&EPA
EPA/600/R-08/016 I January 2008 I www.epa.gov/ord
United States
Environmental Protection
Agency
Pilot-Scale Tests and Systems
Evaluation for the Containment,
Treatment, and Decontamination
of Selected Materials From
T&E Building Pipe Loop Equipment
Office of Research and Development
National Homeland Security Research Center
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EPA/600/R-08/016 January 2008 www.epa.gov/ord
Pilot-Scale Tests and Systems
Evaluation for the Containment,
Treatment, and Decontamination
of Selected Materials From
T&E Building Pipe Loop Equipment
by
Shaw Environmental, Inc.
5050 Section Avenue
Cincinnati, Ohio 45212
EPA Contract No. EP-C-04-034
Work Assignment No. 2-12
PN 121285-12
for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
National Risk Management Research Laboratory
National Homeland Security Research Center
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Shirley J. Gibson, Project Officer
Paul M. Randall, Work Assignment Manager
Office of Research and Development
National Homeland Security Research Center, Water Infrastructure Protection
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Disclaimer
Any opinions expressed in this report are those of the authors and do not necessarily reflect
the official positions and policies of EPA. Any mention of products or trade names does not
constitute recommendation for use by EPA.
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Table of Contents
Acknowledgement viii
List of Acronyms ix
1.0 Introduction 1
1.1 Purpose of Study 1
1.2 Project Objectives 1
2.0 Experimental Methodology 3
2.1 Experimental Design Overview 3
2.2 Experimental Variables 7
2.3 Contaminants Selected for Evaluation 9
2.4 Pilot-Scale Drinking Water Distribution System Simulator (DSS) 10
2.5 Biofilm Cultivation 10
2.6 Injection of Contaminants 11
2.7 DSS Operating Conditions 11
2.8 Sampling Methodology 11
2.9 Sample Extraction and Analyses 14
2.10 Decontamination Approach 14
2.10.1. Decontamination of Arsenic 15
2.10.2. Decontamination of Mercury 16
2.10.3. Decontamination of Bacillus subtilis 16
2.10.4. Decontamination of Diesel Fuel 16
2.10.5. Decontamination of Chlordane 16
3.0 Results and Discussions 17
3.1 Preliminary Test Results on Coupon Sample Extraction 17
3.2 Pilot-Scale Contamination/Decontamination Test Results 17
3.2.1. Biofilm Cultivation 17
3.2.2. Pilot-scale Contaminant Adherence Test Results 18
3.2.2.1. Arsenic Adherence Test Results 18
3.2.2.2. Mercury Adherence Test Results 21
3.2.2.3. Bacillus subtilis Adherence Test Results 24
3.2.2.4. Diesel Fuel Adherence Test Results 26
3.2.2.5. Chlordane Adherence Test Results 27
3.2.3. Pilot-scale Decontamination Test Results 30
3.2.3.1. Arsenic Decontamination Test Results 30
(1) Baseline water flushing 30
(2) Low-pH flushing 33
(3) Phosphate buffer flushing 34
(4) Acidified potassium permanganate flushing 35
(5) NSF Standard 60 Pipe Cleaning Aid Products Flushing 36
3.2.3.2. Mercury Decontamination Test Results 39
(1) Baseline water flushing 39
(2) Low-pH flushing 42
(3) Acidified potassium permanganate flushing 43
3.2.3.3. Bacillus subtilis Decontamination Test Results 44
(1) Baseline water flushing 44
(2) Shock Chlorination 45
3.2.3.4. Diesel Fuel Decontamination Test Results 46
(1) Baseline water flushing 46
(2) Surfactant (Surfonic TDA-6) flushing 47
3.2.3.5. Chlordane Decontamination Test Results 49
(1) Surfactant TDA-6 flushing 49
3.2.3.6. Summary of Decontamination Test Results 50
4.0 Conclusions 53
5.0 References 55
Appendix A: Contaminant Adherence/Decontamination Test Results Data 57
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List of Tables
Table 2-1 Experimental Design Parameters 7
Table 2-2 List of Test Run ID, Adherence Test Flow Rate, Velocity, Reynolds Number,
and Decontamination Approach 8
Table 2-3 Contaminants Selected for Study 9
Table 2-4 Sampling Schedule for Various Phases of Testing 13
Table 3-1 Arsenic/Mercury Recovery From the Bench-Scale Experiments 17
Table 3-2 Experimental Results From Test Run ID: AsFl 19
Table 3-3 Experimental Results From Test Run ID: AsF15 19
Table 3-4 Experimental Results From Test Run ID: As F60 20
Table 3-5 Experimental Results From Test Run ID: HgFl 21
Table 3-6 Experimental Results From Test Run ID: HgF15 22
Table 3-7 Experimental Results From Test Run ID: HgF60 22
Table 3-8 Experimental Results From Test Run ID: BSF60 25
Table 3-9 Experimental Results From Test Run ID: DROF60 26
Table 3-10 Experimental Results From Test Run ID: ChLD TDA 29
Table 3-11 Decontamination Efficiency of Simple Flushing for Arsenic Calculated From Test Run ID: As F1 32
Table 3-12 Decontamination Efficiency of Simple Flushing for Arsenic Calculated From Test Run ID: AsF15 32
Table 3-13 Decontamination Efficiency of Simple Flushing for Arsenic Calculated From Test Run ID: As F60 33
Table 3-14 Decontamination Efficiency of Low-pH Flushing for Arsenic 34
Table 3-15 Decontamination Efficiency of Phosphate Buffer Flushing for Arsenic 35
Table 3-16 Decontamination Efficiency of Acidified Potassium Permanganate Flushing for Arsenic 36
Table 3-17 Decontamination Efficiency of NW-310/NW-400 Flushing for Arsenic 38
Table 3-18 Decontamination Efficiency of Floran Biogrowth Remover/Catalyst Flushing for Arsenic 38
Table 3-19 Decontamination Efficiency of Floran Top Ultra/Catalyst Flushing for Arsenic 39
Table 3 -20 Decontamination Efficiency of Simple Flushing for Mercury Calculated From Test Run ID: Hg F1 41
Table 3-21 Decontamination Efficiency of Simple Flushing for Mercury Calculated From Test Run ID: Hg F15 41
Table 3 -22 Decontamination Efficiency of Simple Flushing for Mercury Calculated From Test Run ID: Hg F60 42
Table 3-23 Decontamination Efficiency of Low-pH Flushing for Mercury 43
Table 3 -24 Decontamination Efficiency of Acidified Potassium Permanganate Flushing for Mercury 44
Table 3-25 Decontamination Efficiency of Simple Flushing for Bacillus subtilis 45
Table 3-26 Decontamination Efficiency of Shock Chlorination for Bacillus subtilis 46
Table 3-27 Decontamination Efficiency of Simple Flushing for Diesel Fuel 47
Table 3-28 Decontamination Efficiency of Surfonic TDA-6 Flushing for Diesel Fuel 48
Table 3-29 Decontamination Efficiency of Surfonic TDA-6 Flushing for Chlordane 50
Table 3-30 Performance of Decontamination Techniques for Various Target Contaminants 51
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List of Figures
Figure 2-1 Schematic of Pipe Loop Distribution System Simulator (DSS) With
Integrated Real-World Pipe Sections 4
Figure 2-2 Photograph of Pipe Loop DSS Located at the EPA T&E Facility 5
Figure 2-3 Overall Experimental Strategy for Decontamination Pilot-Scale Tests 6
Figure 2-4 Cement-lined Ductile Iron Coupon (Real-World Pipe Coupon) 10
Figure 3-1 Arsenic Adherence Study Results 20
Figure 3-2 Mercury Adherence Study Results 23
Figure 3-3 Comparison of Arsenic and Mercury Adherence to Cement-lined Ductile
Iron Pipe Surfaces at Various Flow Rate Conditions 24
Figure 3-4 Bacillus sub tills Adherence Study Results 25
Figure 3-5 Diesel Fuel Adherence Test Results 27
Figure 3-6 Chlordane Adherence Test Results 28
Figure 3-7 Arsenic Simple Water Flushing Test Results From Scenario 1 (Adherence Flow Rate: 1 gpm) 30
Figure 3 -8 Arsenic Simple Water Flushing Results From Scenario 2 (Adherence Flow Rate: 15 gpm) 31
Figure 3 -9 Arsenic Simple Water Flushing Results From Scenario 3 (Adherence Flow Rate: 60 gpm) 31
Figure 3-10 Low-pH (pH 4) Flushing Results for Arsenic Decontamination 33
Figure 3-11 Phosphate Buffer Flushing Results for Arsenic Decontamination 34
Figure 3-12 Acidified Potassium Permanganate Flushing Results for Arsenic Decontamination 35
Figure 3-13 NW-310/NW-400 Flushing Results for Arsenic Decontamination 37
Figure 3-14 Flo ran Biogrowth Remover/Catalyst Flushing Results for Arsenic Decontamination 37
Figure 3-15 Floran Top Ultra/Catalyst Flushing Results for Arsenic Decontamination 38
Figure 3-16 Mercury Simple Water Flushing Test Results (Adherence Flow Rate: 1 gpm) 39
Figure 3-17 Mercury Simple Water Flushing Test Results (Adherence Flow Rate: 15 gpm) 40
Figure 3-18 Mercury Simple Water Flushing Test Results (Adherence Flow Rate: 60 gpm) 40
Figure 3-19 Low-pH Flushing Results for Mercury Decontamination 42
Figure 3 -20 Acidified Potassium Permanganate Flushing Results for Mercury Decontamination 43
Figure 3-21 Simple Flushing Results for Bacillus subtilis Decontamination 44
Figure 3-22 Shock Chlorination Results for Bacillus subtilis Decontamination 45
Figure 3-23 Simple Water Flushing Results for Diesel Fuel Decontamination 46
Figure 3 -24 Surfonic TDA-6 Decontamination Results for Diesel Fuel Decontamination 48
Figure 3-25 Surfonic TDA-6 Decontamination Results for Chlordane Decontamination 49
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Acknowledgement
This report was prepared by Shaw Environmental, Inc.
(Shaw) for EPA under Contract No. EP-C-04-034, Work
Assignment No. 2-12. Tests associated with this evaluation
were performed at EPA's Test & Evaluation (T&E) Facility
in Cincinnati, Ohio. Mr. Paul M. Randall served as the
EPA Work Assignment Manager for this project. Mr. E.
Radha Krishnan, P.E., was the Shaw Program Manager for
this contract. Ms. Haishan (Helen) Piao, Ph.D., from SBR
Technologies, Inc., Shaw Team subcontractor, was the
Project Leader for this Work Assignment. Experimental and
analytical work was performed by the Shaw Project Team in
conjunction with some outside laboratories.
This report was prepared by Mr. Radha Krishan and Dr.
Haishan Piao. The authors of this report wish to acknowledge
the thoughtful guidance and review provided by the EPA
Advisory Team as well as external reviewers, including:
• Paul Randall - EPA Work Assignment Manager
• Vincente Gallardo - EPA Alternate Work Assignment
Manager
• John Hall - EPA Technical Reviewer
• Jeff Szabo, Ph.D. - EPA Technical Reviewer
• Eletha Brady-Roberts - EPA QA Reviewer
• Greg Welter, PE. - O'Brien & Gere Engineers,
external reviewer
• Susan Altman, Ph.D. - Sandia National Laboratories,
external reviewer
Acknowledgement is also made for the contributions from
the following individuals and organizations:
• Dr. Anne Camper, Montana State University, for
guidance on development of the biofilm cultivation
protocol
• Dr. Robert Clark, Shaw Team consultant, for data
assessment and review of experimental design
• Dr. Nur Muhammad, Mr. Alan Zaffiro, Ms. Lenora
Stephens, and Ms. Robyn Richardson of Shaw,
for technical support in experimental design, test
implementation, and sample analyses
• Mr. Tim Gray and Dr. Shekar Govindaswamy of
Lakeshore Engineering Services, Inc., Shaw Team
subcontractor, for technical support in operation of
the pilot-scale test loop and in development of the
biofilm cultivation protocol
• Mr. Harmon Morress, Shaw Team consultant, for
fabrication of coupons used in testing
• Greater Cincinnati Water Works, for donation of
excavated pipe sections
• Ohio Hamilton County Department of Environmental
Services, for providing chlordane for testing
• Severn Trent Laboratories and DataChem
Laboratories, for outside laboratory sample analyses
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List of Acronyms
AA atomic absorption
AwwaRF American Water Works Association Research Foundation
ATI Analytical Technology, Inc.
cells/mL cells per milliliter
CFU/cm2 colony forming units per square centimeter
cPVC chlorinated polyvinyl chloride
CT [chlorine concentration] X [contact time]
DRO Diesel Range Organics
DSS distribution system simulator
EPA United States Environmental Protection Agency
EQL estimated quantification limit
fps feet per second
GC/FID Gas Chromatograph/Flame lonization Detector
gpm gallons per minute
GRAS generally regarded as safe
HOPE high-density polyethylene
HPC heterotrophic plate count
HSPD Homeland Security Presidential Directive
ICP inductively coupled plasma
in2 square inches
Kow Octanol-Water Partition Coefficient
L liter
mg/coupon milligrams per coupon
mg/L milligrams per liter
mL milliliter
NHSRC National Homeland Security Research Center
NRMRL National Risk Management Research Laboratory
NSF National Sanitation Foundation
NTU Nephelometric Turbidity Unit
ORD Office of Research and Development
ORP oxidation-reduction potential
FDD Presidential Decision Directive
PE Professional Engineer
PL Project Leader
psi pounds per square inch
ppm parts per million
PVC polyvinyl chloride
QA quality assurance
QC quality control
QAPP Quality Assurance Project Plan
Re Reynolds number
SCADA Supervisory Control and Data Acquisition
SBRT SBR Technologies, Inc. (subcontractor to Shaw Environmental, Inc.)
Shaw Shaw Environmental, Inc.
SOP standard operating procedure
STL Severn Trent Laboratories
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List of Acronyms
TOC total organic carbon
T&E Test & Evaluation
ug/L micrograms per liter
um micrometer
WA Work Assignment
WAM Work Assignment Manager
WSWRD Water Supply and Water Resources Division
w/v weight/volume
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1.0
Introduction
This summary report has been prepared for the U.S.
Environmental Protection Agency (EPA) National Risk
Management Research Laboratory (NRMRL) to fulfill the
requirement for a summary report for the research study
performed as described in Section 2.3 of the Work Plan for
Work Assignment No. 2-12 (WA 2-12) under EPA Contract
No. EP-C-04-034.
This report summarizes the pilot-scale evaluations conducted
at the EPA Test and Evaluation (T&E) Facility between
April 2005 and January 2007 to investigate removal of
sodium arsenite, mercuric chloride, Bacillus subtilis,
diesel fuel (No. 2), and chlordane from water distribution
systems. The report covers the purpose of the study, detailed
experimental test conditions and methods, analytical results,
and observations. It also incorporates technical reviewer
comments from American Water Works Association Research
Foundation (AwwaRF) and Sandia National Laboratories
on the draft summary reports that Shaw prepared for
contaminant-specific evaluations conducted under this
Work Assignment.
1.1 PURPOSE OF STUDY
The safety and security of water supplies has come under
reassessment in the past year. Issues ranging from public
safety and health, ecological concerns, and national security
are under consideration. The terrorist attacks on the United
States on September 11, 2001, and the subsequent delivery of
anthrax-contaminated letters through the mail raised concerns
about protecting U.S. citizens and the nation's critical
infrastructure. Presidential Decision Directive 63 (FDD 63)
designates EPA as the lead for securing the national water
infrastructure. Therefore, the Agency is working to be
proactive in the anticipation, detection, and identification of
the threat of deliberate or accidental con-tamination of our
water supplies. This proactive approach shall be to prevent,
respond to, mitigate and/or treat contamination of our
essential national resources. EPA has developed strategies
to deter, detect, treat, and respond to physical, biological,
chemical, radiological, and cyber attacks on U.S. water
supplies, utilities, or systems. This preparation includes
understanding the interdependencies among the national
water infrastructure and other critical U.S. infrastructure.
The Agency is guided in its efforts by the requirements of
the Bioterrorism Act of 2002 (107-188). EPA is further
guided in this effort by Homeland Security Presidential
Directive 9 (HSPD-9), which was signed on February 4,
2004. This research also supports the National Homeland
Security Research Center (NHSRC) under other directives,
including Critical Infrastructure Identification, Prioritization,
and Protection (HSPD-7), which was signed on December
17, 2003, and Biodefense for the 21st Century (HSPD-10),
which was signed on April 28, 2004.
One of EPA's more important challenges in dealing with a
contamination threat is how to treat, contain, and dispose of
contaminated water. Depending on where the contaminant is
introduced, this may involve actions within source waters,
drinking water treatment plants, distribution systems, or
points downstream. Any material (including the water) may
need to be disposed of properly. Furthermore, the physical
infrastructure of the water distribution system will require
decontamination before it is reused. To evaluate the efficacy
of various decontamination methods, a series of pilot-scale
tests were conducted, using the pipe loop system located at
the T&E Facility, in Cincinnati, Ohio.
1.2 PROJECT OBJECTIVES
The decontamination study had the following primary goals:
1. Quantitative determination of the potential of target
contaminants for persistence in a dynamic drinking
water distribution system. The key objectives were to:
• Determine the adherence tendency of five
contaminants to drinking water distribution pipe
surfaces
• Investigate the effect of different pipe materials on
the adherence of contaminants to the pipe surface
• Examine the effect of different flow regimes (laminar
and turbulent) on the fate of contaminants and their
adherence to pipe surfaces
2. Quantitative determination of the efficacy of various
decontamination methods for removing contaminants
from a drinking water distribution system. The key
objectives were to:
• Evaluate several decontamination methods for their
effectiveness in removing different contaminants
from a drinking water distribution system
• Determine the optimal decontamination condition
(e.g., flow rate, reagent concentration, pH) of each
decontamination method for each contaminant
• Investigate the effect of pipe materials on the
performance of the decontamination technique
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2.0
Experimental Methodology
2.1 EXPERIMENTAL DESIGN OVERVIEW
A list of target contaminants for the decontamination research
was developed based on EPA NHSRC's Water Contaminant
List and AwwaRFs Contaminant List. Sodium arsenite,
mercuric chloride, Bacillus subtilis, diesel fuel (No. 2), and
chlordane were selected as the target contaminants for the
study. Chlordane was not included in the initial pilot-scale
test plan because its use has been banned for the past twenty
years and it has been very difficult to find suppliers of the
commercial form of chlordane. Also, there was concern over
using a banned pesticide like chlordane in the pilot-scale
decontamination study, and it was thought that it would be
more applicable to use off-the-shelf contaminants. However,
chlordane was one of the contaminants investigated in
AwwaRFs laboratory-scale decontamination study.
Chlordane is a very "sticky" chemical, as shown by its
high Kow value (adsorption coefficient), and would pose
a challenge for decontamination. Therefore, AwwaRF
selected chlordane as one of the "most-difficult-to-treat"
chemicals in their laboratory-scale experiments. In order
to perform a comparison with AwwaRFs laboratory-scale
results, EPA/Shaw Team added chlordane to the list of target
contaminants for the pilot-scale decontamination study. In
December 2006, Shaw was successful in obtaining small
quantities of chlordane for the pilot-scale evaluation from
the Ohio Hamilton County Household Hazardous Waste
Collection site. This summary report includes the adherence
and decontamination tests conducted for the five different
target contaminants.
Each of the pilot-scale adherence/decontamination
experiments was initiated with integration of used "real-
world" pipe sections (coupons) into the existing drinking
water distribution system simulator (DSS) at the U.S.
EPAT&E Facility. Figure 2-1 presents a schematic of the
DSS incorporating the 1-inch "real-world" pipe sections.
Figure 2-2 is a photograph of the DSS located at the EPA
T&E Facility, in Cincinnati, Ohio. Biofilm was cultivated
within the DSS over one to two weeks, using an accelerated
biofilm cultivation strategy. Upon confirmation of the
biofilm development in the pipe loop, the target contaminant
was injected into the DSS. The DSS was operated in a
recirculation mode at the designated flow rate condition.
After a two-day contact period, the coupons (real-world pipe
materials) were sampled to determine the adherence
of contaminant to the pipe loop materials. Upon completion
of the adherence study, a designated decontamination
approach was evaluated. After decontamination, the coupon
walls were analyzed for residual, adsorbed contaminant.
Figure 2-3 depicts the overall experimental strategy for the
planned tests.
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Figure 2-2 Photograph of Pipe Loop DSS Located at the EPA T&E Facility
1
-------
Figure 2-3 Overall Experimental Strategy for Decontamination Pilot-Scale Tests
Integrate used pipe sections into
existing DSS.
Cultivate biofilm in DSS.
Quantify biofilm by use of
heterotrophic plate count
(HPC) assay.
Quantify background
concentrations of the
contaminant in the water
and biofilm.
Inject contaminant into DSS.
Recirculate the contaminated water for
2 days' contact time.
Take bulk and wall samples and analyze
for target contaminant.
Flush the loop with tap water.
Take bulk and wall samples and
analyze for target contaminants.
Repeat experiment to evalute
other decontamination
approaches.
Repeat experiment
with next
contaminant.
The tested
contaminant does not
adsorb to pipe walls.
Is contaminant
detected on walls?
Is contaminant
detected on walls?
NO
Flushing is an
effective
decontamination
technique for the
specific
contaminant.
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2.2 EXPERIMENTAL VARIABLES
Table 2-1 presents a list of primary experimental design
parameters for conduct of the adherence/decontamination
studies on arsenic, mercury, Bacillus subtilis, diesel fuel
(No. 2), and chlordane.
Table 2-1 Experimental Design Parameters
Target contaminants
Pipe material evaluated
Biofilm
DSS operating parameters
Contact time for contaminant adherence
study
Concentration of target contaminant
within loop
Decontamination approaches evaluated
Sodium arsenite, mercuric chloride, Bacillus subtilis, diesel fuel (No. 2), chlordane
Cement-lined ductile iron (from 5-year-old T&E Facility pipe loop system)
Biofilm cultivated on pipe walla
Flow mode: recirculation
Flow rates: 1, 15, 60 gallons per minute
Temperature: ambient high-bay temperature
pH: pH of Cincinnati tap water-8.5
Free chlorine at start of study: ~1.0 milligram per liter (mg/L)
2 days after injection of contaminant into pipe loop system
10 mg/L of mercury, arsenic, and diesel fuel (No. 2), chlordane (as alpha+gamma
chlordane, 40 mg/L as technical chlordane)
104 cells/mL of Bacillus subtilis
Arsenic:
Mercury:
Bacillus subtilis:
Diesel fuel:
Chlordane:
Baseline water flushing (2.5 fps flow rate)
Low-pH (i.e., pH 4) flushing
Phosphate buffer flushing
Acidified potassium permanganate flushing
NSF Standard 60 Products flushing:
NW-310/NW-400 flushing
Floran Biogrowth Remover/Catalyst flushing
Floran Top Ultra/Catalyst flushing
Baseline water flushing (2.5 fps flow rate)
Low-pH (i.e., pH 4) flushing
Acidified potassium permanganate flushing
Baseline water flushing (2.5 fps flow rate)
Shock chlorination
Baseline water flushing (2.5 fps flow rate)
Surfonic TDA-6 flushing
Surfonic TDA-6 flushing
a Target Heterotrophic Plate Count (HPC) of greater than 104 colony forming units per square centimeter (CFU/cm2).
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The experimental test ran ID and the corresponding flow
rate, velocity, Reynolds number (Re), and decontamination
approach are tabulated in Table 2-2.
Table 2-2 List of Test Run ID, Adherence Test Flow Rate, Velocity, Reynolds Number,
and Decontamination Approach
Arsenic
Mercury
Bacillus subtilis
Diesel fuel (No. 2)
Chlordane
AsF1
AsF15
AsF60
AspH4
As Phos
As KMnO4
AsNW
As Floran I
As Floran II
HgF1
HgF15
HgF60
HgpH4
Hg KMnO4
BSF60
BS CT30K
DRO F60
DRO TDA
ChLDTDA
1
15
60
60
60
60
60
60
60
1
15
60
60
60
60
60
60
60
60
0.011
0.17
0.69
0.69
0.69
0.69
0.69
0.69
0.69
0.011
0.17
0.69
0.69
0.69
0.69
0.69
0.69
0.69
0.69
521
7808
31232
31232
31232
31232
31232
31232
31232
521
7808
31232
31232
31232
31232
31232
31232
31232
31232
Water flushing
Water flushing
Water flushing
Low-pH flushing
Phosphate buffer flushing
Acidified potassium
permanganate flushing
NW-310/NW-400 flushing
Floran Biogrowth Remover/
Catalyst flushing
Floran Top Ultra/Catalyst
flushing
Water flushing
Water flushing
Water flushing
Low-pH flushing
Acidified potassium
permanganate flushing
Water flushing
Shock chlorination
Water flushing
Surfonic TDA-6 flushing
Surfonic TDA-6 flushing
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2.3 CONTAMINANTS SELECTED FOR EVALUATION
Five contaminants were selected for the pilot-scale
contamination/decontamination tests. The contaminants and a
summary of their known behaviors in drinking water systems
are provided in Table 2-3. These contaminants were chosen
to represent common chemical and biological agents that are
Table 2-3 Contaminants Selected for Study
potential threats to the water supply as indicated in the table.
Although chlordane was not initially selected for evaluation,
because it is currently a banned chemical in the United
States, it was later included to provide a comparison with the
results from other laboratory-scale AwwaRF studies.
Mercuric chloride
(representing a heavy metal mercury)
Sodium arsenite
(representing an inorganic poison
arsenic)
Bacillus subtilis
(representing a biological spore or cell)
Diesel fuel (No. 2)
(representing a sticky industrial organic
contaminant)
Chlordane (representing a toxic organic
chemical)
o Water soluble
o Fungicide
o Very water soluble
o Chlorine oxidizes arsenite (AsO2") to arsenate (AsO43")
o Bacillus subtilis is a gram-positive, rod-shaped, and endospore-forming aerobic
bacterium. It is found in soil and rotting plant material and is a GRAS (Generally
Regarded as Safe) microorganism
o Typical size: 2- to 3-mierometer (pm) length, 0.5-|jm width
o May be killed by chlorine
o The major components:
> alkanes (estimated to be 65-85 percent by weight)
> alkenes (common in converted products such as catalytic cracker
fractions)
> aromatics (estimated to be 10-30 percent by weight)
o Very low water solubility
o Significant tendency to adsorb to pipe surfaces
o Does not degrade rapidly in water
o Chlorination: unknown
o Organochlorine insecticide: termite control
o Use has been banned since 1988
o Very low water solubility: 0.056 mg/L
o High log Kow: 6.0
o Very persistent and hard to remove
o Does not degrade rapidly in water
o Can exit aquatic systems by adsorbing to sediments or by volatilization
o Volatilization half-life for chlordane in lakes and ponds is less than 10 days
o Chlorination: unknown
o Loses its chlorine in presence of alkaline reagents
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2.4 PILOT-SCALE DRINKING WATER DISTRIBUTION
SYSTEM SIMULATOR (DSS)
A pilot-scale clear poly vinyl chloride (PVC) DSS (refer to
Figure 2-1 and Figure 2-2) was used in the decontamination
study experiments. The main components of the clear PVC
DSS are a 2000-gallon reservoir used to supply water to the
PVC pipe loop, approximately 75 feet of clear PVC pipe
(6-inch diameter except for a 4-inch-diameter section that is
—10 feet long), a 100-gallon recirculation tank (in line with
the main pipe), water pumps, and the associated valves and
electronic control devices necessary to operate the system.
The total volume in the DSS (including the 100 gallons in the
recirculation tank) is approximately 220 gallons. The interior
surface area of the loop including the recirculation tank
(available for adsorption) is approximately 25,000 square
inches (in2).
The whole DSS is of clear PVC pipe construction except for
ten real-world pipe coupons (coupon #1 through coupon #10
in Figure 2-1). As shown in Figure 2-4, the real-world pipe
coupons employed in the current study were machined out
of used cement-lined ductile iron pipe sections scavenged
from an old drinking water distribution simulator within
the T&E Facility, which has been in service for five years.
The cement-lined ductile iron pipes used in this study
did not have an asphalt seal coat. They were originally
purchased from U.S. Pipe and intended for use in drinking
water distribution systems. Each coupon has a 6-inch inside
diameter and is 1 inch in width. Two control coupons (control
coupons A and B in Figure 2-1) were also integrated into the
DSS during each experiment. These control coupons were cut
from a clear PVC section. All twelve coupons were sacrificed
after each run, and "new" coupons were reintegrated in the
following test run.
The DSS is equipped with sensors that continuously measure
the basic water quality parameters of pH, turbidity, free
chlorine, conductivity, and oxidation-reduction potential
(ORP). Total organic carbon (TOC) on grab samples was
measured in the T&E Facility laboratory using a Teledyne
Tekmar Phoenix 8000 TOC analyzer.
2.5 BIOFILM CULTIVATION
The unique clear PVC loop system at the T&E Facility was
newly fabricated in 2003 and the pipes in the loop have been
in limited service; therefore, there is little biofilm buildup
on the inside surfaces. To effectively study the adsorption of
contaminants on pipe walls, it is essential to ensure that there
is a viable biofilm on the pipe wall surfaces. The biofilm
could influence adsorption of the contaminant on the pipe
wall and play a role in the metabolism, biodegradation, or
detoxification of the contaminant.
Shaw conducted a review of the literature (Batte et al., 2003;
Butterfield et al., 2002; Camper et al., 1996; Cloete et al.,
2003; Chu et al., 2004; Hansen et al., 2002; Lawrence et al.,
2000; Pozos et al., 2004; Wasche et al., 2002; Wijeyekoon et
al., 2004) and identified a biofilm cultivation protocol for this
study. Based on this protocol, a viable biofilm can be formed
on the pipe surfaces within one to two weeks by augmenting
the water in the loop with low concentrations of carbon,
nitrate, and phosphate under laminar flow conditions.
According to this protocol, the DSS loop was used as a
tubular reactor, and carbon, nitrate, and phosphate were
introduced into the loop through the recirculation tank to
result in final concentrations of 100 ug/L each of nitrate
and phosphate and 1000 ug/L of carbon. The carbon source
contained equimolar concentrations on the basis of carbon of
acetate, sodium benzoate, propionaldehyde,
Figure 2-4 Cement-lined Ductile Iron Coupon (Real-World Pipe Coupon)
-------
/>-hydroxybenzoic acid and ethanol. Sodium nitrate and
sodium phosphate were used as the source of nitrate and
phosphate, respectively. The water was dechlorinated for the
biofilm cultivation, and the water in the loop was recirculated
using a centrifugal pump at a flow rate of 4 gpm.
During the biofilm cultivation, bulk water samples were
collected on a daily basis and the daily bacterial growth in
bulk water was monitored through heterotrophic plate count
(HPC) analyses until it reached pseudo steady-state. One
coupon sample was taken out of the system at steady-state for
checking the extent of biofilm formation. The biofilm sample
(scraped off the pipe wall) was suspended in sterile water,
homogenized, and subjected to an HPC count to determine
the formation of biofilm in the pipe walls. Based on the
literature review, a bacterial cell count of 104 CFU/cm2 or
higher is considered to adequately represent a viable biofilm
population in the pipe loop system.
Because the pipe sections in the DSS were made of clear
PVC pipe, the interior of these sections was exposed to
light, and it was likely that algae contributed to the biofilm
content in the clear pipe section. However, the sections where
coupons were located were covered by black rubber sleeves;
therefore, a dark environment was provided for coupon
samples, which would have reduced the growth of algae on
the coupon surfaces. A comparison of biofilm composition
for the clear pipe section vs. dark coupon section was out of
the project scope, and such a comparison was not performed
for this study.
Biofilm was cultivated on coupons after the coupons were
installed in the clear PVC DSS, and the biofilm cultivation
was conducted prior to each test.
2.6 INJECTION OF CONTAMINANTS
Each of the target contaminants was injected by use of a
1-L capacity pressurized (~20 psi) syringe fabricated at the
T&E Facility for this purpose to reach a target contaminant
concentration (10 mg/L for arsenic, mercury, diesel fuel,
and alpha+gamma chlordane, and 104 cells/mL for Bacillus
subtilis). Water-soluble chemicals, such as mercuric chloride
and sodium arsenite, were dissolved in deionized water.
(To maintain a reasonable injection volume, 1 liter of
deionized water was used.) Diesel fuel (No. 2) and chlordane
have limited solubility in water; however, they were
also mixed in 1 liter of deionized water for consistency.
Bacillus subtilis was suspended in the growth medium
(i.e., Tween 20) in which it was prepared. The concentrated
contaminant solution was injected into the PVC pipe loop
through the injection port shown on Figure 2-1, using the
pressurized syringe.
2.7 DSS OPERATING CONDITIONS
The DSS was operated in a recirculation mode for prolonged
contact with the contaminant. Shaw performed experiments
in both laminar and turbulent flow ranges. Shaw performed
some calculations to estimate the effect of pipe diameter and
flow rate on contaminant mass transfer coefficients, which
reflect the rate at which a constituent would be transported
from the bulk phase to the pipe wall. These calculations show
that the mass transfer coefficients increase with Reynolds
Number (Re). The flow is laminar if Re < 2300, transient
in the range 2300 < Re < 4000, and turbulent when 4000 <
Re. The flow rates that Shaw tested in the adherence tests
included 1 gpm, 15 gpm, and 60 gpm. The water was at
ambient temperature (13-32 °C), and the pH was the same
as Cincinnati tap water (~8.5). The flow rates and the basic
water quality parameters were monitored continuously during
the experiments.
The DSS design permits direct control over only the flow
rate and the chlorine level. For these experiments, flow
was set at one of the three rates by adjusting the pump
speed to achieve the desired flow rate as measured by the
electronic flow meter (magnetometer) installed in the loop.
The chlorine level was set to 1.0±0.1 mg/L prior to injection
by manually adjusting the chlorine level in the feed tank
and monitoring the concentration by use of the ATI A15/62
free chlorine meter.
Temperature, pH, turbidity, and all other water quality
parameters were not controlled.
2.8 SAMPLING METHODOLOGY
Coupon samples and samples of the bulk liquid and were
collected for each test run. All liquid samples were collected
as grab samples at the liquid sampling port shown in Figure
2-1. For each test run, duplicate liquid samples were collected
for contaminant analyses during and/or after each adherence
and decontamination test. Duplicate coupon samples were
collected at each location to meet the quality control (QC)
duplication requirement. The bulk liquid samples provide
an indication of the concentration of the contaminant in the
bulk water. The coupon samples provide the most useful
information for this study.
Ten used-pipe coupon sample locations are identified in
Figure 2-1. Assuming fast and complete mixing of injected
contaminants within the loop, operation in the recirculation
mode creates an equal opportunity for adsorption of the
contaminant anywhere on the ten coupons. Four of the
coupons are located within 3 feet of the injection point.
The other set of coupons are located 52 feet from the
injection point.
The sampling schedule for each test run is outlined in Table
2-4. There were three sampling events for each injection
of a contaminant: two coupon samples were collected
just prior to contaminant injection to establish the baseline
concentration of the contaminant on the walls (coupon #1)
and determine biofilm availability (coupon #2) before
addition of chlorine to the DSS, four coupon samples were
sacrificed after a contact period of two days to determine
adherence on the pipe walls, and the remaining four
coupon samples were sacrificed after employing a specific
decontamination procedure to quantify residual contaminant
on the pipe walls. Two control coupons (A and B) cut from
a clear PVC section were sampled after the two-day contact
period for the analyses of the target contaminant on the PVC
pipe loop material.
-------
Sensors installed on the DSS provided continuous
measurements of basic water quality parameters, i.e., pH,
turbidity, free chlorine, conductivity, and ORE These
parameters can provide an indication of the fate of the
injected species and the effect on the chemistry of the
drinking water. For example, free chlorine demand and
ORP will provide evidence of reactions that are occurring,
and specific conductance may detect the presence of
dissolved inorganic species. TOC analyses were performed
manually using grab samples. TOC analyses can provide
evidence on the fate of an organic contaminant. These basic
measurements minimize the need for expensive laboratory
analyses during the two-day contact period. Sensor data
were continuously logged during all experimental phases by
use of an existing supervisory control and data acquisition
(SCADA) system.
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Table 2-4 Sampling Schedule for Various Phases of Testing
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
Just prior to
injection
5 minutes
after
injection
1 day after
injection
2 days after
injection
After
draining
loop
Prior to
draining
loop
After
draining
loop
Coupon #1
and #2
Liquid
sampling port
Liquid
sampling port
Liquid
sampling port
Liquid
sampling port
Control
coupon
Coupon #3,
#4
Coupon #5,
#6
Liquid
sampling port
Coupon #7,
#8
Coupon #9,
#10
Coupon #1
Coupon #2
Duplicate water
samples (grab)
Duplicate water
samples (grab)
Duplicate water
samples (grab)
Duplicate water
samples (grab)
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Duplicate water
samples (grab)
Coupon #7
Coupon #8
Coupon #9
Coupon #10
Background:
contaminant on walls
Quantify biofilm
development
Background:
contaminant in liquid
phase
Verify presence of
contaminant in the
loop
Determine fate of
injected contaminant
Determine fate of
injected contaminant
Comparison to
adherence of the
same contaminant
on PVC pipe loop
material
Duplicate
Contaminant on pipe
wall
Duplicate
Contaminant on pipe
wall
Duplicate
Presence of
contaminant in
decontamination fluid
Contaminant on pipe
wall
Duplicate
Contaminant on pipe
wall
Duplicate
pH, ORP, Specific
conductance, Free
chlorine, Total
chlorine, Turbidity
pH, ORP, Specific
conductance, Free
chlorine, Total
chlorine, Turbidity
Not applicable
pH, ORP, Specific
conductance, Free
chlorine, Total
chlorine, Turbidity
Not applicable
TOTAL SAMPLE COUNT
PER TEST RUN:
12 COUPON SAMPLES AND
10 WATER SAMPLES
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2.9 SAMPLE EXTRACTION AND ANALYSES
The DSS was drained prior to removing the coupons. Once
drained, the coupons were removed from the DSS and
immediately rinsed with deionized water with the aid of a
squirt bottle. This step was necessary to remove contaminated
water that might still be in contact with the coupon. Each
coupon was placed in a small glass casserole dish. The
interior surface of ductile iron pipes is primarily composed
of rust and biofilm. The extraction procedure was designed to
remove both of these layers to maximize recovery.
Biofilm was scraped off the coupon with a sterilized
toothbrush, using autoclaved water. The extraction solvent
was recovered by pouring the contents of the dish into an 8-
ounce autoclave glass jar. The biofilm was quantified by use
of a bacterial counting technique. The HPC method (Standard
Method 9215 B) was modified as specified in the Hach test
kits based on the SimPlate™ Technique for HPC developed
by IDEXX Laboratories, Inc. This IDEXX HPC method was
approved by EPA on October 29, 2002, as found in 40 CFR
Part 141.
Arsenic/mercury was extracted from the coupon surface by
physical scrubbing with a toothbrush, using 10% (w/v) nitric
acid solution and deionized water. The extraction solvent was
recovered by pouring the contents of the dish into a 1L HDPE
sample bottle with appropriate preservative (nitric acid for
arsenic and mercury samples). The bulk liquid and coupon
extraction fluid samples were submitted to a commercial
laboratory [Severn Trent Laboratories (STL)] to perform the
sample analyses on arsenic/mercury. Arsenic was analyzed
by inductively coupled plasma (ICP) according to U.S. EPA
methods SW 846 3005A/6010B. Mercury was analyzed by
atomic absorption (AA) according to U.S. EPA method SW
846 7470A.
Bacillus subtilis was extracted from the coupon surface
by physical scrubbing with a toothbrush, using autoclaved
water. The extraction solvent was recovered by pouring
the contents of the dish into a 250-mL sterile sample bottle
with appropriate preservative (sodium thiosulfate). In
analyzing for spores, the bulk liquid and coupon extraction
fluid samples were subjected to heat treatment to inactivate
the indigenous vegetative bacterial cells. During the heat
treatment, the hot water bath was filled with 50:50 deionized
water and tap water, and the temperature was set at 90 °C.
B. subtilis samples, along with positive and negative controls,
were introduced into the water bath and incubated for a
period required to reach the bath water temperature of 80
°C, folio wed by an additional 12 minutes of incubation time
after the water temperature reached 80 °C. Positive and
negative controls were prepared by spiking sterile buffer
with B. subtilis and E. coli, respectively. The absence of any
colonies for negative control confirms the effectiveness of
heat shock. The recovery of B. subtilis from positive control
confirms the viability of injection suspension. The surviving
bacterial spores in the samples were filtered through a 0.45
(jum membrane filter and analyzed by cultural methods that
permit the spore to germinate and produce bacterial cells. A
detailed description on the quantification of Bacillus subtilis
in water samples is provided in the Standard Operation
Procedure (SOP) for Enumeration of Bacillus subtilis Water
Samples (SOP No.: T&E SOP021.00.RO), which was
developed by Shaw in August 2005.
Diesel fuel was extracted from the coupon surface by
physical scrubbing with a brass brush, using 250 mL of
methylene chloride/acetone (1:3 volume ratio) mixture
and 250 mL of acetone. The extraction solvent was
recovered by pouring the contents of the dish into a 1-L
amber glass sample bottle with appropriate preservative
(sodium thiosulfate). The bulk liquid and coupon extraction
fluid samples were submitted to a commercial laboratory
(DataChem Laboratories) to perform the sample analyses on
Diesel Range Organics (DRO).
The term "diesel fuel" incorporates a broad range of
petroleum products that vary significantly in chemical
composition. The major components of diesel fuel include
alkanes (estimated to be 65 to 85 percent by weight),
alkenes (common in converted products such as catalytic
cracker fractions), and aromatics (estimated to be 10 to 30
percent by weight of No. 2 diesel fuel). When assessing
the nature and extent of contamination by diesel fuel, it is
important to use analytical methodologies that distinguish
the diversity and complexity of diesel fuel's chemical
components. Determination of diesel fuel components by
gas chromatography is well established in the petroleum
industry and environmental community. This method enables
the elimination of interferences and provides both qualitative
and quantitative information on the chemical components of
diesel fuel. DRO was analyzed by GC/FID according to U.S.
EPA method SW 846 8015B.
Chlordane was extracted from the coupon surface by
physical scrubbing with a brass brush, using 250 mL of a
hexane/acetone (1:3 volume ratio) mixture and 250 mL of
acetone. The extraction solvent was recovered by pouring
the contents of the dish into a 1-L amber glass sample bottle
with appropriate preservative (sodium thiosulfate). The bulk
liquid and coupon extraction fluid samples were submitted
to a commercial laboratory (STL) to perform the sample
analyses on chlordane. Chlordane was analyzed by GC/ECD
according to U.S. EPAMethod SW 846 3520/8081A.
Technical chlordane consists of over 50 compounds,
including the stereoisomers cis- and /raws-chlordane,
chlordane, heptachlor, and nanochlor (Howard, 1991).
C/s-chlordane (la,2a,3aa,4B,7B,7aa) is also known as
alpha-chlordane; /rans-chlordane (la,2B,3aa,4B,7B,7aa)
is commonly known as gamma-chlordane. For chlordane
sample analyses, laboratories usually analyze for these
two isomers as well as the concentration of total technical
chlordane.
2.10 DECONTAMINATION APPROACH
Based on the literature review, Shaw selected several
decontamination technologies for each target contaminant to
evaluate their decontamination effectiveness and associated
testing issues. The decontamination methods evaluated in
this research included both physical (e.g., water flushing) and
-------
chemical (e.g., low-pH flushing, potassium permanganate
flushing, etc.) cleaning processes. As water flushing is the
most cost-effective and most widely used technique, this
was the baseline decontamination method in the research
program. Shaw coordinated with AwwaRF to ensure that
effective decontamination techniques identified in the
AwwaRF laboratory-scale studies were given priority.
2.10.1. Decontamination of Arsenic
Various decontamination techniques were evaluated to
investigate removal of arsenic from the pilot-scale water
distribution system. As mentioned above, the first (baseline)
decontamination method applied was simple water flushing.
The simple flushing approach consisted of recirculating
tap water within the DSS at a high flow rate of 210 gpm
(corresponding to 2.5 fps for 6-inch diameter pipe) for a
duration of two hours.
Shaw performed a literature review to identify other potential
decontamination techniques for arsenic. Low-pH flushing
and phosphate buffer flushing were identified as alternative
decontamination approaches. Low-pH conditions can
increase the solubility of metals in water; therefore, low-pH
flushing was expected to increase the removal of arsenic from
the drinking water pipe surfaces (Ellison et al, 2002). The
low-pH flushing approach consisted of recirculating low-pH
water (i.e., pH 4, adjusted by hydrochloric acid) within the
DSS at a flow rate of 60 gpm (corresponding to 0.7 fps for 6-
inch diameter pipe) for a duration of four hours, followed by
simple water flushing at a flow rate of 210 gpm for a duration
often minutes in a single-pass mode.
Phosphate buffer has been proven to be effective for
extraction of arsenic from sediment and/or soil samples
(Bruce and Martens, 1997; Gonzalez et al, 2003). Arsenic
(V) anions (H2AsO4" and HAsO42 ~) form strong surface
complexes at the mineral-water interfaces and undergo ligand
exchange with H2PO4" and HPO42 -anions. The phosphate
buffer flushing approach consisted of recirculating 1 mM
phosphate buffer solution (50:50 KH2PO4:K2HPO4) within
the DSS at a flow rate of 60 gpm (i.e., 0.7 fps for 6-inch
diameter pipe) for a duration of four hours, followed by
simple water flushing at a flow rate of 210 gpm for a duration
often minutes in a single-pass mode.
The fourth decontamination approach used for arsenic
was acidified potassium permanganate flushing. Acidified
potassium permanganate is a very strong oxidant that is
widely used in the metal sample digestion. It can significantly
increase the solubility of metals. Also, acidified potassium
permanganate can destroy biofilm in the drinking water
distribution system. Bench-scale drinking water pipe
decontamination studies conducted by Battelle confirmed
the high removal efficiency of acidified potassium
permanganate flushing for mercury from various types of
drinking water pipe surfaces (Chattopadhyay and Fox, 2006).
Therefore, it was speculated that this method would also be
effective in removal of arsenic from cement-lined ductile
iron pipe surfaces. The acidified potassium permanganate
flushing approach consisted of recirculating an acidified
potassium permanganate (1% sulfuric acid/0.4% potassium
permanganate) solution within the DSS at a flow rate of 60
gpm for a duration of four hours, followed by simple water
flushing at a flow rate of 210 gpm for a duration of ten
minutes in a single-pass mode.
Besides the aforementioned chemical decontamination
techniques, some commercially available decontamination
reagents were also evaluated for their effectiveness in
removal of arsenic from the pilot-scale water distribution
system. NSF Standard 60 Products were identified as the
potential decontamination reagents for this evaluation. The
NSF Standard 60 Drinking Water Treatment chemicals are
environmentally friendly products that have successfully
been used in drinking water treatment to stabilize water
quality and extend the lifetime of valuable infrastructure
(NSF Product and Service Listing, 2006). Various NSF
Standard 60 Pipe Cleaning Aid Products are available
in the market. After contacting all of the NSF-certified
manufacturers/vendors, Shaw identified and procured three
different combinations of NSF Standard 60 products, i.e.,
NW-310/NW-400 (manufactured by Johnson Screens,
Inc.), Floran Biogrowth Remover/Catalyst, and Floran Top
Ultra/Catalyst (manufactured by Floran Technologies, Inc.)
as representative decontamination reagents for arsenic. These
pipe-cleaning aid products are being used in commercial
applications for cleaning of drinking water pipes and/or
wells. Accordingly, experiments were conducted using NSF
Standard 60 Pipe Cleaning Aid Products as the potential
decontamination approach to removing arsenic from water
distribution systems.
In the NW-310/NW-400 flushing experiment, after the two-
day contact period of contaminant adherence, the PVC pipe
loop was refilled with fresh tap water. About 5.5 gallons (2.8
liters) of NW-310 and 0.2 gallons (0.7 liters) of NW-400
were then poured into the recirculation tank to reach the final
concentration of NW-310 and NW-400 in the loop (about 3
percent and 0.1 percent by weight, respectively). The water
containing NW-310/NW-400 was then recirculated in the
loop for six hours at a flow rate of 60 gpm. Upon completion
of the NW-310/NW-400 water recirculation, the pipe loop
was drained. This was followed by simple water flushing of
the system at 210 gpm for ten minutes in a single-pass mode.
Coupon samples were taken and analyzed for contaminants
after the decontamination to investigate the decontamination
efficiency of this technique.
Two separate decontamination tests were conducted using
the combination of Floran Technologies Products, Biogrowth
Remover/Catalyst, and Top Ultra/Catalyst. During each
test run, about 1.1 gallons of each component (Biogrowth
Remover/Catalyst or Top Ultra/Catalyst) were poured into
the recirculation tank to reach the final concentration of each
component in the loop, i.e., 0.5% by volume. According to
the manufacturer's suggestion, the flow should be ceased
upon complete mixing of each component in the loop, and
an overnight incubation time should be provided at zero
flow rate. However, in the course of the decontamination
test with Biogrowth Remover/Catalyst, a significant amount
of foam was produced during the incubation with stagnant
-------
loop water, which resulted in an overflow of the recirculation
tank. Therefore, for this test scenario, a flow rate of 25 gpm
was provided during the incubation. Upon completion of the
incubation, the pipe loop was drained, followed by simple
water flushing of the system at 210 gpm for ten minutes in a
single-pass mode. Coupon samples were taken and analyzed
for contaminants after the decontamination to investigate the
decontamination efficiency of these techniques.
2.10.2. Decontamination of Mercury
Three types of decontamination methods were evaluated
for removal of mercury from drinking water distribution
systems: (baseline) water flushing, low-pH flushing, and
acidified potassium permanganate flushing. The procedure
for each decontamination method used for mercury was the
same as that used for arsenic, as described in Section 2.10.1.
The selection of these three decontamination techniques was
based on Shaw's literature review and the test results from
AwwaRFs laboratory-scale studies and Battelle's bench-
scale studies (Welter et al., 2006; Chattopadhyay and Fox,
2006). Simple water flushing was tested as the baseline
decontamination approach. Low-pH flushing was chosen
based on the literature review (Ellison et al, 2002). The
acidified potassium permanganate decontamination method
was proven very effective in removal of mercury from the
drinking water pipe surfaces in Battelle's bench-scale studies
(Chattopadhyay and Fox, 2006) and hence was applied in the
pilot-scale mercury decontamination test.
2.10.3. Decontamination of Bacillus subtilis
Two decontamination approaches were evaluated in this
study to investigate removal of Bacillus subtilis from water
distribution systems: baseline simple water flushing and
shock chlorination. The procedure for baseline water flushing
is described in Section 2.10.1.
Shock chlorination is a very traditional method used to
inactivate microorganisms and surrogates in drinking
water systems. Rose et al. (2005) and Rice et al. (2006)
studied chlorine inactivation of various bacterial agents
under different Chlorine Concentration X Contact Time
(CT) conditions. It was reported that 2-3 log removal of
Bacillus species was achieved using shock chlorination.
The mean CT values for Bacillus globigii (from hundreds
to thousands) were higher than the mean values of the
other Bacillus species tested (i.e., anthracis, cereus, and
thuringiensis). Whitney et al. (2003) performed a literature
review on the various techniques for the inactivation of
Bacillus spores, and they reported 4 log removal of Bacillus
subtilis using 0.05% of sodium hypochlorite at pH 7 at 20 °C
with 30 minutes contact time. AwwaRF's laboratory-scale
decontamination test on Bacillus thuringiensis indicated
that shock chlorination with a CT value of 30,000 mg/L-min
achieved less than 2 log removal of Bacillus thuringiensis
from the old, heavily tuberculated galvanized pipe surfaces
(Welter et al., 2006). The significantly high CT value from
the AwwaRF study demonstrates the challenge associated
with decontamination of microbial contaminants from the
pipe surfaces as compared to removal from bulk water.
Based on the literature review results, Shaw applied the
shock chlorination decontamination approach to inactivate
Bacillus subtilis from the cement-lined ductile iron pipe
surfaces using a CT value of 30,000 mg/L-min. The shock
chlorination approach consisted of flushing the DSS with
an increased chlorine concentration (i.e., free chlorine
concentration of 200 mg/L) at a flow rate of 60 gpm (i.e.,
0.7 fps in 6-inch pipe) in a recirculation mode for a duration
of 2.5 hours to reach a CT value of 30,000 mg/L-min,
followed by simple water flushing at a flow rate of 210 gpm
(i.e., 2.5 fps in 6-inch pipe) for a duration often minutes in
a single-pass mode.
2.10.4. Decontamination of Diesel Fuel
Two different decontamination methods, simple water
flushing and surfactant flushing, were investigated
for removal of diesel fuel from drinking water pipe
surfaces. Simple water flushing was tested as the baseline
decontamination method.
The surfactant, Surfonic TDA-6, was identified based on
AwwaRF's laboratory-scale test conducted on chlordane
(Welter et al., 2006). The AwwaRF study indicated that
Surfonic TDA-6 is a very effective surfactant for removing
chlordane from the drinking water pipe surfaces. Therefore,
Surfonic TDA-6 was applied during the current pilot-scale
decontamination of diesel fuel from the drinking water pipe
surface. The Surfonic TDA-6 flushing consisted of flushing
the pilot-scale DSS with 5% Surfonic TDA-6 solution at
a flow rate of 60 gpm (i.e., 0.7 fps in 6-inch pipe) in a
recirculation mode for a duration of 24 hours, followed
by simple water flushing at a flow rate of 210 gpm (i.e.,
2.5 fps in 6-inch pipe) for a duration of 10 minutes in a
single-pass mode.
2.10.5. Decontamination of Chlordane
The chlordane decontamination study was performed
using Surfonic TDA-6 as the decontamination agent. A
large variety of surfactants were screened initially in the
AwwaRF's bench-scale decontamination study (Welter, et al.,
2006) by a simple procedure to test their ability to dissolve
chlordane. Based on the initial screening of surfactants,
the AwwaRF Project Team identified three surfactants
— Surfonic TDA-6, Surfonic N-60, and Empicol LZV — for
further testing in their bench-scale pipe decontamination
protocol. The test results indicated that Surfonic TDA-6
and Surfonic N-60 are the most promising decontamination
reagents for removal of chlordane from various types of
pipe surfaces. Surfonic N-60 was out of stock from the
manufacturer's (Huntsman Petrochemical Corporation)
warehouse during Shaw's scheduled test for chlordane.
Therefore, Surfonic TDA-6 was selected for testing in the
pilot-scale chlordane decontamination study. The Surfonic
TDA-6 flushing protocol for chlordane was identical to
that employed for diesel fuel as described in the previous
subsection.
-------
3.0
Results and Discussions
3.1 PRELIMINARY TEST RESULTS ON COUPON
SAMPLE EXTRACTION
To quantify the contaminant recovery from the proposed
sample extraction procedure, Shaw conducted an independent
bench-scale study in which two real-world cement-lined
ductile iron pipe coupons were exposed to 50 mg/L of
arsenic/mercury diluted in 15 gallons of dechlorinated water
in a stainless steel container. The coupons were separately
exposed to arsenic/mercury for two days. The water was
continuously stirred during this period. After the two-day
contact time, coupon samples were removed from the
system and collected for arsenic/mercury analyses. The
coupon samples were subjected to the same sampling and
extraction procedures that would be applied in the pilot-scale
decontamination experiments. Duplicate bulk water samples
were also collected in the beginning and at the end of the
experiment for arsenic/mercury analyses. Based on a mass
balance calculation on the bench-scale procedure, the arsenic/
mercury recovery efficiency of the extraction procedure
could be determined. Table 3-1 presents the experimental
results obtained from the bench-scale experiment. As can be
seen from the table, the proposed sampling and extraction
procedure recovered 67 percent and 68 percent of arsenic
and mercury, respectively, from the coupons. It was assumed
that arsenic/mercury removed from the bulk solution was all
adsorbed to the coupons. As the project objectives could be
met with such high recoveries, Shaw applied this extraction
procedure during the pilot-scale experiments.
3.2 PILOT-SCALE CONTAMINATION/
DECONTAMINATION TEST RESULTS
3.2.1. Biofilm Cultivation
To simulate the real-world drinking water distribution
system pipe conditions, biofilm was cultivated on the inner
surfaces of the pilot-scale DSS prior to each adherence/
decontamination test, using the Shaw-developed biofilm
cultivation protocol. During the period of biofilm cultivation,
bulk water samples were collected on a daily basis to monitor
the daily bacterial growth in bulk water through HPC
analyses until it reaches pseudo steady-state. One coupon
sample was taken out of the system at steady-state for the
confirmation of biofilm formation. A bacterial cell count of
104 CFU/cm2 was considered satisfactory for coupons to be
used in the following adherence/decontamination tests.
It was observed from the HPC analytical results that the
bacterial cell counts all exceeded the recommended limit
for viable biofilm growth (HPC levels ranged between
104 CFU/cm2 and 106 CFU/cm2) after one to two weeks of
biofilm development in the system, indicating that a viable
biofilm was developed prior to the injection of contaminant
for each test run.
As mentioned previously, specific nutrients were added to
loop water to enhance the growth of general heterotrophic
bacteria. Dr. Anne Camper of Montana State University
(Camper, et al, 1996) provided the project team with
the recommendation that water with a C:P:N ratio of
1000:100:100 ug per liter be used to enhance the growth
of heterotrophic bacteria and a minimum of 104 CFU/cm2
of HPC be cultivated for confirmation of satisfactory
biofilm development. This guideline was used as general
criteria for biofilm cultivation and contaminant adherence.
Nutrients were added to achieve a representative biofilm for
contaminant adherence within a short time. The addition
of nutrients may have caused growth of certain selective
organisms, but it was beyond the scope of the study to
identify the profile of the biofilm. Since the loop system
was decontaminated after each adherence event, the biofilm
thickness was minimized.
Table 3-1 Arsenic/Mercury Recovery From the Bench-Scale Experiments
Arsenic
Mercury
Initial
contaminant
concentration
in bulk water
(mg/L)
52.4
49.2
Final contaminant
concentration in bulk
water (mg/L)
Sample 1 Sample 2
39.6 37.3
10.9 11.5
Contaminant
adsorbed to coupon
surface (mg/coupon)
Coupon 1 Coupon 2
324 194
812 637
% adsorption
(calculation
based on bulk
water mass
balance)3
27%
77%
% adsorption
(based on
sampling and
analytical
measurements
on the coupon)"
18%
53%
%
extraction
recovery0
67%
68%
a % adsorption = {[Initial concentration in bulk water (mg/L)] - [Final concentration in bulk water (mg/L)]} / [Initial concentration
in bulk water (mg/L)] *100
b % adsorption = [Mass of contaminant adsorbed to coupon surface (measured)] / [Initial mass of contaminant in bulk water]
*100
c % extraction recovery = [% adsorption (based on sampling and analytical measurements on the coupon)] / [% adsorption
(calculated based on bulk water mass balance)] *100
-------
In the first pilot-scale test run (Run ID: As Fl), the free
chlorine level in the water flowing to the DSS was set at
1.1 mg/L just prior to the injection of arsenic by manually
adjusting the chlorine level in the supply water and
monitoring the concentration by use of the ATI free chlorine
meter. However, it was observed that immediately after
introducing the supply water into the pipe loop, the free
chlorine decreased to 0.70 mg/L, eventually stabilizing
around 0.30 mg/L before injection. This is due to the high
chlorine demand in the DSS from the biofilm developed
in the loop. As a result, for the first test run, the initial free
chlorine level for the arsenic adherence study was 0.3 mg/L,
which was lower than the target level of 1.0±0.1 mg/L
free chlorine level (as planned originally). To resolve this
problem, for the second test run (Run ID: As F15), after one
to two weeks of biofilm cultivation in dechlorinated water,
the pipe loop water was drained and refilled with supply
water with free chlorine of ~1.0 mg/L to condition the biofilm
in high chlorine water before injection. The pipe water was
partially recirculated until the free chlorine in the loop was
stabilized at 1.0±0.1 mg/L, which took two to three days. In
order to ensure that the biofilm was not damaged by exposure
to high chlorine water, one coupon sample was taken out
for HPC analysis after the conditioning of biofilm in high-
chlorine water. It was observed that the HPC counts per unit
surface area of the coupon decreased slightly (from 2.2 x io5/
cm2 to 1.8 x lOVcm2) but remained above the recommended
limit for viable biofilm growth. This was confirmed in
another test run (Run ID: As F60) in which the HPC counts
on the coupon surface reduced from 7.0 x lOVcm2 to 1.1
x lOVcm2 after chlorination. Therefore, all the following
test runs were performed according to this adjusted biofilm
cultivation strategy.
3.2.2. Pilot-scale Contaminant Adherence Test Results
3.2.2.1. Arsenic Adherence Test Results
Arsenic adherence tests were conducted at three different
flow rate conditions, (incorporating both the laminar and
turbulent flow regime) using the pilot-scale clear PVC DSS
to evaluate the effect of flow rate on the adsorption of arsenic
on the drinking water pipe surfaces.
The analytical results for the bulk water and coupon samples
collected from the pilot-scale adherence studies for arsenic at
the three different flow rates are summarized in Tables 3-2, 3-
3, and 3-4, respectively. The analytical data for each test run
is also presented in Appendix A.
The bulk water sampling port is located approximately 35
feet downstream of the contaminant injection port. Therefore,
the time taken for the arsenic to reach the sampling port
varied with the different flow rates applied as shown by
concentrations in bulk water samples collected five minutes
after contaminant injection. However, for all three scenarios,
it showed complete contaminant mixing in the pipe loop
system one day after injection, as shown by the target arsenic
concentration in the bulk water at this time point.
Prior to the experiment, there was concern that the adsorptive
properties of the PVC pipe within the DSS might swamp the
contaminants in water at an initial contaminant concentration
of 10 mg/L. Therefore, the bulk water samples were collected
at the designated intervals during the experiments to reveal
whether the contaminant was in contact with the coupons.
This information ensures that the coupons are exposed to
the contaminant during the two-day contact period. As can
be seen from Tables 3-2, 3-3, and 3-4, the presence of the
contaminants in the bulk water samples collected just prior to
the conclusion of each adherence experiment (i.e., two days
after the injection) confirmed the availability of contaminant
within the system.
The arsenic analytical measurements on the coupons were
converted to mass of arsenic adsorbed per unit surface area
of the coupon (mg/in2) based on the surface area of each
coupon sample (19 in2). The results are presented in Figure
3-1 for the three different flow rates that were investigated in
the study. Although the deposition of arsenic on individual
coupons varied, the experimental results indicate that arsenic
adsorbs to cement-lined ductile iron pipe surfaces regardless
of the velocities of the water flow. However, as can be seen
from the figure, the amount of arsenic that adsorbs to the
cement-lined ductile iron pipe surfaces increases with flow
rate, with the highest adherence at the flow rate of 60 gpm
evaluated in this study. This is possibly due to the increased
mass transfer coefficients at higher flow rates. The figure also
shows that the effect of coupon locations within the DSS
on the arsenic adsorption capacity is not very obvious. In
lower flow rate conditions (i.e., for flow rates of 1 gpm and
15 gpm), the coupons closer to the injection port tended to
have more arsenic deposition than the coupons farther from
the source; while the opposite result was observed for the
higher flow rate (i.e., 60 gpm). However, overall, the effect
of coupon location on the arsenic adherence on cement-lined
ductile iron pipe surfaces is not very significant, indicating
complete contaminant mixing under recirculation condition
in the pipe loop during the two-day contact time. It can also
be seen in Figure 3-1 that arsenic has a stronger tendency to
adsorb to the surfaces of cement-lined ductile iron pipe than
to the PVC surfaces.
-------
Table 3-2 Experimental Results From Test Run ID: As Fl (Adherence Test Flow Rate: 1 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
As F1 TO
As F1 TO Dup
As F1 T5M
As F1 T5M Dup
AsF1 T1D
AsF1 TIDDup
As F1 T2D
As F1 T2D Dup
ND
ND
ND
ND
10.4
8.7
9.6
9.5
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
0.029
4.3x10= cells/cm2
0.24
0.097
1.0
2.1
1.5
1.6
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
Table 3-3 Experimental Results From Test Run ID: As F15 (Adherence Test Flow Rate: 15 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
AsF15TO
AsF15TODup
AsF15T5M
AsF15T5M Dup
AsF15T1D
AsF15T1DDup
AsF15T2D
AsF15T2DDup
0.0042
0.0034
2.6
1.6
9.3
9.3
9.3
9.3
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
0.052
1. 8 x105 cells/cm2
0.37
0.18
2.1
2.8
0.81
1.5
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table 3-4 Experimental Results From Test Run ID: As F60 (Adherence Test Flow Rate: 60 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
As F60 TO
As F60 TO Dup
As F60 T5M
As F60 T5M Dup
AsF60T1D
AsF60T1DDup
As F60 T2D
As F60 T2D Dup
0.0036
0.0052
9.6
10.4
9.5
8.8
8.9
8.9
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
0.024
1.1 x105 cells/cm2
0.11
0.64
1.9
4.2
4.9
6.5
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
Figure 3-1 Arsenic Adherence Study Results (Flow Rates: 1, 15, 60 gpm)
0.40-
<
B egimiing of p ipe loop
(Cement-lined ductile
iron coupon)
Near of pipe loop
(Cement-lined ductile
iron coupon)
Beginning of pipe loop
(PVC control coupons")
Coupon Location in the Pipe Loop
-------
Also monitored were basic water quality parameters,
including TOC, pH, ORP, free chlorine, turbidity,
conductivity, and temperature. As expected, free chlorine
readings decreased upon injection of sodium arsenite due
to the reaction of arsenite with free chlorine. The reaction
between arsenite and chlorine is shown below:
AsO2- (Arsenite) + C12 -> AsO43' (Arsenate) + 2C1'
Correspondingly, ORP readings also decreased due to the
consumption of free chlorine (oxidant) in water.
Temperatures fluctuated over time due to the effect of
ambient high-bay temperature change at the T&E Facility.
Turbidity readings fluctuated significantly over the whole
experimental period. The turbidity readings are inconclusive
due to the interference of bubbles generated on the sensor.
The other water quality parameters, i.e., pH, specific
conductance, and TOC, did not show any considerable
change following the arsenic injection.
3.2.2.2. Mercury Adherence Test Results
Mercury adherence tests were also performed at three
different flow rates conditions, i.e., 1 gpm, 15 gpm, and
60 gpm. The analytical results for the bulk water and coupon
samples collected from the pilot-scale decontamination
studies for mercury at the three different flow rates are
summarized in Tables 3-5 through 3-7. For all three
scenarios, complete contaminant mixing was observed
in the pipe loop system one day after injection, as shown
by the steady mercury concentration in the bulk water after
this time point. As can be seen from Tables 3-5, 3-6, and
3-7, the results of the bulk water samples collected just
prior to the conclusion of each adherence experiment (i.e.,
two days after the injection) confirmed the availability of
contaminant within the system. This information ensures that
the coupons were exposed to the contaminant during the two-
day contact period.
Figure 3-2 presents the mass of mercury adsorbed per unit
surface area of the coupon (mg mercury/in2) as a function
of flow rates, coupon locations, and coupon materials. The
experimental results indicate the varying degree to which
mercury adsorbs to cement-lined ductile iron pipe surfaces
at different water flow rate conditions. As can be seen from
the figure, the amount of mercury that adsorbs to the cement-
lined ductile iron pipe surfaces increases with flow rate, with
the highest adherence at the flow rate of 60 gpm evaluated
in this study. This result conforms to the findings obtained
from the arsenic adherence test. Figure 3-2 shows that the
effect of coupon locations within the DSS on the mercury
adsorption capacity is not significant, further indicating
complete contaminant mixing in the pipe loop during the
two-day contact time. Figure 3-2 also shows that mercury has
a stronger tendency to adsorb to the surfaces of cement-lined
ductile iron pipe than to the PVC surfaces.
Table 3-5 Experimental Results From Test Run ID: Hg Fl (Adherence Test Flow Rate: 1 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
Hg F1 TO
Hg F1 TO Dup
Hg F1 T5M
Hg F1 T5M Dup
HgF1 T1D
HgF1 TIDDup
Hg F1 T2D
Hg F1 T2D Dup
0.00005
0.000068
0.000075
0.000079
9.3
8.9
9.6
9.5
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
0.00036
2.8 x106 cells/cm2
0.49
0.048
4.0
2.2
1.2
3.3
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table 3-6 Experimental Results From Test Run ID: Hg F15 (Adherence Test Flow Rate: 15 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
HgF15TO
Hg F15TODup
Hg F15T5M
HgF15T5M Dup
HgF15T1D
HgF15T1DDup
HgF15T2D
HgF15T2DDup
0.0016
0.0016
9.6
4
10.7
8.4
8.1
7.8
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
0.073
1. 4 x103 cells/cm2
0.083
2.3
9.6
12.7
4.3
8.1
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
Table 3-7 Experimental Results From Test Run ID: Hg F60 (Adherence Test Flow Rate: 60 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
Hg F60 TO
Hg F60 TO Dup
Hg F60 T5M
HgF60T5M Dup
Hg F60T1D
HgF60T1DDup
Hg F60 T2D
HgF60T2DDup
0.003
0.0025
11
10.5
9.7
9.7
8.8
9.4
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
0.093
3. 3 x106 cells/cm2
0.078
0.94
25.5
37.8
50.8
23.8
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Figure 3-2 Mercury Adherence Study Results (Flow Rates: 1, 15, 60 gpm)
Beginning of pipe loop
(Cement-lined ductile
iron coupon)
Near end of pipe loop
(Cement-lined ductile
iron coupon)
Beginning of pipe loop
(PVC control coupons)
Coupon Location in Hie Pipe Loop
Figure 3-3 compares the adherence of mercury and arsenic
to the cement-lined ductile iron and clear PVC pipe surfaces
at the three different flow rate conditions. As can be seen,
mercury has significantly stronger adherence to cement-
lined ductile iron pipe surfaces compared to arsenic.
The experimental results also indicate that there is no
considerable difference between the adsorption of mercury
and arsenic on clear PVC pipe coupons.
Also monitored were basic water quality parameters,
including TOC, pH, ORP, free chlorine, turbidity,
conductivity, and temperature.
Free chlorine measurements decreased gradually upon
injection of mercuric chloride. In mercuric chloride, mercury
(II) exists as the most oxidized form of mercury species;
therefore, it cannot be further oxidized by chlorine. As such,
the decrease of chlorine is attributed to the chlorine demand
from biofilm in the loop.
Correspondingly, OPJ3 readings also decreased due to the
consumption of free chlorine (oxidant) in water.
The injection of mercuric chloride resulted in a decrease of
pH in the pipe loop system.
Temperatures fluctuated over time due to the effect of
ambient high-bay temperature change at the T&E Facility.
The other water quality parameters, i.e., specific conductance,
turbidity, and TOC, did not show any considerable change
following the mercury injection.
-------
Figure 3-3 Comparison of Arsenic and Mercury Adherence to Cement-lined Ductile (Iron Pipe Surfaces at Various
Flow Rate Conditions)
Beginning of pipe loop
<: Cement-lined ductile iron coupon? I
Neai end of pipe loop
i Cement-lined ductile iron coupons)
Coupon Location in Hie Pipe Loop
3.2.2.3. Bacillus subtilis Adherence Test Results
A Bacillus subtilis adherence test was conducted at a flow
rate of 60 gpm. From the previous experiments, which were
aimed at evaluating the effect of flow rate on adherence of
inorganic contaminants (e.g., arsenic and mercury) to the
pipe surfaces, it was found that the amount of contaminant
that adsorbs to the cement-lined ductile iron pipe surfaces
increases with flow rate, with the highest adherence at the
flow rate of 60 gpm evaluated (corresponding to turbulent
flow). Therefore, the flow rate of 60 gpm was established for
the adherence test of Bacillus subtilis.
The analytical results for the bulk water and coupon samples
collected from the pilot-scale adherence test for Bacillus
subtilis are summarized in Table 3-8. As can be seen, the
injected Bacillus subtilis showed complete mixing in the
pipe loop system five minutes after injection, as shown by
the steady Bacillus subtilis concentration in the bulk water
after this time point. It was also found that the concentration
of Bacillus subtilis in the bulk water decreased over time
probably due to the strong adherence of Bacillus subtilis to
both PVC and cement-lined ductile iron surfaces. However,
the results of the bulk water samples collected just prior to
the conclusion of each adherence experiment (i.e., two days
after the injection) confirmed the availability of Bacillus
subtilis within the system. This information indicates that the
coupons were exposed to the contaminant during the whole
two-day contact period.
The Bacillus subtilis adherence test results are also presented
in Figure 3-4. As can be seen from the figure, Bacillus
subtilis showed similarly strong adherence to both the
cement-lined ductile iron and clear PVC pipe surfaces as
shown by the same order of magnitude of adherence (i.e.,
~104 cells/in2) on these two types of surfaces.
Also monitored were basic water quality parameters,
including TOC, pH, ORP, free chlorine, turbidity,
conductivity, and temperature.
TOC readings increased slightly upon injection of
Bacillus subtilis probably due to the organic content of
the sporulation media.
Upon injection of Bacillus subtilis, free chlorine readings
decreased gradually due to the chlorine demand from
Bacillus subtilis and sporulation media and biofilm in
the loop.
Correspondingly, ORP readings also decreased gradually due
to the consumption of free chlorine (oxidant) in water.
Temperatures fluctuated over time due to the effect of
ambient high-bay temperature change at the T&E Facility.
The other water quality parameters, i.e., pH, specific
conductance, and turbidity, did not show any considerable
change following the Bacillus subtilis injection.
-------
Table 3-8 Experimental Results From Test Run ID: BS F60 (Adherence Test Flow rate: 60 gpm)
Baseline
Adherence
Study
During
2-day
contaminant
contact
period
After 2-day
contact
period
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
BS F60 TO
BSFBOTODup
BS F60 T5M
BS F60 T5M Dup
BSF60T1D
BSF60T1DDup
BS F60 T2D
BS F60 T2D Dup
0
0
880
900
720
800
330
410
Coupon #1
Coupon #2(a>
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
16
5.3x10= cells/ cm2
1.8E+04
7.1E+03
4.6E+04
3.3E+04
5.5E+04
5.6E+04
' Coupon #2 was taken for HPC analysis to check the biofilm development.
Figure 3-4 Bacillus subtilis Adherence Study Results (Flow Rate: 60 gpm)
l.E-06-
1.E-K)
Beginning of pipe loop Near end of pipe loop Beginning of pipe loop
(Cement-lined ductile (Cement-lined ductile (PVC control coupons)
iron couponj iron coupon!
Coupon Location in the Pipe Loop
-------
3.2.2.4. Diesel Fuel Adherence Test Results
A flow rate of 60 gpm was established for the pilot-scale
adherence test of diesel fuel. The analytical results for the
bulk water and coupon samples collected from the adherence
test of diesel fuel are summarized in Table 3-9.
As can be seen, the injected diesel fuel showed complete
mixing in the pipe loop system five minutes after injection,
as shown by the target diesel fuel concentration in the
bulk water at this time point. It was also found that the
concentration of diesel fuel in the bulk water decreased
significantly over time due to the strong adherence of
diesel fuel to both PVC and cement-lined ductile iron pipe
surfaces. The bulk water samples collected just prior to the
conclusion of the adherence experiment (i.e., two days after
the injection) showed very low or nondetectable levels of
diesel fuel. This information indicates that the coupons might
not have been exposed to diesel fuel during the last day of
the adherence test and the adherence of diesel fuel to the pipe
surfaces could be stronger if higher diesel fuel concentrations
were applied in the bulk water during the adherence test.
The diesel fuel adherence test results are also presented
in Figure 3-5. As can be seen from the figure, diesel fuel
showed strong adherence to both the cement-lined ductile
iron pipe and clear PVC pipe surfaces. Diesel fuel appeared
to have stronger adherence to the cement-lined ductile iron
pipe surfaces (1.1-1.5 mg/in2) than to the clear PVC pipe
surfaces (0.5-0.8 mg/in2).
Also monitored were basic water quality parameters,
including TOC, pH, ORP, free chlorine, turbidity,
conductivity, and temperature.
As expected, TOC readings increased slightly upon
injection of diesel fuel.
Upon injection of diesel fuel, free chlorine readings
decreased gradually due to the chlorine demand from
diesel fuel.
Correspondingly, ORP readings also decreased gradually due
to the consumption of free chlorine (oxidant) in water.
Turbidity increased significantly upon the injection of diesel
fuel, and 10-12 hours later, the turbidity gradually decreased
probably due to the decrease of diesel fuel concentration in
the loop water. (Some diesel fuel might have reacted with
chlorine, and some might have adsorbed to the pipe surfaces.)
Temperatures fluctuated over time due to the effect of
ambient high-bay temperature change at the T&E Facility.
The other water quality parameters, i.e., pH and specific
conductance, did not show any considerable change
following the diesel fuel injection.
Table 3-9 Experimental Results From Test Run ID: DRO F60 (Adherence Test Flow rate: 60 gpm)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
DRO F60 TO
DRO F60 TO Dup
DRO F60 T5M
DROF60T5M Dup
DROF60T1D
DROF60T1DDup
DRO F60 T2D
DROF60T2DDup
ND
ND
13.1
11.1
3.9
1.3
ND
0.7
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
14.0a
4.8 x105 cells/ cm2
8.7
14.8
23.5
21.7
22.4
28.5
a Diesel Range Organics were detected for coupon #1. However, according to the chromatograph, these compounds were not
diesel fuel compounds.
b Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Figure 3-5 Diesel Fuel Adherence Test Results (Flow Rate: 60 gpm)
-------
Turbidity increased significantly upon the injection of
chlordane solution because the chlordane solution injected
was a thick amber liquid.
Temperatures fluctuated over time due to the effect of
ambient high-bay temperature change at the T&E Facility.
The other water quality parameters, i.e., pH and specific
conductance, did not show any considerable change
following the chlordane injection.
Figure 3-6 Chlordane Adherence Test Results
(Flow Rate for Adherence Study: 60 gpm Decontamination: Surfonic TDA-6 Flushing
Beginning of pipe loop
(Cement-lined
ductile iron coupon)
Near end of p ip e loop
(Cement-lined
ductile iron coupon)
Beginning of pipe loop
(PVC control
coupons)
Coupon Location in the Pipe Loop
-------
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-------
3.2.3. Pilot-scale Decontamination Test Results
As described in the previous section, all contaminants tested,
i.e., arsenic, mercury, Bacillus subtilis, diesel fuel, and
chlordane showed strong adherence to cement-lined ductile
iron pipe surfaces. Bacillus subtilis has similar adsorption
capacity on both the PVC pipe surfaces and on the cement-
lined ductile iron pipe surfaces. Diesel fuel and chlordane
also showed considerable amount of adherence to the clear
PVC pipe surfaces. To identify appropriate decontamination
technologies for each of these contaminants, various
decontamination methods were tested in this study. As
described in the overall experimental strategy in Figure 2-3,
each decontamination test was initiated with an adherence
test, using the target contaminant, followed by a designated
decontamination technique.
3.2.3.1. Arsenic Decontamination Test Results
A total of seven different decontamination approaches were
investigated for removal of arsenic from the pilot-scale water
distribution system: baseline water flushing, low-pH flushing,
phosphate buffer flushing, acidified potassium permanganate
flushing, NW-310/NW-400 flushing, Floran Biogrowth
Remover/Catalyst flushing, and Floran Top Ultra/Catalyst
flushing. The arsenic decontamination test results for each of
these decontamination methods are presented below.
(1) Baseline water flushing
Three runs of baseline water flushing tests were
performed on arsenic following three scenarios of
arsenic adherence tests that applied three different flow
rates, i.e., 1 gpm, 15 gpm, and 60 gpm. The test results
are plotted in Figures 3-7, 3-8, and 3-9 for the three
different test scenarios, respectively. As can be seen
from the figures, water flushing of the pipe loop at 210
gpm, i.e., 2.5 fps, did not consistently remove arsenic
from the cement-lined ductile iron pipe surfaces. The
variation from test to test is very high, e.g., in Scenario
1 and 3, the water flushing removed some of the arsenic
from the pipes; in Scenario 2, no arsenic removal was
observed.
Figure 3-7 Arsenic Simple Water Flushing Test Results From Scenario 1
(Flow Rate for Adherence Study: 1 gpm Decontamination: Simple Water Flushing @ 210 gpm)
0.14
Beginning of pipe loop (Cement- Near end of pipe loop (Ceiiient-
lined ductile iron coupon) lined ductile iron coupon)
Coupon Location hi the Pipe Loop
-------
Figure 3-8 Arsenic Simple Water Flushing Results From Scenario 2
(Flow Rate for Adherence Study: 15 gpm Decontamination: Simple Water Flushing @ 210 pgm)
0.18
•3 0
Beginning of pipe loop (Cement- Near end of pipe loop (Cement-
lined ductile iron coupons) lined ductile iron coupons)
Coupon Location in tlie Pipe Loop
Figure 3-9 Arsenic Simple Water Flushing Results From Scenario 3
(Flow Rate for Adherence Study: 60 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Beginning of pipe loop (Cement
lined ductile iron coupons)
Near end of pipe loop (Cemeni-
Imed ductile iron coupons)
Coupon Location in Hie Pipe Loop
The decontamination efficiency of simple water flushing is
calculated for each test scenario by comparing the arsenic
remaining on coupons in the same location before and after
the flushing. The results are shown in Tables 3-11, 3-12, and
3-13 for the adherence test flow rates of 1 gpm, 15 gpm,
and 60 gpm, respectively. According to the calculations, the
decontamination efficiency obtained for arsenic ranged from
-55 to 51 percent. As can be seen, the data from individual
coupons were highly varied (most possibly due to the
variations in the coupons and the extraction procedure).
However, the experimental results indicate that overall
the simple water flushing of the pipe loop at 2.5 fps is a
marginally effective decontamination technique for removing
arsenic from drinking water distribution systems.
-------
Table 3-11 Decontamination Efficiency of Simple Flushing for Arsenic Calculated From Test Run ID: As Fl
(Flow Rate for Adherence Study: 1 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Before flushing
After flushing
Coupon ID
Arsenic adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
1.0
Coupon #4
2.1
1.6
Coupon #7
0.84
Coupon #8
1.0
0.92
41%
Coupon #5
1.5
Coupon #6
1.6
1.6
Coupon #9
0.78
Coupon #10
0.88
0.83
46%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
Table 3-12 Decontamination Efficiency of Simple Flushing for Arsenic Calculated From Test Run ID: As F15
(Flow Rate for Adherence Study: 15 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Before flushing
After flushing
Coupon ID
Arsenic adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
2.1
Coupon #4
2.8
2.5
Coupon #7
2.8
Coupon #8
2.6
2.7
-10%
Coupon #5
0.81
Coupon #6
1.5
1.2
Coupon #9
1.9
Coupon #10
1.7
1.8
-55%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
-------
Table 3-13 Decontamination Efficiency of Simple Flushing for Arsenic Calculated From Test Run ID: As F60
(Flow Rate for Adherence Study: 60 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Before flushing
After flushing
Coupon ID
Arsenic adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
1.9
Coupon #4
4.2
3.1
Coupon #7
2.7
Coupon #8
3.8
3.3
-7%
Coupon #5
4.9
Coupon #6
6.5
5.7
Coupon #9
2.7
Coupon #10
2.9
2.8
51%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(2) Low-pH flushing
From the previous arsenic adherence experiments,
which were aimed at evaluating the effect of flow
rate on adherence of arsenic to the pipe surfaces, it
was found that the amount of arsenic that adsorbs to
the cement-lined ductile iron pipe surfaces increases
with flow rate, with the highest adherence at the flow
rate of 60 gpm evaluated. This is attributed to the
increased mass transfer coefficients at higher flow rates.
Therefore, the flow rate of 60 gpm was established for
the adherence of the contaminants during the evaluation
of the decontamination efficiency of low-pH flushing.
Figure 3-10 shows the results of the low-pH flushing
for arsenic. As can be seen, the low-pH flushing did
not dramatically remove arsenic from the cement-lined
ductile iron pipe surfaces.
The decontamination efficiency of low-pH flushing
is calculated by comparing the arsenic remaining on
coupons in the same location before and after the
flushing. The results are shown in Tables 3-14. The
experimental results indicate that low-pH flushing of
the pipe loop is a marginally effective decontamination
technique for removing arsenic from the drinking water
distribution system. The decontamination efficiency
obtained for arsenic was 6 percent and 36 percent for the
two coupon locations tested in this study, respectively. It
was concluded from the test result, that decontamination
efficiency for arsenic from cement-lined ductile iron
pipe surfaces was not improved by using low-pH
flushing as compared to simple water flushing.
Figure 3-10 Low-pH (pH 4) Flushing Results for Arsenic Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: pH 4 Flushing)
«a
a'
W
i
o
Beginning of pipe loop Near end of pipe loop
(Cement-lined ductile iron coupon) (Cement-lined ductile iron coupon)
Coupon Location in the Pipe Loop
-------
Table 3-14 Decontamination Efficiency of Low-pH Flushing for Arsenic
Before flushing
After flushing
Coupon ID
Arsenic adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on coupon
after flushing (mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
3.6
Coupon #4
2.6
3.1
Coupon #7
2.5
Coupon #8
3.3
2.9
6%
Coupon #5
4.6
Coupon #6
3.0
3.8
Coupon #9
2.2
Coupon #10
2.7
2.5
36%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(3) Phosphate buffer flushing
The previous arsenic decontamination indicated that
simple water flushing at 2.5 fps could remove only up
to ~51 percent of adsorbed arsenic from the cement-
lined ductile iron pipe surfaces. Furthermore, the
decontamination efficiency for arsenic from cement-
lined ductile iron pipe surfaces was
not improved by using low-pH flushing. Therefore,
phosphate buffer flushing was applied to determine
whether this technique could achieve higher arsenic
removal efficiency. The test result is presented in Figure
3 -11. As can be seen from the figure, phosphate buffer
flushing did not show any removal of arsenic from the
cement-lined ductile iron pipe surfaces.
The decontamination efficiency of phosphate buffer
flushing is also calculated by comparing the arsenic
remaining on coupons in the same location before and
after the decontamination. The results are shown in
Tables 3-15. A negative decontamination efficiency
was observed for phosphate buffer flushing, indicating
that phosphate buffer flushing is not an effective
decontamination technique for removing arsenic from
drinking water distribution systems.
Figure 3-11 Phosphate Buffer Flushing Results for Arsenic Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: Phosphate Buffer Flushing)
~f-
3
B eginning o f p ip e lo op (Cement-
lined ductile iron coupon)
Near end of pipe loop (Cement-
lined ductile iron coupon)
Coupon Location in the Pipe Loop
-------
Table 3-15 Decontamination Efficiency of Phosphate Buffer Flushing for Arsenic
Before phosphate
buffer flushing
After phosphate
buffer flushing
Coupon ID
Arsenic adsorbed (mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on coupon
after flushing (mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
5.0
Coupon #4
6.2
5.6
Coupon #7
5.9
Coupon #8
7.1
6.5
-16%
Coupon #5
5.3
Coupon #6
3.9
4.6
Coupon #9
7.0
Coupon #10
4.4
5.7
-24%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(4) Acidified potassium permanganate flushing
Acidified potassium permanganate flushing is a more
aggressive chemical decontamination technique
compared to the previously applied decontamination
approaches for arsenic. As the decontamination methods
tested previously did not show significant removal
efficiency for arsenic, this method was chosen in order
to achieve improved decontamination efficiency.
Figure 3-12 presents the results obtained from the
acidified potassium permanganate flushing test on
arsenic. As can be seen from the figure, the acidified
potassium permanganate flushing consistently removed
approximately half of the adsorbed arsenic from the
cement-lined ductile iron surfaces. The decontamination
efficiency calculated for acidified potassium
permanganate flushing, 54 percent to 61 percent (as
shown in Table 3-16), indicated that the acidified
potassium permanganate flushing is the most efficient
decontamination approach (among the techniques
evaluated) for removing arsenic from the cement-lined
ductile iron pipe surfaces. This is possibly attributed to
the enhanced solubility of arsenic in the presence of acid
(pH of ~2) and permanganate in the solution.
Figure 3-12 Acidified Potassium Permanganate Flushing Results for Arsenic Decontamination
(Flow Rate for Adherence Study: 60 gpm
Decontamination: Acidified Potassium Permanganate Flushing)
0,44
61
Beginning of pipe loop (Cement-
lined ductile Iron coupon)
Near end of pipe loop ("Cement-
lined ductile iron coupon)
Coupon Location in the Pipe Loop
-------
Table 3-16 Decontamination Efficiency of Acidified Potassium Permanganate Flushing for Arsenic
Before
phosphate buffer
flushing
After phosphate
buffer flushing
Coupon ID
Arsenic adsorbed (mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on coupon
after flushing (mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
6.2
Coupon #4
6.3
6.3
Coupon #7
2.9
Coupon #8
2.8
2.9
54%
Coupon #5
5.3
Coupon #6
3.7
4.5
Coupon #9
1.9
Coupon #10
1.6
1.8
61%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(5) NSF Standard 60 Pipe Cleaning Aid Products
Flushing (NW-310/NW-400 flushing, Floran
Biogrowth Remover/Catalyst, and Floran Top
Ultra/Catalyst)
NSF Standard 60 Pipe Cleaning Aid Products
decontamination is a follow-up study to the baseline
simple flushing, low-pH flushing, phosphate buffer
flushing, and acidified potassium permanganate
flushing experiments conducted for arsenic. The
previous test results indicated that the highest arsenic
removal efficiency was observed with acidified
potassium permanganate flushing, which removed
up to 61 percent of arsenic from the cement-lined
ductile iron pipe surfaces. The other decontamination
approaches presented no removal or low removal of
arsenic from drinking water distribution systems. The
NSF Standard 60 Pipe Cleaning Aid Products were
identified for decontamination of arsenic as they were
proven as a very effective technique for the cleaning
of drinking water pipes and wells. In this study, Shaw
conducted three separate decontamination tests using
the combination of NW-310/NW-400, Floran Biogrowth
Remover/Catalyst, and Floran Top Ultra/Catalyst.
The results are presented in Figures 3-13, 3-14, and 3-15
for the three different NSF Standard 60 Pipe Cleaning
Aid Products decontamination approaches that were
investigated in the study. As can be seen from the
figures, approximately half of the adsorbed arsenic was
removed from the cement-lined ductile iron surfaces
after the application of NSF Standard 60 Pipe Cleaning
Aid decontamination procedure.
The decontamination efficiencies of three different
NSF Standard 60 products decontamination procedures
are calculated by comparing the arsenic remaining
on coupons in the same location before and after the
decontamination. The results are shown in Tables
3-17, 3-18, and 3-19, respectively. As shown in
Tables 3-17, 3-18, and 3-19, the NSF Standard 60
Products decontamination methods appear to be
efficient approaches to removing arsenic from the
cement-lined ductile iron pipe surfaces. Compared to
the decontamination technologies tested previously
on arsenic (except for the acidified potassium
permanganate flushing), the decontamination efficiency
was improved by using the NSF Standard 60 Products
as the decontamination reagents. As far as the
decontamination efficiencies are concerned, there is no
significant difference among the three different NSF
Standard 60 products tested, i.e., the decontamination
efficiencies are bracketed in the range of 46 percent
to 67 percent. However, a comparison of the three test
results indicates that the amount of arsenic adsorbed
to the pipe surfaces from Test Run: As NW (1.4 - 2.7
mg of arsenic adsorbed per coupon) was less than that
from Test Run: As Floran I and As Floran II (2.8 - 6.5
mg of arsenic adsorbed per coupon). The reason for
such a difference is not very clear, since the adherence
test condition was the same for all three tests. It is
also noticed that the decontamination efficiency of
the NSF Standard 60 Products flushing for arsenic is
similar to that of the acidified potassium permanganate
flushing. However, compared to the acidified potassium
permanganate, the NSF Standard 60 Products are much
more environmentally friendly; therefore, the NSF
Standard 60 Products should be given higher priority in
a real-world arsenic decontamination scenario.
-------
Figure 3-13 NW-310/NW-400 Flushing Results for Arsenic Decontamination
Flow Rate for Adherence Study: 60 gpm Decontamination: NW-310/NW-400 Flushing)
0.24
B egitming o f p ip e loop (C ement-
lined ductile iron coupon)
Near end of pipe loop (Cement-
lined ductile iron coupon)
Coupon Location ill the Pipe Loop
Figure 3-14 Floran Biogrowth Remover/Catalyst Flushing Results for Arsenic Decontamination
(Flow Rate for Adherence Study: 60 gpm)
Decontamination: Floran Biogrowth Remover/Catalyst Flushing
Beginning of pipe loop
(Cement-lined ductile iron coupon)
Near end of pipe loop
iCenient-lined ductile iron coupon'
Coupon Location In the Pipe Loop
-------
Figure 3-15 Floran Top Ultra/Catalyst Flushing Results for Arsenic Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: Floran Top Ultra/Catalyst Flushing)
0,44
-fi
Beginning of pipe loop
(Cement-lined ductile iron coupon)
Near end of pipe loop
(Cement-lined ductile iron coupon)
Coupon Location in the Pipe Loop
Table 3-17 Decontamination Efficiency of NW-310/NW-400 Flushing for Arsenic
Before phosphate
buffer flushing
After phosphate
buffer flushing
Coupon ID
Arsenic adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on coupon
after flushing (mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
1.4
Coupon #4
2.7
2.1
Coupon #7
1.6
Coupon #8
0.63
1.1
46%
Coupon #5
1.6
Coupon #6
1.7
1.7
Coupon #9
0.5
Coupon #10
0.67
0.6
65%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
Table 3-18 Decontamination Efficiency of Floran Biogrowth Remover/Catalyst Flushing for Arsenic
Before phosphate
buffer flushing
After phosphate
buffer flushing
Coupon ID
Arsenic adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
5.6
Coupon #7
2.3
Coupon #4
6.0
2.1
Coupon #8
1.5
1.9
67%
Coupon #5
5.6
1.7
Coupon #9
1.5
Coupon #6
5.1
Coupon #10
2.5
2.0
63%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
-------
Table 3-19 Decontamination Efficiency of Floran Top Ultra/Catalyst Flushing for Arsenic
Before phosphate
buffer flushing
After phosphate
buffer flushing
Coupon ID
Arsenic adsorbed (mg/coupon)
Average (mg/coupon)1
Coupon ID
Arsenic remaining on coupon
after flushing (mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
6.4
Coupon #4
4.8
5.6
Coupon #7
1.9
Coupon #8
1.7
1.8
46%
Coupon #5
5.2
Coupon #6
2.8
4.0
Coupon #9
2.6
Coupon #10
3.6
3.1
65%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
3.2.3.2. Mercury Decontamination Test Results
Three different decontamination approaches were used
for the mercury decontamination study: baseline water
flushing, low-pH flushing, and acidified potassium
permanganate flushing.
(1) Baseline water flushing
Three runs of baseline water flushing were conducted on
mercury following three scenarios of mercury adherence
tests that applied three different flow rates, i.e., 1
gpm, 15 gpm, and 60 gpm. The results are shown in
Figures 3-16, 3-17, and 3-18 for the three test scenarios,
respectively. As can be seen from the figures, water
flushing of the pipe loop at 210 gpm (corresponding
to 2.5 fps for 6-inch diameter pipe) did not result in
considerable removal of mercury from the cement-lined
ductile iron pipe surfaces. The variation from test to
test and from coupon to coupon is very high, e.g., in
Scenario 2 and 3, the water flushing removed some of
the mercury from the pipes; while in Scenario 1, it did
not remove mercury from the coupons located in the
beginning of the pipe loop.
Figure 3-16 Mercury Simple Water Flushing Test Results
(Flow Rate for Adherence Study: 1 gpm Decontamination: Simple Water Flushing @ 210 gpm)
SI)
Beginning of pipe loop
(Cement-lined ductile iron coupons)
Near end of pipe loop
(Cement-lined ductile iron coupons)
Coupon Location in the Pipe Loop
-------
Figure 3-17 Mercury Simple Water Flushing Test Results
(Flow Rate for Adherence Study: 15 gpm Decontamination: Simple Water Flushing @ 210 gpm)
o 0.80
Beginning of pipe loop Near end of pipe loop
(Cement-lined ductile iron coupons) (Cement-lined ductile iron coupons)
Coupon Location in the Pipe Loop
Figure 3-18 Mercury Simple Water Flushing Test Results
(Flow Rate for Adherence Study: 60 gpm Decontamination: Simple Water Flushing @ 210 gpm)
C
i
Beginning of pipe loop
(Cement-lined ductile iron coupons)
Near end of pipe loop
(Cement-lined ductile iron coupons;
Coupon Location in the Pipe Loop
-------
The decontamination efficiency of simple water flushing is
calculated for each test scenario by comparing the mercury
remaining on coupons in the same location before and after
the flushing. The results are shown in Tables 3-20, 3-21, and
3-22 for the adherence test flow rates of 1 gpm, 15 gpm,
and 60 gpm, respectively. According to the calculations, the
decontamination efficiency obtained for mercury ranged
between -18 percent and 57 percent. As can be seen, the data
from individual coupons were highly varied (most possibly
due to the variations in the coupons and the extraction
procedure), and it was difficult to obtain a representative
number for decontamination efficiency. However, the
experimental results indicate that overall the simple water
flushing of the pipe loop at 2.5 fps is a marginally effective
decontamination technique for removing mercury from the
drinking water distribution systems.
Table 3-20 Decontamination Efficiency of Simple Flushing for Mercury Calculated From Test Run ID: Hg Fl
(Flow Rate for Adherence Study: 1 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Before flushing
After flushing
Coupon ID
Mercury adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Mercury remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
'- :'-•' :::: '-. • '• .:::: •. .• ::v . ;v
Coupon #3
4.0
Coupon #4
2.2
3.1
Coupon #7
3.8
Coupon #8
3.5
3.7
-18%
Coupon #5
1.2
Coupon #6
3.3
2.3
Coupon #9
2.0
Coupon #10
0.71
1.4
40%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
Table 3-21 Decontamination Efficiency of Simple Flushing for Mercury Calculated From Test Run ID: Hg F15
(Flow Rate for Adherence Study: 15 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Before flushing
After flushing
Coupon ID
Mercury adsorbed (mg/
coupon)
Average (mg/coupon)1
Coupon ID
Mercury remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
9.6
Coupon #4
12.7
11.2
Coupon #7
4.7
Coupon #8
5.0
4.9
57%
Coupon #5
4.3
Coupon #6
8.1
6.2
Coupon #9
7.5
Coupon #10
2.6
5.1
19%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
-------
Table 3-22 Decontamination Efficiency of Simple Flushing for Mercury Calculated From Test Run ID: Hg F60
(Flow Rate for Adherence Study: 60 gpm Decontamination: Simple Water Flushing @ 210 gpm)
Before flushing
After flushing
Coupon ID
Mercury adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Mercury remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decontamination Efficiency (%)2
Coupon #3
25.5
Coupon #4
37.8
31.7
Coupon #7
39.6
Coupon #8
11.4
25.5
19%
Coupon #5
50.8
Coupon #6
23.8
37.3
Coupon #9
20.4
Coupon #10
19.9
20.2
46%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(2) Low-pH flushing
To evaluate decontamination approaches that may have
higher removal efficiency for mercury, a chemical
decontamination approach, i.e., low-pH (pH 4) flushing
was applied. The test results are presented in Figure
3-19, and the calculated decontamination efficiency
is summarized in Table 3-23. From the results, it
can be seen that the application of low-pH flushing
could remove a small portion of mercury adsorbed
to the cement-lined pipe surfaces; however, it did not
significantly improve the decontamination efficiency as
compared to simple water flushing.
Figure 3-19 Low-pH Flushing Results for Mercury Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: pH 4 Flushing)
!•*"•
=
Beginning of pipe loop
(Cement-lined ductile iron coupons;
Near end of pipe loop
(Cement-lined due tile iron coupons)
Coupon Location in the Pipe Loop
-------
Table 3-23 Decontamination Efficiency of Low-pH Flushing for Mercury
Before flushing
After flushing
Coupon ID
Mercury adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Mercury remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
27.0
Coupon #7
15.0
Coupon #4
24.1
25.6
Coupon #8
24.3
19.7
23%
Coupon #5
23.9
20.1
Coupon #9
14.4
Coupon #6
16.3
Coupon #10
17.2
15.8
21%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
0 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(3) Acidified potassium permanganate flushing
To improve the decontamination efficiency for mercury,
an aggressive chemical decontamination approach, i.e.,
acidified potassium permanganate flushing, was applied.
The test results are presented in Figure 3-20, and the
calculated decontamination efficiency is summarized in
Table 3-24. From the results, it can be seen that acidified
potassium permanganate flushing could remove a
significant amount of mercury from the cement-lined
pipe surfaces at two different coupon locations within
the pipe loop. The decontamination efficiency ranged
from 72 percent to 96 percent. This is the most effective
decontamination technology evaluated during the pilot-
scale decontamination study for mercury.
In mercuric chloride, mercury (II) exists as the most
oxidized form of mercury species; therefore, it is
obvious from a chemical perspective that the mechanism
involved in the decontamination of mercury by acidified
permanganate is not oxidation. It is rather the enhanced
solubility of mercury in the presence of acid (pH of ~2)
and permanganate in the solution. Similar results were
observed in Battelle's bench-scale decontamination
of mercury using acidified potassium permanganate
(Chattopadhyay and Fox, 2006).
Figure 3-20 Acidified Potassium Permanganate Flushing Results for Mercury Decontamination
(Flow Rate for Adherence Study: 60 gpm
Decontamination: Acidified Potassium Permanganate Flushing)
0,60
0.00
Beginning of pipe loop
(Cement-lined ductile iron coupons!
Near end of pipe loop
('Cement-lined ductile iron coupons)
Coupon Location in the Pipe Loop
-------
Table 3-24 Decontamination Efficiency of Acidified Potassium Permanganate Flushing for Mercury
Before flushing
After flushing
Coupon ID
Mercury adsorbed (mg/coupon)
Average (mg/coupon)1
Coupon ID
Mercury remaining on coupon
after flushing (mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
4.5
Coupon #4
8.5
6.5
Coupon #7
0.25
Coupon #8
0.33
0.29
96%
Coupon #5
3.7
Coupon #6
5.5
4.6
Coupon #9
1.4
Coupon #10
1.2
1.3
72%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
3.2.3.3. Bacillus subtilis Decontamination
Test Results
Two types of decontamination approaches were tested for
the Bacillus subtilis decontamination study: baseline water
flushing and shock chlorination. The results from these
two decontamination tests are discussed in the following
subsections.
(1) Baseline water flushing
Simple water flushing was evaluated for Bacillus subtilis
as the baseline decontamination method, and the results
are plotted in Figure 3-21. It is apparent that the baseline
water flushing approach did not remove any Bacillus
subtilis from the cement-lined ductile iron pipe surfaces.
Table 3-25 presents the results in tabular format.
Figure 3-21 Simple Flushing Results for Bacillus subtilis Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: Simple Water Flushing @ 210 gpm)
l.E-K)6
l.E
Beginning of pipe loop
(C ement-lined ductile iron coupon)
Near end of pipe loop
(Cement-lined ductile iron coupon)
Coupon Location in the Pipe Loop
-------
Table 3-25 Decontamination Efficiency of Simple Flushing for Bacillus subtilis
Before flushing
After flushing
Coupon ID
Bacillus subtilis
adsorbed (cells/in2)
Average (cells/in2)1
Coupon ID
Bacillus subtilis
remaining on coupon
after flushing (cells/in2)
Average (cells/in2)1
Decon Efficiency (%)2
Coupon #3
4.6E+04
Coupon #4
3.3E+04
4.0E+04
Coupon #7
5.4E+04
Coupon #8
4.8E+04
5.1E+04
-29%
Coupon #5
5.5E+04
Coupon #6
5.6E+04
5.6E+04
Coupon #9
7.5E+04
Coupon #10
4.9E+04
6.2E+04
-11%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(2) Shock chlorination
Shock chlorination was performed at a free chlorine
level of 200 mg/L with a contact time of two hours
to reach the target CT value of 30, 000 m/L-min.
The shock chlorination results for Bacillus subtilis
are presented in Figure 3-22, and the calculated
decontamination efficiency is shown in Table 3-26.
Because the cement-lined ductile iron pipe used in this
study is quite smooth on the surfaces without corrosion
tubercles, the chlorine demand from the pipe surfaces
was not very significant, and the chlorine level could
be maintained at the targeted value during the test. The
test results indicated that the decontamination efficiency
of shock chlorination for Bacillus subtilis ranged from
94 percent to 96 percent (i.e., 1.2 to 1.4 log removals).
As mentioned previously, a literature review (Rose et
al. (2005) and Rice et al. (2006)) indicated much higher
Bacillus species removal (i.e., 2-3 log removals) from
bulk water, using much lower CT values. Compared to
these results, 96 percent inactivation (less than 2 log
removal) of Bacillus subtilis from the cement-lined
ductile iron pipe surfaces is not very promising, given
the significantly higher CT value (30,000) applied in
our study. Nevertheless, the relatively poor inactivation
of Bacillus subtilis in our test is consistent with the
AwwaRF's laboratory-scale test results for Bacillus
thuringiensis (Welter et al., 2006), which demonstrates
the difficulty of decontaminating microbes lodged
on pipe surfaces. In addition, Szabo et al. (2007) also
reported that similar experiments with high CT on
corroded iron pipe did not remove Bacillus spores in
the presence of free chlorine. As such, an increased
CT value (e.g., higher chlorine concentration or longer
contact time) might be necessary to achieve higher
Bacillus subtilis inactivation efficiency.
Figure 3-22 Shock Chlorination Results for Bacillus subtilis Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: Shock Chlorination)
Beginning of pipe loop
(C ement-lined ductile iron coupon)
Near end of pipe loop
(Cement-lined ductile iron coupon)
Coupon Location in the Pipe Loop
-------
Table 3-26 Decontamination Efficiency of Shock Chlorination for Bacillus subtilis
Before flushing
After flushing
Coupon ID
Bacillus subtilis adsorbed
(cells/in2)
Average (cells/in2)1
Coupon ID
Bacillus subtilis remaining
on coupon after
decontamination (cells/in2)
Average (cells/in2)1
Decon Efficiency (%)2
Coupon #3
8.2E+04
Coupon #4
7.7E+04
7.9E+04
Coupon #7
4.8E+03
Coupon #8
4.3E+03
4.6E+03
94% (1.2 log removal)
Coupon #5
3.2E+04
Coupon #6
6.5E+04
4.8E+04
Coupon #9
7.4E+02
Coupon #10
2.8E+03
1.8E+03
96% (1.4 log removal)
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
3.2.3.4. Diesel Fuel Decontamination Test Results
Two different decontamination approaches were tested for
diesel fuel decontamination: baseline water flushing and
surfactant (Surfonic TDA-6) flushing. The results obtained
from these two decontamination tests are discussed in the
following subsections.
(1) Baseline water flushing
Simple water flushing was evaluated as the baseline
decontamination method, and the results are plotted
in Figure 3-23. It is apparent that the baseline water
flushing approach removed diesel fuel from both the
cement-lined ductile iron and clear PVC pipe surfaces.
As shown in Table 3-27, the decontamination efficiency
of the water flushing approach for diesel fuel is 36-38
percent for cement-lined ductile iron pipe and 74 percent
for clear PVC pipe surface. Diesel fuel has stronger
adherence to the ductile-iron pipe surfaces than to the
clear PVC pipe surfaces. Simple water flushing proved
to be an effective decontamination method to remove
diesel fuel from the clear PVC pipe surfaces, while it
was less effective for removal of diesel fuel from the
ductile-iron pipe surfaces.
Figure 3-23 Simple Water Flushing Results for Diesel Fuel Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: Simple Water Flushing @ 210 gpm)
o
I
Beginning of pipe loop
(Cement-lined ductile
iron coupon.)
Near end of pipe loop Beginning of pipe loop
(Cement-lined ductile (PVC control coupons)
iron coupon.)
Coupon Location in the Pipe Loop
-------
Table 3-27 Decontamination Efficiency of Simple Flushing for Diesel Fuel
Before
flushing
After
flushing
Coupon ID
Diesel fuel adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Diesel fuel remaining
on coupon after
flushing (mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
23.5
Coupon #4
21.7
22.6
Coupon #7
16.0
Coupon #8
12.2
14.1
38%
Coupon #5
22.4
Coupon #6
28.5
25.5
Coupon #9
15.0
Coupon #10
17.4
16.2
36%
Coupon #A
8.7
Coupon #B
14.8
11.8
Coupon #C
3.1
Coupon #D
3.0
3.1
74%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
(2) Surfactant (Surfonic TDA-6) flushing
Surfonic TDA-6 has been proven as a very effective
decontamination reagent for removing chlordane
from the drinking water pipe surfaces, according to
AwwaRFs bench-scale study (Welter et al, 2006).
Therefore, Surfonic TDA-6 was applied during the
surfactant flushing of diesel fuel from the drinking water
pipe surface.
The Surfonic TDA-6 decontamination test results
for diesel fuel are presented in Figure 3-24, and the
calculated decontamination efficiency is listed in Table
3-28. As can be seen from the results, Surfonic TDA-6
flushing is a very effective decontamination method
for diesel fuel. After flushing with Surfonic TDA-6,
there was no detectable diesel fuel on the cement-lined
ductile iron coupon samples. Because the Surfonic
TDA-6 compounds have interference with the diesel
range organic (DRO) analysis, it is not feasible to
calculate the actual decontamination efficiency of
Surfonic TDA-6 flushing for diesel fuel from cement-
lined ductile iron pipe surfaces. However, according to
the input provided by DataChem Laboratories as well
as the confirmation with GC analyses of these samples,
it is ensured that there are no detectable diesel fuel
compounds for the cement-lined ductile iron coupon
samples after flushing. Therefore, the decontamination
efficiency was calculated based on the initial diesel fuel
adsorbed on coupons before flushing and the laboratory
Estimated Quantification Limit (EQL). The Surfonic
TDA-6 flushing approach showed >91 percent removal
efficiency for diesel fuel from the cement-lined ductile
iron pipe surfaces.
For PVC coupon samples, the Surfonic TDA-6
compounds did not show any interference for DRO
analysis. However, these samples showed some peak
integration issues with the C20-C34 range DRO
analyses. (DRO result for each sample contains both
the C10-C20 range DRO and C20-C34 range DRO.)
Therefore, only C10-C20 range DRO values were
considered during the calculation of decontamination
efficiency. As most hydrocarbons in diesel fuel No. 2
belong to the C10-C20 range DRO, the decontamination
efficiency calculated using the C10-C20 range DRO
should be comparable to that calculated using the
C10-C34 range DRO numbers. As can be seen from the
results, Surfonic TDA-6 appears to be a very effective
decontamination technique for removing diesel fuel
from clear PVC pipe surfaces, as demonstrated by the
removal efficiency of 78 percent for diesel fuel.
-------
Figure 3-24 Surfonic TDA-6 Decontamination Results for Diesel Fuel Decontamination
(Flow Rate for Adherence Study: 60 GPM Decontamination: Surfonic TDA-6 Flushing)
5,00
Beginning of pipe loop
(Cement-lined ductile
iron coupon)
Near end of pipe loop
(Cement-lined ductile
iron coupon)
Beginning of pipe loop
(PVC control coupons';
Coupon Location in the Pipe Loop
Table 3-28 Decontamination Efficiency of Surfonic TDA-6 Flushing for Diesel Fuel
Before
flushing
After flushing
Coupon ID
Diesel fuel adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Diesel fuel remaining
on coupon after
flushing (mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)ze
Coupon #3
30.0
33.8
Coupon #7
<3.03
Coupon #4
37.5
75.0
Coupon #8
<3.03
<3.0
> 91%
Coupon #5
79.0
20.0
Coupon #9
<3.03
Coupon #6
70.9
Coupon #10
NA4
<3.0
> 96%
Coupon #A
17.0=
Coupon #C
5.05
Coupon #B
23.0=
Coupon #D
4.05
4.5
78%
1 The average numbers were rounded, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
3 The DRO contamination in these samples is not diesel fuel. The identity of the compounds in these samples cannot be
determined by GC/FID analysis, but from the information provided by DataChem Laboratories and from the chromatographs, it
is probable that a high molecular weight surfactant is the source of the contamination.
4 This sample appears to contain both diesel fuel contamination and the surfactant present in the previous samples. Therefore, a
DRO number could not be determined for this sample.
5 C20-C34 DRO analyses of Clear PVC coupon extraction samples showed some peak integration issues; therefore, only C10-
C20 DRO numbers are used here.
6 Because the diesel fuel compounds were not detected for the coupons after flushing, the decontamination efficiency was
calculated based on the initial diesel fuel concentration on the coupons before the flushing and the Laboratory Reporting Limit
for diesel fuel.
-------
3.2.3.5. Chlordane Decontamination Test Results
Only one decontamination approach, i.e., surfactant
(Surfonic TDA-6) flushing, was tested for the chlordane
decontamination, to provide a comparison with the results
from AwwaRFs laboratory-scale study. The results obtained
from the Surfonic TDA-6 decontamination test for chlordane
are discussed in the following subsection.
(1) Surfactant TDA-6 flushing
The Surfonic TDA-6 decontamination test results
for chlordane are presented in Figure 3-25, and the
calculated decontamination efficiency is listed in Table
3-29. As can be seen from the results, Surfonic TDA-
6 effectively removed chlordane from both cement-
lined ductile iron and clear PVC pipe surfaces. After
flushing with Surfonic TDA-6, the amount of chlordane
adsorbed on the coupon surfaces reduced significantly.
The decontamination efficiency of Surfonic TDA-
6 flushing for chlordane was calculated using the
alpha and gamma chlordane values, and the results
indicated that the Surfonic TDA-6 flushing is a very
promising decontamination approach for chlordane. The
decontamination efficiency ranged between 89 percent
and 91 percent for the cement-lined ductile iron pipe
material and was 99 percent for the clear PVC pipe
material. The decontamination efficiency calculated
by the technical chlordane values (not shown in Table
3-29) were the same as that calculated by the alpha and
gamma chlordane values.
The excellent removal of chlordane by Surfonic TDA-6
observed in the pilot-scale decontamination test matches
very well with AwwaRFs laboratory-scale test results.
In the AwwaRF study, Surfonic TDA-6 was one of
the three surfactants that showed very good removal
of chlordane from chlorinated polyvinyl chloride
(cPVC), heavily corroded galvanized iron, and epoxy-
coated steel pipes with decontamination efficiencies of
approximately 90 percent.
Figure 3-25 Surfonic TDA-6 Decontamination Results for Chlordane Decontamination
(Flow Rate for Adherence Study: 60 gpm Decontamination: Surfonic TDA-6 Flushing)
Beginning of pipe loop
(Cement-lined ductile
iron coupon)
Near end of pipe loop
(Cement-lined ductile
iron coupon)
B eginning of p ip e
Loop (PVC control
coupons)
Coupon Location in tlie Pipe Loop
-------
Table 3-29 Decontamination Efficiency of Surfonic TDA-6 Flushing for Chlordane
Before
flushing
After flushing
Coupon ID
Alpha & Gamma
chlordane adsorbed
(mg/coupon)
Average (mg/coupon)1
Coupon ID
Alpha & Gamma
chlordane remaining on
coupon after flushing
(mg/coupon)
Average (mg/coupon)1
Decon Efficiency (%)2
Coupon #3
35.0
Coupon #4
24.0
29.5
Coupon #7
2.9
Coupon #8
2.4
2.7
91%
Coupon #5
11.0
Coupon #6
12.8
11.9
Coupon #9
1.2
Coupon #10
1.4
1.3
89%
'-'-. -•'•• .%-•::• '-;;•
Coupon #A
6.5
Coupon #B
6.4
6.5
Coupon #C
0.025
Coupon #D
0.080
0.053
99%
1 The average numbers were rounded to two significant figures, consistent with the laboratory-reported numbers.
2 The decontamination percent removals were calculated (i.e., generated by Excel), using the nonrounded average numbers, to
represent a more accurate calculation. The resulting efficiency value was rounded to two significant figures.
3.2.3.6. Summary of Decontamination Test Results
Table 3-30 presents a summary of the performance
of various decontamination techniques for the target
contaminants tested in this study. Percent removals of each
decontamination method for each contaminant are presented
in Table 3-30. Because conduct of the pilot-scale adherence/
decontamination tests is time-intensive and expensive, a
single test run was conducted for each test condition. The
variability in the decontamination effectiveness was assessed
by the different coupons employed within the pipe loop
system. As such, compared to the quantitative statements, a
qualitative rating would be more appropriate in summarizing
the effectiveness of the decontamination methods in
this study. Therefore, qualitative ratings of the various
decontamination methods are also indicated in Table 3-30.
For arsenic, mercury, and Bacillus subtilis, various
decontamination methods were evaluated for the cement-
lined ductile iron pipe material only. As can be seen from
Table 3-30, for arsenic, baseline water flushing and low-
pH flushing resulted in average removal of arsenic; while
phosphate buffer flushing showed poor removal for arsenic.
Acidified potassium permanganate flushing and flushing
with several NSF Standard 60 Products showed good
arsenic removal. For mercury, baseline water flushing and
low-pH flushing showed average level of effectiveness as
decontamination methods for mercury. Acidified potassium
permanganate flushing was very effective in decontamination
of mercury. Baseline water flushing resulted in no removal of
Bacillus subtilis. Shock chlorination showed an average level
of decontamination efficiency for Bacillus subtilis. For diesel
fuel and chlordane, the performance of decontamination
techniques was evaluated on both cement-lined ductile iron
and the clear PVC pipe materials. As shown in Table 3-30,
baseline water flushing showed average effectiveness in
removal of diesel fuel from cement-lined ductile iron pipe
surfaces, while it showed good removal of diesel fuel from
the clear PVC pipe surfaces. The Surfonic TDA-6 flushing
resulted in very high removal efficiencies for diesel fuel and
chlordane from both cement-lined ductile iron and the clear
PVC pipes surfaces.
-------
Table 3-30 Performance of Decontamination Techniques for Various Target Contaminants
Arsenic
Mercury
Bacillus subtilis
Diesel fuel
Chlordane
Water flushing
Low-pH
Phosphate buffer
Acidified potassium permanganate
NW-310/NW-400
Floran Biogrowth Remover / Catalyst
Floran Top Ultra / Catalyst
Water flushing
Low-pH
Acidified potassium permanganate
Water flushing
Shock chlorination
Water flushing
SurfonicTDA-6
SurfonicTDA-6
-7-51%
6 - 36%
-24 - -16%
54-61%
46 - 65%
63 - 67%
23 - 68%
19-46%
21 - 23%
72 - 96%
-29 --11%
94 - 96% (1 .2-1 .4 log removal)
36 - 38%
74% (for clear PVC pipe)
>91%
78% (for clear PVC pipe)
89-91%
99% (for clear PVC pipe)
Average
Average
Poor
Good
Good
Good
Average
Average
Average
Excellent
Poor
Average
Average
Good
Excellent
Good
Excellent
Excellent
1 The qualitative performance ratings are defined in terms of percent/log removal as shown below:
For Chemical Contaminants
< 20% Poor
20-50% Average
50-80% Good
> 80% Excellent
For Biological Contaminants
< 1 log removal Poor
1-2 log removal Average
2-3 log removal Good
> 3 log removal Excellent
-------
-------
4.0
Conclusions
A pilot-scale experimental test program was conducted at the
EPA T&E Facility over the past two years to investigate the
potential of target contaminants (arsenic, mercury, Bacillus
subtilis, diesel fuel, and chlordane) for adherence to drinking
water pipe surfaces and to evaluate various decontamination
approaches for removing target contaminants from the pipe
surfaces.
The contaminant adherence study demonstrated that all
the contaminants tested have a strong tendency to adhere
to cement-lined ductile iron pipe surfaces. The adherence
capacity of target contaminants to the clear PVC pipe
surfaces varied significantly. Bacillus subtilis showed strong
adherence to both the cement-lined ductile iron and clear
PVC pipe surfaces. Diesel fuel and chlordane showed lower
adherence to clear PVC pipe than to the cement-lined ductile
iron pipe surfaces. Arsenic and mercury showed much
stronger adherence to cement-lined ductile iron pipe surfaces
than to the clear PVC pipe surfaces. It was also found that
mercury has stronger adherence to cement-lined ductile iron
pipe surfaces compared to arsenic.
Experiments studying the effects of flow rates on the
adherence of contaminants to the pipe surfaces indicated that
the inorganic contaminants tested (i.e., arsenic and mercury)
adhere to the cement-lined ductile iron pipe surfaces at both
flow regimes, laminar and turbulent. It was found that the
adherence of arsenic and mercury to pipe surfaces is higher
under turbulent flow conditions.
Various decontamination techniques were evaluated to assess
their effectiveness in removing target contaminants from
cement-lined ductile iron pipe and clear PVC pipe surfaces.
From the decontamination tests performed for arsenic, it
was found that acidified potassium permanganate and NSF
Standard 60 Products flushing showed the most promise as
effective decontamination methods for arsenic from cement-
lined ductile iron pipe surfaces. Baseline water flushing and
low-pH flushing resulted in average removals of arsenic.
Experiments evaluating the removal efficiency of various
decontamination methods for mercury indicated that acidified
potassium permanganate flushing is very effective in
decontamination of mercury from the cement-lined ductile
iron pipe surfaces. Baseline water flushing and low-pH
flushing showed average removal of mercury from cement-
lined ductile iron pipe surfaces.
The shock chlorination of Bacillus subtilis at a CT value of
30, 000 mg/L-min. showed an average level of effectiveness
for removal of Bacillus subtilis from cement-lined ductile
iron pipe surfaces. Baseline water flushing resulted in no
removal of Bacillus subtilis from the cement-lined ductile
iron pipe surfaces.
The decontamination tests conducted for diesel fuel
indicated that Surfonic TDA-6 is a very effective
decontamination reagent for diesel fuel from both
cement-lined ductile iron and clear PVC pipe surfaces.
Baseline water flushing showed lower effectiveness as a
decontamination method for diesel fuel.
The result of the pilot-scale decontamination test performed
for chlordane indicated that Surfonic TDA-6 is very effective
for removal of chlordane from cement-lined ductile iron
and clear PVC pipe surfaces. This result confirmed the
findings from AwwaRF's laboratory-scale tests, which
also demonstrated very high decontamination efficiency of
Surfonic TDA-6 for the removal of chlordane from various
types of pipe materials, including cPVC, heavily corroded
galvanized iron, and epoxy-coated steel pipes.
The pilot-scale adherence/decontamination study provides
valuable information on the adherence potential of various
contaminants to drinking water pipe surfaces and the
performance of a variety of decontamination techniques
on real-world pipe materials under realistic conditions.
Additional experiments are needed to obtain data on other
pipe surface materials and to attain statistically significant
data over a full range of operating conditions. And many of
the conclusions drawn from this study are qualitative rather
than quantitative. Modeling approaches are recommended to
validate the test results attained from this study and to predict
performance for other pipe materials/contaminant scenarios.
-------
-------
5.0
References
Batte, M, Koudjonou, B., Laurent, P., Mathieu, L., Coallier, J., Prevost, M. 2003. Biofilm responses to
aging and to high phosphate load in a bench scale drinking water system. Wat. Res. 37(2003): 1351-1361.
Bruce, A.M. and Martens, D. A. Speciation of Arsenic (III) and Arsenic (V) in Sediment Extracts by High-
Performance Liquid Chromatography -Hydride Generation Atomic Absorption Spectrometry. Environmental
Science and Technology, 31(1997): 171-177.
Butterfield, P. W., Camper, A.K., Ellis, B.D., Jones, W.L. 2002. Chlorination of model drinking water
biofilm: implications for growth and organic carbon removal. Wat. Res. 36(2002): 4391-4405.
Camper, A.K., Jones, W.L., Hays, J.T. Effects of growth conditions and substratum composition on the
persistence of coliforms in mixed-population biofilms. Applied and Environmental Microbiology, 62( 1 996) :
4014-4018.
Chattopadhyay, S. and Fox, K., Adherence and decontamination chemicals and biologicals American
Institute of Chemical Engineering (AIChE) 2006 Annual Meeting, San Francisco, California, November
12-17, 2006.
Chu, C., Lu, C. 2004. Effects of oxalic acid on the regrowth of heterotrophic bacteria in the distributed
drinking water. Chemosphere, 57(2004): 531-539.
Cloete, T.E., Van Vuuren, S.J. 2003. Dynamic response of biofilm to pipe surface and fluid velocity. Wat.
Sci. Technol. 47(5): 57-59.
Ellison, D., Duranceau, S., Ancel, S., Deagle, G., McCoy, R. Investigation of Pipe Cleaning Methods. Awwa
Research Foundation and American Water Works Association, 2002.
Floran Technologies, Inc., 2006, Web site: http://www.florantechnologies.coin.
Gonzalez, J.C., Lavilla I., Bendicho, C. Evaluation of non-chromatographic approaches for speciation of
extractable As (III) and As (V) in environmental solid samples by FI-HGAAS. Talanta, 59(2003): 525-534.
Hansen, R.B., Albrechtsen, A., Arvin, E., Jorgensen, C. 2002. Bulk water phase and biofilm growth in
drinking water at low nutrient conditions. Wat. Res. 36(2002): 4477^1486.
Howard, PH. Handbook of Environmental Fate and Exposure Data for Organic Chemicals. Lewis
Publishers, Inc., Chelsea, MI, 1991, Vol. 3, pp 90-109.
Johnson Screens, Inc., 2006, Web site: http^/wwwJohnsQnscreens^Qm.
Lawrence, J.R., Swerhone, G.D.W., Neu, T.R. 2000. A simple rotating annular reactor for replicated biofilm
studies. J. Microbiol. Meth. 42(2000): 215-224.
Momba, M.N.B., Kfir, R., Venter, S.N., Cloete, T.E. 2000. An overview of biofilm formation in distribution
systems and its impact on deterioration of water quality. Water South Africa, 26(1): 59-66.
Pozos, N., Scow, K., Wuertz, S., Darby, J. 2004. UV disinfection in a model distribution system: biofilm
growth and microbial community. Wat. Res. 38(2004): 3083-3091.
NSF Product and Service Listing, 2006, Mtpj//wwwjis^^
nctiQn=PiBe+Cleanin£+Aid&
-------
Rice, E.W., Adock, N.J., Sivaganesan, M, Rose, LJ. 2005. Inactivation of spores of Bacillus anthracis,
Bacillus cereus, and Bacillus thuringiensis subsp. Israelensis by chlorination, Appl. Envron. Microbiol. 71
(9): 5587-5589.
Rose, L.J., Rice, E.W., Jensen, B., Murga, R., Donlon, R.M., Arduino, MJ. 2005. Chlorine inactivation of
bacterial bioterrorism agents. Appl. Envron. Microbiol. 77: 566-568.
Shaw Environmental, Inc. Quality Assurance Project Plan (Revision No. 1) for Pilot-Scale Tests and
Systems Evaluation for the Containment, Treatment, and Decontamination of Selected Materials from T&E
Building Pipe Loop Equipment, March 2005.
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Containment, Treatment, and Decontamination of Selected Materials from T&E Building Pipe Loop
Equipment, March 2005.
Shaw Environmental, Inc., Standard Operation Procedure for the Enumeration of Bacillus subtilis Water
Samples (SOPNo.: T&E SOP 021.00.RO), August 2005.
SimPlate Modified HPC method as specified in the Hach test kits based on the SimPlate™ Technique for
HPC developed by IDEXX Laboratories, Inc. (Westbrook, Maine, httB^/wwwjdgxx.cQm/wa|gr/).
Szabo, J.G., Rice, E.W., Bishop, PL. 2007. Persistence and decontamination of Bacillus atrophaeus
subsp. globigii spores on corroded iron in a model drinking water system. Applied and Environmental
Microbiology. 73(8): 2451-2457.
U.S. EPA, 1996. SW846 Methods for the Chemical Analysis of Water and Wastes, Update IIIB. Office of
Solid Waste, Washington, D.C.
U.S. EPA, 1983. Methods for Chemical Analysis of Water and Wastes. Office of Research and
Development, Washington, D.C. EPA/600/4-79-020.
Wasche, S., Horn, H., Hempel, D.C. 2002. Influence of growth conditions on biofilm development and mass
transfer at the bulk/biofilm interface. Wat. Res. 36(2002): 4775-4784.
Whitney, E.A.S. et al., 2003. Inactivation of Bacillus anthracis spores. Emerging Infectious Diseases. Vol.
9, No. 6, June 2003.
Welter, G., Lechevallier, M., Cotruvo, J., Moser, R., Spangler, S., Guidance for Decontamination of Water
System Infrastructure, Awwa Research Foundation, 2006.
Wrjeyekoon, S., Mino, T, Satoh, H., Matsut, T 2004. Effects of substrate loading rate on biofilm structure.
Wat. Res. 38(2004): 2479-2488.
-------
Appendix A
Contaminant Adherence/Decontamination
Test Results Data
-------
Table A-l Experimental Results from Test Run ID: As Fl
(Adherence study flow rate: 1 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
As F1 TO
As F1 TO Dup
As F1 T5M
As F1 T5M Dup
AsF1 T1D
AsF1 TIDDup
As F1 T2D
As F1 T2D Dup
As F1 Decon
As F1 Decon Dup
ND
ND
ND
ND
10.4
8.7
9.6
9.5
0.99
0.97
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.029
4.3x105 cells/cm2
0.24
0.097
1.0
2.1
1.5
1.6
0.84
1.0
0.78
0.88
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table A-2 Experimental Results From Test Run ID: As F15
(Adherence study flow rate: 15 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after
injection
1 day after
injection
2 days after
injection
After
draining
loop
Prior to
draining
loop
After
draining
loop
AsF15TO
As F15TODup
AsF15T5M
AsF15T5M Dup
AsF15T1D
AsF15T1DDup
AsF15T2D
AsF15T2DDup
As F15 Decon
As F15 Decon
Dup
0.0042
0.0034
2.6
1.6
9.3
9.3
9.3
9.3
2.9
3.0
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.052
1. 8 x105 cells/cm2
0.37
0.18
2.1
2.8
0.81
1.5
2.8
2.6
1.9
1.7
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table A-3 Experimental Results From Test Run ID: As F60
(Adherence study flow rate: 60 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
As F60 TO
As F60 TO Dup
As F60 T5M
As F60 T5M Dup
As F60 T1 D
AsF60T1DDup
As F60 T2D
As F60 T2D Dup
As F60 Decon
As F60 Decon Dup
0.0036
0.0052
9.6
10.4
9.5
8.8
8.9
8.9
0.39
0.57
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.024
1.1 x105 cells/cm2
0.11
0.64
1.9
4.2
4.9
6.5
2.7
3.8
2.7
2.9
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table A-4 Experimental Results From Test Run ID: As pH4
(Adherence study flow rate: 60gpm, Decontamination: pH 4 flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
After low-
pH water
recirculation
After simple
water
flushing
After draining
loop
As pH 4 TO
AspH4TODup
As pH 4 T5M
As pH 4 T5M Dup
AspH4T1D
AspH4T1DDup
As pH 4 T2D
As pH 4 T2D Dup
As pH 4 Decon
As pH 4 Decon Dup
As pH 4 Decon 2
As pH 4 Decon 2 Dup
NDa
NDa
9.4
9.0
8.4
8.3
7.9
8.3
1.1
1.1
0.0077
ND
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.036
1. 4 x105 cells/cm2
0.25
0.27
3.6
2.6
4.6
3.0
2.5
3.3
2.2
2.7
a ND: nondetectable.
b Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-5 Experimental Results From Test Run ID: As Phos
(Adherence study flow rate: 60 gpm, Decontamination: phosphate buffer flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Phosphate Buffer Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
After
phosphate
buffer flushing
After draining
loop
As Phos TO
As Phos TO Dup
As Phos T5M
As Phos T5M Dup
AsPhosTID
As PhosTID Dup
As Phos T2D
As Phos T2D Dup
As Phos Decon
As Phos Decon Dup
NDa
NDa
9.5
9.9
9.0
8.8
8.3
8.5
1.3
1.4
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.013
2x106 eel Is/cm2
0.29
0.45
5.0
6.2
5.3
3.9
5.9
7.1
7.0
4.4
a ND: nondetectable
b Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-6 Experimental Results From Test Run ID: As KMn04
(Adherence study flow rate: 60gpm, Decontamination: acidified permanganate flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Acidified Potassium
Permanganate Flushing)
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
After acidified
potassium
permanganate
flushing
After draining
loop
As KMnO4 TO
AsKMnO4TODup
AsKMnO4T5M
AsKMnO4T5M
Dup
AsKMnO4T1D
AsKMnO4T1D
Dup
As KMnO4 T2D
As KMnO4 T2D
Dup
As KMnO4 Decon
As KMnO4 Decon
Dup
ND
ND
10.3
10.0
9.0
9.6
9.1
8.9
1.3
0.87
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.15
2.9X1 05 cells/cm2
0.28
0.44
6.2
6.3
5.3
3.7
2.9
2.8
1.9
1.6
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-7 Experimental Results From Test Run ID: As NW
(Adherence study flow rate: 60 gpm, Decontamination: NW-310/NW-400 flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(NW-310/NW-400 Flushing)
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
After NW-
310/NW-400
flushing
After draining
loop
AsNWTO
AsNWTODup
AsNWTSM
AsNWTSMDup
As NW T1 D
AsNWTIDDup
As NW T2D
AsNWT2DDup
As NW Decon
As NW Decon Dup
NDa
NDa
8.9
9.1
8.2
8.0
7.8
8.0
1.2
1.5
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.073
3.7X1 06 cells/cm2
0.26
0.46
1.4
2.7
1.6
1.7
1.6
0.63
0.47
0.67
a ND: nondetectable
b Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-8 Experimental Results From Test Run ID: As Floran I
(Adherence study flow rate: 60gpm, Decontamination: Floran Biogrowth Remover/Catalyst flushing)
Baseline
Adherence
Study
During
2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Floran Biogrowth Remover/
Catalyst Flushing)
Catalyst Flushing
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
After Floran
Biogrowth
Remover/
After draining
loop
As Floran I TO
As Floran I TO Dup
As Floran I T5M
As Floran I T5M Dup
As Floran IT1D
As Floran I T1D Dup
As Floran I T2D
As Floran I T2D Dup
As Floran I Decon
As Floran I Decon Dup
NDa
NDa
10.4
9.3
8.9
9.3
8.8
9.4
0.84
0.86
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.073
8. 7X1 05 cells/cm2
0.41
0.53
5.6
6.0
5.6
5.1
2.3
1.5
1.5
2.5
a ND: nondetectable
b Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-9 Experimental Results From Test Run ID: As Floran II
(Adherence study flow rate: 60 gpm, Decontamination: Floran Top Ultra/Catalyst flushing)
Baseline
Adherence
Study
During
2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Floran Top Ultra/Catalyst
Flushing) Catalyst Flushing
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
After Floran
Top Ultra/
After draining
loop
As Floran II TO
As Floran II TO Dup
As Floran II T5M
As Floran II T5M Dup
As Floran IIT1D
As Floran II T1D Dup
As Floran IIT2D
As Floran II T2D Dup
As Floran II Decon
As Floran II Decon Dup
NDa
NDa
9.9
10.2
9.2
8.5
8.6
8.6
1.4
1.4
Coupon #1
Coupon #2b
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.046
2.2X1 06 cells/cm2
0.48
0.40
6.4
4.8
5.2
2.8
1.9
1.7
2.6
3.6
a ND: nondetectable
b Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-10 Experimental Results From Test Run ID: Hg Fl
(Adherence study flow rate: 1 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
Hg F1 TO
Hg F1 TO Dup
Hg F1 T5M
Hg F1 T5M Dup
HgF1 T1D
Hg F1 TIDDup
Hg F1 T2D
Hg F1 T2D Dup
Hg F1 Decon
Hg F1 Decon Dup
0.00005
0.000068
0.000075
0.000079
9.3
8.9
9.6
9.5
0.37
0.44
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.00036
2.8 x106 cells/cm2
0.49
0.048
4.0
2.2
1.2
3.3
3.8
3.5
2.0
0.71
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-ll Experimental Results From Test Run ID: Hg F15
(Adherence study flow rate: 15 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
Hg F15TO
HgF15TODup
HgF15T5M
HgF15T5M Dup
HgF15T1D
HgF15T1DDup
HgF15T2D
HgF15T2DDup
Hg F15 Decon
Hg F15 Decon Dup
0.0016
0.0016
9.6
4
10.7
8.4
8.1
7.8
0.23
0.28
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.073
1. 4 x103 cells/cm2
0.083
2.3
9.6
12.7
4.3
8.1
4.7
5.0
7.5
2.6
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-12 Experimental Results From Test Run ID: Hg F60
(Adherence study flow rate: 60 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after
injection
1 day after
injection
2 days after
injection
After
draining
loop
Prior to
draining
loop
After
draining
loop
Hg F60 TO
HgFBOTODup
HgF60T5M
Hg F60 T5M Dup
HgF60T1D
HgF60T1DDup
Hg F60 T2D
Hg F60 T2D Dup
Hg F60 Decon
Hg F60 Decon Dup
0.003
0.0025
11
10.5
9.7
9.7
8.8
9.4
0.63
0.61
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.093
3.3 x106 cells/cm2
0.078
0.94
25.5
37.8
50.8
23.8
39.6
11.4
20.4
19.9
1 Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-13 Experimental Results From Test Run ID: Hg pH4
(Adherence study flow rate: 60gpm, Decontamination: pH 4 flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
DecontaminationStudy
(Flushing)
Just prior to
injection
5 minutes
after
injection
1 day after
injection
2 days after
injection
After
draining
loop
After low-
pH water
recirculation
After simple
water
flushing
After
draining
loop
HgpH4TO
Hg pH4TODup
Hg pH 4 T5M
Hg pH 4 T5M Dup
Hg pH4T1D
HgpH4T1DDup
Hg pH 4 T2D
HgpH4T2DDup
Hg pH 4 Decon
HgpH4
Decon Dup
Hg pH 4 Decon 2
Hg pH 4 Decon
2 Dup
0.0011
0.0012
9.6
10.4
9.7
9.2
7.6
8.6
0.86
0.89
0.0035
0.010
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.024
1.3x10= cells/cm2
0.51
1.2
27.0
24.1
23.9
16.3
15.0
24.3
14.4
17.2
a Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-14 Experimental Results From Test Run ID: Hg KMn04
(Adherence study flow rate: 60gpm, Decontamination: acidified permanganate flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Acidified Potassium
Permanganate Flushing)
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
After acidified
potassium
permanganate
Flushing
After draining
loop
Hg KMnO4 TO
Hg KMnO4 TO Dup
Hg KMnO4 T5M
HgKMnO4T5M Dup
HgKMnO4T1D
HgKMnO4T1DDup
Hg KMnO4 T2D
HgKMnO4T2DDup
Hg KMnO4 Decon
Hg KMnO4 Decon Dup
0.0014
0.0012
9.0
5.2
18
6.3
5.3
6.8
0.58
0.53
Coupon #1
Coupon #2a
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
0.0093
1. 2 X105 cells/cm2
0.47
0.12
4.5
8.5
3.7
5.5
0.25
0.33
1.4
1.2
a Coupon #2 was taken for HPC analysis to check for biofilm development.
-------
Table A-15 Experimental Results From Test Run ID: BS F60
(Adherence study flow rate: 60 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact period
After 2-day
contact period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
BS F60 TO
BS F60 TO Dup
BS F60 T5M
BSF60T5M Dup
BSF60T1D
BSF60T1DDup
BS F60 T2D
BSF60T2DDup
BS F60 Decon
BS F60 Decon Dup
0
0
880
900
720
800
330
410
800
500
Coupon #1
Coupon #2(a>
Control
coupon A
Control
coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
16
5.3x105cells/cm2
1.8E+04
7.1E+03
4.6E+04
3.3E+04
5.5E+04
5.6E+04
5.4E+04
4.8E+04
7.5E+04
4.9E+04
1 Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table A-16 Experimental Results From Test Run ID: BS CT30K
(Adherence study flow rate: 60 gpm, Decontamination: shock chlorination)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes after
injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
BS CT30K TO
BSCTSOKTODup
BS CT30K T5M
BS CT30K T5M
Dup
BSCT30KT1D
BSCT30KT1D
Dup
BS CT30K T2D
BS CT30K T2D
Dup
BS CT30K Decon
BS CT30K Decon
Dup
7
5
5300
5400
1000
1200
680
950
0
0
Coupon #1
Coupon #2(a)
Control
coupon A
Control
coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Coupon #7
Coupon #8
Coupon #9
Coupon #10
17
7.6x10= cells/ cm2
5.7E+04
3.4E+04
8.2E+04
7.7E+04
3.2E+04
6.5E+04
4.8E+03
4.3E+03
7.4E+02
2.8E+03
' Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table A-17 Experimental Results from Test Run ID: DRO F60
(Adherence study flow rate: 60 gpm, Decontamination: simple water flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after
injection
1 day after
injection
2 days after
injection
After
draining
loop
Prior to
draining
loop
After
draining
loop
DRO F60 TO
DRO F60 TO Dup
DRO F60 T5M
DRO F60 T5M Dup
DROF60T1D
DROF60T1DDup
DRO F60 T2D
DRO F60 T2D Dup
DRO F60 Decon
DRO F60 Decon
Dup
ND
ND
13.1
11.1
3.9
1.3
ND
0.7
3.5
4.0
Coupon #1
Coupon #2
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Control coupon C
Control coupon D
Coupon #7
Coupon #8
Coupon #9
Coupon #10
14.0
4.8 x105 cells/ cm2
8.7
14.8
23.5
21.7
22.4
28.5
3.1
3.0
16.0
12.2
15.0
17.4
(a) ND: nondetectable
(a) Diesel Range Organics were detected for coupon #1. However, according to the chromatograph these compounds were not
diesel fuel compounds.
(b) Coupon #2 was taken for HPC analysis to check the biofilm development.
-------
Table A-18 Experimental Results From Test Run ID: DRO TDA
(Adherence study flow rate: 60 gpm, Decontamination: Surfonic TDA-6 flushing)
Baseline
Adherence
Study
During 2-day
contaminant
contact
period
After 2-day
contact
period
Decontamination Study
(Flushing)
Just prior to
injection
5 minutes
after injection
1 day after
injection
2 days after
injection
After draining
loop
Prior to
draining loop
After draining
loop
DRO TDA TO
DROTDATODup
DROTDAT5M
DROTDAT5M
Dup
DROTDAT1D
DROTDAT1D
Dup
DROTDAT2D
DROTDAT2D
Dup
DROTDADecon
DROTDADecon
Dup
ND
ND
11
9.9
1.8
0.8
ND
0.7
14500
14500
Coupon #1
Coupon #2
Control coupon A
Control coupon B
Coupon #3
Coupon #4
Coupon #5
Coupon #6
Control coupon C
Control coupon D
Coupon #7
Coupon #8
Coupon #9
Coupon #10
5.0
3.9x 106cells/cm2
22.3
28.6
30.0
37.5
79.0
70.9
15.0
14.0
20.8
24.0
30.0
45.0«>
(a) ND: nondetectable
(b) Diesel Range Organics (DRO) were detected for coupon #1. However, according to the chromatograph these compounds
were not diesel fuel compounds.
(c) Coupon #2 was taken for HPC analysis to check the biofilm development.
(d) C20-C34 DRO analyses of Clear PVC coupon extraction samples showed some peak integration issues; therefore, only C10-
C20 DRO numbers are used here.
(e) The DRO contamination in these samples is not diesel fuel. The identity of the compounds in these samples cannot be
determined by GC/FID analysis, but from the information provided by DataChem Laboratories and from the chromatographs, it
is probable that a high molecular weight surfactant is the source of the contamination.
(f) This sample appears to contain both diesel fuel contamination and the surfactant present in the previous samples.
-------
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