Gibson Canyon WTP Tracer Study Overview

A tracer study conducted at Gibson Canyon Water Treatment Plant in Solano Irrigation District, Vacaville County, CA, on May 8, 2017, aimed to determine t10 disinfection contact time and baffling factor for the clearwell. The study utilized a Modified Step-Dose Tracer Method with Hydrofluorosilicic Acid as the tracer material. Detailed results and analyses were provided by Water Resources Control Board, Division of Drinking Water.

• Water Treatment Plant
• Tracer Study
• Solano Irrigation District
• Water Resources Control Board
• Drinking Water

czar Follow

Uploaded on Feb 24, 2025 | 0 Views

Download Presentation

Please find below an Image/Link to download the presentation.

The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.

You are allowed to download the files provided on this website for personal or commercial use, subject to the condition that they are used lawfully. All files are the property of their respective owners.

The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author.

Presentation Transcript

1. Gibson Canyon WTP Solano Irrigation District Vacaville County, CA Contact Time (t10) Tracer Study May 8, 2017 by Guy Schott, P.E. Amy Little, P.E. Water Resources Control Board, Division of Drinking Water Guy.schott@waterboards.ca.gov 707-576-2732

2. Chlorine Contact Tank - Clearwell Outlet L:W = 11 4-ft 6-ft 8-ft Clearwell volume/ft: 2,844 gal/ft Working volume during tracer study: 34,000 gallons Inlet 2.8-ft off bottom angled 30o up Outlet 2-in off bottom L:W ratio: 11 Has spray aeration for TTHM reduction pumped from outlet pipe back into tank top in last channel. Inlet 40,000 Gal Clearwell 22-ft Dia. Inlet

3. Final Results Test Date: May 8, 2017 Test by: Water Resources Control Board, Division of Drinking Water Tracer Test Method: Modified Step-Dose using Fluoride Clearwell Diameter: 22-ft Clearwell Volume/Ft: 2,844 gal/ft Number of Baffles: 2 Clearwell Flow (inlet/outlet): 400 gpm Clearwell Operating Water Level: 12 feet Clearwell Operating Volume: 34,000 gallons HRT: 85 minutes t10: 31.3 minutes L:W Ratio: 11 Baffling Factor: 0.37 (t10/HRT)

4. Tracer Study Overview 1 A tracer study was conducted at the Gibson Canyon WTP to determine the t10 disinfection contact time and baffling factor for the 40,000 gallon max capacity clearwell with two baffles. The t10 value is the time is takes for 10% of the added tracer mass to exit the reactor. The baffling factor is t10/HRT where HRT is the hydraulic residence time of the clearwell during the time of the tracer study.

5. Tracer Study Overview 2 Tracer Method: Modified Step-Dose Injection Point: Pipeline inlet to Clearwell Sample Points: Inlet/outlet of Clearwell Tracer Analysis: Ion Selective Fluoride Probe Sampler: Amy Little Analysis by: Guy Schott

6. Tracer Material Overview Tracer Material: Hydrofluorosillicic Acid (H2SiF6) Tracer Bulk Density: 10.3 lbs/gal Tracer Product Strength: 28% as H2SiF6 Molecular Weight: 144.09 g/mole (H2SiF6) Fluoride Concentration: 79.11% (144 g/mole) H2SiF6 Tracer Feed Rate: ~21 mL/min Flow: 400 gpm Tracer Dose: 3.9 mg/L as F Method of Injection: Steady-State

7. Tracer Field Results Tracer Conc., Fluoride mg/L Elapsed Time, min F t/HRT Normalized 0.0 0.00 0.00 0.00 4.0 0.05 0.00 0.00 8.0 0.09 0.01 0.00 12.0 0.14 0.02 0.01 14.0 0.16 0.04 0.01 16.0 0.19 0.05 0.01 18.0 0.21 0.07 0.02 20.0 0.24 0.09 0.02 22.0 0.259 0.127 0.033 24.0 0.282 0.162 0.041 26.0 0.31 0.21 0.05 28.0 0.33 0.27 0.07 30.0 0.353 0.312 0.080 32.0 0.376 0.434 0.111 34.0 0.40 0.47 0.12 36.0 0.42 0.53 0.14 t10: 31.3 minutes Working volume: 32,000 gallons @ 12 ft operating level Calculated baffling factor: 0.37 t10/HRT L:W ratio: 11 Flow: 400 gpm; 40,000 gallon baffled Clearwell HRT: 85 minutes Tracer Dose 3.9 mg/L as F

8. Working Volume: 34,000 gallons Average Flow: 400 gpm Clearwell Water Level: 12 ft Total Baffles: 2 HRT: 85 minutes t10: 31.3 minutes Baffling factor 0.37 (t10/HRT)

9. Clearwell and Effluent Pumps Tracer Sample Point (discharge side of effluent pumps)

10. Inlet Sample Point before Clearwell To Verify Tracer Dosage