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

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 MacDonaldMarc A. Lucca, PE, Aqua Pennsylvania, Inc.


AQUA PENNSYLVANIAAQUA PENNSYLVANIAOutline

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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAOverview 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIATaste 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAPAC 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAPlant 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

NeshaminyCreek

Intake, Screening& Raw Water Pumping

Washwater Transfer Pit

Washwater Drying Lagoons(Lagoons Nos. 2 & 3)

8 Gravity Filters &Clearwell

Clearwell Pumps toDistribution

To MechanicalDewatering

2-Stage Flocculation(Typ. of 3)

Plate Settler Unit w/ Chain & FlightSludge Collectors (Typ. of 3)

In-LineMixers(Typ. of 2)

PAC

PAC Contact Tank



Neshaminy Site

Intake

Sedimentation Basin

Filter Building

Clearwell

New Residuals Facility


AQUA PENNSYLVANIAAQUA PENNSYLVANIAIs 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIADesktop 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIACosts 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

Tons

of C

02 E

quiv

alen

ts


AQUA PENNSYLVANIAAQUA PENNSYLVANIAComparison 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‐H2O2Treatment 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAUV 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAUV 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAChemicals

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



NeshaminyCreek










HydrogenPeroxide

UV Reactors

Chlorine

Sulfur Dioxide Neshaminy only



Neshaminy Site

Intake

Sedimentation Basin

Filter Building

ClearwellUV Facility

New Residuals Facility



UV Process Layout Neshaminy WTP

Chlorine

Sulfur Dioxide

Flow MeterUV Reactor

Cooling Water Supply

Cooling Water Return

NC

Existing Filter Discharge to Clearwell


AQUA PENNSYLVANIAAQUA PENNSYLVANIANeshaminy 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



NeshaminyCreek










HydrogenPeroxide

UV Reactors

Chlorine

Sulfur Dioxide Neshaminy only


AQUA PENNSYLVANIAAQUA PENNSYLVANIAOverall 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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAOverall 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 ReactorFlow Meter

Chlorine

Cooling Water Return

Cooling Water Supply

NC


AQUA PENNSYLVANIAAQUA PENNSYLVANIASummary

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.


AQUA PENNSYLVANIAAQUA PENNSYLVANIASummary

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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAAcknowledgements

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


AQUA PENNSYLVANIAAQUA PENNSYLVANIAQuestions?

Contact Information

John Civardi973.912.2418

[email protected]

Jim Rieben [email protected]

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

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