Selection and Installation of a UV Disinfection System as a Retrofit to an Existing Wastewater Treat

1
Selection and Installationof aUV Disinfection
Systemas aRetrofit to an Existing Wastewater
Treatment Plant

• Frank Johns, Paul Grundemann
• Mark Lichtwardt, Deborah Gallegos

2
Wastewater Disinfection Alternatives

• Chlorine Gas / Sulfur Dioxide
• Sodium Hypochlorite / Sodium Bisulfite
• UV Disinfection

3
UV Disinfection Characteristics

• No Risk Management Plans for Disinfection
• Safer for Operators
• No Bulk Chemical Transportation and Handling
• No Chemicals Added to Effluent
• No Change in TDS
• Achieves Disinfection in Seconds

4
What is Ultraviolet (UV) Light?

• Wavelengths Between Visible Light and X-Rays
• Small Doses are Beneficial to Humans
• Larger Doses Cause Skin Cancer and Cataracts

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Does UV Kill the Bugs ..or Just Blind Them so
They Cant Find Mates?
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How UV Disinfection Works
DNA Double Strand
DNA
Bacteria
Dimerization of Thymine Nucleotides

• dimer

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How UV Disinfection Works
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UV Disinfection Depends on . Wavelength

• 240 280 nm Wavelength Known Biocidal Range
• 85 of UV Energy _at_ 253.7 nm for Low P Lamps

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UV Disinfection Depends on . Wavelength
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Marcy Gulch Wastewater Treatment Plant
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Marcy Gulch WWTP Current Permit

• 8.5 MGD
• 12.75 MGD Peak
• 30-Day Fecal Coliform 200 / 100 mL
• 7-Day Fecal Coliform 400 / 100 mL

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Implementation of UV Disinfection Retrofit

• Determine Technical Feasibility
• Develop Design Criteria
• Select UV Equipment
• Design of Modifications
• Construction / Start-up
• Successful Operation

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UV Disinfection Technical Feasibility

• Disinfection Performance
• Plant Hydraulics
• Structural Modifications
• Electrical Requirements

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Technical Feasibility Disinfection Performance

• UV Transmittance (UVT)
• Colloids lt 0.001 mm
• Dissolved organics and inorganics
• Suspended particles
• Microbes Status
• Free
• Adsorbed on surface of particles
• Inside particles
• Depends on .Water Quality

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UV Transmittance (UVT) _at_ 253.7 nm

• Distilled Water 100
• Filtered Drinking Water 95
• Filtered Effluent 60 - 70 - 85
• Secondary Effluent 40 - 65 - 70
• Primary Effluent 5 - 20
• Different from Visible Clarity to Eye

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Technical Feasibility Water Quality

• TSS
• Turbidity
• UVT
• Low Iron and Hardness

• lt5 25
• 2.0 3.9
• 66 69

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Technical Feasibility Plant Hydraulics

• Is Adequate Head Available?
• Headloss Through Chlorine Contact Basins is
  Minimal
• Headloss Through UV System
• Minor flow restrictions through equipment
• Need for water level control
• Marcy Gulch WWTP
• Allow 16.5 MGD peak hour flow
• Not allow 20 MGD peak hour flow

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Technical Feasibility Structural Modifications
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Technical Feasibility Electrical Requirements

• Determine Available Service
• Load Study for Connected Demand
• Future Loads?
• Marcy Gulch
• 70 kVA available after considering future demands
• Majority of UV systems considered required 40 kVA
• Medium pressure, high intensity required 200 kVA

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UV Disinfection Design Criteria

• Average Design Flow
• Peak Hourly Design Flow
• System Headloss
• UV Transmittance, Min
• Fecal Coliforms, 30-day
• Maximum Power Use
• Minimum UV Dose

• 11 MGD
• 16.5 MGD
• 15.84 inches
• 65
• 200 / 100 mL
• 70 kVA
• 30 mW-sec / cm2

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UV Dose

• Dose Intensity x Retention Time
• Intensity µW / cm2
• or mW / cm2
• Retention Time sec
• Dose µW-sec / cm2
• or mW-sec / cm2 (mJ / cm2 )

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UV Disinfection Equipment Selection

• UV Lamp Type
• Configuration
• Cleaning Systems
• Ballasts
• Physical Constraints
• Power Use
• Delivery Time

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Low Pressure Low Intensity UV Systems

• 75 85 W Power Requirement / Lamp
• 3 7 mm Mercury Pressure
• 40 60 C Operating Temperature
• Light Output _at_ 254 nm Wavelength
• 30 35 Efficient
• 50 70 Lamps / MGD

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Trojan System UV3000

• Many Installations
• Manual Cleaning
• Ballasts Contained in Modules
• 28 Lamps / MGD
• 1 20 MGD

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Ondeo (IDI)

• Vertical Configuration
• Ballasts above lamps
• Over 200 Installations

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Low Pressure High Intensity UV Systems

• 165 - 300 W Power Requirement / Lamp
• 3 7 mm Mercury Pressure
• 100oC Operating Temperature
• Light Output _at_ 254 nm Wavelength
• 30 40 Efficient
• 9 - 20 Lamps / MGD

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Wedeco TAK

• Automatic Mechanical Cleaning
• Ballasts in Cabinets
• Flow / UV Dose Pacing for Lamps (50 100)
• 9 Lamps / MGD

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Trojan System UV3000Plus

• Automatic Mechanical / Chemical Cleaning
• Ballasts Contained in Modules
• Flow / UVT Pacing for Lamps (60 100)
• 14 - 18 Lamps / MGD
• 5 60 MGD

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Suntec

• Limited Experience
• Submerged Ballasts
• 18 Lamps / MGD

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Ondeo (IDI)

• Vertical Configuration
• Over 200 Installations
• of Low Intensity Units

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Low Pressure Ultra High Intensity UV Systems

• 1,500 W Power Requirement / Lamp
• Light Output _at_ 254 nm Wavelength
• 30 35 Efficient
• 1 Lamps / MGD

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US Filter Ultra Guard

• Vertical Configuration in Self-Contained Units
• US Filter Marketing for Canadian Company
• Intense Arrangement for High Flows
• Submerged Ballasts

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Medium Pressure High Intensity UV Systems

• 2,800 W Power Requirement / Lamp
• 102 - 103 mm Mercury Pressure
• 600 - 900 C Operating Temperature
• 14 Efficient
• 3 Lamps / MGD

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Trojan System UV4000Plus

• Automatic Mechanical / Chemical Cleaning
• Ballasts Mounted on Modules
• Flow / UVT Pacing for Lamps (30 100)
• 2.5 Lamps / MGD
• 10 20 MGD Up

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Equipment Down Selection

• Low Pressure / Low Intensity Lamp Systems
• Large number of lamps required
• Manual cleaning systems
• Medium Pressure / High Intensity Lamps
• Low efficiency due to wider spectrum wavelength
• High power requirements
• High headloss
• Low Pressure / Ultra-High Intensity Lamps
• Few installations
• High headloss
• Non-conventional design

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UV Disinfection Equipment Procurement

• Low Pressure / High Intensity Lamps
• Further evaluated Wedeco, Trojan, Suntec, IDI
• Bids from Wedeco TAK and Trojan UV3000Plus
• Trojan UV3000Plus - 189,900
• 2 banks
• 10 modules in each bank
• 8 lamps in each module
• 160 lamps

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Construction Bids

• Engineers Estimate
• Low Bid
• High Bid

• 246,000
• 149,633
• 301,386

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Existing Chlorine Storage Room
39
Demolition
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Demolition
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Ready for Construction
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New Interior Walls
43
New Operating Level Slab
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UV Channel
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Completed Installation
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Completed Installation Ballasts
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Completed Installation Controls
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Completed Installation Controls
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Construction Change Orders

• Contractors Bid
• Change Orders
• Final Contract Amount

• 149,633
• 5,009 (3.3)
• 154,642

Total Project Costs
1,000,000 412,092

• Budget
• Actual

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Total Project Costs

• Budget
• Estimate
• Actual

• 1,000,000
• 610,000
• 412,092

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Startup

• Good Training
• 1 Ballast Failure
• 2 Bulb Failures
• 2 Ballast Control Board Failures

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Successful Operation

• Fecal Coliforms
• Before
• Avg. 9 / 100 mL
• Max. 110 / 100 mL
• After
• Avg. 14 / 100 mL
• Max. 98 / 100 mL

• E. Coli
• Before
• Avg. 924 MPN
• Max. 2,419 MPN
• After
• Avg. 19 MPN
• Max. 78 MPN

Based on results from January to August 2002
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Thank you

• Frank and Paul