Bacterial decontamination of water by means of pulsed corona discharges

Abou-Ghazala, A.; Katsuki, S.; Schoenbach, K.H.; Dobbs, Fred C.; Moreira, K.R.

doi:10.1109/ppps.2001.1002170

Cited by 22 publications

(28 citation statements)

References 13 publications

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“…These huge, lightning related discharges above thunderclouds attract large research effort since their first observation in 1989 [2,3,4,5]. Because of the reactive radicals they emit, streamers are used for the treatment of contaminated media like exhaust gasses [6,7], polluted water [8,9] or biogas [10]. More recently, efforts have been undertaken to improve the flow around aircraft wings by coupling space charge regions to gas convection [11].…”

Section: Introductionmentioning

confidence: 99%

An adaptive grid refinement strategy for the simulation of negative streamers

Montijn

Hundsdorfer

Ebert

2006

Journal of Computational Physics

104

178

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The evolution of negative streamers during electric breakdown of a non-attaching gas can be described by a two-fluid model for electrons and positive ions. It consists of continuity equations for the charged particles including drift, diffusion and reaction in the local electric field, coupled to the Poisson equation for the electric potential. The model generates field enhancement and steep propagating ionization fronts at the tip of growing ionized filaments. An adaptive grid refinement method for the simulation of these structures is presented. It uses finite volume spatial discretizations and explicit time stepping, which allows the decoupling of the grids for the continuity equations from those for the Poisson equation. Standard refinement methods in which the refinement criterion is based on local error monitors fail due to the pulled character of the streamer front that propagates into a linearly unstable state. We present a refinement method which deals with all these features. Tests on one-dimensional streamer fronts as well as on three-dimensional streamers with cylindrical symmetry (hence effectively 2D for numerical purposes) are carried out successfully. Results on fine grids are presented, they show that such an adaptive grid method is needed to capture the streamer characteristics well. This refinement strategy enables us to adequately compute negative streamers in pure gases in the parameter regime where a physical instability appears: branching streamers.

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Section: Introductionmentioning

confidence: 99%

An adaptive grid refinement strategy for the simulation of negative streamers

Montijn

Hundsdorfer

Ebert

2006

Journal of Computational Physics

104

178

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“…mately 4 J/ml [10]. However, in continuous processing performed in this experiment, energy needs to be ten times larger than that for batch processing to obtain the same reduction level, indicating the effect of batch processing and flow system processing is unlikely to be the same.…”

Section: E Coli Sterilization In Continuous Flow Systemmentioning

confidence: 70%

“…There are several examples of research on sterilization using a pulsed streamer discharge in water, and the effects on E. coli and Bacillus subtilis have been confirmed experimentally [10]. The research performed in the past has involved experiments using a batch processing.…”

Section: Introductionmentioning

confidence: 99%

Sterilization of E. coli by underwater pulsed streamer discharges in a continuous flow system

Fudamoto

Namihira

Katsuki

et al. 2008

Electrical Engineering Japan

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SUMMARYUnderwater pulsed streamer discharges using a wireto-cylinder electrode contained in a 42-mm-diameter glass tube were investigated with respect to its spatial spread associated with voltage waveforms. A discharge reactor with a continuous flow system was employed to sterilize E. coli suspended in saline water (10 mS/m). The discharge electrode consisted of a 0.1-mm-diameter metal wire for the high voltage and a mesh cylinder for the ground electrode. Tens of disk-shaped discharges emerged from the wire electrode and propagated toward the cylinder as long as the voltage lasted. The spatial expanse of the discharge was proportional to the cube of the pulse duration and to the amplitude of the voltage. The sterilization experiment showed that the survival ratio of bacteria over discharges was proportional to the average number of the exposures to the discharges while in the reactor. The minimum ratio of surviving bacteria was only 15% under 130 exposures, which corresponds to an energy expenditure of 35 J/ml.

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“…This study contributes Townsend discharge regime at a new range of plane-parallel electrode separations (2cm) and different working pressures. Depending upon the energy range level, which can be delivered by these pulsed discharges, their pulse durations and modes of operation, a number of research interests has been developed for applications in medicine (Woloszko et al, 2002;Abou-Ghazala et al, 2002;Nunnally et al, 2005;Akiyama et al, 2007). Helmholtz coils are two identical circular coils of wire with identical electrical currents flowing in the same direction and arranged symmetrically.…”

Section: Introductionmentioning

confidence: 99%