scholarly journals Influence of Acoustic Oscillations on Continuous-Flow Water Disinfection

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1259
Author(s):  
Anna V. Abramova ◽  
Vadim M. Bayazitov ◽  
Igor S. Fedulov ◽  
Roman V. Nikonov ◽  
Vladimir G. Sister ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Vortex Flow ◽  
Synergistic Effects ◽  
Acoustic Power ◽  
Excess Pressure ◽  
Water Disinfection ◽  
Hybrid Reactor ◽  
Acoustic Oscillations ◽  
Physical Treatment ◽  
Microorganism Inactivation

Water disinfection and potential sterilization in continuous flow was achieved in a hybrid reactor with a broadband hydrodynamic emitter combined with ultrasonic vibrations at different frequencies and with excess pressure. Such a combination showed synergistic effects by increasing the acoustic power in the reactor vortex flow. The present combined physical treatment, compared with sonication alone, could increase microorganism inactivation by 15–20%.

scholarly journals Disinfection efficacy of chlorine and peracetic acid alone or in combination against Aspergillus spp. and Candida albicans in drinking water

2011 ◽  
Vol 10 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Maurizio Sisti ◽  
Giorgio Brandi ◽  
Mauro De Santi ◽  
Laura Rinaldi ◽  
Giuditta F. Schiavano
Keyword(s):  
Drinking Water ◽  
Candida Albicans ◽  
Peracetic Acid ◽  
Contact Time ◽  
Distribution Systems ◽  
Water Distribution ◽  
Synergistic Effects ◽  
Water Disinfection ◽  
Experimental Conditions ◽  
Complete Inactivation

The aim of the present study was to evaluate the fungicidal activity of chlorine and peracetic acid in drinking water against various pathogenic Aspergillus spp. and Candida albicans strains. A. nidulans exhibited the greatest resistance, requiring 10 ppm of chlorine for 30 min contact time for a complete inactivation. Under the same experimental conditions, peracetic acid was even less fungicidal. In this case, A. niger proved to be the most resistant species (50 ppm for 60 min for complete inactivation). All Aspergillus spp. were insensitive to 10 ppm even with extended exposure (>5 h). The combination of chlorine and peracetic acid against Aspergillus spp. did not show synergistic effects except in the case of A. flavus. Complete growth inhibition of C. albicans was observed after about 3 h contact time with 0.2 ppm. C. albicans was less sensitive to peracetic acid. Hence the concentrations of chlorine that are usually present in drinking water distribution systems are ineffective against several Aspergillus spp. and peracetic acid cannot be considered an alternative to chlorine for disinfecting drinking water. The combination of the two biocides is not very effective in eliminating filamentous fungi at the concentrations permitted for drinking water disinfection.

scholarly journals Acoustic oscillations in a field-free cavity under solar small-scale bipolar magnetic canopy

2008 ◽  
Vol 26 (10) ◽  
pp. 2983-2989 ◽  
Author(s):  
D. Kuridze ◽  
T. V. Zaqarashvili ◽  
B. M. Shergelashvili ◽  
S. Poedts
Keyword(s):  
Magnetic Field ◽  
Acoustic Waves ◽  
Canopy Structure ◽  
Active Regions ◽  
Acoustic Power ◽  
Lower Atmosphere ◽  
Wave Number ◽  
Small Scale ◽  
Acoustic Oscillations ◽  
Frequency Wave

Abstract. Observations show the increase of high-frequency wave power near magnetic network cores and active regions in the solar lower atmosphere. This phenomenon can be explained by the interaction of acoustic waves with a magnetic field. We consider small-scale, bipolar, magnetic field canopy structure near the network cores and active regions overlying field-free cylindrical cavities of the photosphere. Solving the plasma equations we get the analytical dispersion relation of acoustic oscillations in the field-free cavity area. We found that the m=1 mode, where m is azimuthal wave number, cannot be trapped under the canopy due to energy leakage upwards. However, higher (m≥2) harmonics can be easily trapped leading to the observed acoustic power halos under the canopy.

U-RANS Model for the Prediction of the Acoustic Sound Power Generated in a Whistling Corrugated Pipe

2013 ◽  
Author(s):  
Joachim Golliard ◽  
Néstor González-Díez ◽  
Stefan Belfroid ◽  
Güneş Nakiboğlu ◽  
Avraham Hirschberg
Keyword(s):  
Velocity Profile ◽  
Shear Layer ◽  
Turbulence Modeling ◽  
Acoustic Power ◽  
Gas Production ◽  
Transport Systems ◽  
Navier Stokes ◽  
Acoustic Oscillations ◽  
High Reynolds ◽  
Single Cavity

Corrugated pipes, as used in flexible risers for gas production or in domestic appliances, can whistle when a flow is imposed through the pipe. Nakiboğlu et al [1, 2] have developed a method to compute the acoustic source term for axi-symmetric cavities. The method is based on the resolution of incompressible Navier-Stoke equations without turbulence modeling. This is a quasi-laminar flow model. A single cavity in a short pipe is considered with, as inlet boundary condition, a pipe flow with an imposed harmonic velocity perturbation. At low Reynolds numbers most of the effect of the turbulence is accounted by the steady velocity profile imposed at the inlet. However, this model fails when applied to high Reynolds number flows as encountered in gas-transport systems (Re = 106 or higher). In this paper, a modified model, using a 2-D unsteady Reynolds Averaged Navier Stokes turbulent solver, is presented. Turbulence determines the development of the approaching boundary layer and of the shear layer above the cavity. The shear-layer velocity profile controls the acoustic power generated by the cavity in response to the imposed acoustic oscillations. Comparison with experimental results obtained for a single cavity shows that the modification of the method considerably increases its accuracy for a deep cavity.

Quantification of the energy required for the destruction ofBalanus amphitritelarva by ultrasonic treatment

2010 ◽  
Vol 90 (7) ◽  
pp. 1475-1482 ◽  
Author(s):  
Nishant Seth ◽  
Piyul Chakravarty ◽  
Lidita Khandeparker ◽  
Arga Chandrashekar Anil ◽  
Aniruddha B. Pandit
Keyword(s):  
Power Density ◽  
Ultrasonic Treatment ◽  
Bacterial Abundance ◽  
Treatment Time ◽  
Power Level ◽  
Acoustic Power ◽  
Water Disinfection ◽  
Balanus Amphitrite ◽  
Marine Fouling ◽  
System Operating

Ultrasonic treatment, a relatively less explored technology in water disinfection, was used to quantify the energy required for the destruction of larvae of barnacleBalanus amphitrite, which is a major marine fouling and a potential invasive organism. Since the power used and treatment time for disinfection are economically, and practically, the most important parameters, the energy required to pulverize the larvae into pieces ≤30 µm was determined as a function of the acoustic power density. The present investigation suggests that an ultrasonic system operating at 20 kHz and 0.0975 W/cm3can effectively pulverize barnacle larvae having length (~440 µm) and breadth (~350 µm) within 45 seconds using 0.1 mJ/larva of pulverization energy. It was also observed that following pulverization of the larvae, the bacterial abundance increased and the rate of release of bacteria was dependent on power level and treatment time, which in turn decided the pulverization rate and hence the rate of release of bacteria.

scholarly journals Design of a cost-effective electrochlorination system for point-of-use water treatment

2020 ◽  
Vol 26 (5) ◽  
pp. 200437-0
Author(s):  
Mainak Bhattacharya ◽  
Koyel Bandyopadhyay ◽  
Anirban Gupta
Keyword(s):  
Water Treatment ◽  
Continuous Flow ◽  
Low Cost ◽  
Developed Countries ◽  
Water Disinfection ◽  
Residual Chlorine ◽  
Waterborne Diseases ◽  
Bacterial Inactivation ◽  
Treatment Unit ◽  
Continuous Flow Reactors

Bacteriological contamination in drinking water is known to be responsible for the spread of various waterborne diseases. Although chlorine is frequently used as disinfectant in water treatment, low-cost disinfecting technologies in the villages of developing and under-developed countries are not yet successfully implemented. This study contributed in designing a simple and inexpensive water disinfection unit to produce chlorine from the naturally available dissolved chloride of groundwater by electrochlorination, using inert and cheap graphite electrodes. Laboratory-based experiments were performed in both batch and continuous flow reactors to study the effect of time, current, electro charge loading (ECL), and surface area of electrodes in chlorine generation and bacterial inactivation. Controlled experiments in continuous mode in the absence of chlorine further indicated the possibility of partial inactivation of bacteria under the influence of the electric field. Finally, a treatment unit with drilled anodes, and undrilled cathode electrodes, in continuous flow set-up was installed in four schools of four different villages in West Bengal, India. An average residual chlorine concentration and removal efficiency of total coliform in the designed systems were determined as 0.3 ± 0.07 mg/L, and 98.4% ± 1.6%, respectively.

Hybrid water disinfection system with silver ion in continuous flow ultrasonic reactor

2021 ◽  
Vol 213 ◽  
pp. 64-74
Author(s):  
Fadime Karaer Özmen ◽  
Ali Savaş Koparal
Keyword(s):  
Continuous Flow ◽  
Water Disinfection ◽  
Silver Ion
Sign in / Sign up

Export Citation Format

Share Document