EPA/600/R-09/014
February 2009
Arsenic Removal from Drinking Water by Adsorptive Media
U.S. EPA Demonstration Project at Taos, NM
Final Performance Evaluation Report
by
Abraham S.C. Chen
H. Tien Shiao
Lili Wang
Battelle
Columbus, OH 43201-2693
Contract No. 68-C-00-185
Task Order No. 0029
for
Thomas J. Sorg
Task Order Manager
Water Supply and Water Resources Division
National Risk Management Research Laboratory
Cincinnati, Ohio 45268
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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DISCLAIMER
The work reported in this document was funded by the United States Environmental Protection Agency
(EPA) under Task Order 0029 of Contract 68-C-00-185 to Battelle. It has been subjected to the Agency's
peer and administrative reviews and has been approved for publication as an EPA document. Any
opinions expressed in this paper are those of the author(s) and do not, necessarily, reflect the official
positions and policies of the EPA. Any mention of products or trade names does not constitute
recommendation for use by the EPA.
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FOREWORD
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the nation's
land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to
formulate and implement actions leading to a compatible balance between human activities and the ability
of natural systems to support and nurture life. To meet this mandate, EPA's research program is
providing data and technical support for solving environmental problems today and building a science
knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect
our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for investigation
of technological and management approaches for preventing and reducing risks from pollution that
threaten human health and the environment. The focus of the Laboratory's research program is on
methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and sub-
surface resources; protection of water quality in public water systems; remediation of contaminated sites,
sediments and groundwater; prevention and control of indoor air pollution; and restoration of ecosystems.
NRMRL collaborates with both public and private sector partners to foster technologies that reduce the
cost of compliance and to anticipate emerging problems. NRMRL's research provides solutions to envi-
ronmental problems by developing and promoting technologies that protect and improve the environment;
advancing scientific and engineering information to support regulatory and policy decisions; and provid-
ing the technical support and information transfer to ensure implementation of environmental regulations
and strategies at the national, state, and community levels.
This publication has been produced as part of the Laboratory's strategic long-term research plan.
It is published and made available by EPA's Office of Research and Development to assist the user
community and to link researchers with their clients.
Sally Gutierrez, Director
National Risk Management Research Laboratory
in
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ABSTRACT
This report documents the activities performed and the results obtained for the EPA arsenic removal
technology demonstration project at the Town of Taos in New Mexico. The main objective of the project
was to evaluate the effectiveness of Severn Trent Services' (STS) SORB 33™ adsorptive media in
removing arsenic to meet the maximum contaminant level (MCL) of 10 |o,g/L. Additionally, this project
evaluated 1) the reliability of the treatment system for use at small water facilities, 2) the required system
operation and maintenance (O&M) and operator skill levels, and 3) the capital and O&M cost of the
technology. The project also characterizes water in the distribution system and residuals generated by the
treatment process. The types of data collected include system operation, water quality, process residuals,
and capital and O&M cost.
The STS system consisted of a carbon dioxide (CO2) pH control system and three 63-in-diameter, 86-in-
tall fiberglass reinforced plastic (FRP) vessels in parallel configuration, each designed for approximately
60 ft3 of SORB 33™ pelletized media. The media is an iron-based adsorptive media developed by Bayer
AG and packaged under the name SORB 33™ by STS. The system was designed for a flowrate of 450
gal/min (gpm) (or 150 gpm to each vessel), corresponding to an empty bed contact time (EBCT) of about
3.0 min and a hydraulic loading rate of 6.9 gpm/ft2. The actual amount of media loaded based on
freeboard measurements was 216 ft3 (or 72 ftVvessel), thus resulting in a longer EBCT of 3.2 min even at
a higher flowrate of 503 gpm.
Upon approval of engineering plans by the New Mexico Environment Department/Drinking Water
Bureau (NMED/DWB) and completion of a pipeline project by the Town of Taos, the APU-450 treatment
system began operating on February 14, 2006. From February 14, 2006 through October 23, 2007, the
treatment system operated for only 215 days, with an average daily operating time of only 3.9 hr.
Frequent and prolonged system downtime occurred during the performance evaluation study, caused
primarily by non-system-related issues, such as power outages and facility pipeline leakage. Because the
treatment system and booster pump station were not integrated with the Town's system control and data
acquisition (SCADA) system, the operator had to manually operate the system. The labor intensive
nature of system operations also contributed to the fewer and shorter daily runs. The system treated
approximately 22,977,000 gal of water, or 14,192 bed volumes (BV), which was only 11% of the vendor-
estimated working capacity for the SORB 33™ media. Because the system was far from reaching the
treatment target of 10 (ig/L after about 20 months of operation, a decision was made to discontinue the
performance evaluation study.
Source water supplied by Well 8 had an average total arsenic concentration of 16.9 |o,g/L with soluble
As(V) as the predominating species at 16.8 (ig/L (on average). pH values of source water were high,
ranging from 9.5 to 9.8 and averaging 9.6. After some troubleshooting, the pH control system effectively
reduced pH values of the water entering the treatment system to 7.3 to 7.4, close to the target value of 7.2.
The automatic pH control system used a JUMO pFi/Proportional Integral Derivative (PID) to regulate
CO2 gas flow with signals received from an inline pH probe. CO2 gas was injected to a side stream of
water with a microporous membrane module housed in a sanitary cross.
During the performance evaluation study, total arsenic was reduced to an average of less than 1 (ig/L,
except for the one spike at 7.4, 7.2, and 8.8 (ig/L at the TA, TB, and TC sampling locations, respectively.
The exact cause of the spike was unknown. Little or no iron or manganese was measured in raw water
and system effluent.
Comparison of the distribution system sampling results before and after the system startup showed no
significant differences in concentrations of arsenic and other analytes. This was because the treated Well
IV
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8 water contributed only 10% of the capacity in a 1,000,000-gal water tower, from which water was
distributed either directly to the distribution sytem or indirectly through a 500,000-gal storage tower.
Backwash wastewater was sampled three times during the performance evaluation study. pH values
ranged from 7.4 to 8.1 and averaged 7.7, somewhat higher than that of the treated water used for
backwash. The water used for backwash was withdrawn from a 50,000-gal holding tank. Some CO2
degassing likely took place during storage and transit, thereby elevating the pH values. As expected, total
suspended solids (TSS) values were low, ranging from 16 to 82 mg/L and averaging 37 mg/L.
Concentrations of total arsenic, iron, and manganese ranged from 1.1 to 11.8 |o,g/L, from 0.14 to 8.9 mg/L,
and from 0.7 to 64.0 |o,g/L, respectively, with the majority of iron and manganese existing in the
particulate form. The unexpectedly high iron concentrations in the backwash wastewater might have
been media fines produced during the backwashing process.
The capital investment for the system was $296,644 consisting of $202,685 for equipment, $32,750 for
site engineering, and $61,209 for installation, shakedown, and startup. Using the system's rated capacity
of 450 gpm (or 648,000 gal/day [gpd]), the capital cost was $659/gpm (or $0.46/gpd) of design capacity.
This calculation does not include the cost of the building to house the treatment system.
The O&M included only incremental costs associated with media replacement and disposal, CO2 supply,
electricity, and labor. Although not replaced, the media changeout cost was estimated to be $41,749 for
all three adsorption vessels, which would represent the majority of the O&M cost. CO2 cost was
$0.29/1,000 gal of water treated, most of the CO2 cost was for the lease of four 380-lb dewars and two 50-
Ib back-up cylinders.
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CONTENTS
DISCLAIMER ii
FOREWORD iii
ABSTRACT iv
APPENDICES vii
FIGURES vii
TABLES vii
ABBREVIATIONS AND ACRONYMS ix
ACKNOWLEDGMENTS xi
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Treatment Technologies for Arsenic Removal 2
1.3 Project Objectives 2
2.0 SUMMARY AND CONCLUSIONS 5
3.0 MATERIALS AND METHODS 6
3.1 General Project Approach 6
3.2 System O&M and Cost Data Collection 7
3.3 Sample Collection Procedures and Schedules 7
3.3.1 Source Water 10
3.3.2 Treatment Plant Water 10
3.3.3 Backwash Water 10
3.3.4 Distribution System Water 10
3.3.5 Residual Solids 11
3.4 Sampling Logistics 11
3.4.1 Preparation of Arsenic Speciation Kits 11
3.4.2 Preparation of Sample Coolers 11
3.4.3 Sample Shipping and Handling 11
3.5 Analytical Procedures 11
4.0 RESULTS AND DISCUSSION 13
4.1 Site Description 13
4.1.1 Preexisting Facility 13
4.1.2 Source Water Quality 17
4.1.3 Treated Water Quality 20
4.1.4 Distribution System and Regulatory Monitoring 20
4.2 Treatment Process Description 20
4.3 Treatment System Installation 29
4.3.1 System Permitting 29
4.3.2 Building Construction 29
4.3.3 System Installation, Shakedown, and Startup 31
4.3.3. CO2 pH Control System 32
4.3.4 Media Loading 34
4.3.5 Punch List Items 35
4.4 System Operation 35
4.4.1 Operational Parameters 35
4.4.2 Residual Management 39
VI
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4.4.3 Reliability and Simplicity of Operation 39
4.5 System Performance 41
4.5.1 Treatment Plant Sampling 41
4.5.2 Backwash Water Sampling 47
4.5.3 Distribution System Water Sampling 49
4.6 System Cost 49
4.6.1 Capital Cost 49
4.6.2 Operation and Maintenance Cost 51
5.0 REFERENCES 54
APPENDICES
APPENDIX A: OPERATIONAL DATA A-l
APPENDIX B: ANALYTICAL DATA TABLES B-l
FIGURES
Figure 3-1. Process Flow Diagram and Sampling Schedule and Locations 9
Figure 4-1. Well 8 Wellhead with Pump House in Background 14
Figure 4-2. Inside of Well 8 Pump House 14
Figure 4-3. Holding Pond for Raw Water Discharge During Initial Purge 15
Figure 4-4. Inside of Preexisting Water Treatment Building with Unused Sand Filtration
Vessel 15
Figure 4-5. Modified Treatment Building/Booster Pump Station 16
Figure 4-6. A 50,000-Gal Holding Tank on Hill 16
Figure 4-7. Evaporative Pond for Backwash Wastewater Discharge 17
Figure 4-8. Photograph of APU-450 Arsenic Removal System 22
Figure 4-9. Schematic of STS's APU-450 Arsenic Removal System 23
Figure 4-10. Process Diagram of CO2 pH Adjustment System 25
Figure 4-11. pH/PID Control Panel 26
Figure 4-12. Carbon Dioxide Gas Flow Control System for pH Adjustment 26
Figure 4-13. Process Diagram of MIOX SAL-80 System 28
Figure 4-14. Modified Booster Pump Station 29
Figure 4-15. Removal of Treatment Building Side Wall Panel for APU-45 0 System Off-loading 30
Figure 4-16. Arrival of SORB 33™ Media in Super Sacks 31
Figure 4-17. Media Loading 34
Figure 4.18. System Operation Pressure 38
Figure 4-19. Concentrations of Various Arsenic Species at IN, AP, and TT Sampling Locations 45
Figure 4-20. Total Arsenic Breakthrough Curves 46
Figure 4-21. pH Values Measured throughout Treatment Train 47
Figure 4-22. Media Replacement and Operation and Maintenance Cost 53
TABLES
Table 1 -1. Summary of Round 1 and Round 2 Arsenic Removal Demonstration Sites 3
Table 3-1. Predemonstration Study Activities and Completion Dates 6
Table 3-2. Evaluation Objectives and Supporting Data Collection Activities 7
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Table 3-3. Sampling Schedule and Analyses 8
Table 4-1. Raw Water Quality Data for Town of Taos 18
Table 4-2. NMED/DWB Treated Water Quality Data for Taos, NM 19
Table 4-3. Physical and Chemical Properties of SORB 33™ Media 21
Table 4-4. Design Specifications for STS APU-450 System 24
Table 4-5. Properties of Celgard, X50-215 Microporous Hollow Fiber Membrane 27
Table 4-6. Onsite Backwash and Hydraulic Testing on December 7, 2005 32
Table 4-7. Summary of Problems Encountered and Corrective Actions Taken For pH
Adjustment System 33
Table 4-8. Freeboard Measurements and Media Volumes in Adsorption Vessels 35
Table 4-9. System Inspection Punch-List Items 36
Table 4-10. Summary of APU-450 System Operations 37
Table 4-11. System Instantaneous and Calculated Flowrates 37
Table 4-12. Summary of System Downtimes 40
Table 4-13. Summary of Analytical Results for Arsenic, Iron, and Manganese 42
Table 4-14. Summary of Other Water Quality Sampling Results 43
Table 4-15. Backwash Water Sampling Results 48
Table 4-16. Distribution Water Sampling Results 50
Table 4-17. Capital Investment Cost for APU-450 System 51
Table 4-18. Operation and Maintenance Cost for APU-450 System 52
Vlll
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ABBREVIATIONS AND ACRONYMS
Ap differential pressure
AAL American Analytical Laboratories
Al aluminum
AM adsorptive media
APU arsenic package unit
As arsenic
ATSI Applied Technology Systems, Inc.
ATS Aquatic Treatment Systems
AWWA American Water Works Association
BET Brunauer, Emmett, and Teller
bgs below ground surface
BV bed volume(s)
Ca calcium
C/F coagulation/filtration
Cl chlorine
CO2 carbon dioxide
CRF capital recovery factor
Cu copper
DBFs disinfection by-products
DO dissolved oxygen
DWB Drinking Water Bureau
EBCT empty bed contact time
EPA U.S. Environmental Protection Agency
F fluoride
Fe iron
FedEx Federal Express
FRP fiberglass reinforced plastic
gpd gallons per day
gpm gallons per minute
HIX hybrid ion exchanger
HOPE high-density polyethylene
hp horsepower
ICP-MS inductively coupled plasma-mass spectrometry
ID identification
ISFET Ion Sensitive Field Effect Transistor
IX ion exchange
LCR (EPA) Lead and Copper Rule
IX
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MCL maximum contaminant level
MDL method detection limit
MEI Magnesium Elektron, Inc.
MIOX mixed oxidants
Mg magnesium
Mn manganese
Na sodium
NA not analyzed
NMED New Mexico Environmental Department
NS not sampled
NSF NSF International
NTU nephlemetric turbidity units
O&M operation and maintenance
OIT Oregon Institute of Technology
ORD Office of Research and Development
ORP oxidation-reduction potential
P phosphorus
PID Proportional Integral Derivative
Pb lead
psi pounds per square inch
PLC programmable logic controller
PPE personal protective equipment
PO4 phosphate
POU point-of-use
PVC polyvinyl chloride
QA quality assurance
QA/QC quality assurance/quality control
QAPP Quality Assurance Project Plan
RPD relative percent difference
RO reverse osmosis
Sb antimony
SCADA system control and data acquisition
SDWA Safe Drinking Water Act
SiO2 silica
SMCL secondary maximum contaminant level
SO4 sulfate
STS Severn Trent Services
TBD to be determined
TCLP Toxicity Characteristic Leaching Procedure
TDS total dissolved solids
TOC total organic carbon
TSS total suspended solids
V
vanadium
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ACKNOWLEDGMENTS
The authors wish to extend their sincere appreciation to the system operator, Mr. Amos Torres of the
Town of Taos in New Mexico. Mr. Torres monitored the treatment system and collected samples from
the treatment and distribution systems on a regular schedule throughout this study period. This
performance evaluation would not have been possible without his support and dedication.
Ms. Tien Shiao, who is currently pursuing a Master's degree at Yale University, was the Battelle Study
Lead for this demonstration project.
XI
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1.0 INTRODUCTION
1.1 Background
The Safe Drinking Water Act (SDWA) mandates that the U.S. Environmental Protection Agency (EPA)
identify and regulate drinking water contaminants that may have adverse human health effects and that
are known or anticipated to occur in public water supply systems. In 1975 under the SDWA, EPA
established a maximum contaminant level (MCL) for arsenic at 0.05 mg/L. Amended in 1996, the
SDWA required that EPA develop an arsenic (As) research strategy and publish a proposal to revise the
arsenic MCL by January 2000. On January 18, 2001, EPA finalized the arsenic MCL at 0.01 mg/L (EPA,
2001). In order to clarify the implementation of the original rule, EPA revised the rule text on March 25,
2003 to express the MCL as 0.010 mg/L (10 (ig/L) (EPA, 2003). The final rule requires all community
and non-transient, non-community water systems to comply with the new standard by January 23, 2006.
In October 2001, EPA announced an initiative for additional research and development of cost-effective
technologies to help small community water systems (<10,000 customers) meet the new arsenic standard
and to provide technical assistance to operators of small systems in order to reduce compliance costs. As
part of this Arsenic Rule Implementation Research Program, EPA's Office of Research and Development
(ORD) proposed a project to conduct a series of full-scale, onsite demonstrations of arsenic removal
technologies, process modifications, and engineering approaches applicable to small systems. Shortly
thereafter, an announcement was published in the Federal Register requesting water utilities interested in
participating in Round 1 of this EPA-sponsored demonstration program to provide information on their
water systems. In June 2002, EPA selected 17 out of 115 sites to host the demonstration studies.
In September 2002, EPA solicited proposals from engineering firms and vendors for cost-effective arsenic
removal treatment technologies for the 17 host sites. EPA received 70 technical proposals for the 17 host
sites, with each site receiving one to six proposals. In April 2003, an independent technical panel
reviewed the proposals and provided its recommendations to EPA on the technologies that it determined
were acceptable for the demonstration at each site. Because of funding limitations and other technical
reasons, only 12 of the 17 sites were selected for the demonstration project. Using the information
provided by the review panel, EPA, in cooperation with the host sites and the drinking water programs of
the respective states, selected one technical proposal for each site.
In 2003, EPA initiated Round 2 arsenic technology demonstration projects that were partially funded with
Congressional add-on funding to the EPA budget. In June 2003, EPA selected 32 potential demonstration
sites and the community water system at the Town of Taos in New Mexico was one of them.
In September 2003, EPA again solicited proposals from engineering firms and vendors for arsenic
removal technologies. EPA received 148 technical proposals for the 32 host sites, with each site
receiving from two to eight proposals. In April 2004, another technical panel was convened by EPA to
review the proposals and provide recommendations to EPA with the number of proposals per site ranging
from none (for two sites) to a maximum of four. The final selection of the treatment technology at the
sites that received at least one proposal was made, again through a joint effort by EPA, the state
regulators, and the host site. Since then, four sites have withdrawn from the demonstration program,
reducing the number of sites to 28. Severn Trent Service's (STS) SORB 33™ Arsenic Removal
Technology was selected for demonstration at the Town of Taos.
As of December 2008, 39 of the 40 systems were operational and the performance evaluation of 32
systems was completed.
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1.2 Treatment Technologies for Arsenic Removal
The technologies selected for the Round 1 and Round 2 demonstration host sites include 25 adsorptive
media (AM) systems (the Oregon Institute of Technology [OIT] site has three AM systems), 13
coagulation/filtration (C/F) systems, two ion exchange (IX) systems, and 17 point-of-use (POU) units
(including nine under-the-sink reverse osmosis [RO] units at the Sunset Ranch Development site and
eight AM units at the OIT site), and one system modification. Table 1-1 summarizes the locations,
technologies, vendors, system flowrates, and key source water quality parameters (including As, iron
[Fe], and pH) at the 40 demonstration sites. An overview of the technology selection and system design
for the 12 Round 1 demonstration sites and the associated capital cost is provided in two EPA reports
(Wang et al., 2004; Chen et al., 2004), which are posted on the EPA website at
http://www.epa.gov/ORD/NRMRL/wswrd/dw/arsenic/index.html.
1.3 Project Objectives
The objective of the Round 1 and Round 2 arsenic demonstration program is to conduct 40 full-scale
arsenic treatment technology demonstration studies on the removal of arsenic from drinking water
supplies. The specific objectives are to:
• Evaluate the performance of the arsenic removal technologies for use on small
systems.
• Determine the required system operation and maintenance (O&M) and operator
skill levels.
• Characterize process residuals produced by the technologies.
• Determine the capital and O&M cost of the technologies.
This report summarizes the performance of STS's arsenic removal system at the Town of Taos in New
Mexico from February 14, 2006, to October 23, 2007. The types of data collected included system
operation, water quality (both across the treatment train and in the distribution system), residuals, and
capital and O&M cost.
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Table 1-1. Summary of Round 1 and Round 2 Arsenic Removal Demonstration Sites
Demonstration
Location
Site Name
Technology (Media)
Vendor
Design
Flow rate
(gpm)
Source Water Quality
As
(ug/L)
Fe
(ug/L)
PH
(S.U.)
Northeast/Ohio
Wales, ME
Bow, NH
Goffstown, NH
Rollinsford, NH
Dummerston, VT
Felton, DE
Stevensville, MD
Houghton, NY(cl)
Newark, OH
Springfield, OH
Springbrook Mobile Home Park
White Rock Water Company
Orchard Highlands Subdivision
Rollinsford Water and Sewer District
Charette Mobile Home Park
Town of Felton
Queen Anne's County
Town of Caneadea
Buckeye Lake Head Start Building
Chateau Estates Mobile Home Park
AM (A/I Complex)
AM (G2)
AM (E33)
AM (E33)
AM (A/I Complex)
C/F (Macrolite)
AM(E33)
C/F (Macrolite)
AM (ARM 200)
AM(E33)
ATS
ADI
AdEdge
AdEdge
ATS
Kinetico
STS
Kinetico
Kinetico
AdEdge
14
70(b)
10
100
22
375
300
550
10
250W
38W
39
33
36W
30
30W
19W
27W
15W
25W
<25
<25
<25
46
<25
48
270W
l,806(c)
1,312W
1,61 5W
8.6
7.7
6.9
8.2
7.9
8.2
7.3
7.6
7.6
7.3
Great Lakes/Interior Plains
Brown City, MI
Pentwater, MI
Sandusky, MI
Delavan, WI
Greenville, WI
Climax, MN
Sabin, MN
Sauk Centre, MN
Stewart, MN
Lidgerwood, ND
City of Brown City
Village of Pentwater
City of Sandusky
Vintage on the Ponds
Town of Greenville
City of Climax
City of Sabin
Big Sauk Lake Mobile Home Park
City of Stewart
City of Lidgerwood
AM(E33)
C/F (Macrolite)
C/F (Aeralater)
C/F (Macrolite)
C/F (Macrolite)
C/F (Macrolite)
C/F (Macrolite)
C/F (Macrolite)
C/F&AM (E33)
Process Modification
STS
Kinetico
Siemens
Kinetico
Kinetico
Kinetico
Kinetico
Kinetico
AdEdge
Kinetico
640
400
340(e)
40
375
140
250
20
250
250
14W
13(a)
16W
20W
17
39W
34
25W
42W
146W
127W
466W
l,387(c)
l,499(c)
7827(c)
546W
1,470W
3,078(c)
1,344W
l,325(c)
7.3
6.9
6.9
7.5
7.3
7.4
7.3
7.1
7.7
7.2
Midwest/Southwest
Amaudville, LA
Alvin, TX
Bruni, TX
Wellman, TX
Anthony, NM
Nambe Pueblo, NM
Taos, NM
Rimrock, AZ
Tohono O'odham
Nation, AZ
Valley Vista, AZ
United Water Systems
Oak Manor Municipal Utility District
Webb Consolidated Independent School
District
City of Wellman
Desert Sands Mutual Domestic Water
Consumers Association
Nambe Pueblo Tribe
Town of Taos
Arizona Water Company
Tohono O'odham Utility Authority
Arizona Water Company
C/F (Macrolite)
AM (E33)
AM (E33)
AM(E33)
AM (E33)
AM (E33)
AM(E33)
AM(E33)
AM (E33)
AM (AAFS50/ARM 200)
Kinetico
STS
AdEdge
AdEdge
STS
AdEdge
STS
AdEdge
AdEdge
Kinetico
770(e)
150
40
100
320
145
450
90(b)
50
37
35(a)
19W
56(a)
45
23(a)
33
14
50
32
41
2,068(c)
95
<25
<25
39
<25
59
170
<25
<25
7.0
7.8
8.0
7.7
7.7
8.5
9.5
7.2
8.2
7.8
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Table 1-1. Summary of Round 1 and Round 2 Arsenic Removal Demonstration Sites (Continued)
Demonstration
Location
Site Name
Technology (Media)
Vendor
Design
Flowrate
(gpm)
Source Water Quality
As
(ug/L)
Fe
(Mg/L)
PH
(S.U.)
Far West
Three Forks, MT
Fruitland, ID
Homedale, ID
Okanogan, WA
Klamath Falls, OR
Vale, OR
Reno, NV
Susanville, CA
Lake Isabella, CA
Tehachapi, CA
City of Three Forks
City of Fruitland
Sunset Ranch Development
City of Okanogan
Oregon Institute of Technology
City of Vale
South Truckee Meadows General
Improvement District
Richmond School District
Upper Bodfish Well Cffi-A
Golden Hills Community Service District
C/F (Macrolite)
IX (A300E)
POU RO(1)
C/F (Electromedia-I)
POE AM (Adsorbsia/ARM 200/ArsenXnp)
and POU AM (ARM 200)(g)
IX (Arsenex II)
AM (GFH/Kemiron)
AM (A/I Complex)
AM (HDQ
AM (Isolux)
Kinetico
Kinetico
Kinetico
Filtronics
Kinetico
Kinetico
Siemens
ATS
VEETech
MEI
250
250
75gpd
750
60/60/30
525
350
12
50
150
64
44
52
18
33
17
39
37W
35
15
<25
<25
134
69w
<25
<25
<25
125
125
<25
7.5
7.4
7.5
8.0
7.9
7.5
7.4
7.5
7.5
6.9
AM = adsorptive media process; C/F = coagulation/filtration; HTX = hybrid ion exchanger; IX = ion exchange process; RO = reverse osmosis
ATS = Aquatic Treatment Systems; MEI = Magnesium Elektron, Inc.; STS = Severn Trent Services
(a) Arsenic existing mostly as As(III).
(b) Design flowrate reduced by 50% due to system reconfiguration from parallel to series operation.
(c) Iron existing mostly as Fe(II).
(d) Withdrawn from program in 2007.
(e) Facilities upgraded systems in Springfield, OH from 150 to 250 gpm, Sandusky, MI from 210 to 340 gpm, and Amaudville, LA from 385 to 770 gpm.
(f) Including nine residential units.
(g) Including eight under-the-sink units.
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2.0 SUMMARY AND CONCLUSIONS
The performance evaluation of STS's APU-450 treatment system at the Town of Taos in New Mexico
was conducted during February 14, 2006, through October 23, 2007. Based on the information collected
during the course of the study, the following summary and conclusions were made relating to the overall
project objectives:
Performance of the arsenic removal technology for use on small systems:
• The Carbon Dioxide Gas Flow Control System was effective at consistently reducing raw
water pH values to levels close to the target value of 7.2. However, some troubleshooting
was required during system shakedown.
• SORB 33™ media effectively removed arsenic to below 10 |o,g/L during the performance
evalution study. Because of limited use of the treatment system, it treated only less than
14,200 bed volumes (BV) (or 22,977,000 gal) of water.
• Backwash was not necessary to operate the system. Backwash was performed five times,
primarily for the study purpose.
Required system O&Mand operator skill levels:
• The daily demand on the operator's time was reasonable, typically about 40 min/day to
visually inspect the system and record operational parameters. Extra time was needed from
the operator to help troubleshoot the carbon dioxide pH control system and, to a less extent,
the arsenic treatment system.
• Frequent and prolonged system downtime was observed; it was caused primarily by non-
system related issues, such as power outages and transmission line leakage.
Characteristics of residuals produced by the technology:
• A relatively small quantity of solids (i.e., 4 Ib), was produced during each backwash event,
which produced over 12,000 gal of wastewater. Arsenic constituted only a fraction of the
solids (i.e., 4 x 10"4 Ib). Most iron discharged might have come from media fines.
Capital and O&M cost of the technology:
• The capital investment for the system was $296,644, including $202,685 for equipment,
$32,750 for site engineering, and $61,209 for installation, shakedown, and startup. Using the
system's rated capacity of 450 gal/min (gpm) (or 648,000 gal/day [gpd]), the capital cost was
$659/gpm (or $0.46/gpd) of design capacity. This calculation does not include the cost of the
building to house the treatment system.
• The estimated media changeout cost for all three adsorption vessels was $41,749, which
represents the majority of the O&M cost. Media changeout did not occur during the
performance evaluation period.
-------
3.0 MATERIALS AND METHODS
3.1
General Project Approach
Following the predemonstration activities summarized in Table 3-1, the performance evaluation study of
the STS treatment system began on February 14, 2006. Table 3-2 summarizes the types of data collected
and considered as part of the technology evaluation process. The overall system performance was
evaluated based on its ability to consistently remove arsenic to below the target MCL of 10 |o,g/L through
the collection of water samples across the treatment train. The reliability of the system was evaluated by
tracking the unscheduled system downtime and frequency and extent of repair and replacement. The
unscheduled downtime and repair information were recorded by the plant operator on a Repair and
Maintenance Log Sheet.
Table 3-1. Predemonstration Study Activities and Completion Dates
Activity
Introductory Meeting Held
Project Planning Meeting Held
Final Letter of Understanding Issued
Request for Quotation Issued to Vendor
Vendor Quotation Received
Purchase Order Established
Engineering Package Submitted to NMED
Letter Report Issued
Approval Granted by NMED
System Delivered to Site
Study Plan Issued
System Installation Completed
System Shakedown Completed
Performance Evaluation Begun
Performance Evaluation Completed
Date
December 1, 2004
March 7, 2005
March 24, 2005
March 28, 2005
April 29, 2005
May 12, 2005
June 24, 2005
August 19, 2005
September 12, 2005
October 3, 2005
November 2, 2005
December 8, 2005
February 3, 2006
February 14, 2006
October 23, 2007
NMED = New Mexico Environment Department
The O&M and operator skill requirements were evaluated based on a combination of quantitative data
and qualitative considerations, including the need for pre- and/or post-treatment, level of system
automation, extent of preventative maintenance activities, frequency of chemical and/or media handling
and inventory, and general knowledge needed for relevant chemical processes and related health and
safety practices. The staffing requirements for the system operation were recorded on an Operator Labor
Hour Log Sheet.
The quantity of aqueous and solid residuals generated was estimated by tracking the volume of backwash
wastewater produced during each backwash cycle. Backwash wastewater was sampled and analyzed for
chemical characteristics.
The cost of the system was evaluated based on the capital cost per gpm or gpd of design capacity and the
O&M cost per 1,000 gal of water treated. This task required tracking the capital cost for equipment, site
engineering, and installation, as well as the O&M cost for chemical supply, electricity consumption, and
labor.
-------
Table 3-2. Evaluation Objectives and Supporting Data Collection Activities
Evaluation Objective
Performance
Reliability
System O&M and Operator
Skill Requirements
Residual Management
System Cost
Data Collection
-Ability to consistently meet 10 ug/L arsenic MCL in treated water
-Unscheduled system downtime
-Frequency and extent of repairs including a description of problems,
materials and supplies needed, and associated labor and cost
-Pre- and post-treatment requirements
-Level of automation for system operation and data collection
-Staffing requirements including number of operators and laborers
-Task analysis of preventative maintenance including number, frequency,
and complexity of tasks
-Chemical handling and inventory requirements
-General knowledge needed for relevant chemical processes and health and
safety practices
-Quantity and characteristics of aqueous and solid residuals generated
-Capital cost for equipment, engineering, and installation
-O&M cost for chemical usage, electricity consumption, and labor
3.2
System O&M and Cost Data Collection
The plant operator performed daily, weekly, and monthly system O&M and data collection according to
instructions provided by the vendor and Battelle. On a daily basis (with the exception of Saturdays and
Sundays), the plant operator recorded system operational data, such as pressure, flowrate, totalizer, and
hour meter readings, and the pH control system's operational data, such as CO2 application flowrate,
pressure, and inline pH readings on a Daily System Operation Log Sheet. The operator also conducted
visual inspections to ensure normal system operations. If any problem occurred, the plant operator
contacted the Battelle Study Lead, who determined if the arsenic removal system and/or pH control
system vendors should be contacted for troubleshooting. The plant operator recorded all relevant
information, including the problems encountered, course of actions taken, materials and supplies used,
and associated cost and labor incurred, on a Repair and Maintenance Log Sheet. On a weekly basis, the
plant operator measured several water quality parameters onsite, including temperature, pH, dissolved
oxygen (DO), oxidation-reduction potential (ORP), and recorded the data on an Onsite Water Quality
Parameters Log Sheet. Monthly (or as needed) backwash data were recorded on a Backwash Log Sheet.
The capital cost for the arsenic removal system consisted of the cost for equipment, site engineering, and
system installation. The O&M cost consisted of the cost for chemical (including CO2) usage, electricity
consumption and labor. CO2 consumption by the pH control system was tracked on the Daily System
Operation Log Sheet. Electricity usage was estimated from utility bills. Labor for various activities, such
as routine system O&M, troubleshooting and repairs, and demonstration-related work, were tracked using
an Operator Labor Hour Log Sheet. The routine system O&M included activities, such as completing
field logs, replacing CO2 gas dewars, ordering supplies, performing system inspections, and others as
recommended by the vendor. The labor for demonstration-related work, including activities, such as
performing field measurements, collecting and shipping samples, and communicating with the Battelle
Study Lead and the vendors, was recorded, but not used for the cost analysis.
3.3
Sample Collection Procedures and Schedules
To evaluate system performance, samples were collected at the wellhead, across the treatment system,
during system backwash, and from the distribution system. The sample types and locations, number of
samples taken, and analytes measured during each sampling event are listed in Table 3-3.
-------
Table 3-3. Sampling Schedule and Analyses
Sample
Type
Source
Water
Treatment
Plant Water
Backwash
Water
Distribution
System
Water
Residual
Solids
Sample
Locations
IN
IN, AP, TT
IN, AP, TA, TO,
TC
Backwash
Discharge Line
from Each Vessel
to an Evaporative
Pond
Three LCR
Locations
Spent Media
No. of
Samples
1
3
5
3
3
NA
Frequency
Once
(during
initial site
V1S1)
Monthly
(first week
four-week
referred to
as
speciation
week)
Monthly
(third week
of each
four-week
cycle or
regular
week)
Monthly or
as needed
Monthly
NA
Analytes
Onsite: pH, temperature,
DO, and ORP
Off-site: As(III), As(V),
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble),
Ra (total and soluble)
U (total and soluble),
V (total and soluble),
Na, Ca, Mg, Cl, F, NO3,
NO2, NH3, SO4, SiO2,
PO4, turbidity, alkalinity,
TDS, andTOC
Onsite: pH, temperature,
DO, and ORP
Off-site: As(III), As(V),
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble),
Ca, Mg, F, NO3, SO4,
SiO2, P, turbidity, and
alkalinity
Onsite: pH, temperature,
DO, and ORP
Off-site: As (total),
Fe (total), Mn (total),
SiO2, P, turbidity, and
alkalinity
As (total and soluble),
Fe (total and soluble),
Mn(total and soluble),
pH, TDS, andTSS
As (total), Fe (total), Mn
(total), Cu (total), Pb
(total), pH, and alkalinity
TCLP and total Al, As,
Ca, Cd, Cu, Fe, Mg, Mn,
Ni, P, Pb, Si, and Zn
Collection
Date(s)
12/01/04
See Appendix B
See Appendix B
See Table 4-15
See Table 4-16
Section 3. 3. 5
IN = wellhead; AP = after pH adjustment; TA = after Vessel A; TB = after Vessel B; TC = after Vessel C; and
TT = after effluent combined
NA = not available; TCLP = toxicity characteristic leaching procedure
In addition, Figure 3-1 presents a flow diagram of the treatment system along with the analytes and
schedules at each sampling location. Specific sampling requirements for analytical methods, sample
volumes, containers, preservation, and holding times are presented in Table 4-1 of the EPA-endorsed
Quality Assurance Project Plan (QAPP) (Battelle, 2004). The procedure for arsenic speciation is
described in Appendix A of the QAPP.
-------
INFLUENT
(WELL 8)
Monthly
(first week of each four- week cycle)
pHO), temperature^, DQ
As (total and soluble), As (III), As (V),
Fe (total and soluble), Mn (total and soluble),
Ca, Mg, F, NO3, SO4, SiO2, P,
turbidity, alkalinity
Taos, NM
SORB 33™ Technology
Design Flow: 450 gpm
Monthly
(third week of each four-week cycle)
pH«, temperature^), DO«, ORP«,
>- As (total), Fe (total), Mn (total),
SiO2, P, turbidity, alkalinity
pHW, temperature^), DO^,
As (total and soluble), As (III), As (V),
Fe (total and soluble), Mn (total and soluble),
pH ADJUSTMENT -
CO, INJECTION
As (total and soluble),
Fe (total and soluble),
Mn (total and soluble)
turbidity, alkalinity
POND
A
ros,
ble),^__/^
ble), \^_^/
Ale)
l
i
F 1
'i
' 1
/MEDIA\ /MEDIA\ /MEI
-I VESSEL ) •{ VESSEL 1 ••/ VES
VA/\B/\C
pHW, temperature^), DO
-------
3.3.1 Source Water. During the initial visit to the site on December 1, 2004, one set of raw water
samples was collected from Well 8 and speciated using an arsenic speciation kit (see Section 3.4.1). The
sample tap was flushed for several minutes before sampling; special care was taken to avoid agitation,
which might cause unwanted oxidation. Analytes for the source water samples are listed in Table 3-3.
3.3.2 Treatment Plant Water. During the system performance evaluation study, water samples
were collected across the treatment train by the plant operator for on- and off-site analyses. The original
sampling schedule called for the collection of "speciation samples" at the wellhead (IN), after pH
adjustment (AP), and after effluent combined (TT) during the first of each four week cycle, and "regular
samples" at IN, AP, and after adsorption vessels A, B, and C (TA, TB, and TC) during the third week of
each four week cycle (Table 3-3). However, due to frequent system downtime cuased by a variety of
reasons discussed in Section 4.4.1, sampling across the treatment plant took place rather randomly from
as short as once a week to as long as once in 13 weeks. Further, starting from May 1, 2007, off-site
analytes were reduced to only total arsenic. Onsite measurements, however, were performed during most
of the sampling events.
3.3.3 Backwash Wastewater. Because pressure differential (Ap) across each adsorption vessel
was low and never reached the 10-lb/in2 (psi) vendor-recommended setpoint, backwash was performed
only five times throughout the study period. Backwash was performed when:
• Battelle staff members were onsite to inspect the system and provide operator training on
February 14, 2006,
• STS technicians were onsite to repair the system on March 16, 2006, and
• Backwash was initiated manually by the operator to collect backwash wastewater
samples on April 10, 2006, July 10, 2007, and October 10, 2007.
Backwash wastewater samples were collected from each of the three adsorption vessels. Tubing,
connected to the tap on the discharge line of backwash wastewater, directed a portion of backwash
wastewater at about 1 gpm to a clean, 32-gal container over the duration of the backwash for each tank.
After the content in the container was thoroughly mixed, composite samples were collected and/or filtered
onsite with 0.45-(im filters. Analytes for the backwash samples are listed in Table 3-3.
3.3.4 Distribution System Water. Water samples were collected from the distribution system to
determine the impact of the arsenic treatment system on the water chemistry in the distribution system,
specifically, the arsenic, lead, and copper levels. Prior to system startup from May to August 2005, four
sets of monthly baseline water samples were collected from three Lead and Copper Rule (LCR) sampling
locations designated as DS1, DS2, and DS3, within the distribution system. DS1 and DS2 were within a
residence while DS3 was within the Town Hall. DS1, DS2, and DS3 were located east, north, and center
of the Town with DS3 being the closest to the treatment plant at approximately 5 miles away. Following
system startup, distribution system water sampling continued on a monthly basis at the same three
locations as discussed.
The homeowners/operator collected samples following an instruction sheet developed according to the
Lead and Copper Monitoring and Reporting Guidance for Public Water Systems (EPA, 2002). The
sample collection and dates and times of last water usage before sampling were recorded for calculations
of stagnation times. All first-draw samples were collected from a cold-water faucet that had not been
used for at least 6 hr to ensure that stagnant water was sampled. Analytes for the baseline and monthly
samples are listed in Table 3-3.
10
-------
3.3.5 Residual Solids. Because media replacement did not take place during the duration of this
demonstration study, no spent media samples were collected. No backwash solids were collected, either,
because few solids were present in the backwash wastewater sampling containers.
3.4 Sampling Logistics
3.4.1 Preparation of Arsenic Speciation Kits. The arsenic field speciation method uses an anion
exchange resin column to separate the soluble arsenic species, As(V) and As(III) (Edwards et al., 1998).
Resin columns were prepared in batches at Battelle laboratories according to the procedures detailed in
Appendix A of the EPA-endorsed QAPP (Battelle, 2004).
3.4.2 Preparation of Sample Coolers. For each sampling event, a sample cooler was prepared
with the appropriate number and type of sample bottles, disc filters, and/or speciation kits. All sample
bottles were new and contained appropriate preservatives. Each sample bottle was affixed with a pre-
printed, colored-coded label consisting of the sample identification (ID), date and time of sample
collection, collector's name, site location, sample destination, analysis required, and preservative. The
sample ID consisted of a two-letter code for a specific water facility, sampling date, a two-letter code for
a specific sampling location, and a one-letter code designating the arsenic speciation bottle (if necessary).
The sampling locations at the treatment plant were color-coded for easy identification. The labeled
bottles for each sampling location were placed in separate Ziplock™ bags and packed in the cooler.
In addition, all sampling and shipping-related materials, such as disposable gloves, sampling instructions,
chain-of-custody forms, prepaid/addressed FedEx air bills, and bubble wrap, were included. The chain-
of-custody forms and air bills were complete except for the operator's signature and the sample dates and
times. After preparation, the sample cooler was sent to the site via FedEx for the following week's
sampling event.
3.4.3 Sample Shipping and Handling. After sample collection, samples for off-site analyses were
packed carefully in the original coolers with wet ice and shipped to Battelle. Upon receipt, the sample
custodian verified that all samples indicated on the chain-of-custody forms were included and intact.
Sample IDs were checked against the chain-of-custody forms and the samples were logged into the
laboratory sample receipt log. Discrepancies noted by the sample custodian were addressed with the plant
operator by the Battelle Study Lead.
Samples for metal analyses were stored at Battelle's inductively coupled plasma-mass spectrometry (ICP-
MS) laboratory. Samples for other water quality analyses were packed in separate coolers and picked up
by couriers from American Analytical Laboratories (AAL) in Columbus, OH and TCCI Laboratories in
Lexington, OH, both of which were under contract with Battelle for this demonstration study. The chain-
of-custody forms remained with the samples from the time of preparation through analysis and final
disposition. All samples were archived by the appropriate laboratories for the respective duration of the
required hold time and disposed of properly thereafter.
3.5 Analytical Procedures
The analytical procedures described in Section 4.0 of the EPA-endorsed QAPP (Battelle, 2004) were
followed by Battelle ICP-MS, AAL, and TCCI Laboratories. Laboratory quality assurance/quality
control (QA/QC) of all methods followed the prescribed guidelines. Data quality in terms of precision,
accuracy, method detection limits (MDL), and completeness met the criteria estrablished in the QAPP
(i.e., relative percent difference [RPD] of 20%, percent recovery of 80 to 120%, and completeness of
80%). The quality assurance (QA) data associated with each analyte will be presented and evaluated in a
11
-------
QA/QC Summary Report to be prepared under separate cover upon completion of the Arsenic
Demonstration Project.
Field measurements of pH, temperature, DO, and ORP were conducted by the plant operator using a
VWR Symphony SP90M5 Handheld Multimeter, which was calibrated for pH and DO prior to use
following the procedures provided in the user's manual. The ORP probe also was checked for accuracy
by measuring the ORP of a standard solution and comparing it to the expected value. The plant operator
collected a water sample in a clean, plastic beaker and placed the Symphony SP90M5 probe in the beaker
until a stable value was obtained. The plant operator also performed free and total chlorine measurements
using Hach chlorine test kits following the user's manual.
12
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4.0 RESULTS AND DISCUSSION
4.1 Site Description
4.1.1 Preexisting Facility. The Town of Taos's treatment building, also known as the booster
pump station, is located five miles southwest of the Town at 182 Los Cordovas, Taos, NM. It supplies
drinking water to approximately 5,000 residences and an influx of tourists in the summer. During the
demonstration study, the Town had a total of 10 wells, but only five (i.e., Wells 1 through 5) were used to
meet water demand in the distribution system. Wells 1 through 5 operated on a rotating basis, with two or
three wells operating at a time. According to the Year 2004 Water Production Consumption Report
provided by the facility, the total yearly water production in 2004 was approximately 294,579,000 gal.
The daily water demand varied from 439,000 to 978,000 gpd and averaged 695,000 gpd. Chlorination for
disinfection was accomplished using a mixed oxidants (MIOX) system at each wellhead for a target total
chlorine residual of 0.2 mg/L (as C12).
Designated for the study, Well 8 (Figure 4-1), was not in operation prior to the study due to high pH
values and elevated arsenic concentrations in well water. Well 8 was constructed of 10%-in-diameter
casing to a total depth of 2,520 ft with a screened interval spanning from 1,324 ft to 2,520 ft below
ground surface (bgs). The static water level was approximately 153 ft bgs. The well was equipped with a
150-horsepower (hp) submersible pump set at 900 ft bgs, capable of producing a flowrate of 450 gpm at a
head of approximately 1,000 ft (or 433 lb/in2 [psi]). After the arsenic treatment system was installed,
Well 8 was used as a main supply well.
Located approximately 20 ft from the wellhead, the Well 8 pump house (Figure 4-2) housed all relevant
piping and instrumentation, including one control panel, one hour meter, two electric meters, two pressure
gauges, one flow totalizer/meter, and one raw water sample tap. When Well 8 was activated at the pump
house, water was initially purged into a holding pond (Figure 4-3) for 5 min before being directed to the
treatment building (or booster pump station). The treatment building, as originally designed, was used to
house an infiltration gallery system comprising of a 10-ft-diameter by 6-ft-tall steel filtration vessel
(Figure 4-4), a MIOX injection system, and two booster pumps. The steel filtration vessel, however, was
never used and it was removed to make room for the arsenic removal system. Modifications to the
treatment building, as discussed in Section 4.3, included a concrete pad, an overhead door, and piping and
electrical connections (Figure 4-5).
Water from Well 8 was transported to the treatment building via a 0.8-mile-long, 10-in-diameter high
density polyethylene (HOPE) pipeline, chlorinated in the treatment building, and then stored temporarily
in a 50,000-gal holding tank on a hill approximately 150 ft from the treatment building (Figure 4-6). The
treated water was delivered from the 50,000 gal holding tank to a 1,000,000 gal water tower located
southeast of the Town via two 100-hp, 650-gpm booster pumps located in the treatment building and a
3.2-mile-long, 10-in-diameter polyvinyl chloride (PVC) pipeline. (Note that Well 8 supplied only 10% of
the capacity of the 1,000,000 gal water tower; the balance was supplied by Wells 1, 2, 3, 3a, 4, and 5).
Because Well 8 was not integrated into the Town's system control and data acquisition (SCADA) system,
both Well 8 pump and the booster pumps had to be turned on and off manually by the operator. Due to a
higher booster pump flowrate, the operator controlled the water level in the 50,000-gal holding tank by
turning the booster pumps on and off intermittently. An evaporative pond (Figure 4-7) located outside of
the treatment building was used to discharge backwash wastewater generated by the arsenic removal
system.
13
-------
Figure 4-1. Well 8 Wellhead with Pump House in Background
Figure 4-2. Inside of Well 8 Pump House
14
-------
Figure 4-3. Holding Pond for Raw Water Discharge During Initial Purge
Figure 4-4. Inside of Preexisting Water Treatment Building with
Unused Sand Filtration Vessel
15
-------
Figure 4-5. Modified Treatment Building/Booster Pump Station
Figure 4-6. A 50,000-Gal Holding Tank on Hill
16
-------
Figure 4-7. Evaporative Pond for Backwash Wastewater Discharge
4.1.2 Source Water Quality. Source water samples were collected and speciated from Well 8 on
December 1, 2004, for on- and off-site analyses (Table 3-3). The analytical results are presented in
Table 4-1 and compared to those taken by the facility and submitted to EPA for the demonstration site
selection. The results after the MIOX treatment obtained from the New Mexico Environment
Department/Drinking Water Bureau (NMED/DWB) are presented in Table 4-2.
Arsenic. Total arsenic concentrations in Well 8 ranged from 14.1 to 19 (ig/L. Based on the December 1,
2004, speciation results, arsenic existed primarily in the soluble form. Out of 14.1 (ig/L of total arsenic,
2.1 (ig/L existed as soluble As(III) and 11.8 (ig/L (or 84%) as soluble As(V). Therefore, As(V) was the
predominant species and prechlorination would not be needed. Based on laboratory and field studies,
As(V) is more readily adsorbed onto SORB 33™ media, and oxidation of As(III), if present as the
predominant species, should help improve removal efficiency.
Iron and Manganese. Total iron concentrations were low, ranging from less than the method reporting
limit of 40 (ig/L to 59 (ig/L. Based on the December 1, 2004, speciation results, total iron existed
primarily in the particulate form. The presence of particulate iron in source water was carefully
monitored during the demonstration study to determine if the measurement of particulate iron on
December 1, 2004, was simply due to inadvertent aeration of the sample during sampling.
In general, adsorptive media technologies are best suited to sites with relatively low iron levels in source
water (i.e., less than 300 (ig/L, which is the secondary maximum contaminant level [SMCL] for iron).
Above 300 (ig/L, taste, odor, and color problems can occur in treated water, along with an increased
potential for fouling of the adsorption system components with iron particulates. Because the iron
concentration in Well 8 water was low, iron removal was not required.
17
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Table 4-1. Raw Water Quality Data for Town of Taos
Parameter
Date
pH
Temperature
DO
ORP
Total Alkalinity (as CaCO3)
Hardness (as CaCO3)
Turbidity
TDS
TOC
Nitrate (as N)
Nitrite (as N)
Ammonia (as N)
Chloride
Fluoride
Sulfate
Silica (as SiO2)
Orthophosphate (as P)
As (total)
As (soluble)
As (paniculate)
As(III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
U (total)
U (soluble)
V (total)
V (soluble)
Ra (total)
Ra (soluble)
Na (total)
Ca (total)
Mg (total)
Unit
S.U.
°c
mg/L
mV
mg/L
mg/L
NTU
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
pCi/L
pCi/L
mg/L
mg/L
mg/L
Utility Raw
Water Data(a)
NA
9.7
NS
NS
NS
82
<5
NS
NS
NS
NS
NS
NS
10
NS
38
NS
NS
19
NS
NS
NS
NS
<40
NS
<10
NS
NS
NS
NS
NS
NS
NS
61
1.4
0.1
Battelle Raw
Water Data
12/01/04
9.5
23.9
0.7
NA
96
4.9
1.9
218
0.7
0.04
0.01
0.05
11.0
1.4
41.0
30.4
0.06
14.1
13.9
0.2
2.1
11.8
59
<25
5.0
0.3
0.4
0.4
35.7
34.2
<1.0
<1.0
75.1
1.9
0.03
NA = not available; NS = not sampled; TDS = total dissolved solids; TOC = total
organic carbon
(a) Provided to EPA for demonstration study site selection.
Manganese concentrations in source water were as low as 5.0 (ig/L. Based on the December 1, 2004,
speciation results, total manganese existed primarily in the particulate form. Out of 5.0 (ig/L of total
manganese, 0.3 (ig/L (or 6%) existed as soluble manganese.
pH. pH values ranged from 9.5 to 9.7, which are higher than the target range of 6.0 to 8.0 for arsenic
removal via adsorption with iron media. Therefore, pH adjustment was needed prior to the arsenic
removal system. pH adjustment using a CO2 injection system was proposed by the vendor.
18
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Table 4-2. NMED/DWB Treated Water Quality Data for Taos, NM
Date
Bromoform
Bromodichloromethane
Bromochloroacetic acid
Chlorodibromethane
Total Trihalomethanes (TTHM)
Chloroform
Monochloroacetic acid
Dibromoacetic acid
Monobromoacetic acid
Dichloroacetic acid
Trichloroacetic acid
Unit
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
Hg/L
03/26/02
0
0
0.20
0
0
0
0
0
0
0
0
0
0
0
0
0.40
0.40
0
0.20
0
0
0
0
0
0
0
0
0
0
0.18
0
0.18
0
0
0
0
0
0
0
0
0
0
0
0
06/04/02
NS
NS
NS
NS
NS
NS
NS
NS
0
0
0
0
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
0
0
0
0
0.23
0
0
0.30
0
0
0
0
1.61
0.75
0.67
0.78
0
0
0
0
08/20/02
NS
NS
NS
NS
NS
NS
NS
NS
0
0
0
0
NS
NS
NS
NS
0
NS
NS
NS
NS
NS
NS
NS
0
0
0
0
0.19
0
0.13
0
0
0
0
0
0.66
0.72
0.72
0.75
0.21
0.15
0.17
0.14
10/29/02
0
0.30
0
0
0
0
0
0
0
0
0
0
0
0
0.30
0
0
0
0.60
0.30
0
0.30
0
0
0
0
0
0
0.17
0.17
0.12
0
0
0
0
0
0.54
0.53
0.48
0.51
0
0.052
0.043
0
01/30/03
0
0
0
0
0
0
0
0
1.04
0.8
2.85
0.55
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
05/05/03
0
0
0.09
0
0
0
0
0
0
0
0
0
0
0
0.35
0
0
0
0.44
0
0
0
0
0
0
0
0
0
0
0
0.53
0
0
0
0
0
1.87
1.65
1.61
1.35
0.44
0.42
0.44
0.40
12/09/03
0.22
NS
NS
NS
0.26
NS
NS
NS
0
NS
NS
NS
0.42
NS
NS
NS
0.90
NS
NS
NS
0
NS
NS
NS
0
NS
NS
NS
0.56
NS
NS
NS
0
NS
NS
NS
0
NS
NS
NS
0.27
NS
NS
NS
3/22/04
0.76
NS
NS
NS
0.19
NS
NS
NS
NS
NS
NS
NS
0.46
NS
NS
NS
1.51
NS
NS
NS
0.10
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
06/30/04
0
NS
NS
NS
0
NS
NS
NS
NS
NS
NS
NS
0.10
NS
NS
NS
0.10
NS
NS
NS
0
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
08/25/04
0.70
NS
NS
NS
1.00
NS
NS
NS
NS
NS
NS
NS
1.20
NS
NS
NS
3.60
NS
NS
NS
0.70
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
12/30/04
0.39
NS
NS
NS
0.51
NS
NS
NS
NS
NS
NS
NS
0.71
NS
NS
NS
2.02
NS
NS
NS
0.41
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
Note: Only DBFs results available for treated water quality; samples taken at multiple locations within the distribution system.
NS = Not Sampled.
-------
Silica and Orthophosphate. As shown in Table 4-1, silica was at 30.4 mg/L (as SiO2) and
orthophosphate at less than the method reporting limit of 0.06 mg/L (as P). Usually, arsenic adsorption
can be influenced by the presence of competing anions such as silica and phosphate, but due to the low
levels of these constituents, they were not expected to affect arsenic adsorption onto SORB 33™media.
Other Water Quality Parameters. Nitrate, nitrite, ammonia, and TOC (total organic carbon) were not
detected. Sulfate was at 38 to 41.0 mg/L. Turbidity was at 1.9 NTU. Chloride and fluoride were at 11.0
and 1.4 mg/L, respectively. Alkalinity values ranged from 82 to 96 mg/L. Uranium was at 0.4 (ig/L, well
below its MCL of 30 (ig/L. Vanadium was at 35.7 (ig/L, existing almost entirely in the soluble form.
Sodium concentrations ranged from 61 to 75.1 mg/L. Calcium, magnesium, and hardness were low,
ranging from 1.4 to 1.9 mg/L for calcium and from 0.03 to 0.1 mg/L for magnesium, and at <5 mg/L (as
CaCO3) for hardness. Total dissolved solid (TDS) was at 218 mg/L and below its SMCL of 500 mg/L.
4.1.3 Treated Water Quality. Historic treated water data collected by NMED/DWB are provided
in Table 4-2. Samples of water after chlorination were collected between March 26, 2002, and December
30, 2004, and analyzed only for disinfection by-products (DBPs). As shown in the table, concentrations
of all DBPs were low and did not have any compliance issues.
4.1.4 Distribution System and Regulatory Monitoring. As discussed in Section 4.1.1, the
treated water was transported from the 50,000 gal holding tank by two booster pumps to a 1,000,000 gal
water tower located southeast of the Town. North of the Town was another water tower with a 200,000-
gal capacity that served as a temporary storage for Wells 1 and 2 water before it was transported to the
1,000,000 gal water tower. To supplement the balance of the 1,000,000 gal capacity, water from Wells 3,
3a, 4, and 5 also was pumped to the water tower per schedules established by the SCADA system.
The 1,000,000 gal water tower supplied water to the distribution system either directly or through a
500,000 gal water tower also located southeast of the Town. Based on the information provided by the
facility, the distribution system piping was constructed of primarily 6-in PVC pipe. The service lines
within the residences were primarily %-in copper and %-in HOPE pipe.
Under the LCR, water samples were collected from customer taps at 25 residences every three years. The
Town also collected samples monthly for bacterial analysis and quarterly for DBPs.
4.2 Treatment Process Description
STS provided an Arsenic Package Unit (APU)-450 arsenic removal system for the Town of Taos. The
APU is a fixed-bed, down-flow adsorption system designed for small water systems with flowrates
greater than 100 gpm. The APU uses Bayoxide® E33 media (branded as SORB 33™ by STS), an iron-
based adsorptive media developed by Bayer AG, for the removal of arsenic from drinking water supplies.
Table 4-3 summarizes vendor-provided physical and chemical properties of the media.
SORB 33™ media is delivered in a dry crystalline form and listed by NSF International (NSF) under
Standard 61 for use in drinking water applications. The media exists in both granular and pelletized
forms, which have similar physical and chemical properties, except that pellets are denser than granules
(i.e., 35 vs. 28 lb/ft3). The pelletized form of the media was used for the Town of Taos.
The treatment train consisted of pH adjustment and adsorption. The APU-450 arsenic removal system
consisted of three adsorption vessels arranged in parallel (Figure 4-8), an electrically actuated valve tree,
and associated piping and instrumentation. Electrically actuated butterfly valves diverted raw water
downward through the three adsorption vessels, which reduced arsenic concentrations to below 10 |o,g/L.
Upon reaching 10-|o,g/L, the spent media would be removed and disposed of after being subjected to the
20
-------
Table 4-3. Physical and Chemical Properties of SORB 331M Media
Physical Properties
Parameters
Matrix
Physical Form
Color
Bulk Density (lb/ft3 or g/cm3)
BET Surface Area (m2/g)
Attrition (%)
Moisture Content (%,by weight )
Particle Size Distribution
(U.S. Standard Mesh)
Crystal size (A)
Crystal phase
Values
Iron oxide composite
Dry pellets
Amber
35 or 0.56
142
0.3
<15
10x35
70
a -FeOOH
Ch emical An alysis
Constituents
FeOOH
CaO
MgO
MnO
S03
Na2O
Ti02
Si02
A1203
P205
Cl
Weight (%)
90.1
0.27
1.00
0.11
0.13
0.12
0.11
0.06
0.05
0.02
0.01
Source: Bayer AG
BET = Brunauer, Emmett, and Teller
EPA Toxicity Characteristic Leaching Procedure (TCLP) test. The media life is dependant upon influent
arsenic concentration, pH, and concentrations of interfering ions. Figure 4-9 shows a schematic of the
APU-450 arsenic removal system. Table 4-4 summarizes the design features of the arsenic removal
system. The major process steps and system components are presented as follows:
• Intake. Raw water was pumped from Well 8 and transported to the treatment plant building
via a 0.8-mile-long, 10-in-diameter HDPE pipeline. Water entered the building via a 6-in-
diameter Schedule 80 PVC pipe to the tie-in point, where the inlet piping was connected to
the system through a 6-in-diameter schedule 80 PVC pipe.
• pH Adjustment. A Carbon Dioxide Gas Flow Control System manufactured by Applied
Technology Systems, Inc. (ATSI) of Souderton, PA, was used to lower the pH of raw water
from approximately 9.5 to a target value of 7.2 to increase arsenic removal capacity of the
media. CO2 was used for pH adjustment because 1) CO2 is less corrosive than mineral acids,
such as H2SO4, and 2) when the treated water is depressurized after exiting the treatment
system, some CO2 degases, thereby raising pH values of the treated water and reducing its
corrosivity to the distribution piping.
21
-------
Figure 4-8. Photograph of APU-450 Arsenic Removal System
Figure 4-10 shows a schematic of the pH control system, which consisted of a liquid CO2
supply assembly, an automatic pH control panel (Figure 4-11), a CO2 loop, a CO2 membrane
module, and a pH probe located downstream of the membrane module. Figure 4-12 presents
a composite of photographs of major system components. Details of key process steps and
system components are described below.
o Liquid CO2 in two banks of two 380-lb dewars and two 50-lb backup cylinders
vaporized into gaseous CO2 via a feed vaporizer prior to entering the pH control
panel.
o As CO2 gas flowed to the pH control panel, its flowrate was automatically controlled
and regulated by a JUMO pFi/Proportional Integral Derivative (PID) controller and
an Alicat mass flowmeter to reach the desired pH setpoint. The flowrate also could
be regulated manually through the use of a three-way ball valve and a rotameter. A
solenoid valve interlocked with the well pump allowed gas to flow only when the
well pump was turned on.
o After flowing out of the control panel, CO2 was injected into water through a
Celgard® microporous hollow fiber membrane module housed in a 4-in stainless steel
sanitary cross. Table 4-5 provides relevant properties of the membrane module. The
sanitary cross was located in a side stream from the main water line to allow only a
portion of water to flow through the membrane to minimize the pressure drop. The
membrane module introduced CO2 gas into water at a near molecular level for rapid
mixing/reaction in order to achieve a quick pH response/change.
22
-------
SEVERN
OJ
Filtration
Products
SERVICES
Date:
SORB 33® As Removal
Taos Flow/Pressure Profile
Time:
Enter values for Flow, Pres, AP (PDI) & pH in oval areas. Enter
Valve positions (O - open or C - closed). Fax to RSDennis (813) 886-0651
Figure 4-9. Schematic of STS's APU-450 Arsenic Removal System
jo yan|< Storage
-------
Table 4-4. Design Specifications for STS APU-450 System
Parameter
Value
Remarks
Adsorption Vessels
Vessel Size (in)
Cross-Sectional Area (ft2/vessel)
No. of Vessels
Configuration
63 D x 86 H
21.6
3
Parallel
-
-
-
-
Adsorptive Media Beds
Media Type
Media Weight (Ib)
Media Volume (ft3)
Media Bed Depth (in)
Pressure Drop across Media Bed(psi)
SORB 33™
6,264
180
33
4 psi
-
-
60 ft3/vessel
Across a clean bed
Service
Design Flowrate (gpm)
Hydraulic Loading (gpm/ft2)
EBCT for System (min)
Estimated Working Capacity (BV)
Throughput to Breakthrough (gal)
Average Use Rate (gal/day)
Estimated Media Life (months)
Post-chlorination Dosage (mg/L [as C12])
450
6.9
3.0
130,000
175,000,000
224,000
26
0.5
150 gpm/vessel
-
Based on design flowrate
For pelletized media
1BV= 1,346 gal
8 to 9 hr of daily operation at 450 gpm
Changeout frequency at 33% utilization
WithMIOX
Backwash
Pressure Differential Set Point (psi)
Backwash Flowrate (gpm)
Backwash Hydraulic Loading (gpm/ft2)
Backwash Frequency (per month)
Backwash Duration (mm/vessel)
Fast Rinse Flowrate (gpm)
Fast Rinse Duration (min/vessel)
Wastewater Production (gal/vessel)
10
200
9.3
1
15
200
5
4,000
-
-
-
Based on vendor's recommendation
-
-
-
-
o Located downstream from the sanitary cross was a Sentron Ion Sensitive Field Effect
Transistor (ISFET) type silicon chip sanitary pH probe with automatic temperature
compensation, that continuously monitored pH levels of the treated water and sent
signals back to the pFI/PID controller for pH control.
The CO2 pH control system was designed to feed 60 ft3/hr with a maximum flow of 125 ft3/hr
(or 6.9 to 14.3 Ib/hr based on a gas density of 0.1146 lbs/ft3 at 1 atmosphere and 70°F). The
actual average use rate was 85.2 ft3/hr or 9.8 Ib/hr.
Adsorption. The APU-450 system consisted of three 63-in x 86-in vessels, designed to hold
60 ft3 of pelletized SORB 33™ media supported by a gravel underbed. The skid-mounted
vessels were made of fiberglass reinforced plastic (FRP), rated for 150 psi working pressure,
and piped to a valve rack mounted on a polyurethane-coated, welded frame. According to the
original system design with a flowrate of 450 gpm, the empty bed contact time (EBCT) for
each vessel and the system was 3.0 min and the hydraulic loading was 6.9 gpm/ft2.
24
-------
Taos,
Automatic Cylinder
Switchover Panel
Power IN
ATSI CO,pH Control
Panel (ATSI)
pH Cable (
-------
Horn
Power In
Wellpump
Contacts
C02 Gas
Inlet
4-20 mAmp
Signal to
Control
Module
BV1
Figure 4-11. pH/PID Control Panel
Figure 4-12. Carbon Dioxide Gas Flow Control System for pH Adjustment
(Clockwise from Top Left: CO2 Supply Assembly with Four 380-lb Dewars and Two 50-
Ib Cylinders; pH Control Panel; Sanitary Cross and CO2 Loop; and Port for pH Probe)
26
-------
Table 4-5. Properties of Celgard*, X50-215 Microporous
Hollow Fiber Membrane
Parameter
Porosity (%)
Pore Dimensions (urn)
Effective Pore Size (urn)
Minimum Burst Strength (psi)
Tensile Break Strength (g/filament)
Average Resistance to Air Flow (Gurley sec)
Axial Direction Shrinkage (%)
Fiber Internal Diameter, nominal (urn)
Fiber Wall Thickness, nominal (um)
Fiber Outer Diameter, nominal (um)
Module Dimensions (in)
Value
40
0.04 xO.10
0.04
400
>300
50
<5
220
40
300
1.5 x3.0
Data Source: CelgardR
The three adsorption vessels were interconnected with schedule 80 PVC piping and 15
electrically actuated butterfly valves. As the well pump was activated, a signal was sent from
the control panel in the pump house to the system to open feed valves (BF 121A, 121B, and
121C) and effluent valves (BF 122A, 122B, and 122C). With the other valves remaining
closed, water was diverted downward through the three adsorption vessels. Flow through the
three vessels was balanced by throttling the effluent valves, if needed. Flow meters
(+GF+SIGNET 8550 ProcessPro™ Flow Transmitter) installed on the supply line of each
adsorption vessel monitored instantaneous flowrates through the vessels. The flowmeters
also tracked the volume of water treated in each vessel. Differential pressure (Ap) across
each vessel was monitored by differential pressure gauges (Mid-West Piston-Type
Differential Pressure Gauge). The adsorption vessels were backwashed sequentially
whenever the Ap across one vessel reached 10 psi.
Backwash. STS recommended that the APU-450 system be backwashed on a regular basis,
approximately once a month to loosen up the media bed. Automatic backwash could be
initiated by either a time or a Ap setpoint across each vessel. During a backwash cycle, each
vessel was backwashed individually while the other two remained online, reducing the
service flowrate to 300 gpm. The backwash flowrate, hydraulic loading, duration, and
wastewater production were 200 gpm, 9.3 gpm/ft2, 20 min (including 5 min for forward
flush), and 4,000 gal (including 1,000 gal from forward flush), respectively. The
backwash/forward flush flowrates and the amount of wastewater generated were obtained
from flowrate and totalizer readings shown on the programmable logic controller (PLC).
Backwash and forward flush water was supplied by the 50,000-gal holding tank; the
wastewater generated was discharged into a pipe trench/sump and routed via a 12-in drain
line to the existing evaporative pond located near the treatment building. The evaporative
pond had a capacity of 30,000 gal, enough to hold 12,000 gal of wastewater generated during
each backwash event. To meet the state discharge requirements, backwash wastewater had to
be kept at an average of 2,000 gpd over a month-long period.
Media Replacement. The media in each vessel is replaced when the arsenic concentration
following each vessel approaches 10 (ig/L. A TCLP test will be conducted on the spent
media before disposal to determine whether the media can be considered non-hazardous.
Virgin media is then loaded into each vessel. Based on the vendor's estimate, the media
would need to be replaced after treating approximately 175,000,000 gal of water or every 26
27
-------
months (based on an estimated daily throughput of 224,000 gal). The media was not replaced
during the demonstration study.
• Post-chlorination, Storage, and Distribution. To provide chlorine residual in the
distribution system, post-chlorination was implemented through the use of the existing MIOX
SAL-80 system, an onsite mixed oxidant generator. As shown in Figure 4-13, the system
consisted of an electrolytic cell, a brine generator, and a mixed oxidant tank. The brine
generator served as a salt storage compartment and supplied brine to the electrolytic cell.
Brine was electrolyzed and produced mixed oxidants, including C12, HOC1, and/or OC1" in the
cell. The mixed oxidants, referred to as a MIOX solution, were collected in the mixed
oxidant tank until they were injected into the treated water for disinfection. The MIOX SAL-
80 system was designed for easy salt loading and operated for approximately 500 hr on a
single load of salt (i.e., 1,000 Ib). The system produced up to 10 Ib of chlorine per day, which
met the quantity required to reach a target total chlorine residual of 0.2 mg/L (as C12).
The treated water was stored in the 50,000-gal holding tank located outside of the booster
station on a hill. The booster pumps located in the treatment building were manually
switched on and off to pump water from the holding tank to the 1,000,000 gal water tower
southeast of the town before entering the distribution system.
Control
Panel
Source: MIOX
-IB
Figure 4-13. Process Diagram of MIOX SAL-80 System
28
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4.3 Treatment System Installation
4.3.1 System Approval. An application package including a process flow diagram of the
treatment system and a schematic of the building footprint and equipment layout was prepared by SMA
Engineering, a subcontractor to STS, and submitted by the Town of Taos to NMED/DWB on June 24,
2005. A supplemental submittal followed on July 27, 2005. NMED/DWB reviewed the engineering
plans and issued a conditional Approval to Construct on August 15, 2005, with several comments,
including 1) lack of a proper disinfection and bacteriological sampling plan equivalent to American Water
Works Association (AWWA) standards, 2) incomplete plans and specifications of piping work outside of
STS's APU-450 system, and 3) lack of information concerning ways to prevent cross-connection between
the backwash wastewater discharge line and sanitary sewer. The Town of Taos submitted its responses to
the state's comments on August 18, 2005, including (1) a description of proper disinfection and
bacteriological sampling, (2) a one page submittal consisting of plans and specifications of piping work
outside of the APU-450 system, and (3) a description of backwash wastewater discharge, which was not
connected to the sanitary sewer. NMED/DWB granted its approval of the system application and issued a
final Approval to Construct on September 12, 2005. A permit was not required to discharge backwash
wastewater to the evaporative pond.
4.3.2 Building Construction. The steel filtration vessel in the existing treatment building was
removed to make room for the arsenic removal system. The building was then modified to include a
concrete pad and piping and electrical connections (Figure 4-14). The metal side wall panel was
temporarily removed to allow for off-loading of the APU-450 arsenic treatment system into the treatment
building (Figure 4-15).
Figure 4-14. Modified Booster Pump Station
-------
Figure 4-15. Removal of Treatment Building Side Wall Panel for APU-450
System Off-loading
30
-------
4.3.3 System Installation, Shakedown, and Startup. Prior to the installation of the treatment
system, a pipeline project was undertaken by the Town to rehabilitate water transmission lines. The
project was completed on September 13, 2005.
The APU-450 system arrived at the Town of Taos on October 3, 2005. STS's subcontractor, Pumps and
Service, off-loaded system components and began plumbing work. The pelletized media arrived in five
and a half super sacks (Figure 4-16) on September 30, 2005. Each super sack contained 38 ft3 of media
bringing the total media volume to 209 ft3.
Figure 4-16. Arrival of SORB 33™ Media in Super Sacks
After Pumps and Service performed most of the installation work, STS made three separate trips to the
site from October 17 to 20, 2005, from November 1 to 3, 2005, and from December 1 to 9, 2005, to
complete system installation and perform system shakedown and startup. System installation and
shakedown were completed on December 8, 2005, and February 3, 2006, respectively, and the
performance evaluation officially began on February 14, 2006.
During the site visit from October 17 to 20, 2005, STS loaded underbedding gravel and media and
measured freeboard heights before backwash and forward rinse.
The CO2 pH adjustment system arrived on October 26, 2005, and Pumps and Service installed the system.
Four 380-lb CO2 dewars and two 50-lb backup cylinders arrived on November 1, 2005, delivered by Air
Gas.
STS, SMA Engineering, and ATSI returned to the site from November 1 to 3, 2005, and planned to
program the PLC, perform media backwash and forward flush, measure freeboard heights after backwash
and forward flush, and wire the pH control system to the PLC. However, the plan was set aside after a
31
-------
leak was discovered along the throat of a 4-in nozzle at the top of Vessel C during backwash. Because
the vessel was made of FRP, it could not be repaired onsite and had to be replaced with a new vessel. On
November 14, 2005, STS removed the media from Vessel C with a vacuum truck, capturing the media in
two sacks for future re-loading. A new vessel arrived on November 29, 2005, and Pumps and Service
installed the vessel and conducted a hydrostatic test to approximately 60 psi for about 15 min to ensure
that the vessel was leak-proof
STS and ATSI were onsite from December 1 to 9, 2005, to load underbedding gravel and media for
Vessel C and complete the agenda items for the last site visit. On December 7, 2005, STS took freeboard
measurements for all three vessels after backwash and forward flush and the results are discussed in
Section 4.3.5. In addition, a hydraulic test was performed for the system and the results, along with those
of vessel backwash, are summarized in Table 4-6. As shown in the table, backwash was completed with
flowrates ranging from 200 to 210 gpm, close to the target value of 200 gpm. After a forward flush, the
system was allowed to operate in the service mode. Flowrate readings, as recorded from the flowmeter/
totalizers installed on each of the three vessels, ranged from 145 to 150 gpm, close to the design value of
150 gpm. Ap readings across each of the three vessels from individual differential pressure gauges
ranged from 1.5 to 3.4 psi, less than the target clean bed Ap of 4 psi. The system flowrate reading from
the master flow meter at the wellhead was 510 gpm, higher than the sum of instantaneous readings of the
three vessels. The Ap measured across the inlet and out system piping was 6 psi.
Table 4-6. Onsite Backwash and Hydraulic Testing on December 7, 2005
Parameters
Backwash Flowrate (gpm)
Service Flowrate (gpm)
Pressure Differential at Service Flowrate (psi)
System
—
510
6
Vessel A
205
145
1.5
Vessel B
200
150
3.4
Vessel C
210
150
3.5
STS then disinfected the system in accordance with AWWA Standards C-651 and B-300. Personal
protective equipment (PPE) was used when working with hypochlorite chemicals. Upon completion,
samples were taken for bacteriological tests. System installation was completed on December 8, 2005.
4.3.4 CO2 pH Control System. Since the CO2 control system was installed, a number of
operational problems occurred. These problems, along with the corrective actions taken, are summarized
in Table 4-7. During system shakedown, the CO2 control system often shut itself off after it and the well
pump had been turned on. To resolve to the problem, a 5-min programming delay was added to the pH
control system to avoid an alarm and system shutdown due to over-adjustment of pH before water had
reached the treatment building from the pump house (recall that there is a 5-min purge at the wellhead
immediately after the well pump is turned on).
On January 10, 2006, the operator noticed that the microporous membrane module was contaminated with
solvents. The source of contamination was determined to be PVC pipe cement, which was used to repair
leaks on the PVC inlet piping. The contaminated membrane module was replaced with a new one by the
operator on January 27, 2006.
On February 3, 2006, a significant pressure increase was observed both before (from 30 to 40 psi) and
after the sanitary cross (from 25 to 38 psi), and the target pH value of 7.2 could not be reached. After
consultation with the vendor, the CO2 pH control system was temporarily switched from automatic to
manual mode. While being onsite performing system inspections and operator training on February 13
and 14, 2006, two Battelle staff members attempted to troubleshoot the problems. After comparing inline
32
-------
pH probe readings with those of a VWR field meter, it was determined that the inline pH probe did not
work properly. It also was determined that the pressure gauges before and after the sanitary cross were
broken. The operator replaced both the inline pH probe and pressure gauges on March 17, 2006. The
system appeared to be working fine in manual mode thereafter.
Although the pH control system worked in manual mode, it failed to operate in automatic mode since the
inline pH probe and pressure gauges had been replaced on March 17, 2006. Efforts were made by ATSI
to troubleshoot system components, including the mass flow meter, which, however, was found in good
order. After a new inline pH probe was sent to the site and installed on May 5, 2006, the system operated
in automatic mode thereafter.
On August 16, 2006, the microporous membrane module was found damaged with a visible bent on the
module. The cause of the damage was traced back to a water hammer that occurred after a power outage
on April 18, 2006; details of the chain of events are discussed in Section 4.4.3. The damaged membrane
module was replaced on September 18, 2006.
Table 4-7. Summary of Problems Encountered and Corrective Actions Taken
for pH Adjustment System
Duration
12/16/05
01/10/06-
01/27/06
02/03/06 -
03/17/06
02/03/06 -
03/17/06
03/16/06 -
05/08/06
05/16/06 -
05/22/06
08/16/06 -
09/18/06
09/19/06 -
09/21/06
Problem Encountered
pH control system shut down or
failed to turn on when well pump
was turned on
Presence of solvents in
microporous membrane module
due to contamination from PVC
pipe cement used to repair leaks in
system piping
Pressure prior to and after sanitary
cross experienced sudden increase
from 30 to 40 psi and from 25 to 38
psi, respectively
Inline pH probe failed to reach
target pH value of 7.2
pH control system failed to operate
in automatic mode since inline pH
probe and pressure gauges had
been repaired on 03/17/06
CO2 tanks empty
Damaged CO2 microporous
membrane module discovered
CO2 tanks empty
Corrective Actions Taken
Added a 5-min delay to pH control
system so it switched on only after
water had reached treatment plant
Re-installed new membrane
Replaced broken pressure gauges
before and after sanitary cross on
CO2loop
Replaced broken inline pH probe
Mass flowmeter troubleshot by
ATSI on 03/16/06 but found no
problems. New inline pH probe
was sent to site on 05/05/06 and
system was placed in automatic
mode thereafter
Replaced CO2 tanks
Determined cause of damage to be a
water hammer during 04/18/06
power outage; replaced damaged
membrane module
Replaced CO2 tanks
Work Performed
by/on
By Operator and
ATSI on 12/16/05
ATSI provided new
membrane and
operator re-installed
it on 01/27/06
Operator replaced
gauges on 03/17/06
Operator replaced
probe on 03/17/06
Operator and ATSI
on 05/08/06
Operator/ 05/23/06
Operator/ 09/1 8/06
Operator/ 09/2 1/06
33
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4.3.5 Media Loading. Media loading was performed by STS on October 17, 2006. The media in
super sacks was hoisted to the top of the canopy using a boom truck and loaded through a 12-in x 4-in
rigid funnel connected to the top nozzle by a roof hatch and a 6-in PVC pipe into the adsorption vessel
partially filled with water (Figure 4-17). A garden hose was used to completely submerge the media,
which was allowed to soak for about 4 hr. The top hat distributor with the new sealant was then
reconnected to the top piping. STS was onsite on November 1, 2005, to backwash the vessels. However,
a leak was discovered for Vessel C and the media in that vessel had to be removed via vacuum and
captured into two super sacks. Based on tests conducted by STS's technical center, a 0.85 mm screen
recovered 781.6 gm of wetted media compared to 786.4 gm of wetted media that was vacuumed. After
the new Vessel C was installed on November 29, 2005, STS re-loaded the gravel and media. The vessels
were backwashed on December 7, 2005, with flowrates ranging from 200 to 210 gpm for approximately
30 min. The freeboard heights along with the calculated media volumes in the vessels are summarized in
Table 4-8.
Figure 4-17. Media Loading
34
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Before backwash, freeboard measurements taken from the top of the underbedding gravel to the top of the
nozzle head were 66, 65, and 66 in for Vessels A, B, and C, respectively. Freeboard measurements taken
from the top of each media bed to the top of the nozzle head were 28, 29, and 28 in for Vessels A, B, and
C, respectively. Therefore, the bed depths for Vessels A, B, and C were 38, 36, and 38 in, equivalent to
68.4, 64.8, and 68.4 ft3 of media, respectively, in the vessels. The freeboard measurements after
backwash were taken again, with the total media volume increasing slightly from 202 ft3 to 216 ft3. In
general, free board heights measured after backwash are more accurate because the surface of the media
beds is more even after backwash. However, some bed compaction is expected once the media beds are
put into service under pressure. For the purpose of this study, the media volumes obtained after backwash
were used for all bed volume calculations. (Note that the total amount of media calculated from the
freeboard measurements after backwash was 20% more than that used for the system design, but only
3.3% more than that shipped to the site in super sacks).
Table 4-8. Freeboard Measurements and Media Volumes
in Adsorption Vessels
Date
10/17/05
(Before Backwash)
12/07/05
(After Backwash)
Vessel A
Depth
(in)
38
40
Volume
(ft3)
68.4
72.0
Vessel B
Depth
(in)
36
39
Volume
(ft3)
64.8
70.2
Vessel C
Depth
(in)
38
41
Volume
(ft3)
68.4
73.8
Total
Volume
(ft3)
202
216
4.3.6 Punch List Items. Two Battelle staff members performed system inspections and operator
training for sample and data collection on February 13 and 14, 2006. The performance evaluation study
officially started on February 14, 2006. Table 4-9 summarizes the punch-list items and corrective actions
taken from March 15, 2006, to October 12, 2006.
4.4
System Operation
4.4.1 Operational Parameters. The operational parameters for the duration of system operation
were tabulated and are attached as Appendix A. Key parameters are summarized in Table 4-10. From
February 14, 2006, through October 23, 2007, the system operated for only 838 hr. Because Well 8
(hence the treatment system) and the booster pumps in the treatment building were not tied to the Town's
SCADA system, the operator had to manually operate the system by:
(1) Manually switching on a fuse box in the pump house to start the well pump and send an
electrical signal via the control panel in the pump house to the treatment building to 1) open
the influent and effluent valves on the treatment system, and 2) after a 5-min delay, turn on
the pH control system to begin pH adjustment.
(2) Manually turning on and off the booster pumps to control the water level in the 50,000-gal
holding tank. As the booster pumps were turned on, water was transferred from the 50,000-
gal holding tank to the 1,000,000-gal water tower (see Sections 4.1.1 and 4.1.4).
(3) Manually switching off the fuse box in the pump house to turn off the well pump and send an
electrical signal via the control panel in the pump house to turn off the influent and effluent
valves of the system and the pH control system.
35
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Table 4-9. System Inspection Punch-List Items
Item
No.
1
2
3
4
5
6
7
8
9
Problem Encountered
Imbalanced flow with lower flowrate
through Vessel B than those through
other two vessels
Incorrect Vessel B PLC setting
Leaks on Vessel B piping
Broken backwash flow meter/totalizer
Broken inline pH probe
Broken pressure gauges before and after
sanitary cross
pH control system in manual mode
Lack of pressure gauge before CO2 pH
control system
Leaky bypass valve (GV-133) causing
discrepancy between Well 8 flowrate of
580 gpm and total flowrate across three
vessels of 420 gpm
Corrective Action(s) Taken
• Vessel B's flow meter fixed by removing
paddle wheel from meter, spinning for a
number of times, and then replacing back into
vessel
• Updated PLC program and HMI programs
• Backwash programmed for every 90 days and
Ap backwash trigger disabled
• Replaced 4-in O ring on feed piping to Vessel
B
• Backwash flowmeter/totalizer wired and
calibrated by backwashing vessel C and
comparing Vessel C's flowmeter with
backwash flowmeter/totalizer
• ATSI sent a new inline pH probe to Town
• Probe replaced by operator
• Replaced pressure gauges
• Mass flow controller sent back to ATSI for
examination and found to be fine
• After programming changes with the JUMO
controller, pH adjustment system was placed
in automatic mode
• Town installed pressure gauge before CO2 pH
control system and near raw water sample tap
• Town cleaned and checked leaky bypass valve
(GV-133) and determined there were no
leaks/problems, and re-installed valve back
Resolution
Date
03/15/06
03/15/06
03/15/06
03/15/06
03/17/06
03/17/06
05/08/06
06/06/06
07/31/06
Because of the manual operation of the well pump and booster pumps, the operator had to be physically
present at the pump house and treatment building for the duration of system operations. As a result, the
system operated only when the operator could make time to travel to the pump house and treatment
building. Excluding weekends and system downtime caused by a variety of reasons discussed in
Section 4.4.3, the system operated for only 215 days during the entire study period. Therefore, the daily
system operating time was 3.9 hr/day, equivalent to a use rate of about 16.2%.
As shown in Table 4-11, flowrates and throughputs through the treatment system and individual vessels
were tracked by five flow meters/totalizers, including one each positive-displacement flow meter/totalizer
(preexisting) at the wellhead and the distribution entry point, and one electromagnetic flow meter/
totalizer (new) on each vessel. Instantaneous flowrate/volume readings were taken at the wellhead and on
each vessel. Calculated flowrates also were obtained by dividing volume readings by respective hour
meter readings.
Daily usage based on readings from the three totalizers on the vessels ranged from 5,393 to 271,182 gpd
and averaged 106,870 gpd, compared to the design value of 224,000 gpd shown in Table 4-4. The total
throughput value from these totalizers was 22,977,037 gal, which was 10.6% lower than the 25,704,000
gal throughput value from the master flow meter/totalizer at the wellhead. This wellhead throughput
value matched well with calculated wellhead flowrate values, which ranged from 275 to 631 gpm and
36
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Table 4-10. Summary of APU-450 System Operations
Operational Parameter
Duration
Cumulative Operating Time (hr)
Number of Days of System Operation
Average Daily Operating Time (hr)
Value/Condition
02/14/06-10/23/07
838
215
3.9
System Operation -Adsorption
Average (Range of) Daily Usage (gpd)(a)
Total Throughput (gal)
Bed Volumes (BV)(b)
Average (Range of) System Flowrate (gpm)(c)
Average (Range of) Hydraulic Loading (gpm/ft2)(d)
Average (Range of) EBCT for Each Vessel (min)(e)
Average (Range of) Inlet Pressure (psi)
Average (Range of) Outlet Pressure (psi)
Average (Range of) Ap across System (psi)
Average (Range of) Ap across Vessel A (psi)
Average (Range of) Ap across Vessel B (psi)
Average (Range of) Ap across Vessel C (psi)
106,870 (5,393-271,182)
22,977,037
14,192
503 (410-558)
7.8 (4.2-8.9)
3.2 (2.9-5.7)
26.7 (20.0-30.0)
18.5 (10.0-30.0)
8.1(0-16.0)
4.8 (3.0-5.5)
4.5 (3.5-5.0)
4.5 (3.0-7.0)
System Operation - Backwash
Average (Range of) Backwash Flowrate (gpm)(t)
Average (Range of) Hydraulic Loading Rate
Average Backwash Duration (min)
Average (Range of) Wastewater Generated (gal)(t)
242 (230-260)
11.2(10.6-12.1)
15.0
3,297 (2,614-4,093)
(a) Average daily demand calculated by dividing total throughput by 215 days.
(b) BV calculated based on 216 ft3 of media in three vessels.
(c) Sum of instantaneous flowrate readings from three vessels.
(d) Calculated based on flowrates to each vessel.
(e) Calculated based on 72.0, 70.2, and 73.8 ft3 of media in Vessels A, B, and C,
respectively.
(f) Instantaneous flowrate/totalizer readings from flow meter/totalizer installed on
backwash discharge line; not including forward flush.
Table 4-11. System Instantaneous and Calculated Flowrates
Flow Meter/Totalizer
Type
Positive Displacement
Electromagnetic
Sum of A, B, and C
Positive Displacement
Location
At Wellhead
Prior to Vessel A
Prior to Vessel B
Prior to Vessel C
on Treated Water Line
Instantaneous/
Calculated
Instantaneous
Calculated^
Instantaneous
Instantaneous
Instantaneous
Instantaneous
Calculated^
Flowrate (gpm)
Range
470-600
275-631
128-192
92-184
151-193
410-558
238-643
Average
575
515
171
158
174
503
467
(a) Based on readings on wellhead totalizer and hour meter.
averaged 515 gpm. Instantaneous wellhead flowrate readings were higher and considered less reliable
than the calculated values.
37
-------
Instantaneous flowrate readings for Vessels A, B, and C ranged from 92 to 193 gpm and averaged 171,
158, and 174 gpm, respectively. There was some flow imbalance, with Vessel B receiving approximately
8% less flow. Flowrates through the three vessels combined ranged from 410 to 558 gpm and averaged
503 gpm, which was 2.3% lower than that at the wellhead, but 7.7% higher than that at the distribution
entry point. Because fowrate readings from the various flow meters were never reconciled during the
performance evaluation, the readings from individual vessels were used for all process-related
calculations.
Based on the flowrate readings and media volumes in individual adsorption vessels, hydraulic loading
rates averaged 7.8 gpm/ft2 and EBCTs averaged 3.2 min, both slightly higher than the design values of
6.9 gpm/ft2 and 3.0 min, respectively.
The system pressures were monitored at the inlet and outlet of the system and individual vessels and
plotted in Figure 4-18. Ap readings across each vessel remained rather constant during the study period,
with readings ranging from 3.0 to 7.0 psi and averaging 4.8, 4.5, and 4.5 psi across Vessels A, B, and C,
respectively. Inlet and outlet system pressure readings also stayed in rather tight ranges, fluctuating
between 20 to 30 psi at the inlet and 10 to 30 psi at the outlet. Since backwash would be triggered
automatically when Ap had reached 10 psi across a vessel, no automatic backwash took place during the
study period. However, five backwashes were performed manually by Battelle, STS, and the operator for
the purpose of system inspections and backwash wastewater collections.
40.0
35.0
30.0
25.0
20.0
15.0
10.0
-Differntial Pressure for Vessel A
-Differential Pressure B
Differential Pressure for Vessel C
System Inlet Pressure
-System Outlet Pressure
-System Differential Pressure
02/14/06
05/25/06
09/02/06
12/11/06 03/21/07
Date
06/29/07
10/07/07
01/15/08
Figure 4.18. System Operation Pressure
38
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4.4.2 Residual Management. Because media replacement was not performed during the
performance evaluation, no spent media was produced.
4.4.3 Reliability and Simplicity of Operation. Operational irregularities experienced during the
performance evaluation were related primarily to the pH control system. The problems encountered and
corrective actions taken were discussed in Section 4.3.4.
Frequent and prolonged system downtime was observed, caused mainly by non-system-related issues,
such as power outage and facility pipeline leakage (Table 4-12). On April 18, 2006, a power outage blew
the fuse and damaged the control panel in the pump house. Although the fuse was repaired, the control
panel, which linked the well pump to the APU-450 system and pH control system, was not repaired
because the town wanted to wait until the new control panel could be linked to its existing SCADA
network. Due to its high price, the control panel was never replaced during the study period. As a
temporary measure, the town opened the inlet and outlet valves of the system and kept them open at all
times and installed necessary devices to allow signal to be sent to the pH control system via radio.
Meanwhile, the operator continued to operate the system manually by turning on and off the well pump at
the pump house and booster pumps in the treatment building during daily system operation as he had been
doing. Due to the labor intensive nature of the operation, the system was operated for less than 4 hr/day.
On August 16, 2006, the operator discovered that the membrane module in the sanitary cross was
seriously damaged with a visible dent on the module. After an extensive investigation, it was determined
that a water hammer probably had caused the damage. Recall that on April 18, 2006, a power outage
blew a fuse for the well pump and damaged the control panel in the pump house. After the fuse was fixed
and the well pump was turned on, the signal that should have been sent to open the system inlet and outlet
valves apparently failed to be delivered. As a result, water was pumped against a dead end, causing a
water hammer with an estimated pressure of over 125 psi. The damaged membrane module was replaced
on September 18, 2006, after which time no other problems were experienced with the pH adjustment
system for the rest of the study duration.
The APU-450 system was shut down five times for durations up to eight weeks due to pipeline leaks. In
all cases, the facility utilized its own resources to repair the leaks.
On May 2, 2007, the Town drilled a new well (Well 9) in the proximity of Well 8, and the treatment
system was shutdown for just less than 2 months.
Pre- and Post-Treatment Requirements. A pH control system was used for pretreatment. CO2 was
used to lower the pH value of raw water from an average of 9.6 to a target value of 7.2 to maintain
effective adsorption by SORB 33™. O&M of the pH control system required routine system pressure
checks and regular changeout of CO2 supply dewars. The operator also recorded pH readings of the in-
line probe and performed calibration of the pH probe, as needed. The use of CO2 for pH adjustment also
required relevant safety training and awareness for/by the operator due to added hazards.
System Automation. The system was fitted with automated controls to allow for automatic system
operations. For example, each adsorption vessel was equipped with a flow sensor and totalizer, five
electrically actuated butterfly valves, and a pressure transmitter, all of which were capable of transmitting
and receiving electronic signals to and from the Square D Telemechanique PLC with a Magelis G2220
color touch interface screen. The system also was equipped with an automated Carbon Dioxide Gas Flow
Control System, which included a liquid CO2 supply assembly, an automatic pH control panel, a CO2
membrane module, and an in-line pH probe located downstream of the membrane module. The APU-450
system was capable of automatic backwash triggered by either a timer or a Ap setting.
39
-------
Table 4-12. Summary of System Downtimes
Duration
03/14/06-
03/15/06
03/27/06-
04/09/06
04/18/06-
04/30/06
05/16/06-
05/22/06
05/29/06-
06/19/06
07/14/06-
07/31/06
08/17/06-
09/17/06
09/19/06-
09/21/06
09/23/06-
09/28/06
10/04/06
01/23/07-
01/30/07
02/28/07-
04/30/07
05/02/07-
07/01/07
Cause of System Downtime
System down for maintenance
System down due to leaks in 10-in transmission
line between pump house and treatment building
System down due to power outage that damaged
fuse and control panel in pump house
System down because CO2 ran out
From 05/29/06 to 06/01/06, system ran for only
two days; parameters not recorded
From 06/02/06 to 06/09/06, system down due to
leaks in 10-in transmission line between pump
house and treatment building
From 06/10/06 to 06/19/06, system ran for only
one day; operational parameters not recorded
System ran for only one day; operational
parameters not recorded
System down due to damaged membrane module
within sanitary cross
System down because CO2 ran out
System down due to leaks in transmission line
between 50,000-gal holding tank and 1,000,000
gal water tower
System down due to leaks in 10-in transmission
line between pump house and treatment building
System down because operator could not find
time to operate system
From 02/28/07 to 03/04/07, system ran for only
four days; parameters were not recorded
From 03/05/07 to 04/30/07, system down due to
leaks in transmission line between 50,000-gal
holding tank and 1,000,000 gal water tower
From 05/02/07 to 06/25/07, system down due to
drilling of a new well (Well 9), close to Well 8
From 06/26/07 to 07/01/07, system ran for only
four days; parameters were not recorded
Corrective Actions Taken
None
Repaired leaks
Repaired fuse but control
panel was never repaired
within study period. System
had been operated manually
ever since
Replaced CO2 tanks
None
Repaired leaks
None
None
Replaced membrane module
Replaced CO2 tanks
Repaired leaks
Repaired leaks
None
None
Repaired leaks
Completed new well
NA
Performed
by
Operator
Facility
Facility's
subcontractor
Operator
NA
Facility
NA
NA
ATSI and
facility
Operator
Facility
Facility
NA
NA
Facility
Facility's
subcontractor/
06/25/07
NA
Note: System not operational during weekends.
The automated portion of the system did not require regular O&M; however, operator's awareness and
ability to detect system operation problems were necessary when troubleshooting system automation
40
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failures. In addition to the hands-on training provided by the equipment vendor, a supplemental
operations manual was made available to the operator by the vendor.
Operator Skill Requirements. Under normal operating conditions, the operator skill requirements to
operate the system were minimal. However, because of the operational problems encountered with the
pH control system and the aftermath of the power outage and transmission line leakage, the operator spent
quite a bit of time troubleshooting and repairing the system. Otherwise, the operator was onsite typically
two to three times a week and spent about 40 min each time to perform visual inspections and record the
system operating parameters on the daily log sheets.
Based on the size of the population served and the treatment technology, the State of New Mexico
requires Level 3 Certification for operation of the STS system at the Taos facility. The State of New
Mexico has five levels of certifications for operations of public water supply systems, based on the
complexity of the treatment and distribution system (such as the size and type of the system, the capacity
of the system in terms of size of service area and number of users served, the type and character of the
water to be treated, and the physical conditions affecting the treatment plants). The levels range from
Level 1, the least complex, to Level 5, the most complex. The APU-450 system installed at the Town of
Taos was operated by a Level 3 operator.
Preventive Maintenance Activities. Preventive maintenance included periodic checks of flowmeters
and pressure gauges and inspection of system piping and valves. Typically, the operator performed these
duties when he was onsite for routine activities. Checking the CO2 dewars and cylinders and supply lines
for leaks and adequate pressure and calibrating the in-line pH probe also were performed.
Chemical Handling and Inventory Requirements. CO2used for pH adjustment was ordered on an as
needed basis. Typically, two 380-lb dewars lasted for about two weeks. As the CO2 dewars were
delivered to the site by the CO2 supplier, empty dewars were returned for reuse.
4.5 System Performance
The performance of the system was evaluated based on analyses of water samples collected from the
treatment plant and distribution system.
4.5.1 Treatment Plant Sampling. Table 4-13 summarizes the analytical results of arsenic, iron,
and manganese concentrations measured at the six sampling locations across the treatment train. Table 4-
14 summarizes the results of other water quality parameters. Appendix B contains a complete set of
analytical results through the study duration. The results of the water samples collected throughout the
treatment plant are discussed below.
Arsenic. Water samples were collected on 23 occasions (including two duplicate sampling events) with
field speciation performed during seven of the 23 occasions from IN, AP, and TT sampling locations.
Figure 4-19 contains three bar charts showing concentrations of particulate arsenic, soluble As(III), and
soluble As(V) for each of the seven speciation events.
Total arsenic concentrations in raw water ranged from 14.5 to 19.5 (ig/L and averaged 16.9 (ig/L. Soluble
As(V) was the predominating species, ranging from 14.3 to 18.0 (ig/L and averaging 16.8 (ig/L. Soluble
As(III) and particulate arsenic also existed, but with much lower concentrations at 0.3 and 0.2 (ig/L (on
average), respectively. The arsenic concentrations measured were consistent with those collected
previously during source water sampling (Table 4-1).
41
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Table 4-13. Summary of Analytical Results for Arsenic, Iron, and Manganese
Parameter
As (total)
As (soluble)
As
(paniculate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
Sample
Location
IN
AP
TA
TB
TC
rprp(a)
IN
AP
TT
IN
AP
TT
IN
AP
TT
IN
AP
TT
IN
AP
TA
TB
TC
TT
IN
AP
TT
IN
AP
TA
TB
TC
TT
IN
AP
TT
Unit
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
Sample
Count
23
23
16
16
16
6
7
7
6
7
7
6
7
7
6
7
7
6
19
19
12
12
12
7
7
7
7
19
19
12
12
12
7
7
7
7
Concentration
Minimum
14.5
14.5
0.1
0.1
0.7
<0.1
14.6
15.3
<0.1
<0.1
<0.1
<0.1
0.2
0.2
0.1
14.3
14.6
<0.1
<25
<25
<25
<25
<25
<25
<25
<25
<25
0.4
0.6
<0.1
0.1
0.3
0.4
0.2
0.4
<0.1
Maximum
19.5
18.8
7.4
7.2
8.8
3.7
18.5
18.5
4.0
0.5
0.7
<0.1
0.5
0.6
0.5
18.0
18.3
3.8
270
199
97.1
211
90.3
65.6
<25
<25
<25
6.3
5.0
2.6
2.9
1.9
1.1
0.9
1.1
0.4
Average
16.9
16.6
1.0
1.0
1.9
0.9
17.1
16.9
0.9
0.2
0.2
<0.1
0.3
0.4
0.2
16.8
16.6
0.7
30.7
43.3
32.4
40.0
39.0
23.2
<25
<25
<25
1.3
1.9
0.9
1.0
1.0
0.7
0.5
0.8
0.2
Standard
Deviation
1.2
1.3
1.8
1.8
2.1
1.4
1.2
1.1
1.5
0.2
0.2
-
0.1
0.2
0.2
1.2
1.3
1.5
60.0
44.9
27.5
57.3
26.3
20.4
-
-
-
1.4
1.2
0.7
0.9
0.4
0.3
0.2
0.3
0.1
(a) Total arsenic taken on
One-half of detection limit
calculations.
March 16, 2006 considered an outlier and not included in calculations.
used for samples with concentrations less than detection limit for
After pH adjustment, total arsenic concentrations remained approximately the same, ranging from 14.5 to
18.8 (ig/L and averaging 16.6 (ig/L. Soluble As(V) remained the predominating species, averaging 16.6
(ig/L. Soluble As(III) and particulate arsenic concentrations averaged 0.4 and 0.2 (ig/L, respectively.
The total arsenic breakthrough curves shown in Figure 4-20 indicate that all three vessels removed a
majority of the arsenic from pH adjusted water, leaving less than 1.1 (ig/L in the treated water after
treating approximately 22,977,000 gal of water by the end of the study. This amount of water was
42
-------
Table 4-14. Summary of Other Water Quality Sampling Results
Parameter
Alkalinity
(as CaCO3)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
pH
Temperature
Sample
Location
IN
AP
TA
TB
TC
TT
IN
AP
TT
IN
AP
TT
IN
AP
TT
IN
AP
TA
TB
TC
TT
IN
AP
TA
TB
TC
TT
IN
AP
TA
TB
TC
TT
IN
AP
TA
TB
TC
TT
IN
AP
TA
TB
TC
TT
Unit
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
NTU
NTU
NTU
NTU
NTU
s.u.
s.u.
s.u.
s.u.
s.u.
s.u.
°c
°c
°c
°c
°c
°c
Sample
Count
19
19
12
12
12
7
5
6
6
6
7
7
7
7
7
19
19
12
12
12
7
19
19
12
12
12
7
19
19
12
12
12
7
17
17
10
10
10
7
17
16
10
10
10
7
Concentration
Minimum
86.0
91.0
75.0
83.0
83.0
87.0
1.4
1.4
1.4
39.0
38.0
38.0
0.1
0.1
0.1
<10
<10
<10
<10
<10
<10
31.3
29.1
27.2
27.4
27.9
28.3
0.2
0.2
0.4
0.6
0.4
0.6
9.5
6.7
6.7
7.1
7.1
7.0
18.2
18.9
17.7
17.4
17.0
21.3
Maximum
114
106
111
107
105
105
1.6
1.6
1.6
42.0
45.0
46.0
0.2
0.2
0.2
18.5
18.5
18.1
18.2
15.4
<10
34.7
34.4
36.8
36.2
35.6
37.0
3.0
2.7
2.4
2.0
1.8
1.5
9.8
7.9
7.7
7.5
7.7
7.9
28.4
28.1
28.2
28.1
28.0
25.8
Average
99.7
99.4
97.8
96.5
95.2
98.9
1.5
1.5
1.5
40.7
41.0
41.6
0.2
0.2
0.1
<10
<10
<10
<10
<10
<10
32.8
31.9
32.3
1 1 o
32.8
32.8
33.0
0.9
1.2
1.3
1.0
0.9
1.1
9.6
7.3
7.3
7.3
7.4
7.4
23.6
23.8
24.4
24.5
24.4
22.6
Standard
Deviation
6.5
4.1
9.6
6.1
5.9
5.9
0.1
0.1
0.1
1.0
2.1
2.5
-
-
-
4.6
4.5
5.0
5.1
4.1
-
1.0
1.6
2.9
2.8
2.4
3.3
0.7
0.8
0.7
0.5
0.4
0.3
0.1
0.4
0.3
0.2
0.2
0.3
2.6
2.5
3.1
3.0
3.1
1.5
43
-------
Table 4-14. Summary of Other Water Quality Sampling Results (Continued)
Parameter
DO
ORP
Total Hardness
(as CaCO3)
Ca Hardness
(as CaCO3)
Mg Hardness
(as CaCO3)
Sample
Location
IN
AP
TA
TB
TC
TT
IN
AP
TA
TB
TC
TT
IN
AP
TT
IN
AP
TT
IN
AP
TT
Unit
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mV
mV
mV
mV
mV
mV
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
Sample
Count
13
13
8
8
8
5
17
17
10
10
10
7
7
7
7
7
7
7
7
7
7
Concentration
Minimum
0.9
0.8
0.8
0.7
0.5
1.2
222
224
224
225
222
245
2.9
2.7
0.6
2.8
2.6
0.5
<0.1
<0.1
<0.1
Maximum
2.7
2.6
3.3
3.1
2.8
1.5
348
356
412
361
363
343
4.2
4.5
7.9
4.1
4.4
7.9
<0.1
0.1
0.2
Average
1.4
1.3
1.6
1.7
1.7
1.3
269
273
278
283
282
302
3.7
3.7
4.6
3.6
3.6
4.5
<0.1
<0.1
<0.1
Standard
Deviation
0.5
0.5
0.7
0.7
0.7
0.1
42.3
43.7
62.3
51.4
53.2
39.5
0.4
0.6
3.2
0.4
0.6
3.2
-
0.03
0.05
One-half of detection limit used for samples with concentrations less than detection limit for calculations.
equivalent to 14,200 BV based on 216 ft3 of media in the three vessels. The 14,200 BV represents
approximately 11% of media capacity estimated to be 130,000 BV by the vendor.
A spike occurred on January 31, 2007, with arsenic concentrations increasing to as high as 8.8 ug/L in the
vessel effluent. pH values of these samples were measured at 7.5 to 7.7, just over the average values of
7.3 to 7.4 for all samples collected at the same locations. Therefore, pH was not considered to be the
contributing reason. It is worth noting that the same samples also contained somewhat higher iron
concentrations (i.e., 67 to 97 (ig/L vs. <25 (ig/L). The spike might be due to samples taken after
prolonged system downtime.
Iron and Manganese. Total iron concentrations in raw water ranged from <25 to 270 (ig/L and averaged
30.7 (ig/L, existing mostly as particulate iron. Particulate iron might exist in source water as part of
natural sediment or formed by inadvertent aeration of samples during sampling. The amounts of DO
measured in source water, however, were low, ranging from 0.9 to 2.7 mg/L and averaging 1.4 mg/L.
The source water sample taken during the December 1, 2004, site visit, also contained a similar amount of
total iron (i.e., 59 |og/L) with over 79% existing as particulate iron. Total iron concentrations were close
to or below the method reporting limit of 25 |o,g/L in raw water except for two occasions on August 2,
2006, and January 31, 2007, when total iron concentrations were 78 and 270 (ig/L, respectively. After pH
adjustment and adsorption, total iron concentrations remained relatively unchanged, averaging 43.3, 32.4,
40.0, and 39.0 (ig/L at AP, TA, TB, and TC locations. It is possible that some iron particles penetrated
through the media beds or that some media fines were washed from the media beds. Manganese
concentrations were low in raw water and across the treatment train, ranging from 0.7 to 1.3 |o,g/L.
Manganese existed mostly as particulate.
44
-------
Arsenic Species at Wellhead (IN)
02/14/06 03/16/06
18/02/06 10/11 /06 12/13/06
Arsenic Species after pH Adjustment and Contact Tanks (AP)
02/14/06 03/16/06 05/01/06
07/1 8/06 08/02/06 1 0/1 1/06 12/1 3/06
Date
Arsenic Species after Total Comnined Effluent (TT)
I"
03/16/06 05/01/06 07/18/06 08/02/06
Date
10/11/06 12/13/06
Figure 4-19. Concentrations of Various Arsenic Species at IN, AP, and TT Sampling Locations
45
-------
25.0
20.0 -
1 15.0
c
o 10.0
0.0 »
-At Wellhead (IN)
-After pH Adjustment (AP)
- After Vessel A (T A)
After Vessel B (TB)
-After Vessel C (TC)
-After Effluent Combined (TT)
AsMCL= 10ug/L
Bed Volumes (103)
Figure 4-20. Total Arsenic Breakthrough Curves
(Based on 216ft3 of Media in All Three Vessels)
Competing Anions. Phosphate and silica, which can influence arsenic adsorption, were measured across
the treatment train throughout the demonstration study. Phosphorous concentrations remained below the
method reporting limit of 10 (ig/L (as P) across the treatment train. Silica concentrations in raw water
ranged from 31.3 to 34.7 mg/L and averaged 32.8 mg/L. There were no noticeable reductions of silica
concentration across the treatment train. As such, neither phosphorus nor silica would cause harmful
effects on arsenic adsorption.
Other Water Quality Parameters. All other water quality parameters measured were comparable to
source water results presented in Table 4-1. As shown in Table 4-14, pH values of raw water varied from
9.5 to 9.8 and averaged 9.6. pH values following CO2 injection varied from 6.7 to 7.9 and averaged 7.3,
indicating effective pH adjustment. At near neutral pH values, the media has a greater removal capacity
for arsenic, thereby prolonging the media life. After adsorption vessels at TA, TB, and TC, pH values
remained rather unchanged, ranging from 7.3 to 7.4. Figure 4-21 presents the pH values measured
throughout the treatment train.
As also shown in Figure 4-21, pH values measured with the VWR field meter at the AP location were
comparable to those reported by the in-line pH probe, averaging 7.3 and 7.4, respectively, throughout the
study duration. Degassing of dissolved CO2 did not appear to be a concern in terms of elevating pH
values measured with the VWR field meter.
46
-------
10.0
9.0 --
From 02/13/08 to 05/04/06, in-line pH
^ probe broken and VWR field meter used
to take pH readings
7.0
6.5 --
6.0
-At Wellhead (IN)
- After pH Adjustment (AP)
-After Effluent Combined (TA/TB/TC/TT)
-In-line pH Probe after Adjustment
6 8 10
Bed Volume (103)
12
14
16
Figure 4-21. pH Values Measured throughout Treatment Train
(Based on 216 ft3 of Media in all Three Vessels)
Alkalinity, reported as CaCO3, in raw water ranged from 86.0 to 114 mg/L. The results indicated that the
adsorptive media did not affect the amount of alkalinity in the treated water. The treatment plant samples
were analyzed for hardness only on speciation weeks. Total hardness in raw water ranged from 2.9 to 4.2
mg/L (asCaCO3), and also remained constant throughout the treatment train. Sulfate concentrations in
raw water ranged from 39 to 42 mg/L, and remained constant throughout the treatment train. Fluoride
results ranged from 1.4 to 1.6 mg/L in all samples, indicating that the media did not remove fluoride. DO
levels ranged from 0.9 to 2.7 mg/L and averaged 1.4 mg/L in raw water. ORP readings averaged 269 mV
in raw water and remained approximately the same throughout the treatment train.
4.5.2 Backwash Wastewater Sampling. Table 4-15 presents the analytical results for the three
adsorption vessels during each of the three monthly backwash wastewater sampling events. pH values
ranged from 7.4 to 8.1 and averaged 7.7, somewhat higher than that of the treated water used for
backwash. The water used for backwash was withdrawn from the 50,000-gal holding tank. Some CO2
degassing might have taken place during storage and transit, thereby elevating the pH values. TDS levels
ranged from 204 to 228 mg/L. Because very little iron and manganese existed in the source water, TSS
values were low, ranging from 16 to 82 mg/L and averaging 37 mg/L (excluding an outlier of 450 mg/L).
Concentrations of total arsenic, iron, and manganese ranged from 1.1 to 11.8 |o,g/L, from 0.14 to 8.9 mg/L,
and from 0.7 to 64.0 |o,g/L, respectively, with the majority of iron and manganese existing in the
particulate form. The unexpectedly high iron concentrations in the backwash wastewater suggest some
media fines were produced and removed during backwashing. Assuming an average of 3,297 gal
backwash (see Table 4-10) and 1,000 gal forward flush wastewater production, each backwash cycle
47
-------
Table 4-15. Backwash Water Sampling Results
No.
1
2
3
Date
04/10/06'"1
07/10/07
10/10/07
Vessel A
S.U.
7.6
7.7
8.1
i
mg/L
210
218
222
VI
H
mg/L
450
82
26
As (total)
Mg/L
2.4
2.6
11.8
As (soluble)
Mg/L
1.2
0.1
1.2
As (particulate)
Mg/L
1.3
2.5
10.6
Fe (total)
Mg/L
5,388
5,560
4,742
Fe (soluble)
Mg/L
103
75.2
<25
"«
c
Mg/L
59.4
53.2
13.9
Mn (soluble)
Mg/L
0.5
0.7
<0.1
Vessel B
S.U.
7.5
7.4
7.9
i
mg/L
218
206
228
03
H
mg/L
20
44
16
As (total)
Mg/L
1.8
2.7
3.8
As (soluble)
Mg/L
1.3
2.7
3.9
As (particulate)
Mg/L
0.6
0.1
01
1
Mg/L
1,275
135
3,663
I
Mg/L
51.9
166
<25
"«
c
Mg/L
10.9
0.7
14.7
Mn (soluble)
Mg/L
0.9
1.0
0.4
Vessel C
S.U.
7.5
7.5
7.8
i
mg/L
206
204
210
03
H
mg/L
22
68
21
As (total)
Mg/L
1.1
2.5
4.7
As (soluble)
Mg/L
1.3
2.3
3.7
As (particulate)
Mg/L
0.1
0.2
1.0
1
Mg/L
997
7,465
8,906
I
Mg/L
38.3
100
<25
"«
c
Mg/L
5.8
64.0
25.3
Mn (soluble)
Mg/L
0.3
0.8
0.2
(a) TC samples taken on 04/13/06; TDS = total dissolved solids; TSS = total suspended solids
-------
would have discharged 4 Ib of solids, comprising of 0.46 Ib of iron, 4* 10~4 Ib of arsenic, and 3* 10~3 Ib of
manganese.
4.5.3 Distribution System Water Sampling. Prior to the installation/operation of the treatment
system, baseline distribution system water samples were collected from three LCR locations from May 25
to August 30, 2005. Following system startup, distribution system water sampling continued on a
monthly basis at the same three locations, with samples collected from March 1, 2006, through February
27, 2007. The results of the distribution system sampling are summarized on Table 4-16.
After system startup, arsenic and iron concentrations increased slightly from 0.3 to 1.1 (ig/L (on average)
and from <25 to 29 (ig/L, respectively, while, manganese concentrations decreased from 5.3 to 1.4 (ig/L
at each of the three sampling locations. The fact that the treated water originated from Well 8 represents
only about 10% of the water in the 1,000,000-gal water tower, from which water was sent to the
distribution system (Sections 4.1.1 and 4.1.4), explains why the results remained essentially unchanged
after system startup.
Measured pH values averaged 7.5 after system startup, compared to an average value of 7.3 before system
startup. The higher pH values of Well 8 water did not appear to have affected the pH values in the
distribution system with or without system operation. Copper concentrations decreased from 119 to 56
(ig/L; lead concententrations decreased slightly from 1.5 to 1.1 (ig/L. Alkalinity levels remained
unchanged after system startup and averaged 175 mg/L.
4.6 System Cost
The system cost was evaluated based on the capital cost per gpm (or gpd) of the design capacity and the
O&M cost per 1,000 gal of water treated. The capital cost included the cost for equipment, site
engineering, and installation and the O&M cost included media replacement and disposal, CO2
consumption, electrical power usage, and labor.
4.6.1 Capital Cost. The capital investment for equipment, site engineering, and installation of the
treatment system was $296,644 (Table 4-17). The equipment cost was $202,685 (or 68% of the total
capital investment), which included $26,500 for the automatic CO2 control system, $121,279 for the skid-
mounted APU-450 unit, $35,539 for 180 ft3 of E33 pelletized media ($197/ft3 or $5.64/lb to fill three
vessels), $8,660 for shipping, and $10,707 for labor.
The site engineering cost included the cost for preparing a submittal package for permit application and
supplemental information to respond to the State's comments (see Section 4.3.1). The engineering cost
was $32,750, or 11% of the total capital investment.
The installation cost included the equipment and labor to unload and install the skid-mounted unit,
perform piping tie-ins and electrical work, load and backwash the media, perform system shakedown and
startup, and conduct operator training. The installation cost was $61,209, or 21% of the total capital
investment.
The total capital cost of $296,644 was normalized to the system's rated capacity of 450 gpm
(648,000 gpd), which resulted in $659/gpm (or $0.46/gpd) of design capacity. The capital cost also was
converted to an annualized cost of $28,000/yr using a capital recovery factor (CRF) of 0.09439 based on a
7% interest rate and a 20-year return period. Assuming that the system operated 24 hours a day, 7 days a
week at the system design flowrate of 450 gpm to produce 236,520,000 gal of water per year, the unit
capital cost would be $0.12/1,000 gal. Considering that the system actually operated at an average of
503 gpm for 3.9 hr/day in 215 days during the performance evaluation (see Table 4-10), it would produce
49
-------
Table 4-16. Distribution Water Sampling Results
Sampling
Date
No.
BL1
BL2
BL3
BL4
Date
05/25/05
06/22/05
07/20/05
08/30/05
Average
1
2
3
4
5
6
7
8
03/01/06
4/17/2006
06/28/06
08/02/06
10/11/06
1 1/29/06
01/31/07
02/22/07
Average
"S
£
%
1
"S
1
Hg/L
NA
NA
NA
NA
NA
0.4
NA
NA
0.2
0.7
NA
7.8
3.8
2.6
Fe at Entry Point
Hg/L
NA
NA
NA
NA
NA
<25
NA
NA
<25
<25
NA
79
<25
26
Mn at Entry
Point
Hg/L
NA
NA
NA
NA
NA
0.2
NA
NA
0.4
0.6
NA
2.2
0.6
0.8
DS1
1st Draw
Stagnation
Time
hr
7.3
7.3
6.8
6.7
7.0
14.1
7.5
7.3
7.4
7.3
7.6
8.3
8.3
8.5
S3
s.u.
7.4
7.3
7.4
7.2
7.3
7.7
7.8
7.4
7.7
7.4
7.2
7.7
7.6
7.6
Alkalinity
mg/L
223
163
176
132
174
104
184
251
135
194
160
206
215
181
"3
S
1
Hg/L
0.5
0.4
0.2
0.3
0.4
0.4
0.1
2.0
0.3
0.4
0.3
2.4
3.3
1.1
Fe (total)
Hg/L
<25
<25
<25
<25
<25
<25
<25
<25
<25
<25
80
<25
<25
<25
i*
"8
1
Hg/L
0.2
0.1
0.1
0.1
0.1
<0.1
1.9
0.3
0.2
<0.1
1.0
0.8
<0.1
0.5
j=
ga
Hg/L
0.5
0.4
0.6
0.6
0.5
0.3
2.4
0.8
0.4
0.4
0.5
2.5
<0.1
0.9
3
Hg/L
32.7
26.0
53.6
52.9
41.3
19.7
162
22.4
18.6
43.5
69.2
38.2
17.2
48.9
DS2
1st Draw
Stagnation
Fime
hr
14.6
14.0
14.0
14.3
14.2
8.8
13.5
14.0
13.1
14.2
14.1
14.4
14.4
13.3
S3
S.U.
7.5
7.4
7.4
7.2
7.4
7.7
7.6
7.5
7.6
7.5
7.3
7.5
7.6
7.5
Alkalinity
mg/L
178
163
176
163
170
178
132
147
143
161
209
222
210
175
As (total)
Hg/L
0.4
0.4
0.2
0.2
0.3
0.3
0.1
0.3
0.3
0.4
0.2
1.6
3.8
0.8
Fe (total)
Hg/L
<25
<25
<25
<25
<25
<25
<25
<25
<25
<25
82
<25
<25
<25
i*
"8
1
Hg/L
3.8
5.0
8.1
3.9
5.2
2.8
0.5
<0.1
2.2
1.8
0.9
0.3
<0.1
1.1
j=
ga
Hg/L
1.3
1.4
2.4
2.1
1.8
0.4
0.5
0.3
0.9
1.4
1.6
1.7
<0.1
0.9
3
Hg/L
142
180
208
176
176
77.7
23.1
34.0
127
174
42.0
47.7
38.4
70.4
DS3
1st Draw
Stagnation
Fime
hr
14.6
13.2
8.0
12.4
12.1
14.5
12.5
14.1
13.6
14.6
14.3
15.2
15.2
14.3
S3
S.U.
7.4
7.5
7.3
7.2
7.4
7.6
7.6
7.5
7.3
7.7
7.3
7.5
7.7
7.5
Alkalinity
mg/L
236
198
220
233
222
174
171
172
257
111
72
187
215
170
"3
S
1
Hg/L
0.4
0.4
0.2
0.2
0.3
0.4
0.2
0.4
0.4
1.9
<0.1
1.7
4.4
1.2
Fe (total)
Hg/L
<25
<25
<25
<25
<25
<25
125
<25
<25
169
<25
<25
<25
46
Mn (total)
Hg/L
0.5
20.6
20.0
1.4
10.6
8.6
1.4
10.8
0.3
0.7
0.4
0.3
<0.1
2.8
j=
ga
Hg/L
2.4
2.5
2.6
1.7
2.3
0.2
3.1
1.1
0.7
1.6
2.5
1.0
1.3
1.5
3
Hg/L
48.4
226
189
87.0
138
26.8
47.2
121
88.4
24.8
36.5
13.8
18.7
47.2
BL = Baseline Sampling; NS = not sampled; NA = not analyzed
-------
Table 4-17. Capital Investment Cost for APU-450 System
Description
Quantity
Cost
% of Capital
Investment
Equipment Cost
Automatic CO2 Control System
APU Adsorption Vessels
Process Valves and Piping
Instrumentation and Controls
E33 Adsorptive Media ( ft3)
Shipping
Vendor Labor
Equipment Total
1
3
1
1
180
-
-
-
$26,500
$55,000
$29,500
$36,779
$35,539
$8,660
$10,707
$202,685
-
-
-
-
-
68%
Engineering Cost
Vendor Labor/Travel
Subcontractor Labor/ Travel
Engineering Total
-
-
-
$11,800
$20,950
$32,750
-
-
11%
Installation Cost
Vendor Labor
Vendor Travel
Subcontractor Labor/Travel
Installation Total
Total Capital Investment
-
-
-
-
-
$6,118
$6,197
$48,894
$61,209
$296,644
-
-
-
21%
100%
42,961,000 gal of water in one year. Under these conditions, the unit capital cost increases to
$0.65/1,000 gal at this reduced rate of use.
4.6.2 Operation and Maintenance Cost. The O&M cost included the cost for such items as
media replacement and disposal, CO2 consumption, electricity usage, and labor (Table 4-18). Although
media replacement did not take place during system operation, the media replacement cost would
represent the majority of the O&M cost and was estimated to be $41,749 to change out the three vessels.
This media changeout cost would include the cost for replacement media and underbedding, spent media
analysis and disposal, freight, labor and travel. This cost was used to estimate the media replacement cost
per 1,000 gal of water treated as a function of the projected system run length at the 10 (ig/L arsenic
breakthrough (Figure 4-22).
The chemical cost associated with the operation of the treatment system included the cost for CO2 gas for
pH control. The 380-lb CO2 dewars were replaced a total of eleven times during the performance
evaluation with the system operating for 215 days. Each changeout of two 380-lb CO2 dewars was $150
(or approximately $0.20/lb) and the delivery charges per changeout were $30.00. Therefore, the total cost
incurred for the 11 changeouts was $1,980. The annual rental fees for one 380-lb dewar and one 50-lb
high pressure cylinder were $615.40 and $133.40, respectively. Because the cylinder lease was a fixed
cost, the total rental fees for four 380-lb dewars and two 50-lb cylinders for the 88-week study period was
$4,617. As a result, the CO2 cost for the 215-day system operation was $6,597 or $0.29/1,000 gal of
water treated.
Comparison of electrical bills supplied by the utility before and after system startup did not indicate a
noticeable increase in power consumption. Therefore, electrical cost associated with operation of the
system was assumed to be negligible.
51
-------
Under normal operating conditions, routine labor activities to operate and maintain the system consumed
an average of 40 min/day. For the 215 days of system operation at a labor rate of $19.5/hr, $2,795 labor
cost was incurred when producing 22,977,000 gal of water. Therefore, the estimated labor cost was
$0.12/1,000 gal of water treated.
Table 4-18. Operation and Maintenance Cost for APU-450 System
Cost Category
Volume Processed (gal)
Value
22,977,000
Assumptions
Through October 23, 2007 (Table 4-10)
Media Replacement and Disposal Cost
Media Replacement ($)
Shipping ($)
Vendor Labor/Travel ($)
Media Disposal ($)
Subtotal
Media Replacement and
Disposal ($71,000 gal)
$35,539
$1,080
$3,500
$1,630
$41,749
See Figure 4-22
Vendor quote for 180 ft3 for all three vessels
Vendor quote
Vendor quote
Vendor quote
Vendor quote
CO 2 Usage
CO2 Gas ($71,000 gal)
$0.29
Based on consumption of CO2 for pH
adjustment (380-lb dewars)
Electricity Cost
Electricity ($71,000 gal)
$0.00
Electrical costs assumed negligible
Labor Cost
Labor ($71, 000 gal)
Total O&M Cost/1,000 gal
$0.12
See Figure 4-22
40 min/day for 215 days (Table 4-10) at a
labor rate of $19.5/hr
52
-------
$5.00
$4.50
O&M cost
Media replacement cost
$0.00
10
20
30
40 50 60 70 80 90 100 110 120 130
Media Working Capacity, Bed Volumes (xlOOO)
Figure 4-22. Media Replacement and Operation and Maintenance Cost
53
-------
5.0 REFERENCES
Battelle. 2004. Quality Assurance Project Plan for Evaluation of Arsenic Removal Technology.
Prepared under Contract No. 68-C-00-185, Task Order No. 0029, for U.S. Environmental
Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH.
Chen, A.S.C., L. Wang, J.L. Oxenham, and W.E. Condit. 2004. Capital Costs of Arsenic Removal
Technologies: U.S. EPA Arsenic Removal Technology Demonstration Program Round 1.
EPA/600/R-04/201. U.S. Environmental Protection Agency, National Risk Management
Research Laboratory,Cincinnati, OH.
Edwards, M., S. Patel, L. McNeill, H. Chen, M. Frey, A.D. Eaton, R.C. Antweiler, and H.E. Taylor. 1998.
"Considerations in As Analysis and Speciation." J. AWWA, 90(3): 103-113.
EPA. 2003. Minor Clarification of the National Primary Drinking Water Regulation for Arsenic. Federal
Register, 40 CFRPart 141.
EPA. 2002. Lead and Copper Monitoring and Reporting Guidance for Public Water Systems.
EPA/816/R-02/009. U.S. Environmental Protection Agency, Office of Water, Washington, D.C.
EPA. 2001. National Primary Drinking Water Regulations: Arsenic and Clarifications to Compliance
and New Source Contaminants Monitoring. Federal Register, 40 CFR Parts 9, 141, and 142.
Wang, L., W.E. Condit, and A.S.C. Chen. 2004. Technology Selection and System Design: U.S. EPA
Arsenic Removal Technology Demonstration Program Round 1. EPA/600/R-05/001. U.S.
Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati,
OH.
54
-------
APPENDIX A
OPERATIONAL DATA
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet
Day of
Week
Cumulative
Treated1"*
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
Day of
Week
Cumulative
Bed Volumes
Treated1"*
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
Cumulative
Bed Volumes
Treated"'
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
Day of
Week
Cumulative
Treated'"1
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
Day of
Week
Cumulative
Treated1"*
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
Cumulative
Treated1"*
>
oo
-------
US EPA Arsenic Demonstration Project at Taos, NM - Daily System Operation Log Sheet (Continued)
Day of
Week
Cumulative
Bed Volumes
Treated'"1
31 A, 73 cu ft (546 c
-------
APPENDIX B
ANALYTICAL DATA TABLES
-------
Analytical Results from Long Term Sampling at Taos, NM
Sampling Date
Sampling Location
Parameter Unit
Bed Volume
Alkalinity
(CaC03)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Total Hardness
(CaC03)
Ca Hardness
(CaC03)
Vlg Hardness
(CaC03)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Vln (total)
Vln (soluble)
10A3
mg/L
mg/L
mg/L
mg/L
WJ/L
mg/L
NTU
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
02/14/06
IN
-
112
1.4
40
0.2
346
1.4
9.5
20.3
0.9
340
3.6
3.5
<0.1
17.3
17.1
0.2
0.2
16.9
<25
<25
1.0
0.6
AP
-
104
1.4
40
0.2
340
1.1
7.3
20.9
0.9
350
3.5
3.4
<0.1
17.0
17.8
<0.1
0.3
17.4
<25
<25
1.1
0.8
TT
0.02
100
1.4
40
0.2
300
1.4
7.2
22.3
1.2
338
3.0
2.9
<0.1
<0,
<0.1
<0.1
0.2
<0.1
<25
<25
0.4
0.2
02/22/06
IN
-
96
34 1
0.6
9.6
25.7
1.4
256
16.9
<25
0.7
AP
-
96
344
0.9
7.1
24.0
1.1
259
17.4
<25
0.7
TA
0.5
96
340
0.8
7.1
24.6
1.2
260
0.2
<25
0.2
TB
0.3
83
355
0.7
7.1
24.5
1.1
273
0.4
<25
0.1
TC
0.5
87
356
0.7
7.1
24.3
1.2
282
1.9
31
1.0
03/01 /06(a)
IN
-
95
31 4
0.6
9.7
18.2
1.1
275
16.1
<25
0.7
AP
-
100
296
2.2
7.0
18.9
1.3
278
14.6
66
3.1
TA
0.9
95
31 4
0.5
7.0
17.7
1.3
278
0.3
<25
0.1
TB
0.5
95
295
1.9
7.2
17.4
1.4
277
0.2
<25
<0,
TC
1.0
95
298
1.1
7.2
17.0
1.2
279
0.7
<25
0.3
03/07/06
IN
-
100
322
1.7
NA
NA
NA
NA
16.2
36
2.3
AP
-
100
308
2.1
NA
NA
NA
NA
15.8
76
2.9
TA
1.0
100
28 7
1.1
NA
NA
NA
NA
0.1
<25
0.3
TB
0.6
100
31 3
0.7
NA
NA
NA
NA
0.5
211
2.9
TC
1.1
95
32 1
1.8
NA
NA
NA
NA
1.4
32
1.4
(a) Onsite water quality parameters taken on 03/02/06.
-------
Analytical Results from Long Term Sampling at Taos, NM (Continued)
Cd
to
Sampling Date
Sampling Location
Parameter Unit
Bed Volume
Alkalinity
(CaC03)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Total Hardness
(CaCO3)
Ca Hardness
(CaC03)
Mg Hardness
(CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Vln (soluble)
10A3
mg/L
mg/L
mg/L
mg/L
ng/L
mg/L
NTU
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
03/16/06(a)
IN
-
95
1.6
41
0.2
<10
31.3
0.6
9.6
21.1
1.1
243
3.5
3.4
<0.1
14.5
14.6
<0.1
0.4
14.3
<25
<25
0.9
0.5
AP
-
91
1.6
41
0.2
<10
32.6
0.5
7.7
12.6
1.1
249
3.4
3.3
<0.1
15.1
15.3
<0.1
0.6
14.6
<25
<25
0.8
0.4
TT
1.2
87
1.6
41
0.2
<10
28.3
1.1
7.3
21.4
1.5
267
0.8
0.7
<0.1
19.7
16.7
3.1
0.6
16.1
<25
<25
0.5
<0.1
04/11/06(b)
IN
-
97
-
-
-
<10
32.2
1.3
9.7
25.0
1.1
348
-
-
-
17.9
-
-
-
-
<25
-
1.0
-
AP
-
97
-
-
-
<10
32.3
1.1
6.7
25.7
1.0
356
-
-
-
18.1
-
-
-
-
<25
-
1.2
-
TA
1.9
106
-
-
-
<10
31.9
2.2
7.1
26.1
1.3
360
-
-
-
0.4
-
-
-
-
66
-
1.8
-
TB
1.3
101
-
-
-
<10
32.4
2.0
7.2
25.5
1.6
361
-
-
-
0.4
-
-
-
-
51
-
1.8
-
TC
2.1
97
-
-
-
<10
33.1
1.5
7.1
25.7
1.4
363
-
-
-
1.3
-
-
-
-
76
-
1.5
-
05/01/06(c)
IN
-
96
1.5
41
0.1
<10
32.8
0.8
9.6
21.4
1.1
297
4.2
4.1
<0.1
16.9
17.1
<0.1
0.3
16.8
<25
<25
1.7
0.6
AP
-
96
1.6
41
0.1
<10
32.9
0.9
7.3
21.1
1.2
305
4.3
4.2
<0.1
17.6
17.2
0.3
0.3
16.9
64
<25
2.0
1.0
TT
2.0
96
1.5
42
0.1
<10
34.8
1.5
7.0
21.3
1.2
299
4.8
4.6
0.2
0.2
0.1
<0.1
0.1
<0.1
34
<25
1.1
0.4
05/31/06
IN
-
104
104
-
-
-
18.5
14.8
32.7
31.6
0.4
0.6
NA
NA
NA
NA
-
-
-
15.5
15.4
-
-
-
-
<25
<25
-
0.6
0.6
-
AP
-
104
96
-
-
-
18.5
16.0
30.2
29.1
2.7
1.4
NA
NA
NA
NA
-
-
-
14.7
14.5
-
-
-
-
55
49
-
2.5
2.6
-
TA
2.9
100
96
-
-
-
12.1
18.1
30.7
30.9
0.8
1.3
NA
NA
NA
NA
-
-
-
0.7
0.5
-
-
-
-
<25
38
-
0.8
0.8
-
TB
2.2
100
100
-
-
-
11.9
18.2
30.9
31.5
0.7
0.6
NA
NA
NA
NA
-
-
-
0.8
0.7
-
-
-
-
<25
30
-
0.6
0.5
-
TC
3.1
96
96
-
-
-
11.9
14.0
31.2
31.1
0.6
0.7
NA
NA
NA
NA
-
-
-
1.4
1.3
-
-
-
-
<25
52
-
0.7
0.6
-
(a) Onsite water quality parameters taken on 03/13/06. (b) Onsite water quality parameters taken on 04/14/06.
(c) Onsite water quality parameters taken on 05/04/06.
-------
Analytical Results from Long Term Sampling at Taos, NM (Continued)
Cd
OJ
Sampling Date
Sampling Location
Parameter Unit
Bed Volume
Alkalinity
(CaCO3)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
pH
Temperature
DO
ORP
Total Hardness
(CaCO3)
Ca Hardness
(CaC03)
Mg Hardness
(CaC03)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
10A3
mg/L
mg/L
mg/L
mg/L
ng/L
mg/L
NTU
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
Mg/L
Mg/L
|jg/L
|jg/L
|jg/L
|jg/L
(jg/L
(jg/L
Mg/L
06/21 /06(a)
IN
103
-
-
-
10
32.7
1.1
9.7
24.7
NA
258
-
-
18.4
-
<25
-
0.8
AP
95
-
-
-
10
30.8
0.7
6.7
24.9
NA
256
-
-
16.4
-
76
-
3.2
TA
3.2
75
-
-
-
10
27.2
2.4
6.7
24.8
NA
280
-
-
0.3
-
55
-
1.4
TB
2.5
90
-
-
-
10
27.4
0.8
7.1
24.6
NA
327
-
-
0.5
-
25
-
0.8
TC
3.3
83
-
-
-
10
27.9
0.9
7.4
24.4
NA
341
-
-
1.2
-
90
-
1.1
07/1 8/06(b)
IN
92
4.1
44
0.2
10
33.1
0.3
9.6
23.3
1.6
321
2.9
2.8
0.1
18.3
17.8
0.5
0.2
17.6
<25
<25
1.1
0.2
AP
97
2.1
38
0.2
10
32.6
0.8
7.5
24.1
1.3
324
2.7
2.6
0.1
17.9
18.5
0.1
0.2
18.3
<25
<25
0.7
0.4
TT
3.9
100
2.1
43
0.2
10
30.9
1.1
7.3
23.1
1.3
343
0.6
0.5
0.1
3.7
4.0
0.1
0.2
3.8
66
<25
1.1
0.1
08/02/06
IN
97
2.0
39
0.1
10
32.2
0.7
9.6
23.3
1.6
321
3.8
3.8
0.1
16.8
16.8
0.1
0.2
16.6
78
<25
3.7
0.9
AP
97
1.6
45
0.2
10
30.1
0.4
7.5
24.1
1.3
324
3.9
3.8
0.1
16.7
17.2
0.1
0.2
17.0
38
<25
2.7
1.1
TT
4.2
101
1.6
38
0.2
10
35.3
0.6
7.4
22.5
1.3
340
7.9
7.9
0.04
0.2
0.2
0.1
0.1
0.1
<25
<25
0.4
0.2
08/1 6/06(c)
IN
98
86
-
-
-
<10
32.7
33.9
1.3
0.2
9.6
24.0
2.7
230
-
-
16.6
16.5
-
<25
<25
-
0.5
0.6
AP
98
98
-
-
-
<10
33.5
33.8
0.5
0.2
7.2
22.6
2.6
236
-
-
16.0
16.8
-
<25
<25
-
0.6
0.8
TA
4.2
90
94
-
-
-
<10
32.9
35.2
2.1
1.5
7.0
23.5
3.3
237
-
-
0.2
0.2
-
28
29
-
1.0
1.4
TB
3.5
94
98
-
-
-
<10
34.2
35.7
0.7
0.7
7.5
23.6
3.1
246
-
-
0.2
0.1
-
<25
<25
-
1.0
0.9
TC
4.4
98
102
-
-
-
<10
34.5
35.5
0.4
0.4
7.5
23.7
2.8
250
-
-
0.9
0.8
-
26
27
-
1.0
1.1
(a) Onsite water quality parameters taken on 06/29/06. (b) Onsite water quality parameters taken on 07/06/06.
(c) Onsite water quality parameters taken on 08/08/06.
-------
Analytical Results from Long Term Sampling at Taos, NM (Continued)
Cd
Sampling Date
Sampling Location
Parameter Unit
Bed Volume
Alkalinity
(CaCO3)
=luoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
PH
Temperature
DO
ORP
Total Hardness
(CaCO3)
Ca Hardness
(CaCO3)
Vlg Hardness
(CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
As(V)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
10A3
mg/L
mg/L
mg/L
mg/L
ng/L
mg/L
NTU
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
10/11/06(a)
IN
-
100
1.4
42
0.2
<10
32.9
0.3
9.8
21.1
NA
255
4.2
4.1
<0.1
18.7
18.5
0.2
0.5
18.0
<25
<25
0.6
0.4
AP
-
103
1.4
41
0.1
<10
30.3
2.5
7.8
21.8
NA
258
4.5
4.4
<0.1
15.8
15.7
0.1
0.4
15.3
52
<25
2.7
1.0
TT
5.2
105
1.4
46
0.1
<10
34.9
0.9
7.9
22.1
NA
279
7.9
7.8
<0.1
0.7
0.8
<0.1
0.5
0.3
<25
<25
0.6
0.3
11/14/06
IN
-
101
-
-
-
<10
32.4
0.8
NA
NA
NA
NA
-
-
-
17.4
-
-
-
-
<25
-
0.4
-
AP
-
103
-
-
-
<10
32.1
0.5
NA
NA
NA
NA
-
-
-
18.4
-
-
-
-
<25
-
0.7
-
TA
6.5
111
-
-
-
<10
31.5
0.4
NA
NA
NA
NA
-
-
-
0.4
-
-
-
-
<25
-
0.2
-
TB
5.6
107
-
-
-
<10
36.2
1.5
NA
NA
NA
NA
-
-
-
0.4
-
-
-
-
<25
-
1.0
-
TC
6.8
105
-
-
-
<10
34.9
0.9
NA
NA
NA
NA
-
-
-
1.8
-
-
-
-
<25
-
0.6
-
12/13/06(b)
IN
-
103
1.5
41
0.1
<10
31.9
0.6
9.6
24.2
NA
230
3.4
3.4
<0.1
17.4
17.7
<0.1
0.4
17.2
<25
<25
0.9
0.3
AP
-
105
1.5
41
0.2
<10
31.9
0.6
7.9
25.4
NA
236
3.4
3.3
<0.1
17.6
16.9
0.7
0.5
16.5
<25
<25
1.3
0.9
TT
7.6
103
1.6
41
0.1
<10
37.0
0.8
7.5
25.8
NA
245
6.9
6.8
<0.1
0.4
0.4
<0.1
0.3
<0.1
<25
<25
0.7
0.2
01/31/07(c)
IN
-
102
-
-
-
18.4
34.7
3.0
9.6
23.3
1.0
274
-
-
-
15.8
[15.1]
{15.3}
-
-
-
-
270
[407]
{340}
-
6.3
[8.7]
{7.5}
-
AP
-
102
-
-
-
14.6
33.7
1.2
7.6
22.8
0.8
285
-
-
-
15.7
[15.3]
{15.4}
-
-
-
-
199
[230]
{270}
-
5.0
[6.1]
{6.1}
-
TA
8.8
102
-
-
-
16.7
35.9
1.3
7.7
22.7
0.8
412
-
-
-
7.4
[6.3]
{5.7}
-
-
-
-
97
[125]
{137}
-
2.6
[3.8}
[2.7]
-
TB
7.6
94
-
-
-
17.5
34.6
1.5
7.5
23.8
0.7
341
-
-
-
7.2
[6.0]
{5.4}
-
-
-
-
74
[84]
{90}
-
2.2
[3.4]
{2.1}
-
TC
9.3
92
-
-
-
15.4
34.3
1.4
7.6
24.0
0.5
293
-
-
-
8.8
[7.6]
{7.3}
-
-
-
-
67
[74]
{82}
-
1.9
[3.2]
{1.8}
-
(a) Water quality parameters taken on 10/12/06. (b) Onsite water quality parameters were taken on 12/28/06.
(c) [Rerun with ICPMS bottles], {Rerun with AAL bottles}
-------
Analytical Results from Long Term Sampling at Taos, NM (Continued)
Sampling Date
Sampling Location
Parameter Unit
Bed Volume
Alkalinity
(CaCO.,)
=luoride
Sulfate
Mitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
DH
Temperature
DO
ORP
Total Hardness
(CaCO3)
Ca Hardness
(CaCO.,)
Vlg Hardness
(CaCO.,)
As (total)
As (soluble)
As (particulate)
As ON)
As(V)
=e (total)
=e (soluble)
Win (total)
Win (soluble)
10A3
mg/L
mg/L
mg/L
mg/L
ng/L
mg/L
NTU
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
M9/L
02/21/07
IN
-
114
-
-
-
<10
33.4
0.4
9.8
22.8
NA(b)
259
-
-
-
19.5
-
-
-
-
<25
-
0.9
-
AP
-
106
-
-
-
12.7
31.3
1.9
7.7
22.4
NA(b)
255
-
-
-
17.6
-
-
-
-
37
-
2.2
-
TA
9.6
109
-
-
-
<10
36.8
1.3
7.6
22.1
NA(b)
277
-
-
-
3.0
-
-
-
-
<25
-
0.5
-
TB
8.4
96
-
-
-
<10
34.7
0.6
7.4
23.1
NA(b)
322
-
-
-
3.3
-
-
-
-
<25
-
0.5
-
TC
10.2
96
-
-
-
<10
34.1
0.6
7.7
22.6
NA(b)
343
-
-
-
5.2
-
-
-
-
30
-
0.8
-
05/01/07
IN
-
-
-
-
-
-
-
-
NA
NA
NA
NA
-
-
-
15.0
-
-
-
-
-
-
-
-
AP
-
-
-
-
-
-
-
-
NA
NA
NA
NA
-
-
-
14.7
-
-
-
-
-
-
-
-
TA
NA
-
-
-
-
-
-
-
NA
NA
NA
NA
-
-
-
0.6
-
-
-
-
-
-
-
-
TB
NA
-
-
-
-
-
-
-
NA
NA
NA
NA
-
-
-
0.5
-
-
-
-
-
-
-
-
TC
NA
-
-
-
-
-
-
-
NA
NA
NA
NA
-
-
-
0.9
-
-
-
-
-
-
-
-
07/31/07
IN
-
-
-
-
-
-
-
-
9.6
27.5
1.2
222
-
-
-
16.6
-
-
-
-
-
-
-
-
AP
-
-
-
-
-
-
-
-
7.3
27.8
1.6
225
-
-
-
16.6
-
-
-
-
-
-
-
-
TA
11.6
-
-
-
-
-
-
-
7.6
27.9
1.8
226
-
-
-
0.3
-
-
-
-
-
-
-
-
TB
10.3
-
-
-
-
-
-
-
7.2
27.8
1.9
229
-
-
-
0.3
-
-
-
-
-
-
-
-
TC
12.2
-
-
-
-
-
-
-
7.5
27.8
2.3
222
-
-
-
0.8
-
-
-
-
-
-
-
-
09/12/07
IN
-
-
-
-
-
-
-
-
9.6
28.4
1.6
222
-
-
-
18.1
-
-
-
-
-
-
-
-
AP
-
-
-
-
-
-
-
-
7.2
28.1
1.7
225
-
-
-
18.8
-
-
-
-
-
-
-
-
TA
13.3
-
-
-
-
-
-
-
7.5
28.2
1.9
226
-
-
-
0.8
-
-
-
-
-
-
-
-
TB
11.8
-
-
-
-
-
-
-
7.3
28.1
2.0
225
-
-
-
0.7
-
-
-
-
-
-
-
-
TC
14.0
-
-
-
-
-
-
-
7.3
28.0
2.1
224
-
-
-
1.6
-
-
-
-
-
-
-
-
Cd
-------
Analytical Results from Long Term Sampling at Taos, NM (Continued)
Cd
Sampling Date
Sampling Location
Parameter Unit
Bed Volume
Alkalinity
(CaCO3)
Fluoride
Sulfate
Nitrate (as N)
Total P (as P)
Silica (as SiO2)
Turbidity
DH
Temperature
DO
ORP
Total Hardness
(CaCO3)
Ca Hardness
(CaCO3)
Mg Hardness
(CaCO3)
As (total)
As (soluble)
As (particulate)
As (III)
AsJV)
Fe (total)
Fe (soluble)
Mn (total)
Mn (soluble)
10A3
mg/L
mg/L
mg/L
mg/L
H-g/L
mg/L
NTU
S.U.
°C
mg/L
mV
mg/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
10/23/07
IN
-
-
-
-
-
-
-
-
9.6
26.1
1.4
222
-
-
-
17.6
-
-
-
-
-
-
-
-
AP
-
-
-
-
-
-
-
-
7.3
26.2
1.3
224
-
-
-
18.0
-
-
-
-
-
-
-
-
TA
14.7
-
-
-
-
-
-
-
7.3
26.2
1.5
224
-
-
-
0.4
-
-
-
-
-
-
-
-
TB
13.0
-
-
-
-
-
-
-
7.4
26.3
1.6
226
-
-
-
0.3
-
-
-
-
-
-
-
-
TC
15.3
-
-
-
-
-
-
-
7.3
26.1
2.1
222
-
-
-
1.1
-
-
-
-
-
-
-
-
------- |