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March 20, 2019
UV Disinfection UV Disinfection Nick Landes Nick Landes March 20, - - PowerPoint PPT Presentation
UV Disinfection UV Disinfection Nick Landes Nick Landes March 20, - - PowerPoint PPT Presentation
The Basics of UV Disinfection UV Disinfection Nick Landes Nick Landes March 20, 2019 Agenda What is UV How does UV Disinfect Types of UV Systems Design Considerations What is Ultraviolet Energy 750 nm 390 nm Visible Spectrum UV
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What is Ultraviolet Energy
Visible Spectrum
400 nm 10 nm 390 nm 750 nm
UV Spectrum
Germicidal Range
200 nm 300 nm
Most Effective Range
265 nm 250 nm
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What do we make UV?
- Mercury vapor charged by electric arc inside lamp
- Ionized mercury vapor emits UV irradiation
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How does UV Disinfect?
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UV versus Chemicals
UV Disinfection Chemical Disinfection
Physics Chemistry “Newer” (1910) Older (1890) No residual Residual
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Types of UV Systems
Vertical Inclined Non-Contact Horizontal
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Design Considerations
- What are your Target Microorganisms?
Chlorine Disinfection UV Disinfection
Adenovirus
Dual Protection
Giardia Rotavirus Poliovirus Hepatitus A Legionella E.coli Streptococcus Crypto
UV Dose (mJ/cm2) Chlorine CT
Source: Keep, Terry (2013). Advances in UV Technology for 4-Log Virus Disinfection of Groundwater
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Design Considerations
- UV Transmittance
Inorganic Compounds Compounds Found in Wastewater Bromine Dyes and coloring agents Chlorine Humic acids Chromium Lignin sulfonates Cobalt Extracts from leaves Iodides Orzan S Iron Phenolic compounds Manganese Sunblock PABA Nickel Tea, Coffee Sulfates Carbamide compounds Stanous Choride Sodium Thiosulfate
Source: Sakamoto, G. (1999). UV Transmittance, Trojan Technologies, Inc.
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 20 40 60 80 100 Percent Less Than, % UVT, %
Example for 34 MGD System
UVT 60% 75% Lamps 96 64 Max Power Draw, kW 100 65 Cost $820k $540k
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1 2 3 4 5 6 7 8 9 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0:00 6:00 12:00 18:00 0:00
Number of Rows Online Inflow to the Plant, MGD Time (hrs)
Design Considerations
- Flow Patterns
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Design Considerations
- Protect the UV System with Upstream Filtration
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Design Considerations
- Look at the Life Cycle… not just Capital Costs
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Questions?
Nick Landes, Ph.D., P.E.
nick.landes@freese.com (817) 735-7571