Priyankari Bhattacharya

Effectiveness of Biosorption-Assisted Microfiltration Process for Treatment of Domestic Wastewater

ABSTRACT The efficiency of a biosorbent prepared from Eichhornia crassipes roots (ECR) was explored for the treatment of domestic sewage water in combination with low-cost ceramic microfiltration membrane. Batch sorption studies were conducted as a function of biosorbent dose, initial chemical oxygen demand (COD) loading, and temperature. Sorption equilibrium data of varying initial COD values (116–800 mg/L) indicated high potential of ECR for COD removal. Using 0.25 g/L of biosorbent dose, the equilibrium adsorption capacity was obtained as 2480 mg/g at 20°C for an initial COD loading of 800 mg/L. Microfiltration study was performed using ceramic membrane made from composition of α-alumina and clay. The effect of operating parameters on filtration characteristics was observed in terms of permeate flux. Permeate samples were characterized in terms of various parameters both for the direct filtration, as well as biosorbent-assisted filtration. The filtration behavior of wastewater at varying transmembrane pressure was explained using various membrane fouling models. The results suggested that microfiltration of domestic wastewater with incorporation of biosorbent (0.25 g/L) was highly effective for removal of organic load (>90%), turbidity (>99%), and total suspended solids (TSS) (93–95%) and the treated water quality was suitable for reuse in various purposes, such as gardening, floor and car washing, etc.

Potential of biosorbent developed from fruit peel of Trewia nudiflora for removal of hexavalent chromium from synthetic and industrial effluent: Analyzing phytotoxicity in germinating Vigna seeds

Chromium (VI) removal efficiency of a biosorbent prepared from fruit peel of Trewia nudiflora plant was studied. The effect of pH, sorbent dose, initial metal concentration and temperature was studied with synthetic Cr+6 solution in batch mode. About 278 mg/g of Cr+6 sorption was obtained at 293 K at an optimum pH of 2.0 and biosorbent dose of 0.75 g/L. Equilibrium sorption data with varying initial concentration of Cr+6 (22–248 mg/L) at three different temperatures (293–313 K) were analyzed by various isotherms. Biosorption kinetics and thermodynamics were described using standard model equations. Encouraging results were obtained by the application of the biosorptive treatment for removal of Cr+6 from wastewater collected from common effluent treatment plant of tannery industry. In addition, Cr+6 desorption behavior was studied on different systems. Biosorbent was characterized by FESEM, FT-IR and XRD, etc. Effect of the biosorptive treatement with respect to the phytotoxicity of Cr+6 was analyzed by studying the seed germination behavior and enzyme activity of a pulse seed (Vigna radiata L.). Different concentrations of Cr+6 solution in both synthetic medium, as well as, in tannery effluent was employed and the results were compared with that of biosorbent treated medium. The study showed that due to efficient removal of Cr+6 from aqueous phase, considerable enhancement of seed germination, as well as, increase in root length was obtained for the biosorbent treated solutions which were close to that of the control values. Significant decrease (P < 0.01) in POD activity was observed in seeds irrigated with biosorbent treated wastewater compared to untreated wastewater. The study showed that the novel biosorbent prepared might be utilized for abatement of heavy metal toxicity, i.e., Cr+6 from industrial effluent.

Combination technology of ceramic microfiltration and biosorbent for treatment and reuse of tannery effluent from different streams: response of defence system in Euphorbia sp.

BackgroundThe present study was undertaken to evaluate the efficiency of combined technology involving ceramic microfiltration and biosorbent for the treatment of tannery effluent from different streams, viz. composite effluent, effluent from primary clarifier and secondary clarifier. The membranes were prepared from a cost-effective composition of alumina and clay.ResultsThe effluents had high organic loading of 12,895, 3,890 and 410 mg/L, respectively, in terms of chemical oxygen demand (COD). Apart from these, the effluents consisted of toxic heavy metals, turbidity, biochemical oxygen demand (BOD), etc. It was observed that COD reduction was about 96.5% for effluent 1, 96.6% for effluent 2 and 96.9% for effluent 3. Considerable reduction in suspended solids, total nitrogen, and total organic carbon was obtained. Turbidity for all three types of effluent was below 1 NTU. The average flux value for effluents 1, 2 and 3 was about 13, 19 and 24 L/m2/h (LMH), respectively. Response of the antioxidative defences of Euphorbia hirta was observed which resulted in considerable decrease in the activity of peroxidase, superoxide dismutase and catalase.ConclusionsThe treatment resulted in the reduction of toxicity thereby restoring normal activity when compared to control values. Changes in various biochemical parameters like protein, amino acid, carbohydrate, DNA, RNA and chlorophyll content were observed.

Comparative study on treatment of kitchen-sink wastewater using single and multichannel ceramic membrane

A comparative study was conducted to explore the potential of ceramic microfiltration membrane alone and in combination with different physicochemical treatments, viz. biotreatment and adsorption using kitchen-sink wastewater. Cross-flow microfiltration (CMF) studies were carried out with tubular ceramic membrane in single channel and multichannel configuration. Biotreatment was studied using activated sludge process and adsorptive treatments were studied using a biosorbent prepared from the dried roots of Eichhornia crassipes, an aquatic weed which is abundantly grown in polluted water. The study showed better performance of 19 channel ceramic membrane compared to the single channel membrane in terms of the permeate quality, viz. BOD, COD, turbidity, TSS etc., as well as, permeate flux. Microfiltration of the adsorbent treated feed appeared to be most promising in comparison with the other feeds wherein, about 98% removal of BOD and 99% removal of COD were obtained. The quality of the treated water was found to be fit for use in horticulture, irrigation, etc.

Exposure of composite tannery effluent on snail, Pila globosa: A comparative assessment of toxic impacts of the untreated and membrane treated effluents.

Effluent from tannery industries can significantly affect the aquatic environment due to the presence of a variety of recalcitrant components. The present study focuses on a comparative assessment of the toxic impacts of an untreated tannery effluent and membrane treated effluents using snail, Pila globosa as an aquatic model. Composite tannery effluent collected from a common effluent treatment plant was selected as the untreated effluent. To investigate the effect of treated effluents on the aquatic organism the effluent was treated by two ways, viz. a single stage microfiltration (MF) using ceramic membrane and a two-step process involving MF followed by reverse osmosis (RO). The whole body tissue, gonad and mantle of P. globosa were subjected to enzyme assays like superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GSH-GPx), glutathione S- transferase (GST), etc. for assessing toxic impact. Changes in the biochemical parameters like protein, carbohydrate and amino acid were observed including histological studies of gonad and mantle tissue upon treatment with tannery effluents. To examine potential DNA damage due to the exposure of the effluent, comet assay was conducted. The study revealed that with an exposure to the untreated effluent, activity of the antioxidant enzymes increased significantly while the protein and carbohydrate content reduced largely in the whole body tissue, gonad as well as mantle tissues of P. globosa. Histological study indicated considerable damage in the gonad and mantle tissues following exposure to the untreated effluent. Comet assay using hemolymph of P. globosa following exposure to tannery effluent, showed significant genotoxicity. Interestingly, compared to the untreated effluent, damaging effect was reduced in molluscs tissues when exposed to MF treated effluent and even lesser when exposed to MF+RO treated effluent. Apart from the reduced activities of oxidative stress enzymes, the protein, amino acid and carbohydrate content of molluscs exposed to both of the treated effluent were found close to that of control. Comet assay revealed no damage in the DNA for MF and MF+RO treated effluent indicating that the membrane based treatment procedure restores environmental condition to control level.

Algal Biomass as Potential Biosorbent for Reduction of Organic Load in Gray Water and Subsequent Reuse: Effect on Seed Germination and Enzyme Activity

ABSTRACT Biosorptive treatment using algal biomass of Rhizoclonium riparium was proposed for higher-loading gray water for its effective utilization. A batch sorption study was conducted using composite wastewater having a wide range of initial chemical oxygen demand (COD) values (2400–44,800 mg/L). The study showed an optimum dose of 5 g/L of biosorbent resulted in 96% reduction of COD for wastewater with an initial COD of 10,500 mg/L. The equilibrium isotherm data at different temperatures were fitted to linear and nonlinear isotherms. Biosorption kinetics was studied by various kinetic models. Chemical composition and surface morphology of the biosorbent were characterized by infrared, x-ray diffraction, and scanning electron microscopy techniques before and after biosorption. Applicability of the biosorbent-treated wastewater in agricultural uses was explored by studying the effect of untreated and treated wastewater on the germination of two seeds, i.e., Vigna radiata and Lens esculenta, and subsequently the activity of peroxidase (POD) enzymes were studied to understand the toxicity in plants. The study revealed that compared with seeds treated with different dilutions of untreated wastewater, germination (%) was significantly higher for biosorbent-treated wastewater, with a reduced level of POD activity, indicating positive response of the seeds towards the biosorptive treatment.

Potential of ceramic microfiltration and ultrafiltration membranes for the treatment of gray water for an effective reuse

Abstract Gray water may serve as a water resource for agricultural uses due to their high nutrient content. In this study performance evaluation of indigenously developed low-cost ceramic membrane was investigated for treatment and reuse of high organic loaded gray water. The efficiency of microfiltration (MF) and ultrafiltration (UF) process was studied individually and as a two-stage treatment involving MF followed by UF. Effect of time was observed on reduction of chemical oxygen demand (COD) in the permeate stream and permeate flux in different processes. Depending on the variation in feed loading, about 73–90% COD reduction was achieved in the single-stage UF at 30 min of filtration with operating pressure of 2 bar, which was about 84–94% for two-stage treatment. Permeate quality in terms of organic loading, oil and grease and coliform concentration were found suitable according to the discharge norms for agricultural reuse of water. The effect of untreated, MF- and-UF treated wastewater was observed...

Reuse of textile effluent for dyeing using combined technology of ceramic microfiltration and surface treated sugarcane bagasse: toxicity evaluation using Channa punctatus as model

AbstractAn attempt was undertaken for treatment and reuse of highly concentrated textile dyebath effluent. Ceramic microfiltration membrane prepared from a cost effective composition of alumina and clay was used in combination with a biosorbent prepared from sugarcane bagasse. The combined process was highly effective for removal of chemical oxygen demand (COD), turbidity, colour and total suspended solids. For the concentrated dyebath effluent with initial COD value of 2220 mg/L, COD reduction was about 91%. Dye removal was about 99%, turbidity removal was > 99% and TSS reduction was > 90%. The treated samples were utilized in the dyeing process of cotton fabric under different conditions. The reusability study showed high potential with respect to water reclamation, as well as, reduction of the associated chemicals consumption. Dye uptake using membrane treated water was more compared to that of freshwater in case of light and medium shade dyeing. Toxicity effect of treated and untreated effluent on env...

Biosorbent-assisted ceramic microfiltration process for treatment of herbal pharmaceutical wastewater with high organic loading

The feasibility of treating herbal pharmaceutical wastewater with high Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) values was studied using ceramic microfiltration membrane in combination with an adsorptive treatment. Batch kinetic and isotherm studies were carried out under varying dosages of a biosorbent prepared from the roots of Eichhornia crassipes (ECR). Adsorption kinetic models, based on the assumption of the pseudo-first-order and pseudo-second-order models, were applied to examine the kinetics of the adsorption. Microfiltration study was carried out using uncoated porous ceramic membrane prepared from a mixture of α-alumina and clay in tubular multi-channel configuration. The efficiency of the separation process was evaluated in terms of turbidity, TSS, colour and COD and permeate flux rates were compared for different adsorbent loadings in the effluent. An effective removal of turbidity (>99%) and TSS (98?99%) was observed after 2 hours of microfiltration with colour removal of 87% and COD reduction of 88%.

Anabaena sp. mediated bio-oxidation of arsenite to arsenate in synthetic arsenic (III) solution: Process optimization by response surface methodology.

Blue green algae Anabaena sp. was cultivated in synthetic arsenite solution to investigate its bio-oxidation potential for arsenic species. Response surface methodology (RSM) was employed based on a 3-level full factorial design considering four factors, viz. initial arsenic (III) concentration, algal dose, temperature and time. Bio-oxidation (%) of arsenic (III) was considered as response for the design. The study revealed that about 100% conversion of As (III) to As (V) was obtained for initial As (III) concentration of 2.5-7.5 mg/L at 30 °C for 72 h of exposure using 3 g/L of algal dose signifying a unique bio-oxidation potential of Anabaena sp. The dissolved CO2 (DCO2) and oxygen (DO) concentration in solution was monitored during the process and based on the data, a probable mechanism was proposed wherein algal cell acts like a catalytic membrane surface and expedites the bio-oxidation process. Bioaccumulation of arsenic, as well as, surface adsorption on algal cell was found considerably low. Lipid content of algal biomass grown in arsenite solution was found slightly lower than that of algae grown in synthetic media. Toxicity effects on algal cells due to arsenic exposure were evaluated in terms of comet assay and chlorophyll a content which indicated DNA damage to some extent along with very little decrease in chlorophyll a content. In summary, the present study explored the potential application of Anabaena sp. as an ecofriendly and sustainable option for detoxification of arsenic contaminated natural water with value-added product generation.