Tannery Effluent Treatment Research Articles

Physicochemical and Bacteriological Assessment of Tannery Effluent from Samaru - Zaria, Kaduna State, Nigeria

Physicochemical and bacteriological assessment of tannery effluent from Samaru -Zaria was carried out. A total of six (6) tannery effluent samples (from site A- point of discharge, site B- 20m from point of discharge, site C- 40m from point of discharge, site D- 60m from point of discharge, site E- 80m from point of discharge and site F- 100m from point of discharge) were collected from the Nigerian Leather and Science Technology, Samaru - Zaria, Kaduna State in sterile labeled screw capped bottles. Physicochemical and bacteriological analysis was carried out using standard techniques. The physicochemical analysis revealed the appearance of the effluent to be dark-brown with unpleasant odour. the effluent further revealed the presence and at different concentrations of total solids, total suspended solids, total dissolved solids, total hardness, magnesium, sodium, potassium, iron, manganese, nitrite, nitrate, chloride, fluoride, sulphate, phosphate, cadmium, zinc and copper, chemical oxygen demand (COD), biological oxygen demand (BOD), oil and grease all in mg/L except pH. Bacillus sp had percentage occurrence of 100%, Pseudomonas sp had 83.3%, Flavobacterium , Micrococcus and Staphylococcus sp had 66.7% each, Proteus and Klebsiella sp had 50.0% occurrence each, Streptococcus had 33.3% while Escherichia coli had the least percentage of occurrence of 16.7 from the samples of the tannery effluent analyzed respectively. The highest viable count was observed from site F which is 100m away from the point of discharge and had 4.09 x 10 7 cfu/ml and the lowest from site A (point of discharge) with 1.2 x 10 7 cfu/ml. The treatment of tannery effluents before discharge into the environment is necessary using biotreatment. This will reduce or eliminate environmental pollutions which could be detrimental to humans, animals and plants. Keywords : Physicochemical, bacteria, COD, BOD, effluent

Treatment of tannery effluent by passive uptake-parametric studies and kinetic modeling.

Galactomyces geotrichum was utilized as a potential biosorbent for the treatment of tannery effluent under controlled environmental conditions. Tannery effluent treatment was studied through parametric experiments to study the effect of effluent pH (3.0-10.0), initial COD (1100-4400mg/L), and biosorbent dosage (0.3-3.0g/L).The zeta potential of the biosorbent was determined and found to influence the optimal pH. Increase in effluent COD values resulted in decreased COD removal percentages which attributed to limited availability of surface active sites. The equation relating the COD removal efficiency and biosorbent dose was proposed. Two popular kinetic models, namely pseudo-second order and power function models, were employed to the experimental data. Pseudo-second order model proved to be a good fit with high values of regression coefficient (R 2>0.960). Potential application of a fungal biosorption process was explored and the optimal process parameters were identified.

Advanced oxidation processes for the treatment of tannery wastewater

This study has focused on the treatment of real tannery effluent using different advanced oxidation processes in lab and pilot scale studies. Periodic monitoring was conducted for five months to identify the performance at different stages of treatment in the CETP. Monthly monitoring analysis shows that ratio of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were about 0.1–0.25. It was observed that even after physicochemical treatment the sample had a low biodegradability index (BDI). For this reason, more efficient methods of advanced oxidation processes like Fenton, Ozonation have been experimented with primary settling tank (PST) effluent to improve the biodegradation in the successive activated sludge process and secondary settling tank (SST) effluent to remove the residual inorganics. Sample collection and analysis were performed using standard methods of analysis. Pollutant removal efficiency was measured in terms of reduction in COD and Total Organic Carbon (TOC). The purification effect obtained by Advanced Oxidation Processes (AOPs) was better in Ozone when compared to Fenton. A three step process of (coagulation+aeration+O3) resulted in 80–90% reduction of COD. Coagulation, extended aeration followed by ozonation was recognized as the best method of treatment of tannery wastewater. Lab scale and pilot scale studies were done with real tannery wastewater effluents and the economics of the treatment processes were evaluated.

Removal of organic and inorganic substances from industry wastewaters using modified aluminosilicate‐based polyethersulfone ultrafiltration membranes

Membrane separation processes are attracting increasing interest for the treatment of industrial wastewaters owing to its high organic and inorganic content removal efficiency and material stability. Herein, we have presented an approach to modify polyethersulfone (PES) membrane using aluminosilicate particles (ASPs) for high permeability and separation performance against tannery and distillery wastewater. PES:ASPs ultrafiltration membrane was developed by phase inversion technique at different weight ratios of 0:100, 10:90, 20:80, 30:70, and 40:60 of PES:ASPs. The functional groups and hydrophilicity were analyzed by X‐ray diffraction (XRD) and contact angle, respectively. The modified membranes displayed improved wastewater permeability and higher flux compared to the neat PES membrane. The moderate removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids, chlorides, and sulfates from tannery and distillery wastewaters were attained for all ASPs‐based PES membranes. In the case of tannery effluent treatment, high BOD reduction of 92% was observed for 80:20 weight ratio of PES:ASPs membrane and 75% BOD reduction for the pure PES membrane. The sulfides removal was 2.21 mg L−1 for 90:10 weight ratio of PES:ASPs membrane when compared with the initial quantity of 42 mg L−1 distillery wastewater. The PES:ASPs membrane with 80:20 weight ratios presented the best COD and BOD removal performance. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1612–1620, 2017

Tannery Effluent Treatment by Yeast Species Isolates from Watermelon.

The quest for an effective alternative means for effluent treatment is a major concern of the modern-day scientist. Fungi have been attracting a growing interest for the biological treatment of industrial wastewater. In this study, Saccharomycescerevisiae and Torulasporadelbrueckii were isolated from spoiled watermelon and inoculated into different concentrations of effluent. The inoculants were incubated for 21-days to monitor the performance of the isolates by measurement of biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrates, conductivity, phosphates, sulphates and turbidity. The results showed that Saccharomycescerevisiae had the highest percentage decrease of 98.1%, 83.0%, 60.7%, 60.5%, and 54.2% for turbidity, sulphates, BOD, phosphates and COD, respectively, of the tannery effluent. Torulasporadelbrueckii showed the highest percentage decrease of 92.9%, 90.6%, and 61.9% for sulphates, COD, and phosphates, respectively, while the syndicate showed the highest percentage reduction of 87.4% and 70.2% for nitrate and total dissolve solid (TDS), respectively. The least percentage decrease was displayed by syndicate organisms at 51.2%, 48.1% and 40.3% for BOD, COD and conductivity, respectively. The study revealed that Saccharomycescerevisiae and Torulasporadelbrueckii could be used in the biological treatment of tannery-effluent. Hence, it was concluded that the use of these organisms could contribute to minimizing the adverse environmental risks and health-hazards associated with the disposal of untreated tannery-effluents.

Isolation and biochemical characterization of heavy-metal resistant bacteria from tannery effluent in Chittagong city, Bangladesh: Bioremediation viewpoint

Toxic, mutagenic and carcinogenic heavy metals from tannery industries cause the pollution of agricultural environment and natural water sources. This study aims to isolate, investigate and identify naturally occurring bacteria capable of reducing and detoxifying heavy metals (Chromium, Cadmium and Lead) from tannery effluent. Three isolates were identified up to genus level based on their morphological, cultural, physiological and biochemical characteristics as Gemella sp., Micrococcus sp. and Hafnia sp. Among them Gemella sp. and Micrococcus sp. showed resistance to Lead (Pb), chromium (Cr) and cadmium (Cd), where Hafnia sp. showed sensitivity to cadmium (Cd). All isolates showed different MICs against the above heavy metals at different levels. Degrading potentiality was assessed using Atomic Absorption Spectrophotometer where Gemella sp. and Micrococcus sp. showed 55.16±0.06% and 36.55±0.01% reduction of Pb respectively. On the other hand, moderate degradation of Cd was shown by Gemella sp. (50.99±0.01%) and Micrococcus sp. (38.64±0.06%). Heavy metals degradation capacity of Gemella sp. and Micrococcus sp. might be plasmid mediated, which might be used for plasmid transformation to transfer heavy metal accumulation capability. Therefore, identification of three bacteria for their heavy metal resistance and biodegradation capacity might be a base study to develop the production of potential local bioremediation agents in toxic tannery effluent treatment technology.

Bioremediation of Total Soluble Salt of Tannery Effluent Using Halophilic Microbial Consortium

Tannery effluent is known to contain large amount of dissolved salt (such as NaCl) used in the preliminary preservation of hides and skin, which is known to be highly soluble and stable in nature, difficult to eliminate and toxic in nature, thereby being a burden to the environment (ecosystem) and human health. The aim of this study is to isolate halophilic organisms from Nigerian Institute of Leather and Science Technology, Zaria tannery dumpsite using selective media. The isolated microbes were characterized microscopically and biochemically using standard methods. The microbes isolated include; Staphylococcus aureus, Bacillus sp, Pseudomonas aeruginosa, and Saccharomyces cerevisiae. The isolates were used for the bioremediation of total soluble salt in the tannery effluent. Before the tannery effluent treatment, physicochemical parameters such as temperature, pH, colour, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), chloride content, conductivity, total dissolved solid (TDS) and salinity were determined using standard procedures. The bioremediation of tannery effluent was carried out using the isolated organisms individually and in combination. The highest remediation was observed in the combination of microbial consortium, followed by Saccharomyces cerevisiae, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus sp. The temperature of the effluent ranges between 27.4°C to 27.6°C before the bioremediation, which increased to between 28.4°C and 32.3°C after remediation. Majority of the physicochemical parameters analyzed recorded drastic decrease especially the salinity (7.10 ppt to 1011 ppm), conductivity (1788 µS to 1407 mS), colour (faint ash to ash), BOD (942 mg/l to 1156 mg/l), COD (1239 mg/l to 508 mg/l), chloride content (181.9 mg/l to 579.8 mg/l), pH (6.3 to 9.1) and TDS (8.20 ppt to 1322 ppm) respectively. Most of the physicochemical parameters are above the Federal Environmental Protection Agency (FEPA) and Ethiopian Environmental Protection Authority (EEPA) standard safe limit viz; pH (6.9), Conductivity (2500 µScm−¹), BOD5 (50 mg/l and 200 mg/l), COD (500 mg/l). However, temperature (<40 and 40°C) and chloride content (1000 mg/l and 600 mg/l) are within the acceptable limits. Also, there is significant difference (P= 0.000 at 0.005 level of significance) between the chloride content of the tannery effluent before the bioremediation and the chloride content after ten days bioremediation. Thus, it is recommended to use these organisms in combination to remedy total dissolved salt efficiently than in single. Halophiles can be used in bioremediation of total soluble salt in tannery effluent. It is recommended that natural halophilic microbes should be used in the remediation of total soluble salts in preference to chemicals, which may contain heavy metals that cause toxicity and threat to the environment (ecosystem) and human health.

Enzymatic Treatment of Organics in Tannery Effluent

This study investigates the ability of enzyme technology to treat organics in tannery effluent. Three bacteria strains were tested for their ability to remove organic matter in tannery effluent, and the active sites of the respective enzymes were determined. Subsequently, the active enzymes that remove organics were extracted from the three strains and tested for the optimal activity of tannery effluent under different temperatures, pHs, concentrations, and incubation times. The results demonstrated that all three strains (Bacillus subtilis, Bacillus cereus, and Bacillus fusiformis) are able to remove organics in the tannery effluent. The active enzyme of Bacillus subtilis is an intracellular enzyme, whereas the active enzymes for Bacillus cereus and Bacillus spindle are extracellular enzymes. At pH 7, Bacillus subtilis and Bacillus cereus can, respectively, remove 37.79% and 35.34% of the organic waste in tannery water at 40°C. Bacillus fusiformis can remove up to 49.60% of the organic waste when the incubation time is extended to 8 h. The enzyme concentration is fixed at 2 × 10–4g for all conditions. In this study, enzyme technology provides a novel approach for organic removal in a tannery effluent treatment, and it has the potential to be combined with other methods in the future.

Development of simultaneous partial nitrification, anammox and denitrification (SNAD) in a non-aerated SBR

The objective of this work was to develop simultaneous partial nitrification, anammox and denitrification (SNAD) process in a twenty liter non-aerated sequencing batch reactor (SBR). Flocculent type activated sludge sourced from a tannery common effluent treatment plant was used as seed biomass. The SBR was operated for 161 days in 23 cycles with initial feed concentrations of NH4-N and COD as 250 ± 14.9 mg l−1 and 250 ± 4.6 mg l−1, respectively. The process was developed in a non-mixing condition in a dark room with no temperature control, but the temperature in SBR varied between 30 °C and 36 °C. The average HRT was 10.5 d with SBR cycle time of 7 d. The last three cycles gave the best average removals of NH4-N (94%), COD (92%) and TN (82%). The conversion ratio Y(NO2-N+ NO3-N)/(NH4-N) during the last 10 cycles remained below 0.11, confirming a stable SNAD process. Maximum specific substrate (NH4-N, COD and TN) utilization rates of SNAD biomass were determined as 185 mg NH4-N g−1 MLVSS d−1, 153 mg COD g−1 MLVSS d−1 and 172 mg N g−1 MLVSS d−1. These results contribute towards the application of SNAD process in shallow anoxic ponds/tanks/ditches in the absence of sunlight.

Treatment of tannery effluent using sono catalytic reactor

The effluent released from the leather process industries contain high amount of chemical oxygen demand (COD), biologicaloxygen demand (BOD), suspended solid (SS), ammonia nitrogen, Total Kejeldahl Nitrogen, nitrate, nitrogen, hexavalent and trivalent chromium, chloride, sulphates, etc. In the present study the lime pre-treated effluent is exposed to a sonocatalytic reactor, in which the TiO2 catalyst was used. The parameters such as BOD, COD and total dissolved solids (TDS) were studied by varying the concentration of effluent, time and catalyst load. The results reveal that the efficiency of sono catalytic reactor on percentage removal of COD, BOD and TDS were 89.53, 87.35 and 92.63 respectively. The response surface methodology (RSM) was used to optimize the variables such as catalyst loading and time. Statistical results were assessed with various descriptive such as p value, lack of fit (F-test), coefficient of R2 determination. The predicted and adjusted R2 values were found to be 0.9956, 0.9673 for% COD removal, 0.9484, 0.9926 for% BOD removal and 0.9980, 0.9954 for% TDS removal respectively.

Genotoxicity evaluation of tannery effluent treated with newly isolated hexavalent chromium reducing Bacillus cereus

In this study, the efficiency of free and immobilized cells of newly isolated hexavalent chromium [Cr(VI)] reducing Bacillus cereus strain Cr1 (accession no. KJ162160) was studied in the treatment of tannery effluent. The analysis of effluents revealed high chemical oxygen demand (COD-1260 mg/L), biological oxygen demand (BOD5-660 mg/L), total dissolved solids (TDS-14000 mg/L), electrical conductivity (EC-21.5 mS/cm) and total chromium (TC-2.4 mg/L). The effluents also showed genotoxic effects to Allium cepa. Treatment of tannery effluent with isolated B. cereus strain led to considerable reduction of pollutant load. The pollutant load reduction was studied with both immobilized and free cells and immobilized cells were more effective in reducing COD (65%), BOD (80%), TDS (67%), EC (65%) and TC (92%) after 48 h. GC-MS analysis of pre and post-treatment tannery effluent samples revealed reduction of organic load after treatment with free and immobilized cells. An improvement in mitotic index and reduction in chromosomal aberrations was also observed in A. cepa grown with post-treatement effluent samples compared to untreated sample. Results demonstrate that both methods of bacterial treatment (free and immobilized) were efficient in reducing the pollutant load of tannery effluent as well as in reducing genotoxic effects, however, treatment with immobilized cells was more effective.

Coagulation process for tannery industry effluent treatment using Moringa oleifera seeds protein: Kinetic study, pH effect on floc characteristics and design of a thickener unit

ABSTRACTThe kinetics of coagulation process for turbidity removal from tannery industry effluent using NaCl solution extracted Moringa oleifera protein is reported here. The effect of initial pH of effluent on floc size and strength was analysed. Floc size decrease with increase in velocity gradient and hierarchy of floc size exponent at different pH was: acidic > neutral > basic. It was observed based on the half-life period data that the process follows a second-order kinetic model with 0.000862 (L/mg min) as the rate constant. The Talmadge–Fitch method is used to analyse batch sedimentation data for the calculation of area for the clarifier-thickener unit to treat 5 m3/h of tannery wastewater.

Two-stage phyto-microremediation of tannery effluent by Spirodela polyrrhiza (L.) Schleid. and chromium resistant bacteria

Two-stage sequential treatment of tannery effluent was conducted employing a wetland plant, Spirodela polyrrhiza (L.) Schleid., and chromium (Cr) resistant bacterial strains. The bacterial strains were isolated from Cr-enriched environmental matrices and rhizosphere of Spirodela polyrrhiza. The phyto-rhizoremediation of tannery effluent by Spirodela and its rhizospheric bacteria (Cellulomonas biazotea APBR1-6, Bacillus safensis APBR2-12, Staphylococcus warneri APBR3-5, Microbacterium oleivorans APBR2-6), followed by microremediation by Cr resistant bacteria (Micrococcus luteus APBS5-1, Bacillus pumilus APBS5-2, Bacillus flexus APBE3-1, Virgibacillus sediminis APBS6-1) resulted in reduction of pollution parameters [COD (81.2%), total Cr (97.3%), Cr(VI) (99.3%), Pb(II) (97.0%), Ni (95.7%)]. The LC–MS analysis showed that many pollutants detected in untreated tannery effluent were diminished after bioremediation or long chains of alcohol polyethoxylates viz. C18EO6 in untreated effluent were broken down into smaller unit of alcohol polyethoxylate (+HHO[CH2CH2O]H), indicating that bacteria and Spirodela polyrrhiza, alongwith its rhizospheric associates utilized them as carbon and energy source.

Yeast As a Potential Candidate for Tannase Production: A Review

Tannin acyl hydrolase (E.C.3.1.1.20) is also known as tannase, which hydrolyses ester and depside bonds of tannins to produce gallic acid, glucose, and galloyl esters. It is an inducible enzyme which has wide applications in pharmaceuticals, food, beverage industries, and also potentially used in the treatment of tannery effluents. A lot of emphasis has been paid on the production aspects of tannase from different sources, the major sources for tannase are considered to be fungi and bacteria. Recently, much attention has been paid on the production of these enzymes from yeast sources by conventional and molecular biology approach, because of its shorter generation time and convenience towards molecular genetics. Yeast tannase also finds wide application, because of its similarity with that of tannase from mycelial fungi. This study reviews the yeast sources, modes of production, different molecular approaches used and possible applications of these yeast sources as a potential candidate for tannase production. Keywords: Yeast, tannase, yeast tannase, tannase applications.

Application of heterogeneous catalytic ozonation as a tertiary treatment of effluent of biologically treated tannery wastewater

ABSTRACTThe present study employed a Mn-Cu/Al2O3 heterogeneous catalytic ozonation process for tertiary treatment of actual tannery wastewater, focusing on its feasibility in that application. The primary factors affecting the removal efficiency of organic pollutants were investigated, including catalyst dosage, ozone dosage, and initial pH value. The experimental results showed that the addition of a Mn-Cu/Al2O3 catalyst improved the removal efficiency of chemical oxygen demand (COD) during ozonation, which initiated a 29.3% increase for COD removal, compared to ozonation alone after 60 min. The optimum pH, catalyst dosage, and ozone dosage were determined to be 7.0, 2.0 g/L, and 0.3 g/h, respectively. Under these conditions, following 60 min of reaction, the COD removal efficiency and the concentration in effluent were 88%, and 17 mg/L, respectively. In addition, the presence of tert-butanol (a well known hydroxyl radical scavenger) strongly inhibited COD removal via Mn-Cu/Al2O3 catalytic ozonation, indicating that the Mn-Cu/Al2O3 catalytic ozonation process follows a hydroxyl radical (OH·) reaction mechanism. The Mn-Cu/Al2O3 catalyst exhibited good stability and reusability. Finally, the kinetic analysis revealed that the apparent reaction rate constant of COD removal with the Mn-Cu/Al2O3 catalytic ozonation system (0.0328 min−1) was 2.3 times that of an ozonation system alone (0.0141 min−1). These results demonstrated that the catalytic ozonation using Mn-Cu/Al2O3 is an effective and promising process for tertiary treatment of tannery effluent in biological systems.

Treatment of tannery wastewater by a hybrid electrocoagulation/electrodialysis process

Globally, the leather industry is currently undergoing radical transformation due to pollution and discharge legislations. The present study is based on the investigation of performance of a hybrid electrocoagulation/electrodialysis process for the removal of COD, NH3-N, Cr and color in tannery wastewater. Effects of current density and electrolysis time were analyzed to optimize the electrocoagulation process with aluminum either iron electrodes. The optimized electrocoagulation process was then integrated with electrodialysis (ED) for the treatment of tannery effluents and was found that the hybrid process was capable of promoting the quality of the treated tannery wastewater. In case of treated tannery by EC with aluminum electrodes, ED process was effectiveness where the removal efficiency of COD, NH3-N, Cr and color were 92,100,100,100% respectively corresponds to conductivity value of 0.371mS/cm at 45minute. While, in the case of treated tannery by EC with iron electrodes, ED process was also efficient for removal pollutants, the removal efficiency of COD, NH3-N, Cr and color were 87,100,100,100% respectively corresponds to conductivity value of 1.5mS/cm at 75minute. It is noticeable that the effluent treated with combined EC-ED techniques presents very similar values for the same parameter as the ones presented by normal feed water.

Perspectives on Biological Treatment of Tannery Effluent

Leather processing is an important economic activity around the world and uncontrolled release of tannery effluents to natural water bodies causes environmental degradation and increases health risks to human beings. The treatment of tannery effluent is a complex technological challenge because of the presence of high concentrations of organic and inorganic pollutants of both conservative and non conservative nature. In this review paper information relevant to tannery effluents and its prospective on biological treatment processes and other recent potential biological processes are discussed. Emphasis is laid on the removal of organic matter (COD/BOD), NH4-N and sulphide/sulphate from tannery effluent. Though the aerobic process is efficient in treating tannery effluent, it requires an extended aeration time at low organic loading rates and thereby increasing the overall treatment cost. Anaerobic process is not effective because of sulphide inhibition problems. Sulphide inhibition control is essential for successful anaerobic treatment of tannery effluent. Sequencing Batch Reactor (SBR) and membrane reactor technologies are found to be effective for removal of organic matter and ammonia, but they are having very high operational cost. A recent development is the employment of alternate electron acceptor/donor already present in tannery effluent for simultaneous removals of COD/BOD, NH4-N and sulphide/sulphate with possibility of elemental sulphur recovery at higher organic loading rates. The recent development shows possibility of high rate treatment of tannery effluent in an alternate and an effective way suitable to both developing and developed countries.

Modelling the kinetics of coagulation process for tannery industry effluent treatment using Moringa oleifera seeds protein

The ability of the natural coagulant extracted from Moringa oleifera seeds to remove the turbidity from tannery industry wastewater was studied. Coagulation experiments were performed using conventional jar test apparatus with 4–9 pH range and coagulant dose ranging from 10 to 50 mL. The active coagulation component of M. oleifera seed was prepared separately using NaCl and KCl salt solutions. Turbidity removal efficiency of NaCl-extracted coagulant and KCl-extracted coagulant was compared. The turbidity of raw tannery wastewater was reduced from 121.9 to 29.01 mg/L at an optimum pH 7 and coagulant dosage of 40 mL. The maximum turbidity removal efficiency was observed as 76.2 and 71.2% for NaCl- and KCl-extracted coagulants, respectively. The coagulation kinetic study suggested that the process follows second-order kinetics for both type coagulants, and the parameters for rate equation were obtained from the regression equations.

Evaluation of performance of Planococcus sp. TRC1 an indigenous bacterial isolate monoculture as bioremediator for tannery effluent

An indigenous bacterial isolate Planococcus sp. TRC1 was found to tolerate Cr(VI) solution up to 500 mg/L concentration when grown in mineral salt media. Gene sequencing of the isolated strain using 16S rDNA technique and phylogenetic analysis confirmed that the species was 96% close to Planococcus maritimus (KP8). Studies on cell dynamics in batch bioreactor showed the maximum specific cell growth rate (μmax) to be 0.276 h−1. Removal of Cr(VI) was observed to be dependent on initial chromium concentration and the maximum removal of Cr(VI) (75 ± 3%) was obtained at 25 mg/L Cr(VI) solution for an incubation period of 72 h. Above this value, the removal of Cr(VI) was declined. Scanning electron microscope and Fourier transform infrared spectroscopic studies indicated that the Cr(VI) removal took place by the adsorption process on the cell outer membrane. It is observed that the adsorption process follows the Freundlich adsorption isotherm (R2 = 0.987). Planococcus sp. TRC1 reduced 80 ± 5% chemical oxygen demand (COD) of tannery effluent (COD 7,270 ± 45 mg O2/L) within 48 h of batch treatment. The elimination of cytotoxicity and genotoxicity imparted by the raw tannery effluent and Cr(VI) solution after bacterial treatment is an important observation which reflects the eco-friendly behavior of the Planococcus sp. TRC1 mediated tannery effluent and aqueous Cr(VI) solution treatment. The results revealed the applicability of Planococcus sp. TRC1 in both tannery waste and Cr(VI) reduction without affecting our environment.

Tannery Effluent Treatment by Microfiltration through Ceramic Membrane for Water Reuse: Assessment of Environmental Impacts

The performance evaluation of an indigenously developed ceramic membrane from a clay–alumina mixture was evaluated toward microfiltration treatment of tannery effluent from a secondary clarifier. The study was aimed at observing the reuse efficiency of the membrane treated effluent using Pistia sp. as plant model and Poecilia sp. as fish model. About 70–86% chemical oxygen demand removal and 85% total organic carbon removal was achieved in the ceramic membrane based microfiltration process. The comet assay of Pistia sp. leaves showed formation of DNA tail in the untreated effluent suggesting DNA damage whereas no such observations were noted in treated water. Oxidative stress biomarkers like guaiacol peroxidase, superoxide dismutase, etc., in both Pistia sp. and Poecilia sp. increased considerably in untreated effluent, whereas the treated water values were close to that of control. The overall process demonstrated that microfiltration by ceramic membranes might prove as effective means of wastewater reuse for aquaculture, agriculture, as well as in industrial sectors.