Title: Selection and Installation of a UV Disinfection System as a Retrofit to an Existing Wastewater Treat
1Selection and Installationof aUV Disinfection
Systemas aRetrofit to an Existing Wastewater
Treatment Plant
- Frank Johns, Paul Grundemann
- Mark Lichtwardt, Deborah Gallegos
2Wastewater Disinfection Alternatives
- Chlorine Gas / Sulfur Dioxide
- Sodium Hypochlorite / Sodium Bisulfite
- UV Disinfection
3UV 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
4What is Ultraviolet (UV) Light?
- Wavelengths Between Visible Light and X-Rays
- Small Doses are Beneficial to Humans
- Larger Doses Cause Skin Cancer and Cataracts
5Does UV Kill the Bugs ..or Just Blind Them so
They Cant Find Mates?
6How UV Disinfection Works
DNA Double Strand
DNA
Bacteria
Dimerization of Thymine Nucleotides
7How UV Disinfection Works
8UV Disinfection Depends on . Wavelength
- 240 280 nm Wavelength Known Biocidal Range
- 85 of UV Energy _at_ 253.7 nm for Low P Lamps
9UV Disinfection Depends on . Wavelength
10Marcy Gulch Wastewater Treatment Plant
11Marcy 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
12Implementation of UV Disinfection Retrofit
- Determine Technical Feasibility
- Develop Design Criteria
- Select UV Equipment
- Design of Modifications
- Construction / Start-up
- Successful Operation
13UV Disinfection Technical Feasibility
- Disinfection Performance
- Plant Hydraulics
- Structural Modifications
- Electrical Requirements
14Technical 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
15UV 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
16Technical Feasibility Water Quality
- TSS
- Turbidity
- UVT
- Low Iron and Hardness
17Technical 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
18Technical Feasibility Structural Modifications
19Technical 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
20UV 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
21UV 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 )
22UV Disinfection Equipment Selection
- UV Lamp Type
- Configuration
- Cleaning Systems
- Ballasts
- Physical Constraints
- Power Use
- Delivery Time
23Low 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
24Trojan System UV3000
- Many Installations
- Manual Cleaning
- Ballasts Contained in Modules
- 28 Lamps / MGD
- 1 20 MGD
25Ondeo (IDI)
- Vertical Configuration
- Ballasts above lamps
- Over 200 Installations
26Low 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
27Wedeco TAK
- Automatic Mechanical Cleaning
- Ballasts in Cabinets
- Flow / UV Dose Pacing for Lamps (50 100)
- 9 Lamps / MGD
28Trojan System UV3000Plus
- Automatic Mechanical / Chemical Cleaning
- Ballasts Contained in Modules
- Flow / UVT Pacing for Lamps (60 100)
- 14 - 18 Lamps / MGD
- 5 60 MGD
29Suntec
- Limited Experience
- Submerged Ballasts
- 18 Lamps / MGD
30Ondeo (IDI)
- Vertical Configuration
- Over 200 Installations
- of Low Intensity Units
31Low Pressure Ultra High Intensity UV Systems
- 1,500 W Power Requirement / Lamp
- Light Output _at_ 254 nm Wavelength
- 30 35 Efficient
- 1 Lamps / MGD
32US Filter Ultra Guard
- Vertical Configuration in Self-Contained Units
- US Filter Marketing for Canadian Company
- Intense Arrangement for High Flows
- Submerged Ballasts
33Medium 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
34Trojan 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
35Equipment 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
36UV 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
37Construction Bids
- Engineers Estimate
- Low Bid
- High Bid
38Existing Chlorine Storage Room
39Demolition
40Demolition
41Ready for Construction
42New Interior Walls
43New Operating Level Slab
44UV Channel
45Completed Installation
46Completed Installation Ballasts
47Completed Installation Controls
48Completed Installation Controls
49Construction 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
50Total Project Costs
- 1,000,000
- 610,000
- 412,092
51Startup
- Good Training
- 1 Ballast Failure
- 2 Bulb Failures
- 2 Ballast Control Board Failures
52Successful 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
53Thank you