UV Disinfection of Cryptosporidium for Newly Reclassified Bin 2 Systems in Illinois
Bryan Townsend UV Technology Leader
B&V Water Technology Group
Acknowledgements
• Coauthors
• Ben Freese (Black & Veatch)
• Beth Matthews (Illinois American Water)
• Illinois American Water (ILAW)
• Sarah Boyd
• Rachel Bretz
• Illinois Environmental Protection Agency (IEPA)
• Matt Talbert
• Ian Rischmiller
• Randy Pankiewicz
• David Cook
2
Illinois American Water
• Provides water and wastewater services to 1.3M consumers in >120 communities across IL
• 2nd round LT2ESWTR source water monitoring
• Required six years after initial bin classification
• 4 Facilities reclassified from Bin 1 to Bin 2
• 1-log additional Crypto treatment
• Peoria, Alton, Granite City and East St. Louis Service Areas
• Black & Veatch retained to conduct a conceptual design study on potential solutions
• UV and ozone disinfection
Illinois American Water Major Service Areas
3
UV Disinfection Drivers
• Familiar with UV technology
• Already installed at Peoria for Giardia inactivation
• Established track record and proven performance
• Very effective disinfectant for Crypto and Giardia at low doses
• Use as part of multi-barrier disinfection approach with chlorine/chloramines
• No DBP concerns
Does not offer additional benefits (oxidation, T&O) unless paired with oxidant (Cl2, H2O2) for advanced oxidation
Illinois River Station Control Building Peoria, IL
4
Ozone Disinfection Drivers
• Effective disinfectant with proven track record
• High CT for Crypto inactivation, esp. in cold water
• Provides numerous other treatment benefits*
• T&O control
• DBP reduction (oxidation of NOM)
• Improve filter performance (microflocculation)
• Must consider bromate formation potential
• Several mitigation strategies exist
*Key driver for ILAWs interest in ozone
5
31
1.40
5
10
15
20
25
30
35
40
0 10 20 30
CT
(mg-
min
/L)
Temperature (oC)
1.5-log Crypto 1.5-log Giardia
2oC
Peoria Illinois River Station (IRS)
• Main treatment facility of Peoria, IL water system
• Also includes 3 groundwater treatment systems
• Serves Peoria, IL & adjacent areas (53K customers)
• 17.5 mgd surface water treatment plant
• Source water from Illinois River
• Coag/Floc Sedimentation Filtration Disinfection
• Multi-barrier disinfection
• UV: 0.5-log Giardia inactivation
• Chlorine: 2-log Virus CT
• Chloramines: Distribution system residual
Illinois River Station Peoria, IL
6
Illinois River Station, Peoria, IL ©Google Earth 2018
Peoria IRS UV Facility
• 2+1 Calgon 3x10kW 24-inch Sentinel UV reactors
• Designed for 2-log Crypto inactivation
• 17.5 mgd, 86% UVT
• Microbial surrogate limited to MS2
• 1.3 interim ASCF
• Online in Jan. 2012 / Permitted in Dec. 2012
• Permitted for 2-log Giardia credit
• IEPA reduced max. Giardia credit to 1.5-log in 2015 to reflect ASCF of 1.81 from WRF 4376 tables
Ample capacity to provide Bin 2 Crypto requirements with potential for optimization of UV system operations
Peoria IRS UV Facility 7
IEPA Consultation Opportunities for UV System Optimization
• Dose-monitoring approach / use of alternate surrogates
• T1UV and MS2 acceptable surrogates
• More robust data set required for T7 dose-response QA/QC bounds
• Action spectra correction factor approach
• WRF 4376 default ASCF or reactor-specific ASCF (with report approval)
• Design disinfection capacity
• Design capacity of 2-log Crypto for Bin 2 systems, ability to operate at 1.5 logi once facility gains comfort / familiarity with UV operations
Use of T1UV and proper implementation of 4376 default ASCF results in Crypto disinfection capacity of 2.9 logi at Peoria IRS
8
Peoria IRS UV Facility
Design Approaches Common to all WTFs
UV DISINFECTION
• 2.0 logi Crypto target • Influent source: filter effluent • WRF 4376 default ASCF
• Surrogate: T1UV or MS2 • n+1 reactor redundancy
OZONE DISINFECTION
• 1.5 logi Crypto target, 2oC = 31 mg-min/L CT
• Influent source: settled water • Liquid oxygen (LOX) supply • Closed loop cooling
• Sidestream O3 injection • 2 Contactors, 20 min HDT,
0.7 baffling factor (T10/T) • n+1 generator redundancy
LOX Tanks Grand Strand WSA Myrtle Beach WTP , SC
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Alton WTF
• Serves Alton, IL & adjacent areas (19K customers)
• 16 mgd plant treating water from Mississippi R.
• Coag/Floc Superpulsator® solids contact clarifiers Filtration Disinfection
• Disinfection:
• Chlorine/Chloramines: 2-log Virus & 0.5-log Giardia
• Chloramines: Distribution system residual
Alton WTF, Alton, IL ©Google Earth 2018
10
Alton WTF UV Conceptual Design
• 3 design alternatives (84% UVT, 16 mgd)
• UV-1: Combined filter effluent
• 2 (1 duty + 1 stdby) 24-in reactors
• UV-2/3: Individual filter effluent (6 filters)
• UV-2: 1 x 12-in reactor per filter
• 6 reactors total, 3.2 mgd/reactor
• UV-3: 2 x 12-in reactors per filter
• 12 reactors total, 1.6 mgd/reactor
• Lower head loss and redundancy at avg. flow
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$6.1M
$2.8M
$4.8M
$0M
$2M
$4M
$6M
$8M
UV-1 UV-2 UV-3
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
Alton WTF Ozone Conceptual Design
• Bench-scale testing conducted on single sample*
• 7.7 mg/L O3 dose
• 1+1 x 1,000 ppd generators (12% wt.)
• Residual quenching likely required (> 0.05 mg/L residual after 20 min HDT)
• Bromate formation a concern (> 10 µg/L MCL)
• >95% MIB and Geosmin removal at design dose
*Additional testing required if O3 selected as preferred technology to confirm initial results
12
$0M
$4M
$8M
$12M
$16M
$20M
$24M
O3-1
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
$19.9M
Alton WTF Conclusions
• UV is 3-7x less expensive than ozone = preferred disinfection technology
• Alt. UV-2 not viable due to head loss concerns & lack of redundancy
• Alt. UV-3 viable
• $1.3M (21%) in est. project savings
• Alt. UV-1 recommended
• Fewer reactors to maintain (2 vs. 12 reactors)
• $350K 20-yr PW savings
13
$6.1M
$2.8M
$4.8M
$0M
$4M
$8M
$12M
$16M
$20M
$24M
UV-1 UV-2 UV-3 O3-1
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
$19.9M
Granite City WTF
• Serves residents of Granite City, IL
• 14 mgd plant treating water from Mississippi R.
• Future peak flow of 20 mgd
• Pre-treatment Coag/Floc Sedimentation Filtration Disinfection
• Disinfection:
• Chlorine/Chloramines: 2-log Virus & 0.5-log Giardia
• Chloramines: Distribution system residual
Granite City WTF, Granite City, IL ©Google Earth 2018
14
Granite City WTF UV Conceptual Design
• 3.2 ft. of available head for UV facility
• 2 design alternatives (77% UVT, 14 mgd)
• UV-1: 2 (1 duty + 1 stdby) 24-in reactors
• 3.8 ft. head loss @ 14 mgd per reactor
• 1.7 ft. head loss @ 7 mgd per reactor = operate redundant reactor at high flows
• UV-2: 3 (2 duty + 1 stdby) 24-in reactors
• Redundant reactor offline at high flows
15
$5.4M
$6.3M
$0M
$2M
$4M
$6M
$8M
UV-1 UV-2
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
Granite City WTF Ozone Conceptual Design
• Bench-scale testing conducted on single sample*
• 6.0 mg/L O3 dose
• 1+1 x 750 ppd generators (12% wt.)
• Residual quenching likely required (> 0.05 mg/L residual after 20 min HDT)
• Bromate formation not a concern (< 1 µg/L MDL)
• >80% MIB and Geosmin removal at design dose
*Additional testing required if O3 selected as preferred technology to confirm initial results
16
$0M
$4M
$8M
$12M
$16M
$20M
$24M
O3-1
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
$19.0M
$5.4M $6.3M
$0M
$4M
$8M
$12M
$16M
$20M
$24M
UV-1 UV-2 O3-1
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
$19.0M
Granite City WTF Conclusions
• UV is >3x less expensive than ozone = preferred disinfection technology
• Alt. UV-1 least expensive option
• $0.9M (16%) savings in est. project costs
• $162K 20-yr PW savings
• Alt. UV-2 recommended
• Lower head loss
• Redundant reactor at high flow rates
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$5.4M $6.3M
$0M
$4M
$8M
$12M
$16M
$20M
$24M
UV-1 UV-2 O3-1
Co
st
20-Year O&M Present WorthTotal Project Cost Est.
$19.0M
East St. Louis WTF
• Regional plant serving Metro East (68K customers)
• 56 mgd plant treating water from Mississippi R.
• Future peak flow of 75 mgd
• Two separate treatment trains
• Conventional & Aldrich unit treatment trains
• Disinfection:
• Chlorine/Chloramines: 2-log Virus & 0.5-log Giardia
• Chloramines: Distribution system residual
Ozone not evaluated due to inability to treat settled water in Aldrich treatment train
East St. Louis WTF, East St. Louis, IL ©Google Earth 2018
18
East St. Louis WTF UV Conceptual Design
• 3 design alternatives (72% UVT, 56 mgd)
• UV-1/2: 3 (2 duty + 1 stdby) 48-in reactors
• Alt. UV-1: Gravity flow, UV vault below grade
• Alt. UV-2: Pumped flow, UV facility above grade
• UV-3: 4 (3 duty + 1 stdby) 24-in reactors
• Pumped flow, UV facility above grade
• Recommended option – lowest cost alternative
O&M includes cost of pumping 19
$76M $74M$69M
$0M
$20M
$40M
$60M
$80M
UV-1 UV-2 UV-3
Co
st
20-Year O&M Present Worth Project Cost Est.
Current Status
• Peoria IRS UV Facility
• Working with IEPA on review/approval of new Calgon 24-in validation and ASCF reports
• East St. Louis conceptual design report complete
• RFP for detailed design and construction phase services issued on Jan. 24 (due Feb. 22)
• Alton and Granite City draft conceptual design reports under review by ILAW
• RFP for detailed design and construction phase services issued on Feb. 13 (due Mar. 7)
All UV facilities to be operational by October 1, 2020
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