are a complex family of polyphenolic compounds, widely distributed in the plant kingdom where they act as growth inhibitors towards many microorganisms including bacteria, yeasts, and fungi. Tannins are one of the major components of tannery wastewaters and may cause serious environmental pollution. In the present study, four different tannins (the hydrolysable chestnut ellagitannin and tara gallotannin and the condensed quebracho and wattle tannins) were characterized from a mycological point of view with the aim of selecting fungal strains capable of growing in the presence of high tannin concentration and thus potentially useful in industrial biotransformations of these compounds or in the bioremediation of tannery wastewaters. A total of 125 isolates of filamentous fungi belonging to 10 species and four genera (Aspergillus, Paecilomyces, Penicillium, and Talaromyces) were isolated from the tannin industrial preparations. Miniaturized biotransformation tests were set up with 10 fungal strains and the high-performance liquid chromatography (HPLC) analysis pointed out a strong activity of all the tested fungi on both chestnut and tara tannins. Two strains (Aspergillus tubingensis MUT 990 and Paecilomyces variotii MUT 1125), tested against a real tannery wastewater, were particularly efficient in chemical oxygen demand (COD) and tannin removal (> 60%), with a detoxification above 74%. These results indicate that these fungi are potentially exploitable in the treatment of tannery wastewaters.

Treatment of composite chrome tannery wastewater in a Moving Bed Hybrid Bioreactor

Treatment of composite chrome tannery wastewater in a Moving Bed Hybrid Bioreactor

Use of tannery wastewater as an alternative substrate and a pre-treatment medium for biogas production

This study investigated biogas production as an alternative treatment of tannery wastewater (TWW) and its use as a pre-treatment medium to increase CH4 yield from anaerobic digestion (AD) of wheat straw. The TWW had high levels of sulfate and chloride, so biochemical CH4 potential could be estimated only when the TWW was diluted. Untreated straw yielded 255 NL CH4 (kg VS)−1, whereas straw that had been pre-treated with TWW yielded 314 NL CH4 (kg VS)−1 (35% increase). Treatment of TWW by AD with a co-substrate might be possible using a controlled feedstock mixing ratio. Use of TWW as a pre-treatment medium by simple co-storage before AD would be beneficial as an inexpensive treatment of lignocellulosic biomass.

Facile method to immobilize ZnO particles on glass spheres for the photocatalytic treatment of tannery wastewater

In order to apply the photocatalytic processes on a real scale for the treatment of industrial wastewaters, the use of slurry reactors employing suspended photocatalysts is not suitable due to the need for an uncomfortable and expensive separation phase of photocatalyst. To overcome this disadvantage, the photocatalyst particles must be immobilized on a transparent support: our work proposes, for this reason, a simple and cost effective method for the deposition of ZnO photocatalyst on glass spheres in order to formulate a structured photocatalyst effective in the treatment of aqueous solutions containing various organic dyes, commonly used in the tannery industries and in the treatment of a real wastewater at high COD content (11 g/L) coming from the refining unit of the tanning process. In particular, ZnO was immobilized on glass spheres (ZnO/GS) with a simple dip coating method, starting from zinc acetate aqueous solution, without using complexing agent and strong basic compounds. The optimization of ZnO amount on glass spheres was evaluated employing Acid Blue 7 dye, as model pollutant. In particular, it was found that best performances in terms of discoloration and mineralization of the target dye were obtained using the photocatalyst with a ZnO loading equal to 0.19 wt% (ZnO_ac1), prepared through only one dip-coating step. Moreover, the ZnO_ac1 photocatalyst can be easily separated from the reaction mixture, maintaining excellent photocatalytic activity and durability even after several reuse cycles. Finally, ZnO_ac1 showed a high photocatalytic activity in the treatment of the real wastewater, obtaining a COD removal equal to 70% after 180 min of UV light irradiation.

On the critical use of zero valent iron nanoparticles and Fenton processes for the treatment of tannery wastewater

The use of iron nanoparticles in the heterogeneous Fenton oxidation treatment of tannery wastewater was investigated. A comparison with the conventional oxidation process, involving Fe(II) addition was performed. The main operating parameters influence, such as pH, temperature and reagents amount, on total phenolic species, total organic compounds, Cr(VI) content and chemical oxygen demand reduction was investigated.Heterogeneous Fenton oxidation resulted more efficient and fast with respect to the conventional process, but a higher amount of iron was required in the process. In this case, the optimal conditions were assessed at H2O2/COD (w/w) = 0.5, nZVI/H2O2 (w/w) = 0.75 and pH = 3, achieving a total Cr(VI) removal as well as a remarkable TOC, COD and phenols degradation efficiency (up to 70, 73 and 88%, respectively). The best results were obtained with the combination of the two processes, fixing the optimal conventional Fenton operating parameters (H2O2/COD (w/w) = 0.75, Fe(II)/H2O2 (w/w) = 0.15 and pH = 2.5), adopting a nZVI/H2O2 (w/w) ratio equal to 0.2. In such conditions, that also allowed to reduce the catalyst amount used with respect to the Heterogeneous Fenton process, a noticeable TOC, COD and phenols removal efficiency (81.15, 87.44 and 94.04%, respectively) was achieved. In addition, the iron sludge production of such combined process was close to that obtained in the conventional one.

Treatment of tannery wastewater using a combined UASB (2 stage)-ozonation-BAF system

Treatment of tannery wastewater using a combined UASB (2 stage)-ozonation-BAF system

Elimination of chemical sludge for treatment of tannery wastewater and its effect on biogas generation

Elimination of chemical sludge for treatment of tannery wastewater and its effect on biogas generation

Photocatalytic Reduction of Chromium (VI) in a Typical Hides and Skin Industrial Wastewater using ZnO/γ-Al2o3 Photocatalyst under Visible LIGHT

Photocatalysis is an advanced oxidation process that can degrade and mineralize organic pollutants in wastewater to carbon dioxide and water which was employed in this study. Tannery effluent was treated via batch photoreduction using Zinc oxide photocatalyst supported on y-Al2O3 and irradiated under visible light at the ambient condition of temperature. Zinc oxide obtained from Zinc ore and y-Al2O3 prepared from local kaolin were used to synthesize the ZnO/y-Al2O3. The synthesized photocatalyst was characterized by Brunnaer Emmett Teller (BET), X-ray Diffraction Spectroscopy (XRD), Scanning Electron Microscope (SEM), and X-ray Fluorescence (XRF). The result of the analysis reveals that the total surface area, total pore volume and mean pore size of the photocatalyst prepared were 65.452 m2g-1, 0.151 cm3g-1 and 9.892 nm respectively. The photocatalyst is crystalline and the SEM image shows the presence of pores. The ZnO/y-Al2O3 was used as a photocatalyst to reduce Chromium (VI) of a typical tannery wastewater. 96% reduction of 20 mg/L of Cr (VI) was achieved at 60 min, pH of 3, and a photocatalyst dosage of 2.5 g/L under visible light of 400 W intensity. The kinetic study revealed that the photoreduction was fitted into the pseudo-first-order Lagmuir-Hinshelwood kinetic model. This research demonstrated that ZnO/y-Al2O3 photocatalyst was effective in the photoreduction of the selected response for the treatment of tannery wastewater.

Method for Determining the Optimized Exhaustion of Fatliquors to Minimize the ETP-inflow

The proposed amendment of the German regulation for the treatment of tannery wastewaters (ATV-DVWK-M774-proposal 2015) emphasizes minimization of the pollution burden before treatment (inflow) [1]. Current regulations are directed towards setting limits to what may leave an ETP (outflow). The new provisions, on the other hand, demand that a verifiable reduction of the polluting load is realized before the water enters the treatment system. An absolute decrease at the level of individual components requires the measurement of these components for a starting point. This paper discusses the ways of expressing the exhaustion of a selection of fatliquors on chrome and chrome-free leathers. Each product has a specific affinity to the tanned hide and an individual environmental imprint. This specificity can be used for targeted reduction of the inflowing pollution burden. The findings of the study can act as a starting point for setting up an own methodology and a detailed level of reporting for all who need to understand a fatliquor's true affinity towards the leather and those who endeavor to minimize the environmental impact of their processing.

The investigation of chemical coagulation and electrocoagulation processes for tannery wastewater treatment using response surface methodology

The investigation of chemical coagulation and electrocoagulation processes for tannery wastewater treatment using response surface methodology

Improved treatment of tannery wastewater treatment plant effluent using polymeric coagulants

Improved treatment of tannery wastewater treatment plant effluent using polymeric coagulants