Fenton oxidation and adsorption pretreatment for superior biogas recovery from biomethanated spent wash

Abstract

A key task in alcohol distilleries is the effective treatment of biomethanated spent wash after biogas recovery. This colored washwater exhibits low biodegradability index (BI?<?0.2), high chemical oxygen demand (30,000?<?COD?<?40,000?mg/L), and recalcitrance to aerobic treatment. In this work, pretreatment of biomethanated distillery wastewater by Fenton oxidation was proposed for improved biogas recovery. The effects of temperature, solution pH, and H₂O₂ dosage on the efficacy of the oxidation process were studied. Using ferrous sulfate catalyst (36?mg/L) for diluted wastewater (BOD₅?=?81; COD?=?400?mg/L), 54% reduction in COD was achieved within 1?h in acidic medium (pH?=?3) at ambient temperature (T?=?30?°C). Post-oxidation, the BI value improved (0.33). After subsequent adsorption over activated carbon (loading 5%) for 1?h, COD reduction (70%), and BI value (0.43) improved further. Upon anaerobic treatment with 1% acclimatized biomass, 1?Nm³ of biogas (47% CH₄) was additionally formed per m³ of treated wastewater; without pretreatment, this value was 0.9?Nm³ (just 11% CH₄). Lastly, aerobic treatment was performed and the results were encouraging: BI?=?0.51 and COD reduction?=?94%. Many oxidation products were identified and first-order kinetic plots were made to describe COD conversion kinetics. In this way, useful insight on a plausible technique for valorization of biomethanated washwater was provided.     

A Review: Supplementation of Foods with Essential Fatty Acids—Can It Turn a Breeze without Further Ado?

This paper focuses on the critical aspects of supplementation of foods with essential fatty acids (EFAs), the need, health benefits of supplementation and the constraints of the process. Current trend of supplementation of foods with EFAs has been gaining momentum and more research pioneers due to the health benefits in par with the direct intake of EFA supplements. Technologies including encapsulation, nanotechnology, molecular complexing, genetic engineering and more emerging means, hold promise to food supplementation with EFAs. Food trials with adoption of various technologies, studies of bioavailability and health benefits are still underway and crucial before EFA supplementation in foods can hit the market on a global scale.     

Experimental investigations of direct injection compression ignition engine by using Coconut,and Karanja biodiesel fuels with emulsions of microalgae based antioxidant

The Compression Ignition (CI) engines are playing vital role in the transportation sector; because of their lower maintenance cost even. The practice of Diesel or biodiesel is increasing Green House Gases (GHG) such as NO_x, particulate matter in the environment. Among all GHG emissions, NO_x is most harmful to human, environment. The use of additives in Diesel, biodiesel their blends in CI engine is very well practicing fuel modification technique to reduce GHG emissions. The higher cost of phenol, amine-based antioxidants are causing to increase CI engine operating cost. In this work, to investigate unmodified Direct Injection Compression Ignition engine characteristics. The Mixed culture Microalgae (MCM) biomass particles used as an antioxidant additive in pure Coconut, Karanja biodiesel. The brake thermal efficiency improved because of the explosion of MCM particles. The NO_x emissions reduced due to the absorption of heat from the combustion chamber by microalgae particle.     

Analysis of short circuit and inrush transients in a current transformer using a field-circuit coupled FE formulation

The existing models based on the lumped-circuit approach consider the constant leakage inductance during transient simulations. However, leakage inductance of the current transformer (CT) may not remain constant. In fact, it may vary with the degree of saturation of the core. During severe saturation conditions, leakage inductance variation in fact may result in significant difference between the calculated and the measured secondary currents. In this work, a nonlinear, field-circuit coupled finite element model of a current transformer (CT) is presented. The model considers the variation in leakage inductance during the simulation of transient conditions. Moreover, since geometry of the transformer was taken into account, it was possible to estimate forces associated with the short-circuit current. Hysteresis characteristic of the core was taken into account by using Jiles-Atherton model in conjunction with fixed-point iteration method. The formulation was realized using a code developed in MATLAB and implemented for a 69 kV, 200/5 A current transformer. The normal operation and other cases such as short-circuit, and transformer sympathetic inrush current through the primary of the CT are presented. These cases demonstrate modeling flexibility of the field-circuit coupled formulation.     

Influence of chemical composition on sintering ability of ZTA ceramics consolidated from freeze dried granules

Dense zirconia-toughened alumina (ZTA) ceramic composites with ZrO₂ = 0, 5, 10, 15, 20, 30, 60 and 100 wt.% have been prepared by sintering green compacts obtained by dry powder pressing of freeze dried granules consisting of α-alumina and a yttria partially stabilized zirconia (YPSZ) at various temperatures ranging from 1450 to 1650 °C for 1-2 h. The characteristics of sintered products were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes principle, Vickers indentation method and by 3-point bend test. Characterization results revealed that adding YPSZ increased the 3-point bend (flexural) strength, fracture toughness and homogeneity of the microstructure, but slightly decreased the hardness and the sintering ability of alumina. A 20 wt.% YPSZ was sufficient to increase the fracture toughness and flexural strength of specimens sintered for 2 h at 1600 °C from 2.5 to 4.6 MPa m^1/2 and 150 to 400 MPa, respectively. The XRD results revealed that there is no solid-solution formation between zirconia and alumina constituents of ZTA ceramic composites upon sintering.     

Extraction of cocoa butter alternative from kokum (Garcinia indica) kernel by three phase partitioning

Kokum kernel is a byproduct of agro-processing industry in India containing about 40–50% fat which has the potential as a worthy cocoa butter alternative (CBA). However, inefficient extraction techniques that are practiced at cottage level restrict its industrial applications. This work reports on the optimization of the technique of three phase partitioning (TPP) for efficient extraction of kokum kernel fat. The parameters of TPP were optimized with respect to ammonium sulphate concentration, ratio of slurry to t-butanol and pH of slurry. The optimized protocol resulted in maximum recovery of 95% (w/w) fat recovery within 2 h. The technique is economical and eco-friendly, and is promising for utilization of agro-processing waste in India to a product of commercial significance.     

Comparative analysis of minimum surface potential and location of barrier peaks in various Si MOSFET devices

Comparative analysis of the minimum surface potential (Φ _m) and the respective position (or location of barrier peaks (y ₀)) in various Si MOSFET devices including bulk Si MOSFETs, silicon-on-insulator (SOI) MOSFETs and double-gate SOI MOSFETs has been investigated. For all these three devices we use the same methodology and models to find Φ _m and y ₀. The analytical results from the three models are utilized to compare and analyse performance of the related devices. The effects of three main important parameters affecting the Φ _m and y ₀, namely channel length (or L _g), drain bias (V _d) and gate bias (V _g), are discussed. The main motivation of this paper is to show by comparing the model results how the performance of each device is affected by various changes in physical and electrical parameters. These issues have been elaborately investigated in this work. The short-channel effects including drain induced barrier lowering and threshold voltage roll-off (ΔV _th) are described and their relationship with Φ _m is given.     

Audio analysis of statistically instantaneous signals with mixed Gaussian probability distributions

In this article, a novel method is proposed to measure the separation qualities of statistically instantaneous audio signals with mixed Gaussian probability distributions. This study evaluates the impact of the Probability Distribution Function (PDF) of the mixed signals on the outcomes of both sub- and super-Gaussian distributions. Different Gaussian measures are evaluated by using various spectral-distortion measures. It aims to compare the different audio mixtures from both super-Gaussian and sub-Gaussian perspectives. Extensive computer simulation confirms that the separated sources always have super-Gaussian characteristics irrespective of the PDF of the signals or mixtures. The result based on the objective measures demonstrates the effectiveness of source separation in improving the quality of the separated audio sources.     

Small Punch Creep Studies for Optimization of Nitrogen Content in 316LN SS for Enhanced Creep Resistance

Small punch creep (SPC) studies have been carried out to evaluate the creep properties of 316LN stainless steel (SS) at 923 K (650 °C) at various stress levels. The results have been compared with uniaxial creep rupture data obtained from conventional creep tests. The minimum deflection rate was found to obey Norton power law. SPC rupture life was correlated with uniaxial creep rupture life. The influence of nitrogen content on the creep rupture properties of 316LN SS was investigated in the range of 0.07 to 0.14 wt pct. SPC rupture life increased and the minimum deflection rate decreased with the increase in nitrogen content. The trends were found to be in agreement with the results obtained from uniaxial creep rupture tests. These studies have established that SPC is a fast and reliable technique to screen creep properties of different experimental heats of materials for optimizing the chemical composition for developing creep-resistant materials.