M G Dastidar

Indian Institute of Technology Delhi, New Dilli, NCT, India

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Publications (33)26.02 Total impact

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    ABSTRACT: A comparative study was undertaken using indigenous sulfur-oxidizing microorganisms and iron-oxidizing microorganisms in separate 12 litre continuous stirred tank reactors (CSTRs) for solubilization of heavy metals from anaerobically digested sewage sludge. The CSTRs were operated at hydraulic retention times (HRTs) ranging from 4 to 10 days using sewage sludge feed having near neutral pH. The pH, oxidation-reduction potential (ORP) and solubilization efficiency of metals were found to be highly dependent on HRT and an increase in HRT led to higher solubilization of metals in both the CSTRs. In both the CSTRs, the CSTR operated with sulfur-oxidizing microorganisms at an HRT of 8 days was found to be optimum in solubilizing 58% Cu, 52% Ni, 72% Zn and 43% Cu from the sludge. The nutrient value, nitrogen and phosphorus of bioleached sludge was also conserved (<20% loss) at 8 days HRT. The metals fractionation study conducted using BCR sequential extraction procedure suggested that most of the metals remaining in the bioleached sludge were in the more stable fractions (F3 and F4) and, therefore, can be safely apply as a fertilizer on land.
    Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering 01/2014; 49(1):93-100.
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    ABSTRACT: The feasibility of biodiesel production from microalgae as third generation biodiesel feedstock was studied in the present investigation. The studies were conducted to evaluate the growth patterns of the algae species i.e. Spirulina, Chlorella and pond water algae. The oil was extracted from the algae biomass and then transesterified. Simultaneous extraction and transesterification were also studied using different solvents. Maximum biodiesel yield was obtained using simultaneous extraction and transesterification using hexane as a solvent. The systematic characterization of algae biomass, algae oil and algae biodiesel was carried out to establish the potential of microalgae for biodiesel production.
    Fuel Processing Technology 01/2014; 120:79–88. · 2.82 Impact Factor
  • C.H. Biradar, K.A. Subramanian, M.G. Dastidar
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    ABSTRACT: The work is aimed at conversion of non-edible jatropha curcas de-oiled seed cake (the residue left after extraction of oil from the seed) into bio-oil and bio-char through pyrolysis process. A fluidized bed pyrolysis system with maximum feed rate of 12 g/min was designed and fabricated. The particle size range, sweep gas flow rate and operating temperature were optimized as 0.5 mm–0.99 mm, 8 L/min and 450 °C respectively for obtaining maximum yield of bio-oil (48%) and bio-char (35.1%). The crude bio-oil has lower viscosity (1.98 cSt), higher moisture content (31%) and higher density (1040 kg/m3) as compared to commercial petro-diesel. The crude bio-oil was upgraded to make it suitable for engine application. The moisture content of the crude bio-oil was removed about 3% by weight using Na2SO4 as a reagent. The heavier fractions, tar, moisture and inorganic materials were removed from the crude oil by distillation in the temperature range of 40 °C–80 °C. The density, viscosity and moisture content of the upgraded bio-oil decreased to 1030 kg/m3, 1.77 cSt and 25% respectively.
    Fuel. 01/2014; 119:81–89.
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    ABSTRACT: Adequate information is available on colour and organics removal in batch mode using pure microbial cultures from dye contaminated wastewater. There was a need to develop environment friendly and cost effective treatment technique for actual field conditions. Therefore, the present study was undertaken with an aim to evaluate the potential of acclimatized mixed microbial consortia for the removal of colour and organics from real textile wastewater. Experiments were performed in laboratory scale activated sludge process (ASP) unit under steady state condition varying mixed liquor volatile suspended solids (MLVSS) (2500, 3500 and 5000 mg/l) and hydraulic retention time (HRTs) (18, 24 and 36 h). The results showed that decolourization and chemical oxygen demand (COD) removal increased with increase in MLVSS and HRT. At 18 h HRT, decolourization was found to be 46%, 54% and 67%, which increased to 67, 75 and 90% (36 h HRT) at 2500, 3500 and 5000 mg/l MLVSS respectively. COD removal was found to be 62, 73 and 77% (at 18 h HRT) which increased to 77, 85 and 91% (36 h HRT) at 2000, 3500 and 5000 mg/L MLVSS respectively. On the basis of the results obtained in this study suitable treatment techniques can be developed for the treatment of wastewater contaminated with variety of dyes in continuous mode of operation. This shall have the advantage of treatment of larger quantity of wastewater in shorter duration.
    Water Resources and Industry. 01/2014;
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    ABSTRACT: Biodiesel production from nonedible feedstocks is gaining attention in the recent years as they do not interfere with the global food economy. In this investigation, Spirulina platensis algae biomass was used as the feedstock for biodiesel production. Single stage extraction–transesterification was carried out with an aim to study the effect of reaction temperature, catalyst concentration, algae biomass to methanol ratio (wt:vol), stirring intensity and algae drying duration on the biodiesel yield. The optimum conditions for maximum biodiesel yield (75 ± 0.40%) were found to be 90 min duration for algae drying, 60% catalyst concentration, 1:4 algae biomass to methanol ratio, 450 rpm stirring intensity and 55 °C reaction temperature. The experimental data appeared to be a good fit with the first order reaction kinetics. For the reaction studied at different temperatures, values of rate constant and activation energy were found out to be 0.001 min−1 and 14518.51 J/mol respectively. The values of thermodynamic parameters such as Gibbs free energy (ΔG), enthalpy of activation (ΔH) and entropy of activation (ΔS) were also determined. The positive values of ΔG and ΔH and negative value of ΔS indicated the unspontaneous and endergonic nature of the reaction.
    Fuel. 01/2014; 135:228–234.
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    ABSTRACT: Pitcher irrigation is particularly useful for horticulture in arid zones. It is of interest to see the correlation of water flow (WF) through the pitcher wall into air, water, and soil with the moisture deficit in air (MD). The pattern of WF into the three media was studied for four pitchers filled with water up to the neck, under natural atmospheric conditions and under hydraulic head (HH). WF without HH was in the order air > soil > water, the amount being negligible in water. WF under HH was also in the same order, but with a significant increase in WF. In all cases WF correlated linearly to level of dryness of the air. Hydraulic conductivity (Ks) for all the pitchers also varied in the order air > soil > water. Ks in water was independent of MD, whereas Ks in soil and air increased with MD. Thus total WF through capillary pores of the pot is due to pressure of hydraulic head only when WF is into the water medium. In air and soil there is an additional WF due to the MD in the medium. This is seen as a negative pressure or an equivalent negative hydraulic head. Copyright © 2013 John Wiley & Sons, Ltd. RÉSUMÉ L'irrigation au pichet est particulièrement utile pour l'horticulture dans les zones arides. Il est intéressant de voir la corrélation du débit d'eau (WF) à travers la paroi de la cruche dans l'air, l'eau et le sol, avec déficit d'humidité dans l'air (MD). Le modèle de WF dans les trois médias a été étudié dans quatre cruches remplies d'eau jusqu'au cou, sous des conditions atmosphériques naturelles et sous condition de charge (HH). WF sous conditions atmosphériques était dans l'ordre air > sol > eau, le débit étant négligeable dans l'eau. WF sous HH était aussi dans le même ordre, mais avec une augmentation significative de WF. Dans tous les cas WF est linéairement corrélé avec la sécheresse de l'air. La conductivité hydraulique (Ks) pour tous les pichets varie aussi dans l'ordre air > sol > eau. Ks dans l'eau est indépendant de MD, alors que Ks dans le sol et l'air augmente avec MD. Ainsi WF à travers les pores capillaires du pot est dû à la charge hydraulique uniquement lorsque WF est dans le milieu aquatique. Dans l'air et le sol, il y a plus de WF dû à MD dans le milieu. Ceci est considéré comme une pression négative ou une charge hydraulique équivalente négative. Copyright © 2013 John Wiley & Sons, Ltd.
    Irrigation and Drainage 08/2013; · 0.69 Impact Factor
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    ABSTRACT: Experiments were designed to determine the effect of untreated wastewater (T1), phytoremediated wastewater (T2), and rainwater (T3) irrigation on Capsicum annuum and soil. Morphological parameters of plants and accumulation of metal and nutrients in crop and soil were studied. The biomass of C. annuum was greatest under T1 followed by T2 and T3. Root/shoot ratio decreased in the order T3 > T2 > T1 (P ≤ 0.05), indicating lengthening of roots under nutrient stress. There was a significant increase in the nutrient [nitrate (NO3−), phosphate (PO43−), potassium (K+), magnesium (Mg++), and calcium (Ca++)] content of the soil after harvest under T1 and T2. The metal accumulated by the plant in μg g−1 of dry weight was in the order zinc (Zn) > copper (Cu) > chromium (Cr). The percentage accumulations of metals by the plant out of total applied were only 1–5% for Cr and Cu and 14% for Zn, and the remaining was left in the soil. There was no metal accumulation in fruits.
    Communications in Soil Science and Plant Analysis 01/2013; 44:1-17. · 0.42 Impact Factor
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    International Journal of Environmental Sciences. 01/2013; 2(1):25-33.
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    ABSTRACT: Domestic wastewater is generated continuously and in large quantities. It can serve as an alternative water nutrient source for irrigation. In the present study Abelmoschus esculentus L. (Ladyfinger) was irrigated using untreated wastewater (T1), treated wastewater (T2) and rainwater (T3) in pot experiments. The effect was seen on nutrient fortication, growth and yield of the plant and the nutrient status of the soil. Additionally the build up of Cr, Cu and Zn from the irrigation water were anlayzed in different parts of the plant biomass and in the soil. The sapling survival rate was found to be 87% in T1 followed by T2 and T3. Root shoot ratio under different treatments was found in the order T3 (0.46) >T2 (0.35) >T1 (0.31). The chlorophyll a, b and carotene content in the leaves (mg g(-1)) was found to be 6.3, 0.5, 0.9 under T1, 4.8, 0.4, 0.8 under T2 and 3.2, 0.3, 0.5 under T3 respectively and all the three varied in the order T1>T2>T3. The same trend was found in case of total dry matter (g) T1 (6.3) >T2 (3.7) >T3 (2.3) at p < or = 0.05. There was a considerable increase in nutrients in the soil under T1 and T2 as compared to T3 after final harvest. The organic matter (%), NO3-N and PO4(3-) (mg kg(-1)) content post harvest soil was found to be 3.4, 71, 90 under T1 and 2.9, 52, 63 under T2 respectively. Also, there was an increase in cations Na, K, Ca and Mg in the soil irrigated with T1 and T2 after the final harvest. Thus irrigation with wastewater generally increased soil fertility. Only a small percentage of the heavy metal was bioaccumulated by the plant parts from the irrigation water. There was hardly any metal accumulation in fruits. Bulk of the metal ions remained in the soil.
    Journal of Environmental Biology 09/2011; 32(5):645-51. · 0.68 Impact Factor
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    Journal of Environmental Biology 01/2011; 32:645-651. · 0.68 Impact Factor
  • Journal of scientific and industrial research 01/2011; 70:645-652. · 0.51 Impact Factor
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    Journal of scientific and industrial research 01/2011; 70:616-621. · 0.51 Impact Factor
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    ABSTRACT: In the present study, an attempt was made for the removal of Remazol Black B dye (azo dye) by using Aspergillus Flavus during its growth. Biosorption of the azo dye by growing fungi was investigated in batch reactors as a function of initial concentration of dye (25-1000 mg/L), inoculum concentration (5-20%), and pH (2.5-6.5). The total biomass concentration decreased from 6.3 g/L to 1.44 g/L by increasing the dye concentration from 0 to 1000 mg/L. The dye uptake increased from 4.37 to 233 mg/g of dried biomass by increasing initial concentration of dye from 25 to 1000 mg/L. The nearly complete removal of dye was found at initial concentration upto 250 mg/L and at pH 4.5 which was used as working pH value for removal of dye in all the batch studies. The removal of Chemical Oxygen Demand (COD) was found to be 90% at 100 mg/L initial concentration of dye. The experiments were also performed with wastewater from textile industry with an aim to examine the potential of fungal biomass for the removal of dyes from wastewater under actual field conditions. The maximum dye removal was obtained at 30° C temperature (87%) in presence of 1 % glucose concentration (89%) and 10 % inoculum concentration (91%) after 96 hours from textile wastewater. The surface of the biosorbent before and after the sorption of the dye was examined by FTIR and SEM analysis.
    Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering 08/2010; 45(10):1256-63.
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    ABSTRACT: A two-stage process has been developed for stabilization of sludge and removal of heavy metals from the secondary activated sludge with high rate of energy and time conservation. The first stage of the process involves autoheated thermophilic aerobic digestion at 55-60 degrees C inoculated with less-acidophilic thermophilic sulfur-oxidizing microorganisms (ATAD). The results show that it is possible to maintain the autoheated conditions (55-60 degrees C) in the ATAD reactor up to 24 hr, leading to reduction of 21% total solids (TS), 27% volatile solids (VS), 27% suspended solids (SS) and 33% volatile suspended solids (VSS) from the sludge. The sludge pH also decreased from 7 to 4.6 due to the activity of less-acidophilic thermophilic microorganisms. In the second stage operation, the digested sludge (pH 4.6, TS 31.6 g/L) from stage one was subjected to bioleaching in a continuous stirred tank reactor, operated at mean hydraulic retention times (HRTs) of 12, 24 and 36 hr at 30 degrees C. An HRT of 24 hr was found to be sufficient for removal of 70% Cu, 70% Mn, 75% Ni, and 80% Zn from the sludge. In all, 39% VSS, 76% Cu, 78.2% Mn, 79.5% Ni and 84.2% Zn were removed from the sludge in both the stages.
    Journal of Environmental Sciences 01/2010; 22(2):230-6. · 1.77 Impact Factor
  • Journal of scientific and industrial research 01/2010; 69:146-150. · 0.51 Impact Factor
  • G.H.V.C. Chary, M.G. Dastidar
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    ABSTRACT: The significance of coking coal in the metallurgical sector as well as the meager coking coal reserves across the globe increase the necessity to recover coking coal fines from the fine coking coal slurries generated from coal preparation and utilization activities. Oil agglomeration studies were carried out by varying the experimental conditions for maximum recovery of coking coal fines i.e., yield of the agglomerates. The various operational parameters studied were oil dosage, agitation speed, agglomeration time and pulp density. By using Taguchi experimental design, oil dosage (20%), agitation speed (1100 rpm), agglomeration time (3 min) and pulp density (4.5%) were identified as the optimized conditions. A confirmation experiment has also been carried out at the optimized conditions. The percentage contribution of each parameter on agglomerate yield was analyzed by adopting analysis of variance (ANOVA) statistical method as well as multiple linear regression analysis. The order of influence of the parameters on the agglomerate yield is of the following order: pulp density > oil dosage > agitation speed > agglomeration time. A mathematical model was developed to fit the set of experimental conditions with the yield obtained at each test run and also at the optimized conditions. The experimentally obtained yield was compared with the predicted yield of the model and the results indicate a maximum error of 5% between the two. A maximum yield of 90.42% predicted at the optimized conditions appeared to be in close agreement with the experimental yield thus indicating the accuracy of the model in predicting the results.
    Fuel. 01/2010; 89(9):2317-2322.
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    ABSTRACT: The potential of indigenous iron-oxidizing microorganisms enriched at initial neutral pH of the sewage sludge for bioleaching of heavy metals was investigated at initial neutral pH of the sludge using ammonium ferrous sulfate (FAS) and ferrous sulfate (FS) as an energy sources in two different sets of experiments. After 16 days of bioleaching, 56% Cu, 48% Ni, 68% Zn and 42% C were removed from the sludge using ammonium ferrous sulfate as an energy source. On the other hand, 64% Cu, 58% Ni, 76% Zn and 52% Cr were removed using ferrous sulfate. Further, 32% nitrogen and 24% phosphorus were leached from the sludge using ferrous sulfate, whereas only 22% nitrogen and 17% phosphorus were removed using ammonium ferrous sulfate. The BCR sequential extraction study on speciation of metals showed that using ammonium ferrous sulfate and ferrous sulfate, all the metals remained in bioleached sludge as stable form (F4 fraction). The results of the present study indicate that the bioleached sludge would be safer for land application. Also, the fertilizing property was largely conserved in the bioleached sludge using both the substrates.
    Journal of hazardous materials 07/2009; 171(1-3):273-8. · 4.14 Impact Factor
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    ABSTRACT: During the treatment of sewage, a huge volume of sludge is generated, which is disposed of on land as soil fertilizer/conditioner due to the presence of nitrogen, phosphorus, potassium and other nutrients. However, the presence of toxic heavy metals and other toxic compounds in the sludge restricts its use as a fertilizer. Over the years, bioleaching has been developed as an environmentally friendly and cost-effective technology for the removal of heavy metals from the sludge. The present paper gives an overview of the various bioleaching studies carried out in different modes of operation. The various important aspects such as pathogen destruction, odor reduction and metal recovery from acidic leachate also have been discussed. Further, a detailed discussion was made on the various technical problems associated with the bioleaching process, which need to be addressed while developing the process on a larger scale.
    Journal of Environmental Management 04/2009; 90(8):2343-53. · 3.06 Impact Factor
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    ABSTRACT: The effects of sulfur concentration, initial pH of the sludge and sludge solid content on metal bioleaching were examined using anaerobically digested sewage sludge procured from a typical sewage treatment plant in Delhi, the capital city of India. Experiments on effect of sulfur concentration were carried out using 0-4 g L(-1) of elemental sulfur to optimize the concentration of elemental sulfur for efficient bioleaching. For the type of sludge (20 g L(-1) solid content) used in the present study, 2 g L(-1) of elemental sulfur was found sufficient in metal bioleaching in the following order: Zn 86%, Cu 71.5%, Mn 70%, Ni 58.3% and Cr 43.8%. Changes in pH, sulfate concentration and oxidation-reduction potential (ORP) as a function of time were experimentally monitored. A rapid change in the above parameters took place in 4-6 days followed by a slow change until the 10th day. The change in pH with time was observed to vary at different initial pH values (pH 7 to pH 3) of the sludge; however, there was not much difference in the final pH achieved and final metal solubilization which ranged from: Cu 83.6-94.2%, Ni 27.7-29.8%, Zn 89-94.8%, Mn 67.5-79% and Cr 34.1-44.1% The results of the present studies strongly indicate that using 2 g L(-1) elemental sulfur, indigenous sulfur oxidizing microorganisms can bring down pH to a value needed for significant metal solubilization. Also, bioleaching can be carried out successfully over a wide range of initial pH values of the sludge. Further, at higher sludge solid concentration than 20 g L(-1), lower metal solubilization was achieved due to the buffering capacity of the sludge.
    Journal of Environmental Science and Health Part A 04/2008; 43(4):402-11. · 1.25 Impact Factor
  • Mousumi Sen, Manisha Ghosh Dastidar, Pradip K. Roychoudhury
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    ABSTRACT: In the present work biological removal of Cr(VI) was carried out in batch and continuous modes of operation using the growing cells of Fusarium solani isolated from soil. The growth of the organism and Cr(VI) removal by the organism were studied in batch bioreactor at different initial concentration of Cr(VI) at controlled pH 5.0. Whereas, single and two stage reactors were used in continuous mode of operation for Cr(VI) removal. Batch studies indicated the maximum specific Cr(VI) removal to be 71mgg−1 at pH 5.0 and at 500mgl−1 initial Cr(VI) concentration. The continuous mode of operation was found to be the ideal strategy in which the process could be operated for longer duration with maximum specific Cr(VI) removal of 62.3mgg−1. Nearly complete removal was obtained using a single stage reactor at lower Cr(VI) concentrations up to 100mgl−1 and a two stage reactor at higher Cr(VI) concentration.
    Enzyme and Microbial Technology - ENZYME MICROB TECHNOL. 01/2007; 41(1):51-56.