Analysis of the Radiation Dose in UV-Disinfection Flow Reactors

Artichowicz, Wojciech; Łuczkiewicz, Aneta; Sawicki, J.

doi:10.3390/w12010231

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…Dose plays an important role in the inactivation of microorganisms subjected to ultraviolet radiation; therefore, it is essential to provide an optimal dose of UV radiation during the disinfection process to achieve complete inhibition of cell replication. Artichowicz et al [33] found that the most effective zone in UV reactors in terms of disinfection is the direct radiation zone, while the influence of inflow and outflow zones is insignificant. This means that UV disinfection reactors must be designed to deliver the required amount of radiation at the point at which the fluid velocity is highest.…”

Section: Uv Dosementioning

confidence: 99%

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UV Disinfection Systems for Wastewater Treatment: Emphasis on Reactivation of Microorganisms

et al. 2023

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UV disinfection is cost-effective and easy to maintain for decentralized areas. However, to ensure its effectiveness, some parameters need to be considered. In this study, a general search of Web of Science articles was performed to determine the possible influence of these parameters on the reactivation of microorganisms in UV systems; in addition, different search strings were used focusing exclusively on wastewater treatment, UV systems and Advanced Oxidation Processes (AOPs). It was found that in order to maintain low transmittance, it is essential to remove suspended solids and reduce water hardness. It is recommended to control the zeta potential in the range of 0–5 mV to avoid the aggregation of particles and bacteria. Determining the appropriate UV dose is essential to mitigate the reactivation of microorganisms. A minimum dose of 40 mJ/cm2 can contribute to effective disinfection and reduce the likelihood of reactivation. In addition, maintaining a residual chlorine level of at least 0.5 mg/L provides an additional barrier to reactivation. It is also important to optimize the design flow rate of the UV system as recommended for each individual unit. These measures, together with the combination of UV disinfection and chemical or AOPS, can effectively reduce the reactivation.

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Section: Uv Dosementioning

confidence: 99%

“…Like all forms of radiation, the intensity of ultraviolet radiation decreases as it penetrates a material substance, due mainly to absorption. The intensity of radiation absorbance is known as transmittance (UVT%), which is defined as a measure of the fraction of incident light transmitted through a water column [33].…”

Section: • Transmittancementioning

confidence: 99%

UV Disinfection Systems for Wastewater Treatment: Emphasis on Reactivation of Microorganisms

et al. 2023

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“…Li et al (2019) used low pressure UV lamps to compare the performance of five UV reactors both experimentally and numerically. Artichowicz et al (2020) divided a typical UV reactor into three zones (inflow, radiation and outflow) and concluded that for deactivation of pathogens the effective radiation dose should be equal to the minimal UV dose accumulated by the microorganisms. Ascribed to spatial uneven velocity field and the UV intensity distribution, the UV doses accumulated by microorganisms in different zones of a UV reactor differs.…”

Section: Introductionmentioning

confidence: 99%

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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“…UV radiation intensity decreases when penetrating materials due to its absorption (Artichowicz et al, 2020). Therefore, physicochemical properties of wastewater may affect UV light transmittance, and hence treatment efficiency.…”

Section: Introductionmentioning

confidence: 99%

Effect of turbidity on ultraviolet disinfection of domestic wastewater for agricultural reuse

Garay¹,

Voltolini²,

Bastos³

et al. 2021

Rev. ambiente água

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Water treatment and reuse are fundamental because of the increasing demand for freshwater, especially in agriculture. Accordingly, this study evaluated the effects of turbidity of wastewater processed at the Effluent Treatment Station (ETE) of the UFSCar/Araras and of UV dose on microbial inactivation. The ETE treats up to 2000 L of wastewater daily from toilets and a university restaurant and has five components (grease box, septic tank, microalgae tank, upflow anaerobic filter, and wetlands). Pretreated effluents were used in the experiments, and sampling sites consisted of inspection boxes located after the wetlands. Sample collection, inspection, preservation, and analyses were performed according to standard methods. Sample turbidity was adjusted to 5, 50, 100, 200, and 300 nephelometric turbidity units (NTU), and UV doses of 7.2–28.8 mWs cm-2 were used. A 5 x 5 factorial design (five turbidity levels and five radiation doses) was used, totaling 25 treatments. Each treatment was performed in triplicate. The data were submitted to analysis of variance and Tukey’s test. The results showed that the increase in turbidity significantly decreased disinfection efficiency in samples with turbidity levels higher than 50 NTU. The microbial inactivation coefficients obtained here can be extrapolated to disinfection of wastewater with turbidity up to 300 NTU to eliminate thermotolerant coliforms. The UV sterilizer is feasible for wastewater treatment and its reuse in agriculture. Keywords: domestic effluent, sustainability, ultraviolet radiation, water reuse.

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Analysis of the Radiation Dose in UV-Disinfection Flow Reactors

Cited by 9 publications

References 9 publications

UV Disinfection Systems for Wastewater Treatment: Emphasis on Reactivation of Microorganisms

UV Disinfection Systems for Wastewater Treatment: Emphasis on Reactivation of Microorganisms

Computational analysis of three lamp close conduit water disinfection UV reactor

Effect of turbidity on ultraviolet disinfection of domestic wastewater for agricultural reuse

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