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