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
Treatment
Process
Distribution
System
 Scituate Reservoir
 93 square mile watershed
 Conventional treatment
 144 MGD WTP capacity
 Average - 70 MGD
 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
2.50
mg/L ( TOC)
4.50
**Note – Average Turbidity 0.41 NTU**
2.25
4.00
2.00
3.50
1.75
3.00
1.50
2.50
1.25
2.00
1.00
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
mg/L (Fe, Mn)
5.00
0.00
Month
TOC
ANOVA Monthly Results 2010-2014
Iron
Manganese
7
Raw Water
Manganese (Mn)
Levels
8
Pilot Options
▪ Traditional pilot setup –
consecutive vs. parallel
▪ Raw water quality
 Seasonal impacts
GOAL
Provide direct performance
comparisons between
treatment trains
 Capture rapid changes in water
quality parameters (Mn)
9
Screening
Alternatives
Process
10
Water Quality
Goals
11
Identified
Alternatives
Train #1
MIEX, Potassium Permanganate (KMnO4) & Direct Filtration
Train #2
Ozone & Direct Filtration
Train #3
Ozone & High Rate Plate Settlers (HRPS)
Train #4
Ozone & Dissolved Air Flotation (DAF)
Train #5
Potassium Permanganate, Powdered Activated Carbon (PAC) &
HRPS
Train #6
Potassium Permanganate, PAC & DAF
Train #7
Chlorine Dioxide (ClO2), 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
Final Pilot Train
Selection
Train #0
Control (Existing Conventional WTP)
Train #1
MIEX, Potassium Permanganate & Direct Filtration
Train #3
Ozone, HRPS and Biologically Active Filters
Train #5
Potassium Permanganate with PAC & HRPS
Train #7
Chlorine Dioxide with PAC & DAF
16
General Layout Plan
Ozone generation
& contact tanks
Chemical feed
and storage area
Pilot scale filters
MIEX pilot trailer
DAF Unit
High rate plate
settlers (HRPS)
(Blueleaf, Inc – Dwg 2.06 03/09/2015 Rev5)
Chlorine dioxide
generation
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
▪ Evaluated DBPs in chlorinated vs.
unchlorinated (biologically active)
filters
▪ Managing peak manganese levels
QUARTER 4
Critical Period
▪ 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
(KMnO4)
Train #7
(ClO2)
Train #0
(Control)
Q4 FALL
SDS –TTHM
Results
20
Train #1
(MIEX)
Train #3
(Ozone)
Train #5
(KMnO4)
Train #7
(ClO2)
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