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Terry KeepNE Ohio Summer Conference
Mansfield, OhioAugust 20, 2015
UV ADVANCED OXIDATION FOR THE TREATMENT OF ALGAE-RELATED TASTE AND ODOUR COMPOUNDS IN DRINKING
WATER
2
UV DISINFECTION FOR DRINKING WATER
• Ultraviolet light (UV) one component in the multiple barrier municipal drinking water treatment train
• Well established technology• An excellent option to achieve additional disinfection • UV’s ability to inactivate many microorganisms, especially
Cryptosporidium and Giardia, without forming DBPs drives growth
3
GROWING APPLICATION OF UV ADVANCED OXIDATION
Indirect Potable Reuse (IPR) Wastewater treated to drinking water quality
Groundwater Remediation Plume containment, site cleanup
Drinking Water Contaminated groundwater or surface water sources, Taste & Odour treatmentTotal Flow Rate for Trojan Municipal UV-Oxidation
Projects in
2000: <40 MLD
2011: ~2.2 BLD
4
WATER STRESS IN AN
INTERCONNECTED WATER SUPPLY
Sources of contaminants in our water supply: - Industrial discharge- Agricultural runoff- Chemical releases- Municipal Wastewater
InjectionWell
ExtractionWell
Nutrients increase in Algae Blooms Taste & Odour, Algal Toxins
5
EXAMPLES OF MICROPOLLUTANTS
Nitrosamines (e.g. NDMA) Disinfection byproducts
Pesticides & Herbicides Metaldehyde, Atrazine, Isoproturon, others
Petroleum Additives Including MTBE
Pharmaceuticals & Personal Care Products Includes potential endocrine disruptors
Taste & Odour CompoundsSeasonal occurrences of MIB, geosmin and others
Algal ToxinsChronic and acute effects from cyanobacteria-derived toxins
6
TASTE & ODOUR, ALGAL TOXINS
Seasonal algae blooms occur in surface watersDecaying algae blooms result in MIB, geosmin, algal toxins, other T&O compoundsEarthy/musty, fishy, swampy, grassy tastes & odours at low ppt concentrationsDifficult to remove with conventional technologiesT&O episodes compromise public confidence in the safety of the water
7
TASTE AND ODOUR TREATMENT STRATEGIES
• Potassium Permanganate– Limited Effectiveness
• Powdered Activated Carbon– Messy PAC & Sludge Handling, no Performance Guarantee
• Granular Activated Carbon– Frequent & Expensive Change-outs, no Performance Guarantee
• Ozone– Complicated System & Carcinogenic by-product (Bromate)
• UV-Oxidation– Simple, Effective for T&O with Simultaneous Disinfection,
Guaranteed Performance for life of system
8
UV / H2O2 FOR TASTE AND ODOUR TREATMENT
UV Advanced Oxidation: Using UV and Hydrogen Peroxide to destroy trace organic contaminants in water by:UV-Photolysis UV-Oxidation
9
UV-PHOTOLYSIS
Chemical bonds arebroken by UV light
10
UV-OXIDATIONHydrogen peroxide
Hydroxylradical
Chemical bonds arebroken by hydroxyl radicals
11
CONTAMINANT DESTRUCTION BALANCE
0.0
1.0
2.0
3.0
4.0
5.0
6.0
NDMA Atrazine Geosmin Microcystin-LR
UV-
Phot
olys
is/U
V-O
xida
tion
Con
trib
utio
n to
Tot
al
Con
tam
inan
t Red
uctio
n (r
elat
ive
to N
DM
A) UV + H2O2
UV Photolysis
APPLICATION OF UV ADVANCED OXIDATION FOR TASTE & ODOUR /
ALGAL TOXIN TREATMENT
13
DUAL-MODE OPERATION
14
UV-OXIDATION A RANGE OF T&O COMPOUNDS
0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
80.0%
90.0%
100.0%
geos
min
2-m
ethy
lisob
orne
ol(2
-MIB
)
dim
ethy
l tris
ulfid
e
cis,
4-h
epta
nal
trans
, tra
ns, 2
,4-
hept
adie
nal
cis-
3-he
xeny
lac
etat
e
Earthy Musty Swampy Fishy Rancid fish Grassy(sweet)
Perc
ent R
emov
al
Performance
Target
15
COMPOUNDS GENERATED BY SOME CYANOBACTERIA
Geosmin
2-Methylisoborneol (MIB)GSM and MIB can be detected by sensitive individual down to 4 ng/L (ppt)
[Geosmin] have been measured > 3000 ng/L
Aesthetics: T&O cmpds
Cylindrospermopsin (CYN)
Microcystin-LR (MC-LR) [MC]~1800ug/L meas drng bloom
Public Health: Cyanotoxins
WHO set li
mit at 1
µg/L
USEPA ad
ded CNTX
to th
e CCL
16
ALGAL TOXINS OXIDIZED MORE EASILY THAN MIB
SYSTEM SIZING
Contaminant Quantum Yield
Contaminant - Hydroxyl Radical Rate Constant
Contaminant Molar Absorption Coefficient
Hydrogen Peroxide Concentration
Water Absorbance (UVT)
Water Matrix Hydroxyl Radical Scavenging Capacity
Lamp Type
SIZING FACTORS FOR ECT SYSTEMS
UV-PHOTOLYSIS AND UV-OXIDATION KINETICS
Hydrogen peroxide
Hydroxylradical
The overall kinetic equation describing the photolytic and UV/H2O2 photo-oxidative reactions of a
micropollutant C is:
][][][(
2][][][
22
300
2000
300
2000
22
2222
SkOHkCkV
FFNCk
V
FFNCk
dtCd
SOHC
OHSOHCCSC
UV-Photolysis UV-Oxidation
Fraction of light absorbed by contaminant, scavengers, and peroxide (fxn of wavelength, dependent on absorbance)
Lamp Spectral Photon Flux
Reaction rates with hydroxyl radical for contaminant (C) and scavengers (S)
Quantum Yield of contaminant and peroxide
Where:22
,, OHSC FFF
0N
k
CASE STUDIES
Aqua PA’s Neshaminy WTP, PennsylvaniaHatch Mott MacDonald Presented at New Jersey, Ohio and Pennsylvania Annual AWWA Conferences 2010
21
Researchers Evaluated the following Treatment Technologies:
•PAC
•GAC
•Ozone
•UV AOP
Aqua PA’s Neshaminy WTP, PennsylvaniaHatch Mott MacDonald Presented at New Jersey, Ohio and Pennsylvania Annual AWWA Conferences 2010
Design Conditions:• Flow rate: 57 MLD, average 40 MLD• Design UVT: 93%• Influent [GSM]: 100ppt• Target effluent [GSM]: 10ppt• 1.0-log GSM treatment at average flow, 0.7 log at peak flow
22
23
Estimates were based on a PAC dose of 30 mg/l and a 90-day taste and odor period
24
Analysis was based on 90 days of taste and odor operation with a discount factor of 4%. Costs include capital, construction, operation and maintenance (including dry solids removal for spent PAC). The PAC costs were based on $0.95 per pound and $215 per ton of dry solids removal and a dose of 30mg/L.
25
Estimates were based on a PAC dose of 30 mg/l and a 90-day taste and odor period. UV-oxidation was also evaluated over the same 90 day taste and odour period.
UV Reactor Chamber
Cooling Water Inlet
Cooling Water Outlet
UV Reactor Chamber
Ballasts
UV Reactor Chamber
Flow Meter
UV Reactor Chamber
UV Reactor UV Reactor
Cooling Water Inlet
Chemical FeedHydrogen Peroxide Tank (50%)
Chemical FeedHydrogen Peroxide Metering Pumps
PATOKA LAKE, IN STUDYMalcolm Pirnie – Presented at the WQTC November 2008
Researchers Evaluated the following Treatment Technologies:
• UV- AOP (8 mg/L)• PAC (30 – 110 mg/L)• GAC (7&15 min EBCT)• Ozone (1.2 - 4.8 mg/L)
Design Conditions:• Flow rate: 15 MGD, average 10 MGD• Design UVT: 93%• Influent [MIB]: 300ppt• Target effluent [MIB]: 5ppt• 1.8-log MIB treatment
PATOKA LAKE, IN STUDYMalcolm Pirnie– Presented at the WQTC November 2008
PERFORMANCE TESTING
Test Description UV (% Power) H2O2
No Treatment NONE NONE
UV Alone 100 NONE
H2O2 Alone NONE 8 ppm
50% UV+H2O2 50 8 ppm
100% UV+H2O2 100 8 ppm
• Treatment Target = 1.5-Log MIB
PERFORMANCE TESTING - RESULTS
0
0.49
0.04
1.41
2.23
0
0.5
1
1.5
2
2.5
Log
Redu
ction
Treatment Target
UV SYSTEM – TWO TRAINS OF THREE REACTORS
PERFORMANCE TESTING - CONCLUSIONS
• Neither UV or H2O2 used independently had the capability of achieving the required treatment target of 1.5-log reduction of MIB
• Combination of UV and H2O2 showed near 1.5-Log removal of MIB when UV functioning at 50% output
• 100% UV output and same H2O2 dose showed over 2-log removal of MIB
• Chlorine quenching used to remove residual H2O2 successfully co-functions as a residual disinfectant
LORNE PARK WATER TREATMENT PLANTRegion of Peel, (Serving Mississauga/Brampton, Ontario, Canada
• Largest UV-oxidation installation for T&O treatment in the world
• Flow rate = 390 MLD
• Both UV-oxidation and ozone technologies were evaluated
• UV-oxidation was ultimately selected due to its:
− Smaller footprint
− Safety (no liquid oxygen required on site)
− No carbon to foul membrane
− Performance Guarantee
LORNE PARK WATER TREATMENT PLANTRegion of Peel, Serving Mississauga/Brampton, Ontario, Canada
• Operates in “disinfection-only” mode for most of the year when T&O events do not occur
– Significant energy savings
• Peroxide dosing can be turned on immediately when an event is detected
• GAC-quenching removes residual peroxide before entering distribution
40
REGIONAL MUNICIPALITY OF WEST ELGIN, ON
Source water is Lake ErieFlow rate 14.4 MLDTreatment train: coagulation/settling membranes UV-oxidation final disinfectionAlgal blooms in late summer/early autumnPreviously used Powder Activated Carbon for T&O (membrane fouling)Designed for 1.3-log Geosmin and 1.0-log MIB, algal toxins
41
REGIONAL MUNICIPALITY OF WEST ELGIN, ON
42
PERFORMANCE RESULTS WEST ELGIN, ONTARIO (APRIL 2009)
PLANTS RECENTLY SELECTING UV-OXIDATION
• Franklin, TN – 4 MGD; 1 log MIB/1.3 log GSM• Patoka Lake, IN, USA – 20 MGD; 1.8-log MIB• Lorne Park, Ontario – 100 MGD; 1.3-log GSM/1.0-log MIB• Groesbeck, TX, USA – 2 MGD; 1.0-log GSM• Waxahachie, TX, USA – 14 MGD; 1.4-log GSM• Mansfield, TX, USA – 7.5 MGD; 1.0-log GSM• Neshaminy & Shenango PA, USA – 15 and 16 MGD, 1 log GSM• Lucerne, CA, USA – 1.0 MGD; 1.3-log GSM• Alliance Ohio, USA – 7 MGD; 1.5 log MIB• Otter Lake Water Commission, Illinois, USA – 1.5 log MIB 5 MGD• Wellborne, TX - 2 MGD; 1.1 log GSM/0.8 log MIB
44
CONCLUSIONS• UV-Oxidation (UV + H2O2) is being implemented worldwide
• UV-Oxidation successfully destroys taste and odor compounds, algal toxins, other micro pollutants
• Performance Guarantee: Guaranteed Removal vs. competitive products
• On/Off technology (no event, no O&M)
• Disinfection design for UVDGM
• Barrier for PPCPs/future regulations
• Excellent option post membrane (no PAC needed)
45
Brady Sessums ETEC
Cell 225-955-2160Work 225-295-1200
QUESTIONS?
THANK YOUTerry Keep
Trojan Technologies(519) 457-3400