OBG PRESENTS: OBG PRESENTS: Side by Side Piloting of Process Alternatives Yields Direct Performance Comparison LORI W. REID, P.E. New York State AWWA Spring Meeting, April 26, 2017
Outline Background Project Goals Screening Alternatives Process Parallel Pilot Operation & Results Conclusions Next Steps 2
Supply Scituate Reservoir 93 square mile watershed Treatment Process Conventional treatment 144 MGD WTP capacity Average - 70 MGD Distribution System 1,000 miles of mains Serving approximately 60% of RI and 14 municipalities 3
Existing Water Treatment Process Clearwell Influent Aeration Basin Filter Building North Sedimentation Basin Influent Control Chamber South Sedimentation Basin 4
Unique facility design and treatment strategy Operational Challenges Aging infrastructure and process facilities Positioning for future regulations Original WTP Construction Aeration Upgrades Filter Upgrades 5
Goal of the Pretreatment Pilot Program Create a vision for the Philip J Holton Water Purification Plant, both near term and for many years into the future Improve natural organic matter (NOM) removal to control disinfection by-products (DBPs) for Providence Water s retail and wholesale customers Maintain reliable manganese removal Fit the site and its hydraulic constraints Support long-term optimized corrosion control strategies Position Providence Water as the premier New England water utility, while maintaining economical rates! 6
Raw Water Quality 5.00 2.50 4.50 4.00 **Note Average Turbidity 0.41 NTU** 2.25 2.00 3.50 1.75 mg/l ( TOC) 3.00 2.50 2.00 1.50 1.25 1.00 mg/l (Fe, Mn) 1.50 0.75 1.00 0.50 0.50 0.25 0.00 1 2 3 4 5 6 7 8 9 10 11 12 Month 0.00 TOC Iron Manganese ANOVA Monthly Results 2010-2014 7
Raw Water Manganese (Mn) Levels 8
Pilot Options GOAL Provide direct performance comparisons between treatment trains Traditional pilot setup consecutive vs. parallel Raw water quality Seasonal impacts Capture rapid changes in water quality parameters (Mn) 9
Screening Alternatives Process 10
Water Quality Goals 11
Train #1 MIEX, Potassium Permanganate (KMnO 4 ) & Direct Filtration Train #2 Ozone & Direct Filtration Identified Alternatives Train #3 Train #4 Train #5 Train #6 Ozone & High Rate Plate Settlers (HRPS) Ozone & Dissolved Air Flotation (DAF) Potassium Permanganate, Powdered Activated Carbon (PAC) & HRPS Potassium Permanganate, PAC & DAF Train #7 Chlorine Dioxide (ClO 2 ), PAC & DAF 12
Screening Alternatives Performance goals Factors NOT driven by pilot results GOALS Select process trains for pilot testing Eliminate those that do not meet PWSB s needs, without piloting Hydraulic fit and site planning Reliability Ease of operations Preliminary construction costs and life cycle cost comparison 13
Benchscale Analysis Informed the screening of alternatives through selected preliminary chemical dosages and process performance parameters Raw Water Sample Collection Mobile Field Laboratory Contour Plots
Train #0 Control (Existing Conventional WTP) Train #1 MIEX, Potassium Permanganate & Direct Filtration Final Pilot Train Selection Train #3 Ozone, HRPS and Biologically Active Filters Train #5 Potassium Permanganate with PAC & HRPS Train #7 Chlorine Dioxide with PAC & DAF
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General Layout Plan Ozone generation & contact tanks MIEX pilot trailer Chemical feed and storage area Pilot scale filters DAF Unit High rate plate settlers (HRPS) Chlorine dioxide generation (Blueleaf, Inc Dwg 2.06 03/09/2015 Rev5) 17
Pilot Operation Testing Periods: Q1 WINTER Q2 SPRING: Q3 SUMMER Q4 FALL 09/28/2015 to 02/26/2016 02/22/2016 to 4/18/2016 5/30/2016 to 7/25/2016 7/25/2016 to 10/28/2016 *Including additional evaluation Each testing period had time for optimization, followed by a 15 day continuous demonstration Adaptive changes were made between test periods based on prior quarter s results and anticipated water quality 18
Process Highlights QUARTER 4 Critical Period Evaluated DBPs in chlorinated vs. unchlorinated (biologically active) filters Managing peak manganese levels Optimized MIEX alternative with HRPS Added GAC/sand control filter as alternate to PAC Tested impact of ph on TTHM 19
Train #1 (MIEX) Train #3 (Ozone) Train #5 (KMnO 4 ) Train #7 (ClO 2 ) Train #0 (Control) Q4 FALL SDS TTHM Results 20
Train #1 (MIEX) Train #3 (Ozone) Train #5 (KMnO 4 ) Train #7 (ClO 2 ) Train #0 (Control) Q4 FALL Filter Effluent Total Mn Results 21
Control (existing WTP) performed well coagulation at low ph with extended settling time MIEX direct filtration performed well Conclusions Ozone did not achieve Mn treatment objectives Unchlorinated (biologically active) filters performed well for all pilot trains 22
Final ranking of pilot trains Next Steps Development of hybrid pretreatment options Sedimentation basin conditions assessment Sedimentation Basin Pretreatment Options GAC Benchscale Study 23
ACKNOWLEDGEMENTS Providence Water Supply Board Rhode Island Department of Health Black and Veatch Blueleaf, Inc. 24
QUESTIONS 25