Outline of Presentation Definition of Aquifer Storage and Recovery (ASR) Why ASR? Joint Powers Water Board ASR Well 9 ASR Pilot Testing Results Current ASR Status

Definition of ASR ASR involves storing treated drinking water underground in times when water is available for later withdrawal to meet peak, drought, or emergency demands

Confining Layer Confining Layer ASR Wells Can Provide an Alternative Water Supply Confining Layer Native Ground Water Native Ground Water Buffer Zone Stored Water Stored Water Buffer Zone Target Storage Volume Confining Layer

ASR Applications Peak shaving for water treatment Seasonal, long-term or emergency storage Maintain distribution system flow/pressure Other ASR applications (maintaining wetlands, controlling saltwater intrusion)

Joint Powers Joint Powers Water Board – Albertville, Hanover, St. Michael, Minnesota Seven Wells (4 drift, 3 Mt. Simon), 6,500 gpm firm capacity 10 MGD WTP 8 MGD Max Day, 2.5 MGD Avg. Day 14 MGD max day demand projected in 2020

ASR Site ASR Site

ASR Site

Joint Powers Well 9 Mt. Simon Well – drilled in 2006 504’ deep 30” casing to 197’, 24” casing to 447’ Open hole from 447’ to 504’ Mt. Simon is deep, confined aquifer 150 hp submersible motor, 1,000 gpm pump 3” ASR recharge pipe

Well 9 – Background Chemistry Iron – 1.2 mg/L Manganese – 0.27 mg/L Radium 226/228 – 9 pCi/L Gross Alpha 19 pCi/L

Joint Powers Well 9

Joint Powers Wellhouse 9

Joint Powers Wellhouse 9

Joint Powers Wellhouse 9

Joint Powers Wellhouse 9

Wellhouse 9 Site

ASR Permitting MDH Variances Pilot Cycles 1 & 2 Additional Monitoring Wells (TW-5, TW-6) Continuous Monitoring Pilot Cycle 3 – Second Variance Distribution Sampling Class V Injection Well Permit Draft Permit was issued in Sept. 2008 Minor Modification issued for Pilot Cycle 3 in 2010 Major Modification issued for full scale testing in 2012

Pilot Test Cycles 1 & 2 Pilot Test Cycle 1 – Feb. 2009 Recharged 361,000 gallons @ 310 gpm Stored one day Recovered 1,300,000 gallons to waste Pilot Test Cycle 2 – Feb. 2009 Recharged 6,090,000 gallons Stored one month Recovered 9,400,000 gallons to waste Extensive Sampling

Pilot Test Cycle 3 Started Recharge on May 26, 2010, concluded on October 11, 2010 310 gpm recharge 62,700,000 gallons recharged Started Recovery on January 6, 2011, concluded on February 21, 2011 Recovery rate 700-1,000 gpm continuous, to distribution system Recovered 52,000,000 gallons

Pilot Test Cycle 3 Samples collected during recharge, storage, recovery – Fe, Mn, radionuclides daily Aesthetic water quality good Chemical Feed No fluoride necessary until 50% recovery 2 mg/L chlorine (16 lbs/day @ 700 gpm)

Annual Sampling Requirements Collect background samples from Well 9, TW-6, distribution system Collect monthly injection samples, 95% TW-6, Well 9 Collect 5%, 30%, 60%, 100% recovery samples Distribution sampling for THMs, HAA5

Reporting Requirements Monitor water levels continuously (TW-3, TW-4, TW-5, TW-6, Well 9) Monitor injection pressure, volumes Monthly injection reports to EPA, MDH Annual summary report

Current Status Currently in fifth year of full scale ASR operation. 2012: Recharged 50 MG, Recovered 40 MG 2013: Recharged 58 MG, Recovered 48 MG 2014: Recharged 90 MG, Recovered 80 MG 2015: Recharged 70 MG, Recovered 60 MG 2016: Started recharge in Nov. 2015, on track to recharge 90 MG by June 2016.

ASR Cost/Benefit Analysis Compare capital cost of new treatment plant or expansion to cost of ASR well Need metering and monitoring equipment (wellhouse) with ASR well Sampling costs Still have the cost of treating water and pumping More regulatory hurdles with ASR