Tannery Industry Wastewater Research Articles

Removal of chromium from tannery industry wastewater using iron-based electrocoagulation process: experimental; kinetics; isotherm and economical studies

Chromium is a hazardous compound from industrial processes, known for its toxicity, mutagenicity, teratogenicity, and carcinogenicity. Chemical methods are efficient but cost-effective alternatives with reduced sludge are sought. Electro-coagulation, utilizing low-cost iron plate electrodes, was explored for factual tannery wastewater treatment in this manuscript. Operating parameters such as initial chromium concentration, voltage, electrode number, operating time, agitation speed and current density has been studied to evaluate the treatment effeciency. Under optimal conditions (15 V, 0.4 mA/cm2, 200 rpm, 330 ppm chromium, 8 iron electrodes with a total surface area of 0.1188 m2, 3 h), chromium elimination was 98.76%. Iron anode consumption, power use, and operating cost were 0.99 gm/L, 0.0143 kW-h/L, and 160 EGP/kg of chromium eliminated, respectively. Kinetics studies were pursued first-order reaction (97.99% correlation), and Langmuir isotherms exhibited strong conformity (Langmuir R2: 99.99%). A predictive correlation for chromium elimination (R2: 97.97%) was developed via statistical regression. At HARBY TANNERY factory in Egypt, industrial sewage treatment achieved a final chromium disposal rate of 98.8% under optimized conditions.

Magnetite-impregnated biochar of parthenium hysterophorus for adsorption of Cr(VI) from tannery industrial wastewater

The tannery industry inevitably generates toxic and catastrophic wastewater, which results in a huge threat to public health and water resources. Therefore, this work aimed to synthesize parthenium hysterophorus-based biochar–Fe3O4 composite for removal of Cr(VI) from tannery wastewater under 34 full factorial experimental designs of the Box–Behnken, which was analyzed using response surface methodology under four independent factors of pH (3, 6, and 9), initial Cr(VI) concentrations (40, 70, and 100 mg/L), contact times (30, 60, and 90 min), and adsorbent doses (20, 60, and 100 mg/100 mL). This composite adsorbent was described by a high BET surface area of 237.4 m2/g, XRD prominent peaks, SEM morphology corroborate and FTIR multifunctionalities of O–H at 3296 cm−1, the vibration of ketone C–OH at 1240 cm−1, and the vibration of C–O–C at 1147 cm−1 and Fe–O stretching at 542 cm−1. The maximum Cr(IV) removal efficiency of 91.8% was recorded at an initial Cr(VI) concentration of 40 mg/L, pH of 3, adsorbent dose of 100 mg/100 mL, and a contact time of 90 min, whereas the minimum Cr(VI) removal of 17.3% was observed at an initial Cr(VI) concentration of 100 mg/L, 20 mg/100 mL of adsorbent dose, pH of 9, and contact time of 30 min. The concentration of Cr(VI) in real wastewater was determined to be 85.13 mg/L and its remediation was found to be 81.8%. Langmuir’s model was the best fit with experimental data at R2 0.99 and qmax 400 mg/g, showing that the adsorption process was homogenous and monolayer. In conclusion, the adsorption results were encouraging, and biochar–Fe3O4 appears to be a potential candidate for Cr removal from wastewater.

Removal of chromium from tannery wastewater by rice husk ash nanosilica

AbstractA study on the removal of hexavalent chromium by adsorption of rice husk nanosilica was attempted. The usage of chromium causes immense pollution as it is used in the leather industry, metal finishing, electroplating, and chromate preparations. To understand the adsorption capacity and its behavior, as well as the adsorption potential of rice husk nanosilica, the effluent used in this experiment is tannery wastewater. The experiment was conducted in tannery industrial wastewater using nanosilica extracted from rice husks ash for various pH, contact time, and adsorbent dosages. The result shows 88.3% chromium removal using rice husk ash nanosilica (RHANS) at pH 4, 1.75 mg adsorbent dosage, and 50 min of contact time. Removal of chromium by this method was a more economical and alternative process. RHANS was selected due to its source availability and antimicrobial properties.

Dual step synthesis of chromium removal from tannery industry wastewater with photocatalytic effects of TiO2

Dual step synthesis of chromium removal from tannery industry wastewater with photocatalytic effects of TiO2

Water and wastewater management in a small tanning facility

This paper presents a tannery industry's water and wastewater management problem. Information has been collected on the volume of water demand and, consequently, wastewater generation in these plants. This made it possible to relate them to the values generated by one of the smaller tanning plants located in Poland. The concentration of the pollutants contained in this wastewater, mainly chromium, was also determined from the study. Management of wastewater is a financial nuisance for small plants. The need to conclude contracts with specialized treatment plants, storage and long-distance transport of sewage, also by the respective companies, generates considerable costs, which may be a limiting factor of the willingness to invest in production. Wort reuse reduces the cost of purchasing chromium as a bath ingredient, reduces the frequency of waste disposal and significantly reduces company costs.

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.

Tannery wastewater treatment coupled with bioenergy production in upflow microbial fuel cell under saline condition

Tannery industry handling huge amount of leather materials release immense amount of saline organic content wastewater. The present research was focused on the treatment of tannery industrial wastewater in UMFC (upflow microbial fuel cell) under saline condition (4%). The UMFC reactor was operated at different organic load (OL) such as 0.6, 1.2, 1.8 and 2.4 gCOD/L respectively. Total chemical oxygen demand (TCOD) removal at 0.6, 1.2, 1.8 gCOD/L was 87 ± 1.2%, 91 ± 1.2% and 93 ± 1.8% respectively. Soluble chemical oxygen demand (SCOD) removal in UMFC at 0.6, 1.2, 1.8 gCOD/L was 85 ± 0.6%, 88 ± 1.2% and 91 ± 1.8% respectively. Total suspended solids (TSS) removal was 49%, 78%, 81% at 0.6, 1.2, 1.8 gCOD/L OL in UMFC. Further, raise in OL to 2.4 gCOD/L showed decrease in TCOD, SCOD (80% and 72%) and TSS (60%) removal. Maximal power production of 854 mV with corresponding PD (power density) of 462 mW/m2 and CD (current density) of 523 mA/m2 was registered at 1.8 gCOD/L OL in UMFC. Increase in OL to 2.4 gCOD/L revealed decline in energy production to 810 mV with PD (385 mW/m2) and CD (438 mA/m2) in UMFC. Maximal bioaccumulation of chromium (95%) was recorded at 1.8 gCOD/L OL. Among different OL used 1.8 gCOD/L OL was optimum for the treatment of tannery wastewater and energy production. Bacterial community analysis in anode of UMFC revealed the dominance of promising electrogenic halophilic strains such as Ochrobactrum, Marinobacter, Rhodococcus and Bacillus in all the OL. Thus, the research clearly revealed the efficacy of halophilic consortium to treat the saline tannery wastewater coupled with bioenergy production in UMFC.

Synergetic effects of mixing parameters, settling characteristics and process kinetics on coagulation treatment of tannery industry wastewater

Synergetic effects of mixing parameters, settling characteristics and process kinetics on coagulation treatment of tannery industry wastewater

A bench-scale electrochemical peroxidation reactor performance on removal of organic pollutants from tannery industrial wastewater

A bench-scale electrochemical peroxidation reactor performance on removal of organic pollutants from tannery industrial wastewater

The application of GO-Fe3O4 nanocomposite for chromium adsorption from tannery industry wastewater

The discharge of untreated tannery industrial wastewater into the environment has resulted in an adverse effect on the ecosystem and public health. Therefore, this work aimed to remove chromium ions from tannery wastewater through magnetite graphene oxide-nanocomposite (GO-Fe3O4). The experimental design of the study was a full factorial 24 approach using pH, adsorbent dose, contact time, and initial chromium concentrations. The results of FTIR analysis revealed the presence of functional groups such as hydroxyl (3438 cm−1), alcohol (1230 cm−1), aromatic (1467 cm−1), ketone (1629 cm−1), and ether (1120 cm−1). Similarly, GO-Fe3O4 acquired a high surface area of 296.2 m2/g whereas the XRD analysis showed the presence of predominant peaks which are attributed to the magnetite component. Moreover, the SEM image showed many ups and downs on the surface of the adsorbent. These cracks of morphology can create a conducive environment for the interaction of adsorbent and adsorbate. The maximum chromium removal of 95.9% was achieved at the optimum conditions of the initial chromium concentration of 40 mg/L, pH 4, adsorbent dose 1 g/100 mL, and contact time of 120 min whereas the removal of chromium from real tannery wastewater was found to be 90.3%. Based on the adsorption isotherm, the Langmuir model was the best fit for experimental data at R2 0.99, indicating homogeneous and monolayer adsorption. Finally, it can be concluded that GO-Fe3O4 was effective for chromium removal, which is a promising technology to be scaled up at the industrial level for wastewater treatment.

Membrane distillation crystallization for simultaneous recovery of water and salt from tannery industry wastewater using TiO2 modified poly(vinylidene fluoride-co-hexafluoropropylene) nanocomposite membranes

Membrane distillation crystallization (MDCr) is a promising technology for simultaneous water recovery and salt crystallization from tannery industry wastewater. We synthesized TiO2 modified poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanocomposite flat sheet membranes to treat tannery industry wastewater by MDCr. The influence of TiO2 nanoparticles morphologies on membrane performance (salt rejection and water flux) was investigated. The nanocomposite membranes were analyzed for surface morphology, thermal stability, porosity, water flux, and salt rejection. It was demonstrated that the TiO2 modified PVDF-HFP nanocomposite membrane showed improved hydrophobicity, porosity and number of pores; thus, water flux significantly increased without any deterioration in salt rejection. Among different membranes, decanoic acid-modified TiO2 nanoparticles (bipyramidal morphology) nanocomposite membrane (M-1B) showed 6.1 kg m−2 h−1 water flux with ~100% salt rejection with mixed synthetic salt solution (1% NaCl and Na2SO4, each) feed. Using real tannery industry wastewater, the M-1B membrane showed 5.9 kg m−2 h−1 water flux and 99.97% salt rejection. The crystallization of salts revealed cubic NaCl crystals and monoclinic Na2SO4 crystals in the wastewater. The XRD spectra revealed a high purity of salts and ruled out any co-crystallization. These findings suggested the potential candidature of the M-1B membrane for the treatment of tannery industry wastewater by the MDCr process. The recovered salt and water can also be re-used in the tannery industry.

Assessment of algal biomass towards removal of Cr(VI) from tannery effluent: a sustainable approach.

The current investigation focuses on a systematic study of application of two dried algal biomass (i.e., Nostoc sp. and Turbinaria vulgaris) in removal of Cr(VI) from synthetic solution as well as tannery industrial wastewater. The optimized conditions for Cr(VI) removal are nearly same for the both the biosorbents (i.e., pH 2.8, initial Cr(VI) concentration 100 mg L-1, biomass dosage of 1.2g L-1, contact time 120 and 110 min). Nostoc sp. (qmax=23.94mg g-1) was observed to possess a superior removal capability when compared to Turbinaria vulgaris (qmax=21.8mg g-1). Desorption studies were performed with four different desorbing agents. Application study was conducted using tannery wastewater with Nostoc sp. and 94.20% removal of Cr(VI) was obtained. Hence, this study revealed that Nostoc sp. and T. vulgaris both have great potential to be an environment friendly and economic biosorbent for removal of Cr(VI) containing industrial effluent.

Constructed wetlands as a sustainable technology for wastewater treatment with emphasis on chromium-rich tannery wastewater

Water scarcity is a major threat to agriculture and humans due to over abstraction of groundwater, rapid urbanization and improper use in industrial processes. Industrial consumption of water is lower than the abstraction rate, which ultimately produces large amounts of wastewater such as from tannery industry containing high concentration of chromium (Cr). Chromium-contaminated tannery industry wastewater is used for irrigation of food crops, resulting in food safety and public health issues globally. In contrast to conventional treatment technologies, constructed wetlands (CWs) are considered as an eco-friendly technique to treat various types of wastewaters, although their application and potential have not been discussed and elaborated for Cr treatment of tannery wastewater. This review briefly describes Cr occurrence, distribution and speciation in aquatic ecosystems. The significance of wetland plant species, microorganisms, various bedding media and adsorbents have been discussed with a particular emphasis on the removal and detoxification of Cr in CWs. Also, the efficiency of various types of CWs is elaborated for advancing our understanding on Cr removal efficiency and Cr partitioning in various compartments of the CWs. The review covers important aspects to use CWs for treatment of Cr-rich tannery wastewater that are key to meet UN’s Sustainable Development Goals.

Particle size distribution modeling and kinetic study for coagulation treatment of tannery industry wastewater at response surface optimized condition

The presence of considerable amounts of Total Suspended Solids (TSS) in wastewater streams can pose a severe threat to aquatic and human life. A high level of TSS will increase water temperature at an alarming rate and decrease dissolved oxygen levels. This study aims to remove TSS from raw tannery wastewater using an active coagulating protein extracted from Moringa oleifera (MO) seeds. The process variables such as, coagulant dosage and pH are varied to test the potential of the coagulant extracted using NaCl and KCl salt solutions, for TSS removal from tannery wastewater. The results show that the NaCl extracted coagulant could effectively remove 89.87% of TSS whereas the KCl extracted coagulant eliminated 76.23% of TSS, at the optimum condition of 40 mL coagulant dosage and 7 pH. The assessment of coagulation rate parameters using differential method of analysis reveals that at optimum condition, the TSS reduction process obeys second order kinetics with a rate constant 3.556 × 10– 5 (mg/L)– 1 min– 1. The volume distribution of suspended solids in raw wastewater is fitted with a log-normal distribution model and Gaussian distribution model. From the magnitude of the coefficient of determination (R2) and Akaike information criterion (AIC) of the Gaussian model (R2 = 0.6864 and AIC = 3.89), it is concluded that the Gaussian model is better than the log-normal distribution model (R2 = 0.4708 and AIC = 6.31) for explaining the volumetric distribution of suspended particles. The numeric distribution of suspended solids in raw wastewater is explained well by the variable β model (R2 = 0.668) rather than the power law model (R2 = 0.196). The 3D response surface plot indicates that maximum TSS removal can be achieved at an optimal condition of 40 mL coagulant dose and 7 pH. The quadratic model developed for the treatment process utilizing the NaCl extracted coagulant shows better response prediction ability (R2 = 0.8118) when compared to the model built for the KCl extracted coagulant (R2 = 0.7911). Both the model equations have a p-value less than 0.05 which indicates that the proposed models are statistically significant. The elliptical contours for TSS removal using NaCl extracted coagulant demonstrate the significant interactions between the process variables. This study exhibited the applicability of MO seed extract for real-time tannery wastewater treatment.

Statistical modeling and optimization of tannery wastewater treatment in a fluidized bed bioreactor with low density biomass support

Treatment of tannery industry effluent is a serious challenge due to the presence of toxic pollutants including dyes and heavy metals. This work is focused on the optimization of bed height and air flow rate for tannery industry wastewater treatment in a fluidized bed reactor with low density biomass support. Response surface methodology was adopted for the optimization of process parameters viz air flow rate, bed height and wastewater dilution ratio and the best operating conditions were identified. The optimum values for the maximum chemical oxygen demand (COD) removal are: air flow rate—233 LPH, Bed height—82 cm and wastewater dilution ratio—1:2. The results from the IFBR showed that a maximum of 90.2% of COD reduction obtained at an airflow rate of 233 LPH and initial bed height of 82 cm. In this research, a maximum colour removal of 83.4% was achieved. A high correlation coefficient (R2) value of more than 0.94 for all the three models indicates that the RSM based models predict the data well. The relative effect of variables on COD removal, colour removal and air hold up were depicted in perturbation plots.

Establishing the process kinetics and appraising model predictive behavior for coagulation treatment of tannery industry wastewater

The residual coloring agents present in tannery wastewater degrades the quality of ecosystem and limits photosynthetic activity in aquatic biosphere apart from causing displeasing appearance. This study is conducted to test the ability of protein coagulant extracted from Moringa oleifera (MO) seeds for removing the color from tannery wastewater. Different salt solutions such as NaCl, KCl, MgCl2 and NH4Cl were used individually to extract the coagulant from MO seeds. The color removal efficiency was the highest for NaCl extracted coagulant (75.14%) and least for MgCl2 extracted coagulant (62.38%). The coagulant extracted for 30 min duration and stored for one day at 278 K removed 75.14% coloring agents from wastewater. The efficiency of NaCl-extracted coagulant was investigated by varying the parameters such as NaCl concentration (0.1 N–0.4 N), initial pH (3–10), coagulant dose (10 mL–50 mL) and coagulant storage temperature (278 K–298K). The differential method of analyzing kinetic data indicates that process obeys second order mechanism because a plot between the rate of change in color intensity and square of the fraction of residual color is a parabolic curve. The interrelationship between response and process variables was studied using linear, exponential, logarithmic, second order polynomial and power law models. Highest color removal of 75.14% was achieved at optimal conditions of 0.2 N NaCl solution, pH 8, 40 mL dose and 278 K storage temperature. It was ascertained that the power law model (R2 = 0.906) truly reflected the system behavior, while the linear model (R2 = 0.797) had poor prediction capability.

Efficiency of Electrocoagulation Method to Reduce COD, BOD and TSS in Tannery Industry Wastewater: Application of the Box-Behnken Design

This study intends to assess the removal efficiency of the chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS) from raw tannery wastewater using electrocoagulation by aluminum electrodes as well as to determine the effects of its main operating factors. Therefore, the response surface methodology was applied through an experimental Box-Behnken design by considering the current intensity (I), treatment time (T), and pH levels as the factors. In addition, the BOD, COD, and TSS removal percentages were considered to be the response variables. The results indicate that the treatment time, current intensity, and pH level were significant for COD and TSS, whereas only the treatment time was significant at a confidence level of p-value < 0.05 for BOD. For COD, the optimal operating conditions were I = 3 A, T = 24 min, and pH = 8.4; for BOD, the optimal operating conditions were I = 3 A, T = 24 min, and pH = 5.5; and for TSS, the optimal operating conditions were I = 2.7 A, T = 19 min, and pH = 7.4. Under these conditions, removal efficiencies of 56.8%, 69.2%, 99.9% were observed for COD, BOD, and TSS, respectively. The results suggest that electrocoagulation is an effective method for removing the parameters under study; therefore, it is a viable alternative for reducing the pollution issues caused by the tannery industry.

Evaluación de la eficiencia de un sistema de electrocoagulación en los vertimientos de curtiembres en el sector de Villapinzón (Cundinamarca)

espanolEl presente articulo presenta el analisis del vertimiento de curtiembres en Villapinzon (Cundinamarca, Colombia) y propone un sistema de electrocoagulacion para la minimizacion de contaminantes (principalmente metales pesados) vertidos directamente a los cuerpos de agua. Las descargas directas al Rio Bogota (tramo Villapinzon-Choconta) sin previo tratamiento generan afectaciones en la calidad de los cuerpos de agua, ademas de afectar la salud de la poblacion. Por ende, para este estudio se diagnostico el estado actual de los vertimientos en el Rio Bogota. Adicionalmente, se llevo a cabo una busqueda de informacion acerca del proceso de electrocoagulacion, la cual sirvio de base para el diseno e implementacion a escala laboratorio con las muestras del vertimiento de una curtiembre del sector a analizar. Despues de la implementacion del sistema se obtienen los siguientes porcentajes de remocion: Cr (52,8 %), dqo (36 %), nitritos (99,6 %), nitratos (99,4 %), sulfatos (92,9 %) y fosfatos (99,1 %). Estos parametros fueron evaluados de acuerdo con la normativa vigente (Resolucion 0631 de 2015 del Ministerio de Ambiente y Desarrollo Sostenible) y el acuerdo 08 del 2004 de la car, donde 6 de 10 parametros se ajustaron a la normativa. De esta manera, se concluye que el sistema de electrocoagulacion es una alternativa viable como tratamiento no convencional para el tratamiento de aguas residuales industriales de curtiembre, contribuyendo asi a la disminucion de los impactos generados a la cuenca alta del Rio Bogota. EnglishThis article presents the analysis of the shedding of tanneries in Villapinzon (Cundinamarca, Colombia) and proposes an electrocoagulation system for the minimization of pollutants (mainly heavy metals) discharged directly to the bodies of water. Direct discharges to the Bogota River (Villapinzon-Choconta section) without prior treatment generate effects on the quality of water bodies, in addition to affecting the health of the population. Therefore, for this study, the current state of the discharges in the Bogota River was diagnosed. Additionally, an information search was conducted on the electrocoagulation process. This search served as the basis for the design and implementation of the laboratory-scale electrocoagulator model with the samples of the shedding of a tannery in the sector to be analyzed. After the implementation of the system, the following removal percentages are obtained: Cr (52.8%), cod (36%), nitrites (99.6%), nitrates (99.4%), sulfates (92.9%) and phosphates (99.1%). These parameters were evaluated in accordance with current regulations (Resolution 0631 of 2015 of the Ministry of Environment and Sustainable Development) and agreement 08 of 2004 by the car, where 6 out of 10 parameters were adjusted to the regulations. Thus, it is concluded that the electrocoagulation system is a viable alternative as an unconventional treatment for the treatment of tannery industrial wastewater, thus contributing to the reduction of the impacts generated to the upper Bogota River basin.

Facile development of sunlit ZnO nanoparticles-activated carbon hybrid from pernicious weed as an operative nano-adsorbent for removal of methylene blue and chromium from aqueous solution: Extended application in tannery industrial wastewater

Abstract In this study, zinc oxide nanoparticles (ZnO-NPs) and activated carbon (AC) are produced from parthenium weed plant using a green synthesis technique. ZnO-NPs loaded parthenium weed activated carbon (ZnONPs-PWAC) is used to remove pollutants (Methylene Blue (MB) and Chromium (Cr (VI)) from aqueous solution and also extended to treat with real industrial tannery wastewater. A comprehensive analysis is done with various forms of ZnO based particles (ZnO-NPs, ZnONPs-PWAC) to test its photocatalytic activity. Further, the photocatalytic activity of biosynthesized ZnO-NPs is evaluated by measuring the efficiency of decolorization (>93%) for different dyes (Malachite Green, Congo Red, and Methylene Blue) under sunlight irradiation. The maximum removal (> 99%) of MB is obtained at 60 min by ZnONPs-PWAC and 130 min by PWAC. The maximum equilibrium percentage removal of Cr (VI) is found to be 99% around 90 min for ZnONPs-PWAC and 160 min for PWAC. The enhancement in removal efficiency is due to the combined reaction of photocatalysis and adsorption. The parameters such as pollutant concentration, pH, and the amount of ZnONPs-PWAC are varied to understand its effective removal of MB and Cr (VI) in wastewater. Moreover, the efficiency of ZnONPs-PWAC is found to be more than 92% against industrial tannery wastewater. Overall, ZnONPs-PWAC can be used as an alternative and operative material to remove MB and Cr (VI) in wastewater treatment.

Application of Dbaf Technique for Tannery Industry Wastewater Treatment

With the interest in environmental protection the interest in industrial wastewater treatment had increased especially with enlargement in industry and the increase of the treatment cost that affect the products prices. This study aimed to investigate the suitability of applying the Dual Biological Aerated Filter (DBAF) as new low cost technique system for biological treatment preceded by a chemical precipitation to treat industrial wastewater of tannery industry. This new technology decreases construction costs, O&M costs and safe land required with high efficiency. The research made on a plant erected in Shahien tannery in Alexandria operated for five months. Where studied the factors affect the plant efficiency under all operation conditions due to operation program, chemicals used, rates and the effects on plant loads to obtain its suitability for such type of wastewater. The study proved the applicability of the system for such wastewater. The removal ratios for BOD, COD & Cr were 88.05%, 85.5%, 98.85% respectively .Which are high values for treatment efficiency of such type of wastewater and a good efficiency for TSS removal achieved. Also the system did not affected by sudden variations in loads or the non uniformity in tannery operation. The economic comparison with other treatments previously used approved the economy of this system.