Arsenic Removal with Bayoxide® E33 Ferric Oxide …nysawwa.org/docs/pdfs/7B - Drinking Water is no...
Transcript of Arsenic Removal with Bayoxide® E33 Ferric Oxide …nysawwa.org/docs/pdfs/7B - Drinking Water is no...
Arsenic Removal withBayoxide® E33 Ferric Oxide Media
& SORB 33® As Adsorption
Frank StanishSevern Trent Services, Inc.
AWWA New York ConferenceSaratoga Springs, NY
April 15, 2015
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Agenda
Background on arsenic Arsenic Toxicity Sources of arsenic Arsenic in Water Arsenic Regulations Arsenic Treatment Methods Case Study Problem and Solution:
Hilltown Township Arsenic Removal Project
Frequently Asked Questions
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Arsenic Background
Natural occurring metalloid element Atomic Symbol: As Atomic number: 33 Atomic Weight: 74.92
Arsenic Toxicity
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USEPA Group A Human Carcinogen Short-term (acute) and long-term (chronic) effects Skin, lung and bladder cancer Acute GI damage Cardiac problems Vomiting / Diarrhea Dehydration Partial paralysis / blindness Hemolysis Vertigo Shock / Death
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Arsenic Chemistry
“Oxidized” As(V) Oxyanion DissociationH3AsO4 H2AsO4
- + H+ pKs = 2.2
H2AsO4- HAsO4
2- + H+ pKs = 6.9
HAsO42- AsO4
3- + H+ pKs = 11.5
“Reduced” As(III) Oxyanion DissociationH3AsO3 H2AsO3
- + H+ pH 6 - 8
In waters within a natural pH range, the following species are present:
H3AsO3, H2AsO3-, H2AsO4
- & HAsO42-
As(III) occurs mainly under reducing conditions, e.g., in the absence of oxygen.When this water comes in contact with air, As(III) is oxidized to As(V).
Arsenic found in ground waters is normally in an inorganic form as a soluble oxyanion species. It has 2 valence states, As(III) and As(V).
Arsenic Sources in US Drinking Water
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USEPA Arsenic Rule & Severn Trent’s Role
Timeline - Lower Potable Water Arsenic LevelsCurrent Limit in 1990’s - 50 g/L1993 WHO Recommends 10 g/L1994 USEPA Recommends 2-20 g/L2000 New EC Directive 2003 UK Adopts 10 g/L Standard2006 USEPA Compliance for 10 g/L MCL
Severn Trent WaterSevern Trent Services’ Sister Company in the UK16 Well Water Sites with As > 10 g/LTotal Treatment Capacity - 46.8 MGD (177 ML/Day) since 2003
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As Removal – Treatment Selection
Adsorption Simple & non-regenerative in most cases Single step process for most applications
Coagulation/Filtration Cost effective for large scale systems (over 4 MGD) Effective for high Fe/Mn waters No chemicals besides disinfection if Fe/As wgt ratio > 25
Reverse Osmosis Effective if other TDS must be removed Won’t remove As(III)
Ion Exchange Good for waters with high As & pH and low SO4 & HCO3
Hybrid resins with impregnated Fe Oxide – Selective for As Requires regeneration/postreatment; won’t remove As(III)
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SORB 33® Adsorption with Bayoxide® E33 Media
SORB 33® - Severn Trent’s Adsorption Process STS & Lanxess Partnered to Develop Granular Ferric Oxide
(GFO) Media for As Removal Lanxess: Large Technical Oxide Producer Specialists in Iron Oxide Technologies Bayoxide® E33 (GFO) - Adsorption Media Exclusive Agreement between STS & Lanxess NSF Standard 61 Approved
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Adsorption - SORB 33® Systems
Water Flows through a bed of media Pros
Easy Operation Little automation Simple Maintenance Not complex Lowest Capital Commonly lowest O&M
Cons Complex Waters with multi
contaminants Causes low bed volumes
Most accepted technology Majority of projects in US have
selected adsorption
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Adsorption - SORB 33® Systems
Loma Linda, CAFour 14’-Ø Adsorbers
3,000 gpm
Bernallilo, NMFour 4’-Ø Adsorbers
450 gpm
Adsorptive Media Pilot Testing – 3rd Party Breakthrough Curves – determine best performance 4 different medias tested at Mesa, AZ by DSWA
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B ed V olum e vs. A rsen ic
0
5
10
15
20
25
30
35
0 10,000 20,000 30 ,000 40,000 50,000 60 ,000
B ed V olu m es
Ars
enic
, ppb
A verage InfluentW R T Z33G FHSolm etex A sX npB ayox ide E 33
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Test Evaluation – Breakthrough Curves
0
10
20
30
40
0 25,000 50,000 75,000 100,000 125,000 150,000
Con
cent
ratio
n (μ
g/L)
Bed Volumes of Water Treated (BV’s)
Typical SORB 33® Arsenic Adsorption Curve
TreatedWater As
Influent As
As MCL As Breakthrough
6 Mos 12 Mos 18 MosTime (based on 75% Use Factor):
0
10
20
30
40
0 25,000 50,000 75,000 100,000 125,000 150,000
Con
cent
ratio
n (μ
g/L)
Bed Volumes of Water Treated (BV’s)
Typical SORB 33® Arsenic Adsorption Curve
TreatedWater As
Influent As
As MCL As Breakthrough
6 Mos 12 Mos 18 MosTime (based on 75% Use Factor):
Breakthrough Curve Measures Media Performance - Longevity Arsenic effluent levels vs volume treated (“BV’s” or gallons H2O/cu ft of media) As Breakthrough – Point at which media needs replacement The higher the BV’s to breakthrough, the lower the operating cost
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On-site Pilot Test Program
MediaDrain
VentV-11
B’wash Discharge
PDI
Efflu
ent/M
edia
Bac
kwas
hMedia
Support
BackwashSample
Treated WaterSample/Drain
E33 FeedSample
P-01
P-04
P-02
S-06
S-08
S-07
E33GFO
Media
PG
P-09
TreatedWater
OrBackwashEffluent
B’wash Supply
FQI FI
Pres
Reg
’rR
ate
Set
WellWater
P-01
P-03
FI/FQI
P-04
P-02
Rate Set
P-03
MediaDrain
VentV-11
B’wash Discharge
PDI
Efflu
ent/M
edia
Bac
kwas
hMedia
Support
BackwashSample
Treated WaterSample/Drain
E33 FeedSample
P-01
P-04
P-02
S-06
S-08
S-07
E33GFO
Media
PG
P-09
TreatedWater
OrBackwashEffluent
B’wash Supply
FQI FI
Pres
Reg
’rR
ate
Set
WellWater
P-01
P-03
FI/FQI
P-04
P-02
Rate Set
P-03
MediaDrain
VentV-11
B’wash Discharge
PDI
Efflu
ent/M
edia
Bac
kwas
hMedia
Support
BackwashSample
Treated WaterSample/Drain
E33 FeedSample
P-01
P-04
P-02
S-06
S-08
S-07
E33GFO
Media
E33GFO
Media
PG
P-09
TreatedWater
OrBackwashEffluent
B’wash Supply
FQI FI
Pres
Reg
’rPr
es R
eg’r
Rat
e Se
tR
ate
Set
WellWater
P-01
P-03
FI/FQI
P-04
P-02
Rate Set
P-03
Program Scope
Test Protocol
4”- Clear Column with Media
Manual Valves
Simple Instruments
Consistent Water Supply
Data Collection & Monitor
Weekly Sampling
2-6 Month Program
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Coagulation / Filtration - Omni-SORB™ Media Product Composition
5% Manganese Dioxide (MnO2) impregnated quartz (sand)
Non-porous blackish gray “catalytic” filtration media
Dense media – 88 lb/ft3
Screen Size – 18 x 60 mesh Dustless – facilitates backwash
Producer Fermavi (Brazil) – Mines rich MnO2 ore, refines into product
Media Life – 9+ Years; Disposable as nonhazardous waste
Service Conditions Filtration rates of 7-10 gpm/ft2
Backwash rates of 14-16 gpm/ft2
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Coagulation / Filtration Iron Removal
Removes Fe and Mn Removal As/Fe/Mn
Needs high Iron level Fe:As - 25:1 or better
As/Fe/Mn or Fe/Mn Catalyze the Fe and Mn in
an oxidation/precipitation process
Coagulation / Filtration of Fe oxide & Mn oxide
Ferric chloride addition if needed
As adsorbed by Fe oxide Backwash
Coagulation / Filtration - Omni-SORB™ Media
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Omni-SORB Systems Parallel Flow Filters Automated Valves Process Controls & PLC
Rozel, KS – 600 gpmFe & Mn RemovalThree 6’-Ø Filters
Houghton, NY – 700 gpmAs Coag FiltrationFour 7’-Ø FiltersN+1 Redundancy
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Application Inquiry toFull Scale System …Step 1
Site Qualification Form Complete & Submit Client & Contact Info Flows, contaminants &
concentrationsSevern Trent Analysis Conceptualize
Design Flexibility
Budget Proposal Budget Capital Budget O&M
Water Quality
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Characterization Key to Design Site Qualify Form’s analytical table highlights key species
Key Species Arsenic (As, g/L) – Bypass if As <25; Series if As >25 pH (no units) – Use CO2 or Acid to adjust if water pH >8.0 and/or high
SiO2
Phosphate (PO4 or P mg/L) – Consumes media capacity; Use Omni-SORB if PO4 > 0.8 (0.3 mg/L as P)
Silica (SiO2, mg/L) – Coats media above 40; use pH adjust Iron (Fe, mg/L) – If Fe >0.2, As is reduced; chlorination required; If Fe
>0.35, consider Omni-SORB Manganese (Mn, mg/L) – If Mn >0.06, Mn buildup in bed, makes
backwash difficult; chlorination required; Omni-SORB pretreat Vanadium (V, g/L) – Consumes media capacity; pH adjust helps
reduce its effect
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Sizing & EstimateSummary …Adsorption Example
Process Sizes System Vessel Size Media Volume Performance – BV’s, etc. Flows Configuration Operating Costs: Includes
annualized media replace & chemicals
Proposals Estimates Cost ROM or Budget
Rough Order of Magnitude Issue to Client
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Media Replacement & DisposalMedia Removal STS subcontractors Vacuum removal or
vactor truck Fill rolloffs or sacks TCLP analysis – verify
media is non-hazardousMedia Replacement Gravity fill - 52 ft3 sacks Hydraulic fill -
eductors
Aqua Pennsylvania SiteRoof Hatch Added for Gravity Fill30 Minute Fill - 52 ft³ per Vessel
Roof Hatch Added
Case Study – Hilltown Township, PA
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Hilltown Township Well No. 2Hybrid Fe/Mn Filtration & As Adsorption
Well No. 3 – 300 gpm Multiple Contaminants
Arsenic – 15 µg/L Iron – 250 µg/L Manganese – 110 µg/L
Aside from As removal, needed to remove Fe & Mn Black & red water issue
Hybrid design – 1 OmniSORB filter & 2 E33 Adsorbers Oxidize & filter all of the water to remove Fe & Mn Treat 50% of filtered water through adsorption Bypass and blend remainder
System in service for 9 years Bayoxide E33 lasted 7 years before replacement Severn Trent Services 23
Hilltown TownshipHybrid Fe/Mn Filtration & As Adsorption
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www.severntrentservices.com
Severn Trent Water Purification, Inc.Gary M. Lohse, P.E. – Regional Sales Manager3000 Advance LaneColmar, PA 18915
T: +1 215 859-3814E: [email protected]
Questions?Acknowledgements:
Gary Weaver - PrincipalCastle Valley Consultants, Inc.10 Beulah Road215 348 [email protected]