LARGE SCALE BIOREMEDIATION OF PETROLEUM HYDROCARBON CONTAMINATED WASTE AT INDIAN OIL REFINERIES: CASE STUDIES

ABSTRACT The petroleum industry effluents, oily sludge and oil spills cause a serious threat to the environment as their constituents are toxic, mutagenic and carcinogenic. Safe disposal of these wastes is serious problem. None of the available conventional disposal methods are environment friendly. Biological methods have been well reviewed and acknowledged for remediation of petroleum hydrocarbon contaminated waste (oily waste). An indigenous microbial consortium was developed by assemble of four species of bacteria, isolated from various oil contaminated sites of India, which could biodegrade different fractions of total petroleum hydrocarbon (TPH) of the oily waste to environment friendly end products. The said consortium was applied on field scale at different oil refineries in India and successfully bioremediated 48,914 tons of different types of oily waste. In 44 field case studies of different batch size of ex situ bioremediation process, the initial TPH content varying from 83.50 to 531.30 gm/kg of oily waste, has been biodegraded to < 10 gm/kg of oily waste in major cases in 2 -12 months. In one refinery due to coastal climate, the bioremediation time was > 20 months. The bioremediated soil was non-toxic and natural vegetation was found to be grown on the same. Bioremediation technology has helped various oil industries for the management of their hazardous oily wastes in environment friendly manner

Mesospheric backscatter echoes as observed by the Indian MST Radar Facility at Gadanki

489-501The Indian Mesosphere Stratosphere Troposphere (MST) radar facility at Gadanki (13.5ºN, 79.2ºE) has been utilised to characterise the mesospheric backscattered signals by considering already available results and new analysis of past and recent data sets. Individual days data as well as continuous and long term Common Mode Observation (CMO) data have been used to study (1) the basic features of mesospheric return echoes, (2) scattering layer heights, (3) relation to mesospheric turbulence governed through weather phenomena, (4) spatial and temporal variability, (5) seasonal patterns and, (6) inter-annual changes. While the present results have been found to be consistent, with the earlier results, some new aspects have been brought out. A broad theoretical background is provided relevant to turbulent scattering of radar waves so that the results are interpreted from this perspective. The main results of the mesospheric studies with the Gadanki radar include the very intermittent nature of echoes varying with radar beam directions and time. Temporal variations of the radar returned signals are found to be related to the growth and decay of eddies, generated by atmospheric turbulence. The mean height of mesospheric scattering layer is around 72 km and the life period of the turbulence patches generally lies in the range 10-20 min. In the months of June-July and September-October of 2003, the intensity of radar returned signals were stronger compared to other months and there is an elevation of the mean scattering layer by ~2 km with the decrease in solar activity between 2003 and 2005

Search for cheap and efficient counter electrodes for some redox couples for potential aqueous PEC solar cells

847-853Electrocatalytie activities of some noble metal [M= Pt, Pd, Rh, Ru and Au]-coated graphite, (C)M, platinized platinum (Pt)Pt, as well as bare Pt and C electrodes have been studied for the redox couples like hydroquinone-quinone (QH2/Q) and ferrocene-ferricinium (Fic/Fic+) in water by determining the rate constant (ks) of the redox reactions by cyclic voltammetric (CV) measurements. As on commonly used bright Pt, CVG's for Foc/Fic+ system on most of the metallized surfaces are characterized by single cathodic and anodic peaks and found to be quasi-reversible. Exactly similar behaviour is exhibited in the case of H2Q/Q redox system in 1M H2SO4 solution. The observed order of ks; values based on apparent area of 1 em/ on different surfaces is found to be (C) Ru > Pt(Pt) > (C)Rh > Pt > (C)Pd > (C) > (C)lr (C)Au > (C)Pt for H2Q/Q redox system (C(Au (Pt)Pt > (C)Pt (C)Pd (C)Ru > (C)lr > Pt > C for Foc/Fic+ system. The observed orders are shown to be dictated by the roughness factor as well as the combined effect of 'electronic' and 'geometric' characters of the polycrystalline metallized surfaces guiding differently the coverage (θ) by solvent water molecules (θw) and the involved redox species (θr)

Effect of Surfactants on Kinetics of Alkaline Fading of Crystal Violet & Acid-catalyzed Inversion of Sucrose

115-12

Liquid Junction Potentials Across Aqueous Saturated Calomel Electrode/Some Aquo-organic Solvents Interface

197-201The liquid junction potentials (Ej) generated at the boundaries of saturated KCI solution of aqueous saturated calomel electrode [SCE (W)] and mixed aqueous organic solvents have been determined within the framework of tetraphenylarsonium tetraphenylboride (TATB) reference electrolyte extra-thermodynamic assumption. The organic solvents comprise protic methanol (MeOH) and ethanol (EtOH), aprotic dioxane (D) and dipolar aprotic acetonitriJe (ACN), N,N-dimethylformamide (DMF) and dimethyl sulphoxide (DMSO). The Ej values increase almost monotonically in the cases of DMF and DMSO and remain almost invariant till 50 wt % MeOH and EtOH, while in ACN and D, the values lie in between. The contribution to Ej values is mainly from difference of ion-solvent interactions in these mixed solvents, which becomes significant only in the organic-rich compositions

Solvent and electrode kinetic effects on the anodic oxidation of Br^- in water and some dipolar aprotic solvents on bare and platinized Pt and C surfaces ^†

291-296The solvent effects on the exchange current densities (io)for anodic oxidation of Br- on platinum (Pt),-graphite (C) and their platinized surfaces, (Pt)Pt or (C)Pt at 15, 25 and 35°C have been determined in water as well as in some pure non-aqueous solvents like acetonitrile (ACN), N,N-dimethylformamide (DMF) and propylene carbonate (PC) by potentiostatic polarization technique under near equilibrium condition. For all the electrodes except C, the observed order of io values in different organic solvents followed the sequence: ACN> DMF> PC and that on C electrode: ACN > PC > DMF. On the other hand, for any solvent except water, the observed io values on different electrodes are in the order: (C)Pt≥(Pt)Pt>Pt>C and that in water: (Pt)Pt>Pt≥(C)Pt>C.. The kinetic solvent effect (KSE) data at 25°C relative to that in water have been analyzed in the light of relative stabilization of the initial state (Br-] and the transition state (TS), as well as the extent of free surface (1 - s,), the coverage, s being guided by image interactions' inducted by dipolar and dispersion interactions of the cosolvents with the surfaces. The observed virtual heats of activation at the reversible potentia. (H0 #) which ref1ectintrinsic electrocatalytic activities of the electrodes, being of the order C≥ Pt > (Pt)Pt > > (C)Pt, suggest that graphite (C) electrode is intrinsically a weaker electrocatalyst than both the (C) Pt and (Pt)pt or even bare Pt electrode and that the superiority of (C)Pt over (Pt)Pt is seemingly due to the porous nature of C substrate

Kinetics of hydrogen evolution reaction on bright platinum electrode in aqueous dimethylformamide solutions by cyclic voltammetry

86-90Kinetic behaviour of hydrogen evolution reaction (HER) has been studied on bright platinum electrode in aqueous mixtures of 0,25,50,75,90 and 100 wt% N,N-dimethylformamide (DMF) from both HCl and HClO4 solutions by cyclicvoltammetry under varying sweep rates [500-1 mVs-1] in the cathodic potential region of 0-1000 mV. The cyclic voltammograms are characterized by single cathodic and the corresponding anodic peaks and are found to be quasi-reversible in nature. The relevant kinetic parameters like the diffusion coefficient (DR) of the reductant and the rate constant (ks) (based on apparent area of the electrode) have been derived using the formulations of Shain and Nicholson. The values of DR and ks in aq. DMF mixtures decrease from that in pure water due to possible increased protophilicity of DMF-water mixtures which hinders the solvated H+ ions to approach the electrode surface for undergoing HER