ANGLE WELLS, OZONE, AND MEMBRANES: A GREAT COMBINATION

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Barry McDonald
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1 2007 Eastern South Dakota Water Conference and 52 nd Annual Midwest Ground Water Conference ANGLE WELLS, OZONE, AND MEMBRANES: A GREAT COMBINATION Presented by: Joseph Honner, P.E. Bartlett & West, Inc. in Cooperation w/ South Central Regional Water District

3 WATER SOURCE GOALS 9 Achieve SCWD Yield Objectives ¾ Phase 1 1,000 gpm ¾ Phase 2 2,400 gpm (Total, Ultimate Design) 9 Acquire Water Quality Comparable to Missouri River TDS 400 mg/l Fe 0.70 mg/l ¾ Hardness 220 mg/l (13 gr) Mn mg/l ¾ PIOC < MCL ¾ 9 Use Existing SCWD WTP/Well Site River Front Property ¾ Existing Riprap Protection ¾ Existing WTP Building & Power ¾ 9 Meet Budget Objectives ¾ $1.2 to $1.4 Million Capital Costs 9 Riverbank Filtration Practical Applications ¾ Conducive Soil Formations ¾

4 INTAKE FACILITIES CONSIDERED Vertical Wells (VW) Traditional Intake Sloped Pipe into River Horizontal Directional Drilled Wells (HDDW) Horizontal Collector Wells (HCW) Angle Wells (AW)

5 METHOD SELECTED Angle Wells Surface Water Influenced Missouri River

6 METHOD SELECTED Angle Wells ¾ Achieves All Objectives ¾ ¾ ¾ ¾ ¾ ¾ Estimated Construction Cost of $1.2 Million Test Well at gpm, was converted to a Production Well at a Cost of $135,000 4 Additional Angle Wells Under Phase 1; at 400 gpm 450 gpm each, Cost at $170,000 per Well 23 Additional Angle Wells Under Phase 2; at 400 gpm 450 gpm each, Cost at $170,000 per Well Total of 78 Wells, Firm Capacity of a minimum of 2,400 gpm Total Cost Approximately $1.2 million

7 Angle Well Layout

8 Angle Well Profile

9 Soil Formation

10 MuniPak Screen All but one of the Angle Wells utilized a MuniPak Screen which aides in eliminating silts and fine sands from the source water.

11 Angle Well Construction

12 23 Deg Angle Well

13 23 Deg Angle Well

14 14 Deg Angle Well

15 14 Deg Angle Well

16 Cost/Benefit Comparison Of Angle Wells To Vertical Wells & Horizontal Collector Wells 3.5 mgd water source capacity, unconfined aquifer, fine medium grain sands 33 Vertical wells; 80 gpm from each well; (Includes 3 wells for backup capacity) 1 Collector well with horizontal laterals; (No backup, & may only be 1200 to 1900 gpm) 7 Angle wells; gpm from each well; (1 for backup capacity)

17 Cost/Benefit Comparison Vertical Well Field (33): $553k per MGD $1.50 m capital cost $.45 m 10 year maintenance cost $1.95 m projected well field cost over 10 years Collector Well Field (1): $600k per MGD $2.00 m capital cost $.11 m 10 year maintenance cost $2.11 m projected well field cost over 10 years Angle Well Field (8): $383k per MGD $1.20 m capital cost $.14 m 10 year maintenance cost $1.34 m projected well field cost over 10 years

18 Angle Wells A Cost Efficient Design Alternative Reduces number of wells (compared to vertical well field design) Reduces capital cost (compared to horizontal collector well field design) Reduces Maintenance Cost Fewer wells Easier rehabilitation compared to collector wells

19 Treatment Objectives Remove Fe and Mn Reduce Total Dissolved Solids (TDS) Reduce Hardness Current and Pending Surface Water Standards

20 SCWD Source Water Parameters Iron (0.4 to 3.5 mg/l) Manganese (0.45 to 0.73 mg/l) Total Dissolved Solids (450 to 700 mg/l) Hardness (12 to 23 grains) Arsenic (7.4 to 9.2 ug/l) Total Organic Carbon (2.7 to 3.5 mg/l) Likely considered GWUDI

21 Deg Angle Well2, 127' Slope Length In Ground, 25' Screen Under River, Water Quality Elevation of Screen from 1592' to 1603' Tot Alk TDS Hardness (CaCO3) Fe Mn River 503 Gauge Ht TDS 4 m g /L Hardness ALK m g / l /28/2005 8/30/2005 8/31/2005 9/1/2005 9/20/2005 9/21/2005 9/22/2005 9/23/2005 9/26/ /3/ /10/ /17/ /24/2005 0

22 South Central Regional Water District (SWCD) Microscopic Particulate Analysis Results Sample Date 10/2526/2005 9/1920/2005 8/1516/2005 8/1516/2005 Sample Source Missouri River 12" AW2 16" VW36' 2" HDD Sample Location Surface WaterRaw Under River Riverbank Under River Units Per 100 Gal Per 100 Gal Per 100 Gal Per 100 Gal Algae 10,000, Diatoms 30,000,000 5,514 9 Plant Debris Rotifers 20,000 Nematodes Pollen (pine) Ameba 6,000 Ciliates 3, Colorless Flagellates Crustaceans Other Arthropods 10,000 Other Giardia Detected #/100 L 58 <0.21 <0.25 <0.22 Cryptosporidium Detected #/100 L <58 <0.21 <0.25 <0.22

23 MF and RO Train MF System MidApril to early August RO System MidMay May to early August NF membranes installed for approx. last week Oxidants potassium perm. and chlorine midapril to midjune, ozone midjune to early August

26 T

28 MF and RO Train MF effluent Fe and Mn consistently below MCLs MF effluent consistently at 0.1 ntu Flux rates, backwash intervals adjusted to maintain minimum recovery of 95% (ozone did not impact) EFM was utilized throughout MF study (intervals varied) Arsenic after MF was nondetect Little TOC reduction through pretreatment and MF TOC reduced through RO RO and NF effluent lowered dissolved constituents as expected

29 Final Design Angle Wells Oxidation Basin Ozone MF Membranes Softening Membranes Contact Basin Ozone Clearwell

Plan Review and Standards

Plan Review and Standards Minnesota Rules, part 4720.0010, states that prior to the installation, alteration, or extension of any water supply infrastructure, plans and specifications must be submitted