Impact of asymmetric lamp positioning on the performance of a closed-conduit UV reactor

Sultan, Tipu; Ahmad, Zeshan; Anwar, Zahid; Khurram, Muhammad Shahzad

doi:10.1016/j.asej.2016.08.022

Cited by 12 publications

(7 citation statements)

References 33 publications

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“…The hydraulic retention time and UV light intensity are different at different positions in the reactor. To solve this problem, one solution is the fluid dynamics simulation [ 22 , 23 ], but the accuracy still needs to be improved especially for wastewater which is rich in dissolved organic carbon (DOC) and suspended solids (SS). The other is biodosimetry.…”

Section: Virus Inactivation By Uv Irradiationmentioning

confidence: 99%

The virus removal in UV irradiation, ozonation and chlorination

Kong

Ren

et al. 2021

Water Cycle

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The COVID-19 pandemic draws much attention to virus inactivation since the SARS-CoV-2 was detected in miscellaneous environments and the wastewater can be a potential transmitting pathway. UV irradiation, ozonation and chlorination are widely used disinfection processes in water treatment. In this review, the mechanisms and applications of three disinfection processes are introduced, and their inactivation effects on virus as well as other microorganisms are compared and discussed. The resistance of viruses to UV irradiation is generally stronger than that of bacteria. 4-log inactivation of bacteria can be easily obtained within a UV dose of 10 mJ/cm 2 . However, the doses to reach the same virus removal rate vary greatly from 10 to 140 mJ/cm 2 . The coronaviruses have even stronger UV resistance. Comparatively, ozonation and chlorination are effective methods to inactivate viruses, and the CT values of 4-log removal for most viruses concerned are lower than 1 mg·min/L and 10 mg·min/L, respectively. Protozoa, fungal spores and bacterial spores are more resistant to disinfection. Temperature, pH, organic matters, turbidity and other parameters all have influences on the disinfection. With a 10 °C decrease in temperature, the CT value required for certain removal rates doubles. Generally low pH promotes disinfection and high pH is against it. In drinking water and wastewater treatment process, the resistance properties of microorganisms and other influence parameters should be taken into consideration when choosing disinfection technologies.

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Section: Virus Inactivation By Uv Irradiationmentioning

confidence: 99%

The virus removal in UV irradiation, ozonation and chlorination

Kong

Ren

et al. 2021

Water Cycle

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“…2. The geometry of the reactor is taken from our research work (Sultan et al 2017). There are three lamps in each case study and diametral length of each lamp is 0.039 mm.…”

Section: Geometric Model Descriptionmentioning

confidence: 99%

“…A 0.318 m diameter pipe having a length of 7.2 m was designed taking into account the fact that the flow should be fully developed before the entry to the UV reactor chamber (Sultan et al 2017). A steady velocity (uniformly distributed on the inlet of the reactor), was assured and zero relative pressure was applied at the outlet.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…They observed that proper baffle positioning will result in an increase in reduction equivalent fluences. Sultan et al (2017) also analyzed numerically the four-asymmetric lamp positions in the UV chamber of a cross flow water disinfection UV system. Li et al (2019) used low pressure UV lamps to compare the performance of five UV reactors both experimentally and numerically.…”

Section: Introductionmentioning

confidence: 99%

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Computational analysis of three lamp close conduit water disinfection UV reactor

Sultan

Ahmad

Hayat

et al. 2021

Int. J. Environ. Sci. Technol.

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The purpose of ultraviolet (UV) disinfection is to bring to end the growth and procreation of microorganism. UV reactors are used for the UV disinfection of the drinking water. Our goal of the current research work was properly locating the positions of the UV lamps in a three-lamp close conduit water disinfection UV reactor. Three positions of UV lamps are based on vertices of the four basic types of triangles (Equilateral, Right angle, Scalene and Isosceles). The objective function for optimized lamp positioning was Reduction Equivalent Dose (RED). To ascertain efficient UV dose delivery to pathogen, water disinfection UV reactors was simulated with the aid of computational fluid dynamics. The computational investigation was achieved employing ANSYS ® Fluent 15.0 academic version. The turbulent flow was modeled using standard k−ε model, fluence rate (FR) was modeled using UVCalc3D model and pathogen transport was modeled using discrete phase model. The scalene lamp positioning results in highest RED value and isosceles lamp positioning results in lowest RED value. There is meager difference between the RED values of equilateral and scalene lamp positioning. Moreover, we found two lamps on the upstream side and one lamp on the downstream side results in better UV disinfection. The proposed methodology for the three-lamp model provides useful insights to the design and optimization of close conduit water disinfection UV reactor. This research work has evaluated, for the first time, a systematic methodology for three-lamp positioning to ameliorate the performance of UV reactor and has revitalized the comprehension about the contribution of FR distribution within the UV reactor. KeywordsCFD • Fluence rate • Reactor design • Turbulence modeling • UV lamp • Water disinfection List of symbols A and B Constants in logarithm microbial inactivation rate function dt Pathogens residing time (s) I Irradiance of UV radiation (W m −2 ) k Inactivation rate constant (m 2 J −1 ) K in Turbulent kinetic energy (m 2 s −2 ) N Pathogen influent ( −) N 0 Pathogens effluent ( −) N/N 0 Log inactivation ( −) p Means pressure ( −) t Time (s) u i and u j Velocity components (m s −1 ) u in Velocity at inlet (m s −1 ) u i u j Reynolds stress tensor (m 2 s −2 ) ij Kronecker delta function ε in Turbulent dissipation at inlet (m 2 s −3 ) Laminar kinematic viscosity (m 2 s −1 ) t Turbulent kinematic viscosity (m 2 s −1 ) Density (kg m −3 ) k Prandtl-Schmidt number for K in ( −) Prandtl-Schmidt number for K (−) Subscripts i, j Position of a cell in Inlet Abbreviations CFD Computational fluid dynamics DBPs Disinfection-by-products DPM Discrete phase model FR Fluence rate RED Reduction equivalent dose SURF Simultaneous UV FR and fluid dynamics Editorial responsibility: Samareh Mirkia.

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“…CFD analyses for the performance improvement of a closedconduit UV reactor were performed by changing the lamp positions from symmetric to asymmetric. It was found that the performance parameters (higher reduction equivalent dose and system dose performance) were improved by using asymmetric lamp positioning (Sultan et al, 2017). Impact of inner-wall reflection on UV reactor performance was evaluated in annular single-lamp UV reactors by using CFD, with an emphasis on the role of diffuse reflection.…”

mentioning

confidence: 99%