Big Valley Rancheria Corrosion Control Study
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- Angelica King
- 5 years ago
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1 Big Valley Rancheria Corrosion Control Study Funded by: EPA Region 9 RCAC is a subcontractor to the Horsley Witten Group, Inc.
2 Big Valley Rancheria Corrosion Control Study Big Valley Rancheria Sarah Ryan, Environmental Director RCAC Lee Schegg, RDS Environmental Engineer
3 Rural Community Assistance Partnership, Inc. Western Rural Community Assistance Corporation 916/ Midwest Assistance Program 952/ Southern Community Resource Group 479/ Northeast RCAP Solutions 800/ Great Lakes WSOS Community Action Commission 800/ Southeast Rural Community Assistance Project 866/ /
4 Funding The Study recounted in this presentation was funded by a Environmental Protection Agency, Region 9 Drinking Water Tribal Set-Aside Grant
5 Big Valley Rancheria Corrosion Control Study Background Water System Lead and Copper Compliance Variations
6 Location Big Valley Rancheria - Lake County, CA Tribe: Big Valley Band of Pomo Indians of the Big Valley Rancheria Serves: 38 Residences Konocti Vista Casino Motel Tribal Offices RV Park Plans: 200 more residences
7 Big Valley Rancheria Location Clear Lake Lake County
8 Big Valley Band of Pomo Indians Lakeport Clear Lake
9 Big Valley Rancheria Site Residences Casino Residences Well Water Treatment Plant
10 Original Treatment Features (2003) Potassium Permanganate Injector Ozone and Air Preparation System Iron Filters Ultraviolet Light System Multimedia Filters Carbon Filters Water Softener Chlorine Injection System External Potable Water Holding Tank Grundfos Boosterpaq Pumps Diesel Fire Pump
11 Existing Water System Schematic
12 Original Treatment Features (2003) Potassium Permanganate Injector Ozone and Air Preparation System Iron Filters Ultraviolet Light System Multimedia Filters Carbon Filters Water Softener Chlorine Injection System External Potable Water Holding Tank Grundfos Boosterpaq Pumps Diesel Fire Pump
13 Well Pump Station
14 Water Treatment Plant Building
15 Green Sand Filters in WTP Building
16 GAC Filters and Zeolite Softeners
17 Hypochlorite and Phosphate Tanks and Pumps
18 Treated Water Storage Tank
19 Distribution Pumps and Diesel Driven Fire Pump
20 Lead and Copper Rule Compliance History 2003 Plant went on line 2006 Sarah Ryan produced a report as result of lead and copper exceedances
21 Lead and Copper Rule Testing (20 Residences in Fall 2016) Copper Lead Test Site mg/l Rank Percentile ug/l Rank Percentile 500 YH YH th 570 YH YH th RF ND YH th RF th The rest of the sites are under LCR action limit.
22 Water Quality Conditions High corrosivity Constant High iron Variable High manganese Constant High hardness (Motel softens water) High CO 2 Constant High turbidity Periodic High color Periodic Taste Okay Odor Okay
23 Big Valley Rancheria Corrosion Control Study Creative Process Professional Search EPA Collaboration Contract
24 Creative Process Professional Search EPA Collaboration Contract Negotiation
25 Contract EPA Funded Investigation: $25,000 Corrosion control and quality improvement testing: Kennedy/Jenks Consultants Corrosivity Evaluation Corrosion Control Options Pilot Testing Comparison of alternatives Cost: Capital and Operations Report and Recommendations
26 Big Valley Rancheria Corrosion Control Study Bench Scale Testing Theory Methods Used Results
27 Corrosion Control Theory Water Quality Parameter Testing Plotting Milliequivalents of Cations and Anions at Various Points in System
28 Corrosion Control Options ph Elevation: Air stripping Caustic addition Inhibitors: Phosphate: Previously used 3 mg/l, 30% ortho, and 70% poly blend and other phosphate blends and dosages. Not sufficiently effective. Silicate: Too much silica with 80 mg/l in well water can inhibit iron and manganese removal at ph above 7.2
29 CO 2 Air Stripping Alternatives Type: Packed tower Diffused air Subsurface aeration Spray aeration Vacuum pressure stripping Condition: Iron fouling: Double Pumping Apparent best Storage tank: High iron settling High energy Iron fouling
30 Anticipated Testing Phosphate Blend Dosage Testing Caustic Additions
31 Actual Testing 18 Liter Capacity Tub 3.4 Liters per Minute small aquarium aerator
32 Test Instruments and Lab Equipment
33 Initial Pour Testing Raw Water 250 ml Beakers phtester 1
34 CO 2 Stripping Preliminary Testing Initial pour testing back and forth in 250 ml beakers. Pours ph
35 Diffused Air Stripper Testing 18-Liter Tubs Photo at ph 6.94 Photo at ph 7.56
36 Diffused Air Stripper Testing 18-Liter Tubs Photo at ph 7.87 Photo at ph 8.27
37 Diffused Air Stripper Testing 18-Liter Tubs Aeration: 3.4 liters/minute Blower ph: Initial minutes: minutes: minutes: minutes: 8.3
38 Caustic Additions to Elevate ph
39 Bench Scale Testing Linear polarization test method by Metal Samples Company (portable) MS 1500L data logger with 3-inch length x ¼-inch copper probes. 3-inch x ⅜-inch lead probes Electrochemical method of potential displacement ΔE/ΔI polarization resistance that provides a real-time measurement of uniform and/or pitting corrosion.
40 Bench Scale Tub Aeration and ph Testing Each Week of 4- Week Test Period
41 Copper and Lead Linear Polarization Probes
42 Lead and Copper LPR Probes in Tub Cover
43 Bench Scale LPR Test Assembly Tested Each Week after Aeration CO 2 Stripping
44 Linear Polarization Testing Each Week of CO 2 Stripped, ph Elevated Phosphate Inhibited Water
45 Corrosion Rate Readout in mils/year
46 Copper Probes Before and After
47 Lead Probes Before and After
48 Bench Scale Corrosivity Testing Week ph Existing Water Copper Corrosion Rate mils/yr ph CO 2 Stripped Water Copper Corrosion MPY Lead Rate MPY Corrosion Reduction Percent
49 Big Valley Rancheria Corrosion Control Study Solutions Interim Long Range
50 Recommended Interim Water Treatment Improvements Interim: Diffused air stripper: 60-minute detention at 130 GPM Improved iron and manganese removal: Pyrolusite media to three existing and conversion of two GAC and four Zeolite filters to pyrolusite to reduce loading rate by two-thirds.
51 Recommended Interim Water Treatment Improvements - Continued Interim: Storage tank: Sludge removal and cathodic protection Cost: $200,000 interim treatment and $300,000 wastewater treatment plant separation by containment wall ($100,000 CO 2 stripping and $100,000 improved iron removal)
52 Existing Water System Schematic
53 Interim Treatment Schematic
54 Long Range Treatment (for wastewater separation) CO 2 Stripping Water Softening by Lime with Iron- Manganese Precipitation Filtration Chlorination Phosphate Inhibitor Cost: $3 million
55 Long-Term Treatment with CO 2 Stripping
56 Long-Term Treatment Schematic
57 Faucet Replacement Alternatives An option to provide water treatment for LCR compliance possibly is removal of brass faucets. Six faucets were removed and found three high lead and copper and three from low lead and copper test residences. All faucets found to be different types of chrome-plated faucets. Copper plumbing removal from eight residences. Cost was about $15,000 each = $120,000 and more expensive than corrosion control treatment
58 Big Valley Rancheria Corrosion Control Study Lessons Learned Find the right engineer/scientist Collaboration between parties involved Obvious treatment methods aren t Importance of monitoring
59 Find The Right Engineer/Scientist Right level of expertise Civil Engineers Sanitary Engineers Firms with Engineers and Scientists Right level of experience
60 Collaboration Between Parties Involved Communication Needs Technology/Abilities Funding Education Process (Patience)
61 Obvious Treatment Methods Aren t The inclusion of treatment processes and their sequence and interaction must be based on: Sound and complete raw water data Knowledge of the water chemistry Water treatment design, construction and maintenance
62 Importance of monitoring Timely chemical adjustments and their effects on the water served through a specific monitoring program is extremely important.
63 Big Valley Rancheria Corrosion Control Study For Further Information Lee Schegg
64 Big Valley Rancheria Corrosion Control Study Questions?