PA-AWWA 70th Annual Conference
Pocono Manor, PA
Utilization of Mixed Oxidants to Improve Residual& Overall Water Quality in Distribution Systems
May 10, 2018

What are Mixed Oxidants?

Mixed Oxidants are Produced by On-site Generation• On-site generation is when basic, simple chemicals are used to generatechemical at the point of use• In this case, the chemical produced is a chlorine-based disinfectant generatedusing saltWhy Use On-Site Generation?

Safety is One Major Reason
OSG• Regulations• Trend toward the safest solution• Limit on hazardous chemical storage• Incidents• Recent near miss of Cl2 leak at twolarge industrial facilities South East US• Chlorine dioxide related fatalities: GMplant in 2014, Midland TX Oilfield 2016

• Sustainability• Less trucks, lower carbon footprint• Water conservation, less chemicals

Operational Cost is Another…
To produce 1 lb of 100% Free Available Chlorine
equivalent to 1 gallons of 12.5% hypoSalt$0.30 +
3 lbs salt at $0.10/lbs (or delivered brine)Electricity

Operational Cost

$0.18 =
2.5 kW-hr power at $0.07/kW-hr

MIOXCost~$0.50

Equivalent to 1 gallon of delivered
12.5% sodium hypochlorite~$0.10 addt’l including parts
maintenance

Equivalent Operational Cost
12.5% Sodium Hypochlorite $0.65 ~ $2.50

Chlorine Gas$0.40 ~ $.75

and Performance is the Third• Mixed Oxidants outperform typical bleach generators by providing enhanced
behaviorsFuture Challenges - Chlorate• Chlorate (ClO3-) is on the EPA’s Third Chemical Contaminant List(CCL3)• indicating that the intention of the Environmental Protection Agency (EPA)
to review chlorate as a potential candidate for regulation under the Safe
Drinking Water Act.

• Chlorate is suspected to have negative health impacts such as
thyroid issues, reduced hemoglobin production, and reduced
weight gain.
• Chlorate is a highly oxidized form of chlorine, can be introduced toa water source as an industrial or agricultural contaminant or intoa finished water as a disinfection byproduct (DBP).
• As a DBP, chlorate can result from water disinfection with bulk
sodium hypochlorite, chlorine dioxide, or hypochlorite formed
through electrolytic on-site generation (OSG) systems.
8Future Challenges - Chlorate• Currently, chlorate in drinking water is not regulated in the UnitedStates and there is no enforceable Maximum Contaminant Limit(MCL).
o Canada MCL is 1.0 mg/L (1000µg/L).
o The World Health Organization (WHO) recommends a chlorate limit of 0.7
mg/L (700 µg/L)• While no final recommendation has been promulgated, literatureon the topic indicated that the regulation may fall within the rangeof 0.21 mg/L (210 µg/L) to 0.8 mg/L (800 µg/L) in the US.
• While 210 µg/L as established by the EPA as a health reference
level, it is conjectured that the EPA will not establish such a low
level as it will seriously impact the viability of using delivered bulk
hypochlorite in the marketplace.

9Chlorate Impacts on Bulk Hypochlorite• To limit chlorate formation, users of bulk hypochlorite may needto:o Move storage indoor, if not already located there.
o Cool the room where the hypochlorite is stored to retard degradation.
o Require “born-on dating” from the manufacturers to ensure freshness.
o Limit storage volumes.
o Purchasing lower concentrations to slow the degradation.
o Dilute the concentrated hypochlorite once it has been delivered to thetreatment plant.

• All of these will have significant cost impacts!!!!!

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“Future Proof” Against Chlorate with OSG• Testing shows MIOX’s RIO OSG systems typically produce less than
40 micrograms per milligram of free available chlorine (FAC).
• Even at a high FAC dose of 5 mg/L, the expected chlorate
concentration in the treated water will be less than 200 µg/L.
• Water treatment plants usually dose 2 – 3 mg/L FAC so chlorate
content will likely be half of the lowest contemplated chlorateregulatory limit.
• Generated on-site – always fresh.
• Less than 1% chlorine concentration = very slow degradation rate.
• Modular in natureo as regulations change, upgrades are simple and easy to implement.

11How Does It Work?

Typical Process FlowHYPO HYPOCHLORITEMOS HYPO + PEROXIDE

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Cell Reactions••••

Anode Primary Reaction (+ Side): 2 Cl- → Cl2 + 2 eCathode Reaction (- Side): 2 H2O + 2 e- → H2↑ + 2 OHChlorine Hydrolysis Reaction: Cl2 + H2O → HOCl + Cl- + H+HOCl Equilibrium Reaction: HOCl ↔ OCl- + H+ (depends on pH)
If you stop here, you have a hypochlorite generator…

Cell Reactions••••

Anode Primary Reaction (+ Side): 2 Cl- → Cl2 + 2 eCathode Reaction (- Side): 2 H2O + 2 e- → H2↑ + 2 OHChlorine Hydrolysis Reaction: Cl2 + H2O → HOCl + Cl- + H+
HOCl Equilibrium Reaction: HOCl ↔ OCl- + H+ (depends on pH)
If you stop here, you have a hypochlorite generator…
…But if you add more power…

Cell Reactions••••

Anode Primary Reaction (+ Side): 2 Cl- → Cl2 + 2 eCathode Reaction (- Side): 2 H2O + 2 e- → H2↑ + 2 OHChlorine Hydrolysis Reaction: Cl2 + H2O → HOCl + Cl- + H+HOCl Equilibrium Reaction: HOCl ↔ OCl- + H+ (depends on pH)
If you stop here, you have a hypochlorite generator…
…But if you add more power…

• Anode Secondary Reaction (+ Side): 2 OH- → H2O2 + 2 e-Performance and Benefits of Mixed OxidantsMunicipal Water Treatment• The peroxide component in Mixed Oxidant Solution (MOS) enhances theperformance of the chlorine• Superior microorganism inactivation• Control/Eliminate biofilm• Reduced coagulant consumption• Longer-lasting residual• Reduced formation of DBPs, AOX• Accelerated breakpoint chlorination - Improved taste and odor
• Cost effective removal of Ammonia and Sulfides• Faster oxidation of manganeseMunicipal Water Treatment• The peroxide component in Mixed Oxidant Solution (MOS) enhances theperformance of the chlorine• Superior microorganism inactivation• Control/Eliminate biofilm• Reduced coagulant consumption• Longer-lasting residual• Reduced formation of DBPs, AOX• Accelerated breakpoint chlorination - Improved taste and odor
• Cost effective removal of Ammonia and Sulfides• Faster oxidation of manganese••

Produces more powerful disinfectant than Hypochlorite
More power is derived from Hydrogen Peroxide in solution with Hypochlorite in 24-48 hrs

Superior Disinfection Indicates Chemistry is Different

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Biofilm Creates Multiple Challenges• Acts as an oxidant demand (consumes chlorine)• Provides an additional carbon source• Therefore - High chlorine + more organics = DBP troubles

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Why is Biofilm so Hard to Control?
• Bacteria secrete it for several reasons• Helps transport nutrients to the organisms• Helps transport waste from the organisms• Protects the organisms from adverse environmental conditions• Example: Chlorine!!!

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Biofilm Harbors Legionella & Corrosion
Biofilm Harbors Organisms

Microbially Influenced Corrosion (MIC)

Although Hypochlorite and otherproprietary biocides inactivates
Legionella, it cannot inactivate
Legionella in the Biofilm

Pitting corrosion on 316S
stainless steel** Montana State University, Center of Biofilm Engineering (MSU-CB)

Where MOS Fits In
Typical Drinking Water Treatment Facility Layout

1234



Control/Eliminate biofilm

Reduce Demand  Reduce Dosage  Reduce DBPsLonger-lasting residual

Accelerated breakpoint chlorination - Improved taste and odor



Reduced coagulant consumption

1.
2.
3.
4.

Pre-oxidation
MF/UF Pre-feed
Clean in Place (CIP)
Final Disinfection

Biofilm Removal Across Many Applications
PipingPool

Condenser

Frac Pond

Gravity Filter

Hot TubCooling

HVAC
Cost

SafetyControlCASE STUDY
Spa in Japan previously using Bulk Hypochlorite 1.5
mg/L had Legionella cases. In 5 hours of Mixed
Oxidant solution biofilm started sloughing22 days
BEFORE MOSAFTER MOS

Extensive biofilm► Legionella CFU >5► Dose: 1.5 mg/L Hypo
► Residual: 0.2 mg/L►

Biofilm eliminated► No bacterial hits
► Dose: 0.6 mg/L Hypo
► Residual: 0.4 mg/L

CASE STUDY
A city in Texas was using Gas Chlorine wherebrown biofilm slime on pipes in distribution
system commonly noticed.
1 Year
BEFORE MOSAFTER MOS►

Distance from
Treatment Plant:
200 feetDistance from
Treatment Plant:
1/2 mileLower Disinfection Byproduct Formation

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Reduced Dose + Higher residuals

Disinfection By-Product Formation Reduction• DBP troubleshooting can help identify if MOS makes sense…

Surface
SourceMix/Floc/ClarFiltration
Clearwell

Distribution

Disinfection By-Product Formation Reduction• DBP troubleshooting can help identify way forward…
If High DBPs are measured
prior to Distribution System,
Improved pretreatment may
help

Surface
SourceMix/Floc/Clar

Filtration
Clearwell

Distribution

Microflocculation Effect May Improve Organic Matter
Reduction and Reduce Coagulant Cost
• Effect can improve removal and settleability at a lower effective dose
• Enhanced DOC removal can lead to lower formation potentialReduce Coagulant Usage by up to 40%

Disinfection By-Product Formation Reduction• DBP troubleshooting can help identify way forward…
If High DBPs are measured
prior to Distribution System,
Improved pretreatment mayhelp

Surface
SourceMix/Floc/Clar

If High DBPs are formingin Distribution System,
consider Mixed Oxidants

Filtration
ClearwellDistribution

Some Additional Testing Can Help Decide
DBP Formation Potential (DBPFP) can help tell you what is going on:• This would be done on the filtered water before the clearwell orstorage. This should be timed to emulate the distribution timing
expected during the worst DBP formation times of the year. For
example, if you have calculated that the distribution system hasa residence time of 24 hours at the test point, the DBPFP test
should have a hold time of 24 hours.
• This should then also be compared to the actual DBPs as
measured at the test point.
• Ideally, you will take a sample at your testing point after thesame residence time, so that you are comparing roughly thesame water.

Some Additional Testing Can Help Decide
DBP Formation Potential (DBPFP) can help tell you what is going on:
Scenario 1
If the DBPFP is say 40 ppb, but the sample from the furthest test
location is 100 ppb, then you know the distribution system isstrongly contributing to the formation.
This is usually due to the presence of biofilm in the distribution
system acting as an additional carbon source. In this case, this is atextbook case of where MOS can be of significant value.

Some Additional Testing Can Help Decide
DBP Formation Potential (DBPFP) can help tell you what is going on:
Scenario 2
If the DBPFP is high, say 85 ppb, and the sample at the furthest
point is something like 90 ppb, then the distribution system ispretty clean.
Therefore more focus should be given to improving thepretreatment to reduce the DBP precursors coming through thewater treatment plant.

Some Additional Testing Can Help Decide
DBP Formation Potential (DBPFP) can help tell you what is going on:
Scenario 3
If the DBPFP is high, say 85 ppb, and the sample returns atsomething like 125 ppb, then you know that both the precursors
and the distribution system are contributing to the problem andboth areas should be targeted for improvement – once again, andideal case where MOS could be used.

Case Studies

Paducah Water, Paducah, KY
Contact: Ricky Gilbert, Plant Superintendent

Plant Capacity: 20 MGD
System: (3) RIO M5 SC (900#FAC/day)Prior Disinfection: Chlorine Gas
Installation Date: February 2015
Source Water: Surface
Application: Pretreatment
Final Disinfection
Benefits: Safety, TTHM reduction,
chlorine residual enhancement,
They no longer re-chlorinate at four (4)booster stations in their distribution
since switching to MOSPrestonsburg Utility Commission, KY
Contact: Donald Compton,
WTP/WWTP Manager
Plant Capacity: 5 MGD
System: MIOX- 5001 (2004)
RIO-M5 SC (2014) & RIO-S M900
(2018)
Total Capacity: 1200# FAC/day
Prior Disinfection: Chlorine Gas
Installation Date: August 2004
System Upgrades: 2014, 2018
Source Water: Surface
Application: Pretreatment, Final
Disinfection
Benefits: Safety, TTHM reduction,
chlorine residual enhancement

Danville WTP, Danville, KY
Contact: Andy Tompkins,WTP Superintendent
Plant Capacity: 10 MGD
System: (3) RIO-M5 SC (900#FAC/day)Prior Disinfection: Chlorine Gas
Installation Date: Legacy MIOX units initiallyinstalled in 2002 were replaced in 2016 & 17
Source Water: Surface
Application: Pretreatment, Final Disinfection
Benefits: Safety, Reduced Liability, TTHM
reduction, chlorine residual enhancement,
They no longer re-chlorinate at five (5)booster stations in their distribution systemsince switching to MOS

Holiday Hills WTP
Holiday Hills WTP
Crossville, TN
System: Two (2) RIO-M3
Total Capacity: 360 #FAC/day
Installation Date: July 2008
Applications: Surface Water
Final Disinfection, DBP Reduction,
Chlorine Residual Improvement
50% reduction in TTHM & HAA
after first year in operation.
The original MIOX system wasinstalled in 2000 & upgraded to
RIO units in 2008

Laguna Beach County Water District
Summit Reservoir (600K gallons)Hastie Reservoir (1.95 M gal)
Laguna Beach, CA
System: One (1) VAULT M15
Total Capacity: 15 #FAC/day
Installation Date: March 2016
Source Water: Purchased Surface
Applications: Reservoir ResidualManagement; DBP Reduction,
Chlorine Residual Improvement,
Residual Stability
District has reported that water quality
improved & residual benefits have extended toother reservoirs in system.

MIOX Wide Range of GeneratorsHYPOCHLORITEMOS (HYPO + PEROXIDE)
1 to 2000 lb/day per generator

RIO Zuni

AE Series

Potable Water
Pools & Spas
Dairy Farms
Waste Water

200 People
10,000-----toVAULT------------------

to--------------- 10 Million

1 M Gallons

100 ---- to ---- 5000 Milk Cows

1,000 Gallons

Produced Water-------- to

0.5 ------ toFrack/Flood Water
Cooling Tower

RIO-S

RIO

----------------

100 MGD

5 MGD

10 to 100 Barrels / Minute
50 Tons-------to--------

200,000 GPM

Mobile TrailerThank You for Your Time…..............
Questions?

Bob Newton
Senior Director Global Municipal Business(215) 272-8966 (Mobile)robert.newton@matthey.com

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