Howell Mountain Mutual Water Napa County, CA PAX Clearwell Mixer

Howell Mountain Mutual Water Napa County, CA PAX Clearwell Mixer Tracer Studies, July, Sept, Oct 2015 by Guy Schott, P.E. [email protected] 707-576-2732

Clearwell – 488,000 Gal Max Capacity Tank Diameter: 54-Ft Volume: 488,000 Gal (full) 17,132 gal/ft (28.5 ft max opt) Outlet (8-in) (8-in off bottom) PAX Mixer (3-ft off bottom) 123 Deg Inlet (30 ft) Outlet (8-in) (8-in off bottom) Inlet PAX Mixer Figure 1: Test 1 – 4 (July 2015) PAX location 1

Clearwell – 488,000 Gal Max Capacity Outlet (8-in) (8-in off bottom) Tank Diameter: 54-Ft Volume: 488,000 Gal (full) 17,132 gal/ft (28.5 ft max) PAX Mixer (3-ft off bottom 10-ft from wall) 123 Deg Inlet (8-in, plate in front) (2.3-ft off bottom or 30-ft off bottom) Inlet (30 ft) Outlet PAX location 2 PAX Mixer Inlet Figure 2: Test 5 – 6 (Sept-Oct 2015)

Tracer Test Overview for 488,000 Gal Max Capacity Clearwell PAX Mixer ON PAX Mixer ON Figure 1 PAX Location Figure 2 PAX Location Inlet Configuration Baffling Factor Inlet Configuration Baffling Factor Bottom to Bottom 0.033 Bottom to Bottom 0.058 Top to Bottom 0.063 Top to Bottom 0.084 PAX Mixer Off PAX Mixer Off Inlet Configuration Baffling Factor Inlet Configuration Baffling Factor Bottom to Bottom 0.049 Top to Bottom 0.091 Clearwell: No baffles Inlet flow: 250-280 gpm Outlet flow varied: 114-142 gpm Clearwell Level: 19 – 23.2 ft Clearwell Operating Volume: 325,500 – 397,500 gal Tracer Test Type: Modified Step-Dose/Volume10 (V10) combination methods

Test 1 & 2 Figure 1 for PAX location in Clearwell PAX Mixer ON Test 1: Bottom to Bottom (inlet/outlet) July 7, 2015 Baffling factor (t10/T) 0.033 PAX Mixer Off Test 2: Bottom to Bottom (inlet/outlet) July 14, 2015 Baffling factor (t10/T) 0.049 Avg tank level Avg tank volume Inlet Flow Avg outlet flow Hydraulic Retention Time *Accumulated exit volume Avg tank level Avg tank volume Inlet Flow Avg outlet flow Hydraulic Retention Time *Accumulated exit volume 22.2 ft 379,000 gal 255 gpm 139 gpm 2,727 min 12,500 gal *Accumulated exit volume is the total volume that exit the Clearwell when 10% of tracer mass has exited the Clearwell. Clearwell: 17,132 Gal/ft (Diameter: 54-ft) 23.2 ft 401,000 gal 250 gpm 114 gpm 3,518 min 19,500 gal

Inlet/Outlet Configuration: Bottom to Bottom Baffling factor: 0.033 t10/T Accumulated exit volume: 12,500 gallons at 10% of tracer mass Average operating volume: 379,000 gallons

Inlet/Outlet Configuration: Bottom to Bottom Baffling factor: 0.049 t10/T Accumulated exit volume: 19,500 gallons at 10% of tracer mass Average operating volume: 401,000 gallons

Test 3 & 4 Figure 1 for PAX location in Clearwell PAX Mixer ON Test 3: Top to Bottom (inlet/outlet) July 23, 2015 Baffling factor (t10/T) 0.063 PAX Mixer Off Test 4: Top to Bottom (inlet/outlet) July 28, 2015 Baffling factor (t10/T) 0.091 Avg tank level Avg tank volume Inlet Flow Avg outlet flow Hydraulic Retention Time *Accumulated exit volume Avg tank level Avg tank volume Inlet Flow Avg outlet flow Hydraulic Retention Time *Accumulated exit volume 19.0 ft 321,000 gal 255 gpm 131 gpm 2,360 min 20,200 gal *Accumulated exit volume is the total volume that exit the Clearwell when 10% of tracer mass has exited the Clearwell. Clearwell: 17,132 Gal/ft (Diameter: 54-ft) 21.6 ft 370,500 gal 260 gpm 142 gpm 2,609 min 33,800 gal

Inlet/Outlet Configuration: Top to Bottom Baffling factor: 0.063 t10/T Accumulated exit volume: 20,200 gallons at 10% of tracer mass Average operating volume: 321,000 gallons

Inlet/Outlet Configuration: Top to Bottom Baffling factor: 0.091 t10/T Accumulated exit volume: 33,800 gallons at 10% of tracer mass Average operating volume: 370,500 gallons

Test 5 & 6 Figure 2 for PAX location in Clearwell PAX Mixer ON Test 5: Top to Bottom (inlet/outlet) September 29, 2015 Baffling factor (t10/T) 0.084 PAX Mixer ON Test 6: Bottom to Bottom (inlet/outlet) October 13, 2015 Baffling factor (t10/T) 0.058 Avg tank level Avg tank volume Inlet Flow Avg outlet flow Hydraulic Retention Time *Accumulated exit volume Avg tank level Avg tank volume Inlet Flow Avg outlet flow Hydraulic Retention Time *Accumulated exit volume 21.0 ft 360,700 gal 259 gpm 138 gpm 2,610 min 30,230 gal *Accumulated exit volume is the total volume that exit the Clearwell when 10% of tracer mass has exited the Clearwell. Clearwell: 17,132 Gal/ft (Diameter: 54-ft) 23.1 ft 395,600 gal 280 gpm 115 gpm 3,440 min 23,000 gal

Inlet/Outlet Configuration: Top to Bottom Baffling factor: 0.084 t10/T Accumulated exit volume: 30,230 gallons at 10% of tracer mass Average operating volume: 360,700 gallons

Inlet/Outlet Configuration: Bottom to Bottom Baffling factor: 0.058 t10/T Accumulated exit volume: 23,000 gallons at 10% of tracer mass Average operating volume: 395,600 gallons

488,000 Gal Clearwell Inlet (bottom or Top) Outlet (bottom)

Outlet (bottom)

Inlet (bottom or top)

Inlet (Top) Deflector Plate

Inlet (Top)

Fluoride Injection System

Fluoride Dosage Sampling Point

Fluoride sampling point (after clearwell)

SCADA Info on Plant and Distribution Flows

Fluoride Analysis

Fluoride Analysis

Modified Step-Dose Method Similar to Step-Dose Test Differences: – Shorter test duration: tracer is discontinued when 10% of mass has exit reactor ( Theoretical Detention Time) – Allows for higher dosage (i.e., 4 to 10 mg/L of F-) – Ion selective probes response better and faster at higher salt concentration (i.e. 10% of dosage) Test Application – suitable for long test duration or when operating conditions up to 3Ƭ is impractical. Presented at the CA-NV AWWA Oct 25, 2007

Volume10 (V10) Method For non-steady-state flows V10: Is the recorded total volume of water that has exited the reactor from to to t10 when 10% of the tracer mass has exited the reactor. t1 0 V10 Flow Time t0