1. "Computational modeling and photometry
in UV Disinfection Technology for water and wastewater“
Pablo Fredes Donoso, Ernesto Gramsch,
Optical and Semiconductors Laboratory
University of Santiago de Chile ( USACH )
Physical and Biology Principles
Engineering and Implementation
We will first study sistems with cylindrical geometry. This device has one main cylinder that contains the water and the UV lamps; these are electrically isolated with a quartz sleeve that also protects them. If the flow rate of water is appropriate, then the exposure time is sufficient to sterilize
LIGHT GERMICIDAL RANGE: The range is often called GERMICIDAL RANGE because the UV light is absorved by DNA and RNA of microorganisms. The absorption of UV photons causes changes in the structure of DNA and RNA, rendering the microorganism incapable of replicating.
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FLUENCE: The UV power incident on a infinitesimally small sphere of cross-sectional área dA divided by dA.
For the cylindrical symmetry can express UV Dose :
UV Dose: Is the product of UV fluence , I , and exposure time t .
Reactors manufactured by our working group in collaboration with Aquair Process.
Units of meassure:
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Computational Modeling - Spatial distribution of UVC radiation inside of cylindrical reactors.
The objective of Computational Modeling is to analyze the spatial distribution of intensity within the system, also to study the behavior of the fluid, and to determine an average value of UV Dose. This allows characterizing any system, knowing the number of lamps, the power, their position, the transmittance of the fluid to be treated and the Germicidal dose required. The modeling allows to decide the best configuration according to the volume of water to be treated.
Multi Lamp
Single Lamp
The elements of the MATRIX contain information about the spatial distribution and dose intensity on the inside of the reactors.
Where: is vector position, is the radius of cylinder,
is absorbance of water and is Fluence Rate in the surface of lamp. L contents number of lamp and positionof this lamp. L= 1, 2…N, with N number of lamps on the system
Where: is vector position, is the radius of cylinder, is absorbance of water and is Fluence Rate in the surface of lamp.
Results
Aplications of UVC Photometry :
RESULTADOS
The graph shows the turn on time of the lamps. After stabilization the intensity of the lamp covered with quartz sleve is 10% lower than lamp with out slive.
New York City’s Catskill/Delaware UV Water Disinfection Facility
Acknowledgments
The UVC technology may allow to discontinue the use of chlorine and other disinfecting chemicals. It does not alter the color or taste of the water. It has been used since 1957 in industries and local governments with great success. This is a expanding technology that intends to substitute traditional chlorine treatment modernizing cities and reduce the environmental impact. An example is the “Catskill and Delaware Ultraviolet Light Disinfection Facility” in New York.
Viviana Claveria, President student Chapter Usach.
Danit Berezin, Assistant scientific translations.
Rodrigo Morgado, Technology Management Department (DGT).
Carlos Cornejo, Project Manager AQUAIR PROCESS.
References
[1] James R. Bolton, Christine Cotton. The Ultraviolet Desinfection Handbook. Page .2.
[2] Ultraviolet Desinfection Guidance Manual for the final long term 2 enhanced surface water treatment rule. Figure 2.2, pag 2-7. USEPA nov
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