Tamal Mandal

Treatment of leather industry wastewater by aerobic biological and Fenton oxidation process.

Degradation of leather industry wastewater by sole aerobic treatment incorporating Thiobacillus ferrooxidans, Fentons reagents, and combined treatment was investigated in this study. The sole treatment by Fentons oxidation involving the introduction of 6g FeSO(4) and 266 g H(2)O(2) in a liter of wastewater at pH of 3.5 and 30 degrees C for 30 min at batch conditions reduced COD, BOD(5), sulfide, total chromium and color up to 69%, 72%, 88%, 5%, 100% and T. ferrooxidans alone showed maximum reduction to an extent of 77, 80, 85, 52, 89, respectively, in 21 d treatment at pH 2.5, FeSO(4) 16 g/L and temperature of 30 degrees C. The combined treatment at batch conditions involving 30 min chemical treatment by Fentons oxidation followed by 72 h biochemical treatment by T. ferrooxidans at batch conditions gave rise up to 93%, 98%, 72%, 62% and 100% removal efficiencies of COD, BOD, sulfide, chromium and color at pH of 2.5 and 30 degrees C. Decrease in photo absorption of the Fentons reagent treated samples, as compared to the banks, at 280, 350 and 470 nm wave lengths was observed. This may be the key factor for stimulating the biodegradation by T. ferrooxidans.

Effect of pH and temperature on stability and kinetics of novel extracellular serine alkaline protease (70 kDa).

A novel extracellular serine protease (70 kDa by SDS-PAGE) was purified and characterized. This enzyme retained more than 93% of its initial activity after preincubation for 30 min at 37 °C in the presence of 25% (v/v) tested organic solvents and showed feather degradation activity. The purified enzyme was deactivated at various combinations of pH and temperature to examine the interactive effect of them on enzyme activity. The deactivation process was modeled as first-order kinetics and the deactivation rate constant (k(d)) was found to be minimum at pH 9 and 37 °C. The kinetic analysis of enzyme over a range of pH values indicated two pK values at 6.21 and at 10.92. The lower pK value was likely due to the catalytic histidine in the free enzyme and higher pK value likely reflected deprotonation of the proline moiety of the substrate but ionization of the active site serine is another possibility. Inhibition kinetic showed that enzyme is serine protease because enzyme was competitively inhibited by antipain and aprotinin as these compounds are known to be competitive inhibitors of serine protease. The organic solvent, thermal and pH tolerances of enzyme suggested that it may have potential for use as a biocatalyst in industry.

Recovery of value added products from rice husk ash to explore an economic way for recycle and reuse of agricultural waste

Rice husk ash (RHA) is the major by-product left after the burning of rice husk, which is profusely present throughout the process of the rice milling. The burnt rice husk, as RHA, in turn causes more environmental pollution and its disposal becomes a difficult problem, hence requiring serious attention from the scientific community regarding its disposal and proper reuse if possible. The major economic reason for recycling the ash is the value added products which can be generated from it. The focus is on the use of RHA as adsorbent and subsequent silica production owing to the fact that the ash is mainly composed of carbon and silica. As regards other potential applications of ash, research is still going on and some of the products, which are under development phase, have also been brought to limelight in this review. This literature review provides an effective scheme to utilize RHA and discussed process pathway for economically valuable products to provide a solution to the problem associated with its proper disposal through superior recycle of this agriculture waste.

Optimization of culture condition for growth and phenol degradation by Alcaligenes faecalis JF339228 using Taguchi Methodology

Abstract The optimization of five process parameters such as pH, agitation, temperature, inoculum percentage and incubation time were optimized by Taguchi robust design method for obtaining enhanced biomass and phenol degradation by the isolated Alcaligenes faecalis JF339228 from Durgapur steel industry (DSP), India. About 18 experiments were conducted with a different combination of factors and the results obtained in terms of growth of specific bacterial strain and phenol degradation rates were processed in the Qualitek-4 software to study the main effect of individual factors. The main effect, interaction effects and optimal levels of the process factors were determined using signal-to-noise (S/N) ratio. The effect of factors has been studied for bacterial growth and phenol degradation by A. faecalis JF339228. Optimization of the said parameters has been evaluated by Taguchi method and analysed by analysis of variance. Predicted results showed enhanced process performance such as biomass (131.78%) and ...

Designing polymeric microparticulate drug delivery system for hydrophobic drug quercetin

The aim of this study was to investigate pharmaceutical potentialities of a polymeric microparticulate drug delivery system for modulating the drug profile of poorly water-soluble quercetin. In this research work two cost effective polymers sodium alginate and chitosan were used for entrapping the model drug quercetin through ionic cross linking method. In vitro drug release, swelling index, drug entrapment efficiency, Fourier Transforms Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Differential Scanning Calorimetric (DSC) studies were also done for physicochemical characterization of the formulations. Swelling index and drug release study were done at a pH of 1.2, 6.8 and 7.4 to evaluate the GI mimetic action which entails that the swelling and release of the all the Formulation1 (F1), Formulation2 (F2) and Formulation3 (F3) at pH 1.2 were minimal confirming the prevention of drug release in the acidic environment of stomach. Comparatively more sustained release was seen from the formulations F2 & F3 at pH 6.8 and pH 7.4 after 7 h of drug release profiling. Drug entrapment efficiency of the formulations shows in F1 (D:C:A = 2:5:30) was approximately 70% whereas the increase in chitosan concentration in F2 (D:C:A = 2:10:30) has shown an entrapment efficiency of 81%. But the comparative further increase of chitosan concentration in F3 (D:C:A = 2:15:30) has shown a entrapment of 80% which is not having any remarkable difference from F2. The FTIR analysis of drug, polymers and the formulations indicated the compatibility of the drug with the polymers. The smoothness of microspheres in F2 & F3 was confirmed by Scanning Electron Microscopy (SEM). However F1 microsphere has shown more irregular shape comparatively. The DSC studies indicated the absence of drug-polymer interaction in the microspheres. Our XRD studies have revealed that when pure drug exhibits crystalline structure with less dissolution profile, formulated microparticles can help us to obtain amorphous form of the same drug that is likely to have more dissolution property. The findings of the study suggest that the microsphere formulations were a promising carrier for quercetin delivery and can be considered as a favorable oral controlled release dosage form for hydrophobic drug quercetin.

Unleashing the potential of ligninolytic bacterial contributions towards pulp and paper industry: key challenges and new insights

AbstractLignocellulose biomass predominantly constitutes the main feedstock for pulp and paper industry. Though some products of pulp and paper industry require the presence of lignin content, for most of the useful products formation lies in the efficient and selective removal of lignin component to make use of the intact cellulose fraction during the pretreatment of pulp. Lignin is a recalcitrant heteropolymer comprised of several complex stable bonds and linkages. The chemicals or intense energy processes used for delignification process release the hazardous chemicals compounds in the wastewater which cause toxicity and environmental pollution. The implementation of bacterial species has elucidated an effective approach in the generation of value-added products while degrading lignin from pulp biomass as well as detoxification of effluent. The direct use of bacterial cells in lignocellulose biomass and wastewater streams is promising as it outperforms the practical and technical constraints largely confronted by fungal and enzymatic means. The present review paper thus unleashed the potential of ligninolytic bacteria towards delignification of pulp biomass and treatment of effluent together with bioconversion of biomass and lignin into value-added products. Graphical abstractSchematic illustration of potential possible contribution of ligninolytic bacteria towards pulp and paper industry

A statistical approach for optimization of media components for phenol degradation by Alcaligenes faecalis using Plackett–Burman and response surface methodology

ABSTRACT In the present study, phenol degrading bacterial species was isolated from coke oven wastewater of Durgapur steel plant, India. The biochemical, morphological, and 16s rDNA study were performed to identify the isolated microbes. The studies revealed that the high concentration phenol (2,100 mg L−1) degrading isolating microbe is Alcaligenes faecalis. Optimization of media components and incubation time for phenol degradation was carried out by two-step statistical approach. Six key determinants such as phosphate, iron sulfate, calcium chloride, magnesium chloride, ammonium sulfate concentrations, and incubation time were screened using Plackett–Burman design and were further optimized by response surface methodology (RSM) using practical central composite design. The experimental results of the RSM were fitted via a second-order polynomial regression equation having the correlation coefficient (R 2) 0.9998 that indicates appropriate predictions of the above variables for significant phenol degrad...

Current techniques in rice mill effluent treatment: Emerging opportunities for waste reuse and waste-to-energy conversion.

Rice mills release huge volumes of wastewater and other by-products when processing paddy rice. The wastewater often contains toxic inorganic and organic contaminants which cause environmental damage when released. Accordingly, cost-effective techniques for removing contaminants are needed. This article reviews current processes for curbing pollution and also reusing and recycling waste products. Novel techniques exist for converting waste products into energy and value-added products.

Reactive red 120 retention through ultrafiltration enhanced by synthetic and natural polyelectrolytes.

Two cationic chelating polymers, namely synthetic polyethylenimine (PEI), and biopolymer chitosan were employed in the present study to bring about the retention of anionic reactive red 120 (RR 120) from its aqueous solutions by way of polymer enhanced ultrafiltration (PEUF). The effects of process parameters, namely, cross-flow rate, transmembrane pressure, time, polyelectrolyte loading, and ionic strength on dye retention and permeation flux were examined. PEI enhanced ultrafiltration achieved dye retentions as high as 99.9%, and significant permeation fluxes around 148 L/m(2)h. However, in case of chitosan, relatively low retention (88%), and flux (120 L/m(2)h) levels were observed. A careful comparison of the changes induced in the UV-vis spectra of RR 120 by PEI and chitosan indicated a predominant electrostatic interaction between PEI and RR 120, as opposed to the relatively weak and sterically as well as chemically hindered interaction between chitosan and the dye ion. The respective binding constants of PEI-RR 120, and PEI-chitosan complexes, in addition to the relatively more pronounced permeation flux decline witnessed in the presence of chitosan, clearly advocated the use of PEI, rather than chitosan, as the most appropriate complexing agent in the present context.

Study of Ammonia Removal from Simulated Coke Oven Wastewater Using Commercial Charcoal Activated Carbon

Organic pollutants from iron steel, coke, petroleum and other chemical process industries are basically responsible for releasing phenols, cyanides, ammonical and phenolic compounds, biphenyls, thiocyanates and various complex hydrocarbons that pose a threat to the existing flora and fauna of the ecosystem. Individual as well as combined treatment for phenol and cyanide using commercial and low-cost adsorbents has been investigated. But inadequate focus on removal of ammonical compounds leads to algal growth due to conversion into nitrites and nitrates. Thus, elimination of ammonia from simulated wastewater was studied using commercial grade charcoal activated carbon and acid-modified charcoal activated carbon from a mixture of phenol, cyanide and ammonia. The nature of the uptake was investigated and was observed that phenol removal showed a wide range of variation in percentage removal in terms of effect of initial concentration, pH and adsorbent dosage while the removal was enhanced for modified activated carbon. This has been found similar with the literature as reported earlier. But for ammonia, the removal was quite satisfactory irrespective of the variation of mentioned parameters. Also, it was found that modified activated carbon could bring about better removal in case of phenol, but ammonia removal was unaltered.