Time domain generalized telegrapher’s equations for the electromagnetic field coupling to finite-length wires buried in a lossy half-space

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Biogas production by an anaerobic digestion process from orange peel waste and its improvement by limonene leaching: Investigation of H2O2 pre-treatment effect

Orange peel waste is considered as an important feedstock for anaerobic digestion to generate bio-energy such as bio-hydrogen and bio-methane; however, its use as an energy source is still not important worldwide. Therefore, in the current study, the biochemical methane potential test was carried out to estimate the biogas production from orange peel waste by using an anaerobic digestion process in the thermophilic phase (T = 55°C). In order to investigate the antimicrobial and the inhibiting effect of limonene contained in orange peels on biogas production two experimental setups were operated simultaneously using de-oiled and crude orange peel wastes, respectively. For further enhancement of the biogas production, a pre-treatment was applied using hydrogen peroxide (H2O2) at different concentrations up to the optimum value to increase soluble chemical oxygen demand (COD). The obtained results showed an important increase in biogas production: From 170 mL.gTVS−1 for the untreated sample to 750 mL.gTVS−1 after pre-treatment, and the composition analysis of the biogas indicated that average methane yields represent up to 50% of the total production. This increase was observed after steam distillation and was attributed to the removal of the antimicrobial compound

Alkaline pretreatment of tannery wastewater impact on biochemical methane potential tests: experimental study and kinetic modeling

Studies were carried out on anaerobic digestion of tannery wastewater obtained from leather processing. Degassed activated sludge biomass collected from a wastewater treatment plant was used as source of microorganisms. The study was carried out to examine the impact of alkaline pretreatment on a real tannery wastewater prior anaerobic digestion process. Bio-methane potential tests were conducted at 35±2°C on tannery wastewater pretreated by adding different volumes of 2N NaOH solution up to set pH values at 9, 10, 11, and 12, respectively. NaOH solution addition resulted in a partial removal of total Cr showing efficiency from 16.84 to 95.72% as well as in an increase of the soluble chemical oxygen demand concentration from 8.53 to 29.02%. The effects of this pretreatment affected significantly the results obtained with bio-methane potential tests that showed methane production from all the pretreated tannery wastewater samples much higher than from that unpretreated. Finally, the lag phase duration and the maximum specific methane production rate of the anaerobic digestion process were evaluated by fitting the experimental results from bio-methane potential tests with the following three models: (i) the modified Gompertz model, (ii) the Logistic function, and (iii) the Richards model. All the previous models showed a high level of accordance with the experimental data, even though Richards model resulted in being the most accurate

Generalized from of Telegrapher’s Equations for the Electromagnetic Field Coupling to Buried Wires of Finite Length

In this paper, a generalized form of telegrapher's equations for electromagnetic field coupling to buried wires is derived. The presented approach is based on thin-wire antenna theory. The effect of a dissipative half-space is taken into account via the reflection/transmission coefficient approximation. The conductor losses can be taken into account via the surface impedance per unit length. The derived equations are treated numerically via the Galerkin-Bubnov indirect boundary element method. Numerical results are presented for induced current along the wire, and compared with transmission-line (TL) and modified TL (MTL) approximations, respectively, for the case of perfectly conducting electrode buried in a lossy medium. It is shown that the TL and MTL approximations can result in an inaccurate induced current distribution along the conductor at HFs and for shorter electrode lengths, respectively