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SPWSTAC 2006
Arsenic Treatment and Monitoring for Small Water
Systems
2006 NGWA Ground Water Summit
J. Mitchell Spear, Charles A. Cole, Yuefeng Xie and Alison Shuler
Penn State Harrisburg
Objectives
• Assist small public water systems better achieving arsenic compliance
Evaluate several arsenic field test kits used for operational monitoring
Perform a demonstration case study on a POU treatment device for removal of arsenic in a small public water system
SPWSTAC 2006
Overview
Arsenic field test kit evaluation
POU Case Study
Community Background
POU Installations
Arsenic Removal Results
POU Costs
Summary
SPWSTAC 2006
Evaluate several commercially available field test kits and determine reliability and applicability to water utilities currently conducting noncompliance arsenic analyses.
Arsenic Test Kits Evaluation
SPWSTAC 2006
Laboratory performance Accuracy Precision Linearity
Operator performance “ease of use”
Methods
SPWSTAC 2006
Field test kits
SPWSTAC 2006
General Characteristics
Test Kit Concentration Intervals Number of Reagents
Test Time (min)
BVC-100 10, 25, 50, 100, 500 2 13
ECO-W10025, 50, 100, 150, 200, 300, 500, 750 4 35
Hach 10, 30, 50, 70, 300, 500 5 40
LaMotte 4, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 100, 140, 160 3 16
Merck 10, 25, 50, 100, 500 2 32
Quick II 1, 2, 2.5, 3, 4, 5, 6, 7, 10, 12, 14, 20, 30, >30, >40, >60, >80, >100 3 16
Trace Detect Continuous 3 10
SPWSTAC 2006
General Characteristics
Test KitSample size
(ml)Unit Price
($ US dollars) Samples per kit $ Cost / test
BVC-100 10 30.00 100 0.30
ECO-W100 10 36.00 100 0.36
Hach 50 106.00 100 1.06
LaMotte250 153.00 50 3.06
Merck 10 69.60 100 0.70
Quick II100 219.99 50 4.40
Trace Detect
50 12,500.00 5000 2.50
SPWSTAC 2006
• US EPA approvedUS EPA approved
•EPA Method 7060A EPA Method 7060A Graphite Furnace Atomic Graphite Furnace Atomic Absorbance (GFAA)Absorbance (GFAA)
SPWSTAC 2006
Reference Method
Laboratory Performance
SPWSTAC 2006
Accuracy and PrecisionAccuracy and Precision
•Traditionally (Method Detection Traditionally (Method Detection Limit)Limit)• Accuracy (percent recovery)Accuracy (percent recovery)
% Recovery = ConcTestKit / % Recovery = ConcTestKit / ConcGFAA * 100ConcGFAA * 100
• Precision (standard deviation)Precision (standard deviation)• Arsenic III, V, III + VArsenic III, V, III + V• ConcentrationConcentration• ReplicatesReplicates
SPWTAC 2006
0
20
40
60
80
100
120
HACH Quick II LaMotte Merck BVC ECO TraceDetect
Pe
rce
nt
Re
co
ve
ry
As III
As V
As III+V
Tap As III + V
Percent Recoveries
SPWSTAC 2006
Linearity5, 10, 25, 50, 75 ug/L
Test Kit Slope Y-intercept
BVC 0.28 - 2.4
ECO 0.66 - 4.1
HACH 0.73 - 6.5
LaMotte 0.85 3.2
Merck 0.56 - 4.1
Quick II 0.77 1.4
Trace Detect 0.90 - 1.5
Operator “Ease of Use”
SPWSTAC 2006
b b
a aa
c
a
0
2
4
6
8
10
BVC-100
ECO-W
100
Hach
LaM
otte
Mer
ck
Quick
II
Trace
Det
ect
"ea
se
of
us
e"
Applications
Routine monitoringPilot testingMonitoring raw water Monitoring removal efficienciesTesting reliability of surrogate analyses
i.e. conductivity on RO devices
Offset required compliance monitoring?
SPWSTAC 2006
Perform POU evaluation to determine arsenic removal efficiency and applicability to small water utilities for centralized management as a potential cost savings technology for achieving compliance.
POU Demonstration
SPWSTAC 2006
BackgroundSystem selection
Mohrsville, PA
Population size 375
Service Connections 125
Production (GPD) 17000
Storage Capacity (Gallons) 125000
Well 1
Disinfectant 12.5% sodium hypochlorite
SPWSTAC 2006
Treatment Design
POU Treatment Design
Sed
imen
t filt
er
GA
C C
artr
idge
Isol
ux M
edia
RawTreated
FlowMeter
SPWTAC 2006
Installations
SPWSTAC 2006
Installations
Licensed Plumber
9 POU units installed
Time Minutes
Average 102
Mode 60
Minimum 35
Maximum 225
SPWSTAC 2006
Initial Results on Arsenic Removal
POU I.D. Raw water (µg/L) Treated water (µg/L)
GFAA Field Test GFAA Field Test
1 20.0 20 <1.5 < 4
2 15.5 18 <1.5 < 4
3 18.8 18 <1.5 < 4
4 17.7 18 <1.5 < 4
5 26.1 20 <1.5 < 4
6 25.9 20 <1.5 < 4
7 25.1 20 <1.5 < 4
8 23.5 18 <1.5 < 4
9 23.8 20 <1.5 < 4
Avg 21.8 19.1 <1.5 < 4
SPWSTAC 2006
Monitoring Results on all POUsby GFAA
SPWSTAC 2006
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Months after installation
Ars
en
ic (
ug
/L)
Raw
Treated
POU Piloting Costs (1st year)Items Dollar amountInstallation 90.00POU system 267.50
T-valve 6.50Housing 95.00
Pre filter (2X/year) 18.00 Carbon Filter (2X/year) 36.00
Isolux™ 70.00 Flow Meter 42.00
Field testing (2X) 6.00Compliance testing 15.00Operation & Maintenance* 0 - 200.00
Total 378.50 - 578.50
POU Annual Cost
Capital Costs $ 2004
Installation 90.00
T-Valve 6.50
Housing 95.00
Flow meter 42.00
Total 233.50
6% for 10 years 317.30
Total (yearly) 31.73
Total (monthly) 2.64
SPWSTAC 2006
Operating Costs $ 2004
Pre-filter 18.00
Carbon filter 36.00
Isolux™ 70.00
Field testing 6.00
Compliance 15.00
O & M 200.00
Total (yearly) 345.00
Total (monthly) 28.75
Total - $31 / unit / month
Management Plan Template
Find Technical Assistance
Community Outreach and Education
POU Vendor Selection
Establishing Control of POU
Determining Service Charges
SPWSTAC 2006
Management Plan Template
Securing Funding
Educate Technicians (install, O&M, etc.)
Ensuring Access
Managing Files and Records
SPWTAC 2006
Conclusions
• Performance varies on arsenic field test kits
• Test Kits can be used for operational monitoring
• POU effective for removing arsenic
• POU may be more economical solution in very small water systems
• POU and field test kits can represent cost saving when appropriately applied
SPWSTAC 2006
Acknowledgements
• US EPA Small Public Water Systems Technology Assistance Center Grant
• Magnesium Elektron, Inc. and Jim Knoll for their technical guidance
• The PA DEP District Office, Alice Renshaw (President of Mohrsville Water Association) and participating homeowners for their cooperation
• Mark Zhou, Ralaene Gabriel, Peng Chen, Mukesh Pratap, Brian Montalbano, Paul Deardorff, and Julia Stiles
• Trace Detect for loan of their instrumentation
SPWSTAC 2006