Numerical and Experimental Characterizations of Dose Distributions in UV Disinfection Systems

2015 ◽  
Vol 4 (0) ◽  
pp. 9781843397342-9781843397342
Author(s):  
E. Blatchley
Keyword(s):  
Uv Disinfection ◽  
Dose Distributions

NUMERICAL AND EXPERIMENTAL CHARACTERIZATIONS OF DOSE DISTRIBUTIONS IN UV DISINFECTION SYSTEMS

2000 ◽  
Vol 2000 (8) ◽  
pp. 104-118
Author(s):  
Lian-Shin Lin ◽  
Philippe Savoye ◽  
Dennis A. Lyn ◽  
Anna A. Lyssandridou ◽  
Yousheng Guan ◽  
...  
Keyword(s):  
Uv Disinfection ◽  
Dose Distributions

Chemical effects on UV irradiation absorption of fouled quartz sleeves in ultraviolet disinfection

2008 ◽  
Vol 8 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Beibei Zhu Sun ◽  
Ernest Blatchley ◽  
Mike Oliver ◽  
Cheng Zheng ◽  
Kristofer Jennings
Keyword(s):  
Statistical Analysis ◽  
Uv Disinfection ◽  
Uv Absorbance ◽  
Ultraviolet Disinfection ◽  
High Chemical ◽  
Chemical Surface ◽  
Chemical Effects ◽  
Uv Transmittance ◽  
Main Effects ◽  
Iron And Manganese

The effects of foulant chemical composition on ultraviolet (UV) absorbance of fouled quartz sleeves in UV disinfection systems were studied. Statistical analysis was conducted to examine the effects of nine fouling chemicals on the UV transmittance changes of fouled quartz lamp sleeves. The results demonstrated that the main effects were attributable to surface concentrations of iron and manganese. The surface concentrations of calcium and copper had no significant effects on the UV absorbance of fouled sleeves. The interaction effects of copper with iron and magnesium with manganese were also revealed from the statistical analysis. The model is able to give reasonable predictions of the UV absorbance characteristics of foulants from other UV systems. However, several limitations of this model were identified. First, the model does not accurately predict the absorbance at relatively high chemical surface concentrations. Second, the model does not account for the possible effects of anions and organics on UV absorption of fouled quartz sleeves.

scholarly journals Molecular and culture-based assessment of the microbiome in a zebrafish (Danio rerio) housing system during set-up and equilibration

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Aaron C. Ericsson ◽  
Susheel B. Busi ◽  
Daniel J. Davis ◽  
Henda Nabli ◽  
David C. Eckhoff ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Housing System ◽  
Particulate Filter ◽  
Uv Disinfection ◽  
Sequencing Data ◽  
Network Analyses ◽  
Recirculating Aquaculture Systems ◽  
Filter Water ◽  
Disinfection Unit ◽  
Time Point

Abstract Background Zebrafish used in research settings are often housed in recirculating aquaculture systems (RAS) which rely on the system microbiome, typically enriched in a biofiltration substrate, to remove the harmful ammonia generated by fish via oxidation. Commercial RAS must be allowed to equilibrate following installation, before fish can be introduced. There is little information available regarding the bacterial community structure in commercial zebrafish housing systems, or the time-point at which the system or biofilter reaches a microbiological equilibrium in RAS in general. Methods A zebrafish housing system was monitored at multiple different system sites including tank water in six different tanks, pre- and post-particulate filter water, the fluidized bed biofilter substrate, post-carbon filter water, and water leaving the ultra-violet (UV) disinfection unit and entering the tanks. All of these samples were collected in quadruplicate, from prior to population of the system with zebrafish through 18 weeks post-population, and analyzed using both 16S rRNA amplicon sequencing and culture using multiple agars and annotation of isolates via matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry. Sequencing data were analyzed using traditional methods, network analyses of longitudinal data, and integration of culture and sequence data. Results The water microbiome, dominated by Cutibacterium and Staphylococcus spp., reached a relatively stable richness and composition by approximately three to four weeks post-population, but continued to evolve in composition throughout the study duration. The microbiomes of the fluidized bed biofilter and water leaving the UV disinfection unit were distinct from water at all other sites. Core taxa detected using molecular methods comprised 36 amplicon sequence variants, 15 of which represented Proteobacteria including multiple members of the families Burkholderiaceae and Sphingomonadaceae. Culture-based screening yielded 36 distinct isolates, and showed moderate agreement with sequencing data. Conclusions The microbiome of commercial RAS used for research zebrafish reaches a relatively stable state by four weeks post-population and would be expected to be suitable for experimental use following that time-point.

scholarly journals Woven-Fiber Microfiltration (WFMF) and Ultraviolet Light Emitting Diodes (UV LEDs) for Treating Wastewater and Septic Tank Effluent

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1564
Author(s):  
Sara Beck ◽  
Poonyanooch Suwan ◽  
Thusitha Rathnayeke ◽  
Thi Nguyen ◽  
Victor Huanambal-Sovero ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Light Emitting Diodes ◽  
Domestic Wastewater ◽  
Septic Tank ◽  
Uv Disinfection ◽  
Small Community ◽  
Photochemical Process ◽  
Light Emitting ◽  
Decentralized Wastewater Treatment ◽  
Septic Tank Effluent

Decentralized wastewater treatment systems enable wastewater to be treated at the source for cleaner discharge into the environment, protecting public health while allowing for reuse for agricultural and other purposes. This study, conducted in Thailand, investigated a decentralized wastewater treatment system incorporating a physical and photochemical process. Domestic wastewater from a university campus and conventional septic tank effluent from a small community were filtered through a woven-fiber microfiltration (WFMF) membrane as pretreatment for ultraviolet (UV) disinfection. In domestic wastewater, WFMF reduced TSS (by 79.8%), turbidity (76.5%), COD (38.5%), and NO3 (41.4%), meeting Thailand irrigation standards for every parameter except BOD. In septic tank effluent, it did not meet Thailand irrigation standards, but reduced TSS (by 77.9%), COD (37.6%), and TKN (13.5%). Bacteria (total coliform and Escherichia coli) and viruses (MS2 bacteriophage) passing through the membrane were disinfected by flow-through UV reactors containing either a low-pressure mercury lamp or light-emitting diodes (LEDs) emitting an average peak wavelength of 276 nm. Despite challenging and variable water quality conditions (2% < UVT < 88%), disinfection was predictable across water types and flow rates for both UV sources using combined variable modeling, which enabled us to estimate log inactivation of other microorganisms. Following UV disinfection, wastewater quality met the WHO standards for unrestricted irrigation.

scholarly journals 3D heterogeneous dose distributions for total body irradiation patients

2011 ◽  
Vol 12 (3) ◽  
pp. 205-214 ◽  
Author(s):  
Marie-Claude Lavallée ◽  
Sylviane Aubin ◽  
Marie Larochelle ◽  
Isabelle Vallières ◽  
Luc Beaulieu
Keyword(s):  
Total Body Irradiation ◽  
Dose Distributions ◽  
Total Body

scholarly journals 10 Years of Pulsed-Xenon Ultraviolet Disinfection

2020 ◽  
Vol 41 (S1) ◽  
pp. s438-s438
Author(s):  
Mark Stibich ◽  
Sarah Simmons ◽  
Deborah Passey
Keyword(s):  
Relative Risk ◽  
Meta Analysis ◽  
Outcome Studies ◽  
Uv Disinfection ◽  
Clostridioides Difficile ◽  
Environmental Effectiveness ◽  
Meta Analyses ◽  
Hospital Acquired ◽  
And Control ◽  
Effectiveness Studies

Background: Ultraviolet light (UV) disinfection using low-pressure mercury lamps has been around since the 1940s. The advent of pulsed-xenon UV for hospital use in 2010 has provided a nontoxic and novel technology for hospital disinfection with the first data presented at the 2010 SHEA Decennial. The purpose of this systematic review and meta-analysis is to examine the current body of evidence for pulsed xenon UV disinfection. Methods: The literature search criteria included the following: research conducted in domestic and international settings using pulsed-xenon for surface disinfection, published between 2000 and 2019, and reporting on environmental effectiveness or hospital-acquired reductions (HAIs). We searched PubMed, Google Scholar, and Web of Science. The meta-analysis included 24 studies: 12 HAI outcome studies and 12 environmental effectiveness studies. Meta-analyses were conducted by calculating the percentage reductions for environmental effectiveness, and for the HAI outcome studies, we used a random-effects model to pool the relative risk of HAI. The outcome studies used 272 and 299 months of data for the experimental and control groups, respectively. Results: There was an overall benefit of using pulsed-xenon UV. The overall relative risk of infection decreased compared to the control arm (RR, 0.64; 95% CI, 0.54–0.76). The percentage reductions in environmental studies were as follows: Clostridioides difficile (94.8%), methicillin-resistant Staphylococcus aureus (91.5%), vancomycin-resistant Enterococcus (99.2%), and aerobic bacteria (94.2%). Conclusions: Overall, pulsed-xenon UV was effective for reducing environmental contamination and had the ability to significantly reduce HAIs.Funding: Xenex, Inc., funded this study.Disclosures: Mark Stibich receives a salary from Xenex and is a shareholder of Xenex. Deborah Passey receives a salary from Xenex Disinfection Services.

scholarly journals Deep learning prediction of proton and photon dose distributions for paediatric abdominal tumours

2021 ◽  
Vol 156 ◽  
pp. 36-42
Author(s):  
F. Guerreiro ◽  
E. Seravalli ◽  
G.O. Janssens ◽  
J.H. Maduro ◽  
A.C. Knopf ◽  
...  
Keyword(s):  
Deep Learning ◽  
Dose Distributions ◽  
Photon Dose ◽  
Abdominal Tumours
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