peracetic acid for disinfection of municipal wastewater...

Water Environment Association of Texas

Peracetic Acid for Disinfection of Municipal Wastewater

Effluent Dr. Carl Linden, University of Colorado Part 1: PAA Fundamentals

Dr. Allegra da Silva, Stantec Part 2: PAA Current Regulatory Status & Issues

Part 3: WERF LIFT PAA Study Update

Webinar and CEU sheet can be found at:

http://www.weat.org/peraceticacidwebinar.shtml

Dr. Michael J. Watts, Garver Part 4: Case Study #1: Pilot Testing of PAA with UV Disinfection at Little Rock, AR

Sarah Stewart, CDM-Smith Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running

Leonard Levine, Gulf Coast Authority Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running


Michael Watts, Garver Moderator

Webinar, slides, and CEU sheet can be found at:



Effluent


Part 1: Peracetic Acid (PAA) Fundamentals

Dr. Carl Linden

University of Colorado


Part 1 Agenda

• PAA Chemistry and Composition

• Inactivation of Indicator Organisms

• PAA Residuals and Effluent Quality

• PAA Residuals and Aquatic Life

• PAA Compatibility

• Benefits of PAA


Major Classes of Disinfectants Applied for WW Treatment

Halogen-releasing

• Cl2

• HOCl

• OCl-

Peroxygens

• H2O2

• O3

• CH3COOOH Peracetic Acid

Ultraviolet

• LP

• LPHO

• Amalgam

• MP


WW market is still dominated by halogen-releasing chlorine

Chlorination

UV

Ozone

WRRFS 7 Facilities

Hypo or Gas 2009 WEF Survey of WRRF Disinfection Strategies (>4,000 facilities in U.S.)


With limited market share, why so much talk about peroxygens like PAA?

Peracetic Acid (PAA)

Inherently Safer

Stable Bulk Solutions

Low-Cost, Fast Retrofits

No Halogenated DBPs


PAA solutions are an equilibrium mixture of H2O2 and PAA

H2O2 + CH3COOH ↔ CH3COO-OH + H2O

Chemical Typical

Composition

Peroxyacetic Acid (PAA) >5%

Acetic Acid >7%

H2O2 >20%

PAA

Up to 22%


PAA is a colorless liquid, at low pH (<3), with a pungent odor

Most frequent application is

surface disinfection in medical and food

industries


When free of impurities (reducing agent, metals), PAA is stable for up to 1 year

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Lbs/

gal

Months

Stored in original tote, or clean bulk tank

Typical 15% solution

<2% loss in strength


Unlike Cl2, low instantaneous PAA demand has been observed in secondary effluent

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PA

A R

esid

ua

l, m

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Contact Time, min.

Test No. 1 (HACH) Test No. 2 (HACH) Test No. 2 (I-2020)

Test No. 3 (HACH) Test No. 3 (I-2020)


PAA is an effective biocide for E. coli

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uct

ion

of

E. C

oli

(-

log

N/N

0)

PAA CT (mg-min/L)

20 to 30 min of contact time with a final 1 mg/L PAA residual

Batch reactor trials with tertiary effluent


A 2016 NYC DEP study found that PAA is less effective for enterococci inactivation compared to Fecal Coliform

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Chlorine PAA

Ave

rage

CT

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mp

lian

ce, m

g-m

in/L

Fecal Coliform Enterococcus


Normalizing for other effects, PAA adds 0.9 to 1 ppm of BOD5 per ppm of PAA


If PAA residuals are relatively sturdy what effects do they have in receiving water body?

Effluent

Sample

15% PAA

PAA+Effluent

Lab

Water

0%, 31%, 41%,

55%, 74%, 98%

Serial Dilutions

Modified EPA Method 1000

C. dubia P. promelas


C.dubia shows significant sensitivity to residual PAA

Organism Survival Reproduction

C. dubia

No Effect Conc. 31% 0%

Lowest Observed Effect Conc. 41% 31%

Survival Growth

P. promelas

No Effect Conc. 98% 98%

Lowest Observed Effect Conc. -- --

Equates to a final PAA conc. of ~0.3 mg/L

Dilutions in tertiary effluent


Resolution on PAA toxicity required. . . however, in general . . .

Discharge to WW-dominated Streams

PAA Quenching Likely (e.g., Sodium Bisulfite)

Surface-spreading, Rapid Infiltration, or Ocean Discharge

PAA Quenching Unlikely


Part 2: PAA Current Regulatory Status & Issues

Dr. Allegra da Silva

Stantec


Interest in PAA

• Criteria for halogenated DBPs are becoming increasingly more stringent – PAA doesn’t form these – PAA low aquatic toxicity, relative to chlorine

• Safety of handling toxic gases including chlorine and sulfur dioxide – No Risk Management Plan (RMP)

• Low capital cost for chlorine retrofit – May not require quenching – Cheaper than capital cost to convert to UV

• Cost effective for difficult to treat wastewaters • Long shelf-life


Typical Path to PAA

Bench test

Pilot test Full-scale

trial Change permit

Install & start up

Photos courtesy of PeroxyChem


PAA in Texas

Bench test


trial Change permit

Install & start up

Photos courtesy of PeroxyChem

Marshall Fort Worth North Texas Dallas Austin El Paso

Gulf Coast Waste Disposal Authority (Pasadena, TX)

Industrial effluent

Trinity River Authority


Chlorine Retrofit: Weighing chemical costs

1. PAA

2. Quenching agent

1. SHC

2. Ammonia

3. Quenching agent


Chlorine retrofit: weighing the chemical costs

Bench test


trial Change permit

Install & start up

1. PAA

2. Quenching agent

1. SHC

2. Ammonia

3. Quenching agent


Regulatory Status and Issues Current USEPA approved PAA products


What goes in a permit

Bench test


trial Change permit

Install & start up

Residual limit pH BOD/cBOD/COD WET testing


Regulatory Status and Issues TCEQ standing on use of PAA


Regulatory Status and Issues TCEQ process – implementation of innovative technology

• Application

• Administrative Review – Notice of Receipt of Application and Intent to

Obtain Permit is published after the application is declared

administratively complete

• Technical Review – if the application is complete, staff will proceed a draft

permit, technical summary or fact sheet for the application and public

notice and a Notice of Application and Preliminary Decision is published

• Comments from the Applicant – Review and comment on TCEQ draft;

publish notice of draft permit and provide instructions for public comment

• Public Comments

• Final Action on the Application

• Engineering Review – Plans and specs for innovative technologies shall be

submitted plans along with the summary transmittal letter


Regulatory Status and Issues TCEQ process – lessons from other states/agencies?

State Allowable PAA Residual (ppm)

Alabama 1 mg/L

Arkansas Up to 2 mg/L in trials California Allowing trials and supplemental PAA for underperforming UV systems

Colorado 0.4 mg/L (monthly average) at DF=0; up to 0.7 mg/L as a daily max (trial) Florida 1 mg/L

Georgia 1 mg/L (trials) Illinois 1 mg/L

Iowa 0.7 mg/L Kentucky Per engineer recommendation, generally 1 mg/L Missouri 1 mg/L as a daily maximum, 0.7 mg/L as a monthly average

New Jersey 1 mg/L for trials (under review) Ohio 0.33 mg/L (Steubenville, OH)

Oklahoma 1 mg/L (Guidance published August 2017) Oregon 1 mg/L, requiring monitoring of enteric viruses

Tennessee 0.4 mg/L for low DF; site specific for high DF, up to 2 mg/L Texas Anticipate EPA label requirements (1 mg/L); GCWDA did not reopen permit

BALLAST WATER 0.5 mg/L as PAA per USCG 33 CFR Part 151


Regulatory Status and Issues Current USEPA efforts on PAA

EPA Technical Assessment Report:

Operational Experiences with Peracetic Acid (PAA) for

Disinfection of Municipal Wastewater

• Literature review

• Full-scale experiences

• Implementation strategies

• Technology performance

• Capital and O&M costs

• Lessons learned

• Case studies

States’ Permitting Challenges: How to handle residual with no AWQC How to measure residual PAA with no approved method listed in 40 CFR 136

EPA’s draft is in review; coordinated with:

1. Ongoing $1.3M WE&RF/LIFT 14T16

PAA research

2. WEF PAA guidance document – 2018


WE&RF LIFT 14T16 study update Project team


WE&RF LIFT 14T16 study update Research project objectives

• Document current state of knowledge; identify knowledge gaps – Conduct testing and fill knowledge gaps

– Bench, pilot, full-scale testing

– Peer-reviewed publications

• Specific research questions – What is PAA disinfection efficacy for:

• Fecal and total coliforms

• E. coli and Enterococcus

• Bacteriophage or other viruses

– How does wastewater quality impact PAA efficacy?

– How does PAA effect effluent pH, cBOD, COD, TOC, DO, and solids?

– What effect does PAA-treated effluent have on aquatic life?

– How else can PAA be used in wastewater treatment?

– What is needed to reduce regulatory ambiguity for PAA?


WE&RF LIFT 14T16 study update Project schedule

2016

• Contract start – September 15 • Preliminary Texas utility workshop October 7 • Demonstration pilot reactor testing commences at 4 Texas utilities

2017

• PAA piloting completed, and full-scale demonstrations • Pilot testing of UV+PAA • Data analysis and peer-review publications

2018

• Publication of comprehensive guidance document • Research report summarizing findings


WE&RF LIFT 14T16 study update

• High level overview of study and status of work

Participating Utility Task 4 – Demonstration Testing

Bench Test Pilot -test Full-scale test

PAA Efficacy, Kinetics and Water Quality Impacts

Denver MWRD Norovirus/MS2,

UV+PAA Pilot reactor for E. coli --

Dallas Water Utilities E. coli Pilot reactor for E. coli/WET --

North Texas MWD E. coli Pilot reactor for E. coli/WET --

El Paso Water Utilities E. coli Pilot reactor for E. coli/WET --

Austin Water Utilities E. coli Pilot reactor for E. coli/WET --

Metro Vancouver Langley WWTP -- -- Cold weather; toxicity

City of Memphis Maxson and Stiles WWTPs E. coli E. coli inactivation & DBPs E. coli at Stiles

NYCDEP, Hunts Point WWTP -- FC, Enterococcus, CN --

GCWDA, Washburn Tunnel Enterococcus Enterococcus, DBPs

East Bay MUD FC and Enterococcus -- --

San Francisco PUC FC and Enterococcus Pilot reactor for FC and

Enterococcus/WET --

Napa Sanitation District FC and Enterococcus Pilot reactor for FC and

Enterococcus/WET --

East Bay Dischargers Authority E. coli E. coli inactivation E. coli inactivation

Metro Nashville Dry Creek WWTP -- -- E. coli inactivation

Ft. Worth Village Creek WWTP Biosolids E. coli inactivation --

Secondary Uses of PAA at WWTPs

Gwinnett County FWH WRC FC -- UV+PAA for FC/WET

TRA CRWS WWTP -- E. coli/WET Tertiary filter trial


WE&RF LIFT 14T16 study update Project deliverables

Peer reviewed articles to meet EPA QA/QC data requirements • Overview articles

– State of the knowledge of PAA applications in municipal wastewater disinfection (Texas pilot results; target WER)

– PAA impact on effluent quality, results from bench tests (target WER)

– Economic evaluation of PAA (Texas pilot results; target WE&T)

• Viruses – Murine Norovirus and MS2 Bacteriophage

(ES&T 2017 and J. Environ. Mgt., accepted)

• Toxicity – PAA and ecotoxicity; WET data from field trials (target WS&T)


WE&RF LIFT 14T16 study update Project deliverables, continued

• Methods for measuring and monitoring PAA – A path for EPA 40 CFR 136 status (target WE&T)

Other project deliverables • Economic evaluation tool, spreadsheet tool • Final research report, 12 –16 page practical executive summary of

work, referencing peer reviewed manuscripts from project • WEF Special publication on PAA implementation at municipal WWTP


Looking ahead

[email protected]

PAA is a viable tool in our disinfection toolbox, supplementing our existing options Scientific and regulatory data sharing/ collaboration is critical to success of PAA


Part 4: Case Study #1 – From Pilot to Full Scale with PAA Supplemental Disinfection at

Little Rock, AR

Dr. Michael J. Watts

Garver


The Adams Field Treatment Facility (AFTF) is the largest municipal water reclamation facility in Central Arkansas

Avg. Day Q = 36 MGD


Peak influent flow at Adams Field WRRF is linked with elevated effluent E. coli

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UV Disinfection at

Adams Field WRRF


Suppressed UVT has also affected the plant’s ability to meet effluent coliform limits

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In 2014, LRW faced a key decision. . .

Replace existing UV?

Only 6 years old. . .

Supplement UV with chemical

disinfection?

Effluent permit

contained restrictive TRC limits

What about PAA?


A PAA pilot study was conducted in 2015 to assess the dosing requirements in secondary clarifier effluent that could assist UV in meeting effluent coliform limits


Key Outcomes of the Pilot Study

• PAA CT of 10 mg-min/L: <1000 cfu/100mL

• PAA CT of 20 mg-min/L: <100 cfu/100mL

• 1:1 PAA:DO increase in effluent DO

• Some pH suppression in low alkalinity effluent: ~0.3 pH units in pilot effluent

• ~1:1 PAA:BOD increase in pilot effluent


The encouraging FCB kill in the pilot study led to a full-scale trial (2016-2017)

UV

PAA Feed


Former Cl2 storage area was utilized for PAA storage and feed


New carrier piping was installed for injection of PAA into the clarifier effluent box at AFTF


Full-Scale trial testing with PAA began in 08/2016

Test Parameter

Min. PAA Dose 0.5 mg/L

Max. PAA Dose 1.5 mg/L

Data Collected

Secondary Eff. FCB, cfu/100mL

UV Influent FCB, cfu/100mL

Final Effluent FCB, cfu/100mL

Final Effluent PAA Residual

Effluent UVT, %

No. of UV Channels in Operation

UV Lamps in Operation

Effluent DO, mg/L

Effluent TSS, mg/L

PAA Feed Rate, gal/hr


PAA upstream of UV has assisted LRW in meeting seasonal effluent coliform limits

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10

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1000

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1000000

cfu

/10

0m

L

Sec Eff FCB Pre-UV FCB Final Eff FCB October - April FCB Limit


During this trial period, without PAA, effluent FCB concentrations were ~1-log greater


This ~1-log FCB inactivation is occurring with relatively short PAA contact times

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cfu

/10

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Contact Time, min

Sec Eff FCB Pre-UV FCB


PAA/UV maintained a consistent effluent FCB even with variability in effluent UVT(%)

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lue

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, cfu

/10

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UV

T(%

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UVT(%) FCB with PAA & UV


Short-term PAA decay in good agreement with PAA decay observed during pilot scale treatment

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Photodegradation?


PAA has provided the following benefits as a supplemental disinfectant to UV at Adams Field

PAA has assisted in maintaining consistent effluent FCB even with fluctuating UVT

~1-log additional FCB inactivation due to PAA

• Low initial PAA doses of 1 mg/L (on avg.)

• Short contact times (less than 10 min)


Sequential PAA/UV may not be feasible for WRRF with restrictive effluent BOD limits . . .

Sequential PAA/UV may not be feasible for WRRF with restrictive effluent BOD limits

• ~1:1 PAA Dose:ΔBOD(in effluent)


Acknowledgements

• Walter Collins, LRWRA

• John Thompson, LRWRA

• Jo Anna Brown, LRWRA

• Eric Wassell, LRWRA

• Aaron Stallmann, Garver

• Paul Strickland, Garver


Part 5: Case Study #2 – The First Peracetic Acid Disinfection System in Texas – Up and

Running!

Sarah A. Stewart, P.E. CDM Smith

Leonard Levine, P.E. GCA


GCA Overview

• Created by Legislature 1969

• Initially served Galveston, Harris and Chambers Counties, now all Texas

• No ad valorem taxes

58

Central Lab Pasadena, TX

Washburn Tunnel WWTP Pasadena, TX

Bayport Industrial WWTP Pasadena, TX

Blackhawk Regional WWTP Friendswood, TX

40-Acre Industrial WWTP Texas City Area

Odessa South Industrial WWTP Odessa, TX


Washburn Tunnel • Flow:

– Two trains for a combined flow: • 12 MGD ADF • 43 MGD PHF

• Water Quality Characteristics: – Temperature: Up to 105 degrees F – UVT: 16% – Nitrite up to 28 mg/L

• Permit Requirements: – Effluent Enterococcus: 168 CFU/100 ml as a 30-day

geometric mean – 500 CFU/100 mL Maximum Grab – Chlorine Limit: Non-detect

Washburn Tunnel WWTP Pasadena, TX


Disinfection Evaluation

DISINFECTION ALTERNATIVES

• Chlorination/ Dechlorination

• Chloramination/ Dechlorination

• UV

• Ozone

• PAA

• Ferrate

• Chlorine Dioxide

CRITERIA

• Capital/Operation and Maintenance (O&M) costs

• Performance with Varying Water Quality

• O&M Complexity and Safety

• Equipment Life Expectancy

• Expandability

• Site Impacts

• Electrical Needs versus Current Capacity

• Permitting Effort

60


Pilot Testing • GCA conducted several pilot tests:

– 5 gpm pipe reactor for 3 weeks

– Side-by-side 25 gpm pipe reactors for both chloramination/ dechlorination and PAA


Reasons for Selecting PAA

• Reduced contact time (as compared to chloramination) of 7.5 minutes

• Lower capital cost than chloramination/chlorination disinfection system

• Less variability in dosing than chloramination/chlorination under similar water quality

62


PAA Design Criteria

• Contact time: 7.5 minutes

• Design Doses: 3.5 mg/L average and 8 mg/L peak

• Temporary Quenching System was included

– Retained due to the chlorine effluent limit • PAA gives a false positive in the TRC test if present


Unique Features of the Design

• Value Engineering Session

• Limited Site Availability

• Flow Measurement and Hydraulic Limitations

• PAA Procurement

Construction Trailers

Disinfection Area


PAA Procurement – From Scratch!

• Preconstruction Services – CFD modeling to confirm mixing efficacy – Shop drawings

• Equipment procurement – Feed pumps – Tanks – Controls

• Chemical purchase • System Maintenance (preventive and reactive) • System operations

65


Inner and Outer Asymmetrical Channels

Parshall Flume SBS Contact Area

PAA/ SBS Storage

Disinfection Design Considerations

CFD for Flow Split – CDM Smith CFD for Mixing – PeroxyChem


Construction Methodology

Study Design Bid Construct

Study Design Construct

January 2016

• Permit required operation by January 2016

• Due to schedule limitations, CDM Constructors (CCI) was hired as Construction Manager at Risk (CMAR)

Design – Bid – Build

Design – Build


Construction

• Duration = 14 months (On time!)

• $9.2M budget and constructed for $9.2M (On budget!)


Start Up Period • 6 Month Start-up Period

• Extended sampling through the Contact Basin

• Enterococcus testing interference

• Optimization resulted in $100,000 per year savings in chemical dose

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10

Design PAA Dose

Do

se (

mg/

L)

Average Dose

Maximum Dose


• Selection of the PAA Provider prior to construction was critical

• Close coordination between all parties during construction was crucial to meet schedule and budget.

• Maintenance of plant operations was imperative. – Identifying critical design and construction elements early allowed for the

project to proceed with as little interruption as possible.

• The contact tank design should include a means to address algae control and scum buildup. – Covered top of the basin and coating the interior walls

– As well as adding an opening from which to collect scum.

Lessons Learned


• Start-up testing is vital to confirm dosing requirements and optimize the system. – For Washburn, this resulted in substantial cost savings.

• CFD modelling provided benefits for the asymmetrical basin.

• On-line PAA monitoring equipment did not provide the accuracy needed for process control. – Additional sampling was required to optimize the system.

• PAA interferes with TRC measurements, so make sure that your permit allows for that.

Lessons Learned


Acknowledgements • GCWDA:

– Leonard Levine, Carl Hennigar, Ed Murphree, Daniel Williams, Greg Seay, Phyllis Frank and MANY others

• CDM Smith – Josh Goldman, Janelle Amador, Adam Eaton

– CCI – Luis Tamariz, Rob Monk, Tom Kline

• PeroxyChem – Alberto Garibi and Philip Block

TEAM T – Together E – Everyone A – Achieves M - More



Effluent Dr. Carl Linden, University of Colorado Part 1: PAA Fundamentals

Dr. Kati Bell, Stantec Part 2: PAA Current Regulatory Status & Issues


Webinar and CEU sheet can be found at:


Dr. Michael J. Watts, Garver Part 4: Case Study #1: Pilot Testing of PAA with UV Disinfection at Little Rock, AR

Sarah Stewart, CDM-Smith Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running

Leonard Levine, Gulf Coast Authority Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running


CEU Questions

1. Peracetic acid is an effective disinfectant for E. coli A. True B. False

1. Which of the following is the driver for the use of peracetic

acid for disinfection: A. Safer than chlorine B. More stable than liquid chlorine C. No disinfection by products D. All of the above

2. A dose of 1 mg/L of peracetic acid will approximately add 1 mg/L of BOD to the effluent:

A. True B. False

Webinar, slides, and CEU sheet can be found at:


peracetic acid for disinfection of municipal wastewater...

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