uv disinfection of cryptosporidium for bryan townsend ... · residual after 20 min hdt) •bromate...

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

9

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


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

11

$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


$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


$19.9M

Granite City WTF

• Serves residents of Granite City, IL


• Future peak flow of 20 mgd

• Pre-treatment Coag/Floc Sedimentation Filtration Disinfection

• Disinfection:



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


• 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


• Redundant reactor offline at high flows

15

$5.4M

$6.3M

$0M

$2M

$4M

$6M

$8M

UV-1 UV-2

Co

st


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


$19.0M

$5.4M $6.3M

$0M

$4M

$8M

$12M

$16M

$20M

$24M

UV-1 UV-2 O3-1

Co

st


$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

17

$5.4M $6.3M

$0M

$4M

$8M

$12M

$16M

$20M

$24M

UV-1 UV-2 O3-1

Co

st


$19.0M

East St. Louis WTF

• Regional plant serving Metro East (68K customers)


• Future peak flow of 75 mgd

• Two separate treatment trains

• Conventional & Aldrich unit treatment trains

• Disinfection:



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


• 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


• 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

20

THANK YOU [email protected]

mailto:[email protected]

uv disinfection of cryptosporidium for bryan townsend ... · residual after 20 min hdt) •bromate...

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