Treatment Plant: Light on Taste and Odor · Shining a Light on Taste and Odor Margie Gray, PE,...

AQUA PENNSYLVANIAAQUA PENNSYLVANIA

Pennsylvania Section AWWA Annual ConferenceMay 7, 2014 Bethlehem, Pennsylvania

Shenango Water Treatment Plant:Shining a Light on Taste and Odor

Margie Gray, PE, Hatch Mott MacDonaldJohn Civardi, PE, Hatch Mott MacDonaldMarc Lucca, PE, Aqua Pennsylvania




Outline

Background

Overview of Taste and Odor Concepts

Treatment Evaluation

Design

Operation



Background



Shenango Water Treatment Plant

16 MGD

Actiflo, dual media filtration, free chlorine, chloramines

T&O Compounds:

Aerial Imagery © 2014 DigitalGlobe; State of Ohio / OSIP; USDA Farm Service Agency; Landsat

Geosmin(ng/L)

MIB(ng/L)

Max 159 15795%ile* 21 115*During T&O events.



Plant Location

Shenango River Lake

Shenango River Dam*

Shenango WTP 1 mi

Aerial Imagery © 2014 DigitalGlobe; Landsat; State of Ohio / OSIP; USDA Farm Service Agency; Cnes / Spot Image

* Operated by the Army Corps of Engineers



Existing Plant Schematic



Overview of Taste and Odor Concepts



Taste and Odor in Drinking Water

Source: Advances in Taste‐and‐Odor Treatment and Control, AWWARF, 1995.



Taste and Odor Standards

Threshold Odor Number (TON)

– Number of times a water must be diluted withodor free water before the odor is just barely perceptible

– Secondary Standard: TON < 3

Geosmin & MIB: < 5‐10 ng/L (parts per trillion)



Taste and Odor Treatment Options

For MIB and Geosmin

– Source water protection/ management

– Activated carbon

– Ozone

– Chlorine dioxide

– Advanced oxidation processes (combinations of UV, ozone, hydrogen peroxide)

Hydrogen peroxide

Hydroxyl radical

Chemical bonds broken by hydroxyl radicals




Treatment process evaluation performed in conjunction with a second Aqua plant

– Powdered Activated Carbon

– UV Advanced Oxidation Processes

Treatment goal

– 90% (1‐log) Removal of Geosmin and MIB



PAC Jar Testing

Evaluated:

– Different types of PAC

– Optimal PAC dose

– Removal efficiency with respect to contact time

– Effect of coagulant on PAC efficiency



PAC Jar Testing

Key Findings– Dosing PAC with alum resulted in significantly lower MIB removal than dosing PAC prior to alum (29% vs. 54%)

– Dose: 30 – 60 mg/L

– Minimum Detention Time: 45 minutes (prior to alum)

– Max removal achieved: 64% MIB, 82% Geosmin



PAC Evaluation Findings

Plant Impacts– 500,000 gal. contact tank with mixers required prior to Actiflo

– 30 mg/L dose at 16 MGD generates additional 4,000 ppd residual solids



UV Advanced Oxidation Process Evaluation

Considered:– Medium pressure and low pressure high output reactors

– Hydrogen peroxide and ozone

Trojan UVSwift Wedeco K-Series




AOP evaluation based on UV‐Hydrogen Peroxide system with medium pressure lamps– Medium pressure UV reactors had significantly smaller footprint than LPHO reactors

– If Ozone were being used for DBP control, Ozone‐AOP would have been given additional consideration

Hydrogen Peroxide

Quench with Chlorine

UV Reactor




Comparison to PAC:– No increase in solids production

– Smaller footprint

– Able to provide desired 1‐log removal

– Similar lifecycle cost, lower 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 TechnologyTo

ns o

f C02

Equ

ival

ents

UV – Hydrogen Peroxide system selected



Design



Design Criteria

UV Reactors– Max. System Flowrate: 16 MGD

– Min. UVT: 91%

– Min. Geosmin and MIB Reduction: 1‐log

– No. Reactors: Two, each with 8 MGD capacity

– Future use of reactors for disinfection credit

50% Hydrogen peroxide system– Dose: 2 – 10 mg/L

– Storage: 6,500 gallons



UV‐Hydrogen Peroxide Process Integration

Locate UV reactors post filtration

– Increases reactor efficiency

– Most hydraulically feasible



North Clearwell

South Clearwell

Clearwell “C”

EastClearwell

(Filters Above)

Filter Pipe Gallery

UV‐Hydrogen Peroxide Process Integration



North Clearwell

South Clearwell

Clearwell “C”

EastClearwell

UV‐Hydrogen Peroxide Process IntegrationBuried chamber

adjacent to North Clearwell

Chamber in portion of North Clearwell

Adjacent to chemical storage areas



UV Reactor Layout

Adjacent to chemical storage areas

North Clearwell

Flow

Flow



UV Reactor Layout

North Clearwell

Hydrogen Peroxide

NC

Cooling Water Supply UV Reactor

Flow Meter

Chlorine

Cooling Water Return



Piping Design Verification ‐ CFD Modeling



CFD ModelingSymmetrical Diffuser Holes Asymmetrical Diffuser Holes

H2O2 Distribution

Configuration Outlet 1 Outlet 2

Symmetric Holes 52.1% 47.9%

Asymmetric Holes 47.6% 52.4%



Hydrogen Peroxide System Location



Constructed Facilities – UV Reactors



Constructed Facilities – Hydrogen Peroxide



Operation



Operation

UV‐Hydrogen Peroxide effectively removes taste and odor at the Shenango Plant



Summary

UV‐Hydrogen Peroxide System

– Superior Geosmin and MIB removal compared to PAC

– Does not produce residuals

– Lower carbon footprint

– Can be used to provide additional disinfection

– Lifecycle costs can be competitive with PAC



Acknowledgements

Aqua PennsylvaniaMarc Lucca, James Rieben, Craig Lutz, Bill McGinty,

Pete Kusky, Bill Young, Larry Wehr, Jack Walter

Trojan TechnologiesTerry Keep, Neil Brown

Hatch Mott MacDonaldMark Tompeck, Kemal Niksic, Julie Puskar

Treatment Plant: Light on Taste and Odor · Shining a Light on Taste and Odor Margie Gray, PE,...

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