Aqua PA & Hatch Mott's John Civardi presentation on UV Oxidation Selection for Neshaminy & Shenango WTP IUVA 2012


IUVA Conference on Moving Forward: Sustainable Solutions to Meet Evolving Regulatory Standards, August 14, 2012
AQUA PENNSYLVANIAAQUA PENNSYLVANIA
Aqua PA’s Experience with UV Hydrogen Peroxide for
Reduction of Taste and Odors at Two Water Treatment Plants
John F. Civardi, PE, Hatch Mott MacDonald
Marc A. Lucca, PE, Aqua Pennsylvania, Inc.


Outline
 Aqua PA Operations – Regional Overview
 T&O at Two Plants and Treatment Limitations
 Treatability Study at the Neshaminy WTP
 Design Goals for both plants
 Design and Operation at the Neshaminy WTP
 Design and Construction at the Shenango WTP


Overview of Aqua PA
 Subsidiary of Aqua America
– Publically traded (NYSE: WTR)
– Operations in 10 ‐ states serving 3‐million people.
 Aqua PA – Operations
– Southeast serves 350,000 customers in portions of the 5
counties surrounding the City of Philadelphia
– Western PA serves 48,000 customers in Mercer County
and surrounding area


Taste and Odor at Plants
Neshaminy Shenango
Max Capacity 15 MGD 16 MGD
Source Neshaminy Creek: Mixture of
Industrial and Agricultural
Shenango River: intake 3 miles
downstream of Reservoir
Plant Features Settling Basing (current), Plate
Settlers (upgrading), Dual Media
Filtration, Free Chlorine (gas),
Chloramination
Actiflo, Dual Media Filtration, Free
Chlorine (gas), Chloramination
Residuals Mechanical Dewatering Mechanical Dewatering
Geosmin ng/L 240 159
MIB ng/L 45 157


Historical T&O Treatment
and Problems
 Powdered Activated Carbon
 Residuals Generation
 PAC provided limited removal
 Competitive effects of alum
 Could PAC be optimized and is AOP a suitable option?


Bench Testing & Feasibility
Evaluation at Neshaminy WTP
 Removal of up to 90% Geosmin & MIB is desired at
maximum plant capacity
 Aqua and Carbon Supplier performed jar tests with
Geosmin to assess :
– Potential competitive effects of alum on carbon usage –
literature contained limited data
– Optimum type of PAC
– Optimum dose and detention time


PAC Testing Results
 Dosing PAC together with alum results in significantly
lower MIB removal (28% removal Alum/PAC vs 55%
PAC then alum)
 Testing found that PAC should be added prior to alum
 Minimum PAC detention time is 45 minutes
 Min./Max. PAC dosage is 30 mg/L ‐ 60 mg/L


Plant Impacts of Testing
 45 Minutes of Detention Time at 15 MGD requires at
500,000 gallon pre‐carbon contact tank with mixers
 30 mg/L dosage results in an additional 3,800 ppd of
Dry Solids
 This would double the plant solids production and
require additional residuals treatment equipment
 Footprint was especially limited at Neshaminy


PAC Contact Tank Option
Neshaminy
Creek
Intake, Screening
& Raw Water Pumping
Washwater Transfer Pit
Washwater Drying Lagoons
(Lagoons Nos. 2 & 3)
8 Gravity Filters &
Clearwell
Clearwell Pumps to
Distribution
To Mechanical
Dewatering
2-Stage Flocculation
(Typ. of 3)
Plate Settler Unit w/ Chain & Flight
Sludge Collectors (Typ. of 3)
In-Line
Mixers
(Typ. of 2)
PAC
PAC Contact Tank


Neshaminy Site
Intake
Sedimentation
Basin
Filter Building
Clearwell
New Residuals Facility


Is AOP an option?
 Performed desktop evaluation
 Contacted Trojan, Calgon, and Wedeco
 Evaluated capital, operating and lifecycle costs and
compared to PAC option
 Wedeco reactors are LPHO and space was not available
for the LPHO reactors
 Ozone AOPs not feasible due to cost of generators and
size of generators


Desktop Evaluation
 If Ozone was being used for DBP control then
Ozone‐AOP would have merited additional
consideration
 UV‐Peroxide using medium pressure reactors were
compact and used a maximum 5 mg/L of hydrogen
peroxide


Costs Associated with AOP
 Capital Cost: $2.5 million
 Operating Cost: $200,000/yr
– Energy
– Hydrogen Peroxide
– Lamp Replacement
– Chlorine for Quenching
 Equivalent Uniform Annual Cost: $384,000 per year (20
yrs@ 4%)
 Note Operating cost is based on a unit 90 days per year at
12 MGD and does not include savings for solids handling.


Cost Comparison AOP vs PAC
UV – H2O2 PAC
Capital $2.5 Million $2.2 Million
O&M $200,000 $310,000
Equivalent Uniform
Annual Cost
$384,000 $475,000


A Bit About Carbon Footprint
20 Year Total Carbon Footprint Comparing UV-
oxidation and PAC
0
5000
10000
15000
20000
25000
30000
35000
PAC TrojanUVSwift™ECT
Taste and Odor Technology
TonsofC02Equivalents


Comparison with PAC
 No additional sludge handling is needed whereas the PAC
process will generate approx 1.5 tons per day of dry solids
(100% increase in solids production)
 Ability to provide 1 log and higher removal of MIB and Geosmin
 Ability to achieve additional microbial disinfection
 Smaller footprint than the PAC option
 Produces less than 25% CO2 compared to UV/Peroxide
 Aqua Selected UV‐Peroxide


Procurement of the UV System
 Bench Testing Performed by UV Suppliers
 Bench Testing evaluated UV Transmittance (UVT)
along with contaminants that have hydrogen
peroxide demand
 Owner issued a Bid Document to the vendors and
selected vendor based on cost & experience specific
for UV‐Hydrogen Peroxide.
 Selected Trojan


Components of the UV‐H2O2
Treatment Facility
 UV Reactors
 Hydrogen Peroxide Feed System
– Feed pumps
– Hydrogen Peroxide Tank
 UV‐ Hydrogen Peroxide Treatment
Chamber for Neshaminy and In Pipe
Gallery at Shenango
 Flow meters
 Chlorine Feed
 Automatic valves


UV Reactors
 UV reactors: 30‐inch diameter units, constructed of
stainless steel.
 Each reactor contains 16 medium‐pressure, high
output lamps in quartz sleeves, mounted
horizontally in a cross‐flow arrangement inside the
reactor.
 Each reactor requires 200 KW


UV Reactors (Continued)
 The selected number of lamps based on:
– flow rate of 8.0 MGD per treatment train
– 93% UV Transmittance (UVT)
– removal of 0.7‐log of both Geosmin and MIB at max
plant capacity
– Up to 1 log removals can be achieved at approximately
10 MGD


Chemicals
 50% Hydrogen Peroxide – stored outside in
double walled HDPE tank
 Diaphragm metering pumps
 Only 1‐2 mg/L of hydrogen peroxide is used in the
reaction
 Hydrogen Peroxide residual is quenched using
chlorine at 2:1 ratio


Neshaminy
Creek
Intake, Screening
& Raw Water Pumping
Washwater Transfer Pit
Washwater Drying Lagoons
(Lagoons Nos. 2 & 3)
8 Gravity Filters &
Clearwell
Clearwell Pumps to
Distribution
To Mechanical
Dewatering
2-Stage Flocculation
(Typ. of 3)
Plate Settler Unit w/ Chain & Flight
Sludge Collectors (Typ. of 3)
In-Line
Mixers
(Typ. of 2)
Hydrogen
Peroxide
UV Reactors
Chlorine
Sulfur Dioxide Neshaminy only


Neshaminy Site
Intake
Sedimentation
Basin
Filter Building
Clearwell
UV Facility
New Residuals Facility


UV Process Layout
Neshaminy WTP
Chlorine
Sulfur
Dioxide
Flow Meter
UV Reactor
Cooling Water
Supply
Cooling Water
Return
NC
Existing Filter Discharge to Clearwell


Neshaminy Operating Data
 Performed testing to evaluate impacts of DBP
formation in Winter and Summer 2012
 Developed baseline in plant without UV
– Raw
– Basin Inlet and Outlet
– Filter top and Filter Composite
– Pre Chlorine Contact Tank and Post Contact Tank
– Plant Effluent
– UV is located between filter composite and pre tank


Overall Change in HAAs
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
Winter HAA Baseline Winter HAA UV On Summer HAA Baseline Summer HAA UV On
Delta PPb
Delta Values For HAAs Pre to Post UV


Overall Change in THMs
The UV system does not show a statistically significant difference in the immediate
formation of HAAs and THMs when compared against traditional chemical treatment
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Winter THM Baseline Winter THM UV On Summer THM Baseline Summer THM UV On
Delta PPb
Delta Values For THMs Pre to Post UV


UV Process Layout
Shenango WTP


UV Process Layout
Shenango WTP
Hydrogen
Peroxide
UV Reactor
Flow Meter
Chlorine
Cooling Water
Return
Cooling Water
Supply
NC




Summary
 AOPs gaining in popularity for drinking water
applications;
 PAC especially wood based provide greater Geosmin
removal efficiencies if added PRIOR to coagulant
addition;
 AOPs can be cost effective:
– for T&O especially if a component of the AOP such as O3 is
being used for DBP control;
– UV is also being used for disinfection;
– when considering costs of solids handling.


Summary
 The UV/Peroxide System:
– Provides superior T&O removal compared to PAC;
– Provides the operational flexibility to provide additional
disinfection capabilities which may be required to adjust
to changing raw water quality;
– Generates 50% less solids compared to PAC thereby
saving labor & disposal costs; and
– Produces less than 25% CO2 compared to UV/Peroxide


Acknowledgements
 William McGinty – Water Quality Manager
 James Rieben Jr. – Water Quality
 Curt Steffy – Manager of Production
 Tom Walton – Plant Superintendent
– Mike Whitaker ‐ Treatment Technician
 Peter Kusky – Aqua Shenango
 Terry Keep – Trojan Technologies


Questions?
Contact Information
John Civardi
973.912.2418
John.Civardi@hatchmott.com
Jim Rieben Jr.
JCRieben@aquaamerica.com

Aqua PA & Hatch Mott's John Civardi presentation on UV Oxidation Selection for Neshaminy & Shenango WTP IUVA 2012

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