September 2000
NSF 00/16/EPADW395
Environmental Technology
Verification Report
On-Site Generation of Sodium
Hypochlorite
ClorTec, a Division of Capital
Controls, Inc.
ClorTec Model MC 100
Prepared by
®
NSF International
Under a Cooperative Agreement with
U.S. Environmental Protection Agency
eiVetVeiV
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
•a* ®
U.S. Environmental Protection Agency NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE:
ON-SITE GENERATION OF HALOGEN DISINFECTANTS
USED IN PACKAGED DRINKING WATER TREATMENT
SYSTEMS
APPLICATION:
ON-SITE GENERATION OF SODIUM HYPOCHLORITE
TECHNOLOGY NAME:
ClorTec MODEL MC 100 SYSTEM
COMPANY:
CLORTEC, A DIVISION OF CAPITAL CONTROLS, INC.
ADDRESS:
1077 DELL AVENUE PHONE: (408) 871-1300
CAMPBELL, CA 95008 FAX: (408) 871-1314
WEB SITE:
www.clortec.com
EMAIL:
Greg@ClorTec.com
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative or improved environmental
technologies through performance verification and dissemination of information. The goal of the ETV
program is to further environmental protection by substantially accelerating the acceptance and use of
improved and more cost-effective technologies. ETV seeks to achieve this goal by providing high
quality, peer reviewed data on technology performance to those involved in the design, distribution,
permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; stakeholders groups which
consist of buyers, vendor organizations, and permitters; and with the full participation of individual
technology developers. The program evaluates the performance of innovative technologies by developing
test plans that are responsive to the needs of stakeholders, conducting field or laboratory tests (as
appropriate), collecting and analyzing data, and preparing peer reviewed reports. All evaluations are
conducted in accordance with rigorous quality assurance protocols to ensure that data of known and
adequate quality are generated and that the results are defensible.
NSF International (NSF) in cooperation with the EPA operates the Drinking Water Treatment Systems
(DWTS) Pilot, one of 12 technology areas under ETV. The DWTS Pilot recently evaluated the
performance of an on-site sodium hypochlorite generation (SHG) system used in package drinking water
treatment system applications. This verification statement provides a summary of the test results for the
ClorTec Model MC 100 System. Gannett Fleming Inc., an NSF-qualified field testing organization
(FTO), performed the verification testing.
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ABSTRACT
The EPA and NSF verified the performance of the ClorTec Model MC 100 System under the EPA's ETV
program. The concentrated hypochlorite generator stream from the treatment system underwent a twice-
daily analysis from March 8 to April 6, 2000. The chlorine analyses were conducted on site in United
Water Pennsylvania's Hummelstown Water Treatment Plant (WTP) operators lab. The hypochlorite
generator stream was analyzed using two methods of measuring total chlorine: Standard Method 4500-C1
F (EPA approved) and Standard Method 4500-C1 B. The average sodium hypochlorite concentration was
0.90% ± a standard deviation of 0.04% using Standard Method 4500-C1 B and 0.91% ± a standard
deviation of 0.08% using Standard Method 4500-C1 F. The average sodium chloride concentration in the
brine fed to the generator electrolytic cells during the verification testing was 3.53%, higher than
ClorTec's specified value of 3.0%. The average DC current and voltage applied to the electrolytic cells
during the ETV were 183 amps and 46 volts, respectively. ClorTec states that the amperage and voltage
should be approximately 185 amps and 48 volts. No attempt was made to adjust the brine pump feed rate
during the verification testing; it is factory set to deliver the concentrated brine (30% sodium chloride) to
a softened side stream from the WTP finished water by a ratio of approximately ten parts water to one
part brine prior to entering the generator. After the tenth day of testing, the chlorine concentration in the
hypochlorite concentrate stream generally trended higher. This roughly correlated with a higher sodium
chloride concentration.
TECHNOLOGY DESCRIPTION
On-site sodium hypochlorite generation systems for drinking water treatment are used in place of gas
chlorine for primary and/or residual disinfection. The concentration of on-site generated sodium
hypochlorite is typically less than 1%, sufficiently dilute so that the generation equipment does not
require special handling or containment.
The process involves the application of a low-voltage DC current to a brine containing an approximate
3.0% sodium chloride concentration to generate a sodium hypochlorite concentration of approximately
0.8%. The generation process occurs inside clear four inch PVC tubes housing ten pairs of anode and
cathode electrolytic plates. Current is applied to the electrolytic plates as the brine is pumped between the
plates. The product generated from this reaction is sodium hypochlorite, plus the byproduct hydrogen.
The cells are designed so that the hydrogen is readily separated from the sodium hypochlorite and vented
to the outside.
The ClorTec Model MC 100 system is a modular system whose primary components consist of a power
supply and rectifier, brine pump and electrolytic cells, and a Programmable Logic Controller (PLC)-based
control panel. A brine saturator and day tank, water softener, sodium hypochlorite storage tanks and
metering pumps are required in addition to the modular components. The system operates in the
automatic batch mode based on setpoints entered into the PLC and liquid level signals transmitted back
from the hypochlorite storage tanks. Only limited operator intervention is required.
The ClorTec Model MC 100 system is designed to produce up to 100 pounds per day of sodium
hypochlorite as chlorine.
VERIFICATION TESTING DESCRIPTION
Test Site
The test site was United Water Pennsylvania's Hummelstown WTP. The water source for this plant is the
Swatara Creek, a supply that can vary significantly in water quality, particularly turbidity, pH, alkalinity
and hardness. The plant is a conventional WTP consisting of prechlorination, coagulation, clarification,
granular media filtration and post chlorination. The pre- and post chlorination was supplied by the
ClorTec Model MC 100 sodium hypochlorite generation system, permanently installed in the chemical
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room of the WTP. For monitoring purposes, the post chlorine feed point was selected as the ETV testing
location.
Methods and Procedures
Measurement of the equipment's physical parameters occurred at least once daily during the ETV test
period. This includes monitoring brine and sodium hypochlorite storage tank levels; feed water, brine
dilution water and treated water flow rates; brine specific gravity; dilution water and brine temperatures;
on-line analyzer sample flow rates; and rectifier amperage and voltage.
Softener waste stream flow rate and composition were also noted during the ETV test period.
All field analyses (i.e. pH, turbidity, chlorine residual, temperature and hydrogen sulfide) were conducted
daily or, in the case of chlorine residual, twice daily, using bench test equipment in accordance with
Standard Methods for the Examination of Water and Wastewater, 19th Ed. (1995).
All laboratory analyses were conducted by Microbac Laboratories (Microbac) using procedures from
Standard Methods or EPA-approved methods. These analyses included the following inorganic
parameters: alkalinity, ammonia nitrogen, UV254, and true color, which were analyzed weekly and TDS,
iron, manganese, chloride, bromide, and sodium, which were analyzed once during the test period. The
disinfectant byproduct parameters analyzed by Microbac were chlorite, chlorate, total trihalomethanes
(TTHMs) and haloacetic acids (HAA5). Samples were analyzed by Microbac five days per week for total
coliform and heterotrophic plate counts.
Simulated Distribution System (SDS) Disinfectant Byproduct (DBP) Formation Testing was performed
due to the fact that the ClorTec Model MC 100 system is used as the chlorine source for both primary
disinfection and residual disinfection. The uniform formation conditions (UFC) of the EPA Information
Collection Rule (ICR) were followed to estimate DBP formation in the distribution system, including
TTHMs using EPA Method 524.2, HAA5 using Standard Method 6251B, and chlorite and chlorate, both
using EPA Method 300.0.
VERIFICATION OF PERFORMANCE
System Operation
As previously indicated, the system operated in the auto batch mode. Generator operation was initiated
based on the sodium hypochlorite level in the storage tanks. A 4-20 mA signal from level transmitters
situated on top of each storage tank was sent to the PLC controller, which would activate the generator
from standby if the levels in the hypochlorite storage tanks were below the previously entered setpoint.
Generator operation was terminated based on sodium hypochlorite levels in the storage tanks reaching a
previously entered high level setpoint. This mode of operation was effective during the ETV.
The number of SHG continuous hours of operation was primarily contingent on the WTP production rate,
and varied from 3 hours to 25 hours with an average of 13 hours. The hypochlorite metering pumps,
which are not an integral part of the ClorTec MC 100 system, typically had to be adjusted manually
several times daily to account for this operating variable (there was no pacing system for the metering
pumps).
No adjustments were made to the SHG dilution water flow, voltage or amperage during the ETV because
these parameters and the brine specific gravity were within the ranges specified in the ClorTec MC
Operator Interface PLC Manual.
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Water Quality Results
The feed water turbidity was low due to coagulation/clarification/filtration of the raw water by the
Hummelstown WTP, averaging 0.067 NTU during the verification testing. A free chlorine residual was
maintained in the feed water, averaging 0.36 mg/1 during the test period. Due to the high quality filtered
water and the chlorine demand having been satisfied with prechlorination, the addition of post sodium
hypochlorite provides a free available chlorine residual for achieving compliance with CT requirements
under the EPA Surface Water Treatment Rule (SWTR), and provides a residual disinfectant throughout
the distribution system.
Table 1 summarizes the results of on-site analytical testing for the 30 day verification test. The only
change in water quality of any significance between the feed water and treated water was the
concentration of chlorine. The addition of post sodium hypochlorite resulted in an average total chlorine
concentration of 1.46 mg/1, an increase of 0.95 mg/1 over feed water total chlorine level. As stated
previously, the treatment prior to post sodium hypochlorite either removed or satisfied almost all of the
chlorine demand, resulting in post chlorine being available largely as free chlorine. Temperature of the
feed water averaged 11.4°C. Hydrogen sulfide was not detected in the feed water; the minimum method
detection level for hydrogen sulfide was 0.1 mg/1.
Table 1. On-Site Water Quality Analyses
Feed Water
(Filter Room Pumped Sample)
Treated Water
(Finished Water - Lab Sink)
Flypochlorite
Generator
Turbidity
Turbidity
FAC
TAC
Bench
PH
Bench
(NTU)
On-
Bench line TAC
On-line H2S FAC FAS(1)
(NTU) (mg/1) (mg/1) (mg/1)
On-
line Bench
pFl pFl
Bench
(NTU)
On-line
(NTU)
On- TAC
FASf1' line FAS(1)
(mg/1) (mg/1) (mg/1)
FAS(1)
(%)
Iodo®
(%)
Mean
Minimum
Maximum
Std Dev
95% Conf
Interval
7.0
6.2
7.6
0.3
7.0±
0.1
0.067
0.040
0.100
0.017
0.067±
0.006
0.060
0.040
0.094
0.014
0.060±
0.005
0
0
0
0
N/A
0.36
0.01
1.38
0.24
0.36±
0.06
0.51
0.08
1.58
0.29
0.51±
0.07
7.07
6.80
7.53
0.15
7.07±
0.05
7.0
6.5
7.4
0.2
7.0±
0.1
0.063
0.046
0.100
0.013
0.063±
0.005
0.059
0.040
0.098
0.014
0.059±
0.005
1.33
1.05
1.80
0.17
1.33±
0.04
1.23
1.00
1.69
0.16
1.23±
0.04
1.46
1.00
2.00
0.22
1.46±
0.05
0.91
0.80
1.11
0.08
0.91±
0.02
0.90
0.78
0.97
0.04
0.90±
0.01
(1)FAS=Ferrous Ammonium Sulfate Titration (Standard Method 4500-C1 F)
<2)Iodo=Iodometric Titration (Standard Method 4500-C1 B)
FAC=Free Available Chlorine
TAC=Total Available Chlorine
Total Coliform, indicator bacteria for potential fecal contamination, and Heterotrophic Plate Count
(HPC), a general indicator for total bacterial levels, were sampled five days per week for the test period.
There were no positive indications for the presence of Total Coliform in either the feed water or treated
water. HPC were detected in two feed water samples at 15 and 73 colony forming units (cfu)/ml and
three treated water samples at 1, 58 and 71 cfu/ml. The dates that exhibited the two higher detections in
the treated water corresponded to the sample dates of the two detections in the feed water. There is no
indication in the WTP operating records or the ETV logbook of having lost hypochlorite feed during the
sampling period when HPC were detected. The most likely reason for the detections was improper
sampling procedures.
Six inorganic contaminants commonly found in water supplies were analyzed in the feed water and
treated water once during the test period. Iron, manganese and bromide were below detection limits in
both the feed water and treated water. TDS increased from 139 mg/1 in the feed water to 147 mg/1 in the
treated water; sodium increased from 11.6 mg/1 to 13.3 mg/1; and chloride increased from 23.8 mg/1 to 27
mg/1. The TDS of the softener wastewater was much higher (7785 mg/1) than the feed water due to the
removal and concentration of dissolved minerals in the softener treatment process. These increases in
TDS, sodium and chloride are likely due to the addition of sodium hypochlorite to the feed water process.
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The presence of ammonia can have a significant impact on disinfection due to the demand it places on
chlorine. No ammonia was detected in either the feed water or treated water. The impact of feeding
sodium hypochlorite on the alkalinity level was negligible, increasing it from an average of 28 mg/1 as
CaC03 to 30 mg/1 as CaCGj. Feed water and treated water alkalinity levels were, with the exception of
one set of samples, the same.
UV254 and true color are parameters commonly used as indicators of the relative concentration of natural
organic matter (NOM). The primary significance of NOM is as potential precursors for producing
disinfection byproducts when combined with a disinfectant such as chlorine. The levels of UV254 and true
color were relatively low, with no significant difference between the feed water and treated water.
Organic and inorganic disinfectant byproducts are presented on Table 2.
Table 2. Disinfectant Byproduct Analyses
Feed Water
Treated Water
Parameter
(mg/1)
(mg/1)
TTHM - Inst.
0.0140
0.0160
HAA5 - Inst.
0.0060
0.0187
TTHM - SDS
NT
0.0390
HAA5-SDS
NT
0.0277
Chlorite - Inst
<0.02
<0.02
Chlorate - Inst
0.081
0.112
Chlorite - SDS
NT
<0.02
Chlorate - SDS
NT
0.262
Inst.=Instantaneous
SDS=Simulated Distribution System
NT=Not Tested
As indicated on Table 2, instantaneous analyses were conducted on both the feed water and treated water
samples for TTHM and HAA5. DBP levels were anticipated to be higher in the treated water relative to
the feed water due to the addition of post sodium hypochlorite and the additional contact time in the WTP
finished water storage. As expected, TTHM and HAA5 levels were higher in the treated water, although
only slightly for TTHM. In contrast, HAA5 levels increased by a factor of three.
A portion of the treated water sample was subject to UFC, as defined under the EPA ICR, for the purpose
of producing SDS samples. These conditions resulted in a three-fold increase in TTHM and 30% increase
in HAA5.
As with the organic DBP, instantaneous samples were collected for the feed and treated water inorganic
DBP analyses. The promulgated Disinfectant/Disinfectant Byproduct Rule (D/DBPR) has an MCL of 0.8
mg/1 for chlorite. Chlorite was not detected in either sample. Chlorate was detected in both the feed
water and treated water. SDS conditions resulted in a doubling of the instantaneous chlorate level to
0.262 mg/1. There are presently no proposed regulations for chlorate.
Another disinfectant byproduct of ongoing concern using on-site generation of sodium hypochlorite is
bromate. Bromate will be regulated under Stage 1 of the D/DBPR with an MCL of 0.01 mg/L. Although
bromate was not a parameter required to be analyzed under the NSF on-site halogen production protocol,
the precursor of bromate (bromide) was a required analysis. No bromide was detected in either the feed
water or treated water. Bromide was also not detected in the chemical analysis of the sodium chloride
used during the testing.
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Feed Stock Consumption
Feed stock consisted of a solar grade salt and softened water used to dilute the salt into a brine solution.
The salt is certified to be 99% pure sodium chloride, and contains a calcium concentration of less than
0.23%. The calcium concentration is important due to the scaling effect it can have on the generator
electrode plates. Over the course of the 30 day test period, an average of 247 pounds of salt were used on
a daily basis, producing an average of 842 gpd of 0.9% sodium hypochlorite.
Power Consumption
Power consumption was recorded daily for voltage and amperage, which was displayed locally on the
power supply/rectifier, and remotely on the PLC cabinet LCD screen. The average daily DC current and
voltage applied to the electrolytic cells was 183 amps and 46 volts, respectively.
Maintenance
There were a few items that required maintenance during the ETV, none of which directly involved the
ClorTec MC 100 system but rather the softener, pump feed line and pH meter.
The hypochlorite generator electrodes had started to develop a scale formation by the end of the 30-day
test, although the scaling had not developed to the point of loss in generator efficiency, requiring acid
cleaning. (A loss in generator efficiency becomes evident when an increase in power is required to
maintain the same level of concentrated chlorine).
Original Signed by
E. Timothy Oppelt 10/10/00
E. Timothy Oppelt Date
Director
National Risk Management Research Laboratory
Office of Research and Development
United States Environmental Protection Agency
Original Signed by
Tom Bruursema 10/13/00
Tom Bruursema Date
General Manager
Environmental and Research Services
NSF International
NOTICE: Verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. EPA and NSF make no
expressed or implied warranties as to the performance of the technology and do not certify that a
technology will always operate as verified. The end user is solely responsible for complying with
any and all applicable federal, state, and local requirements. Mention of corporate names, trade
names, or commercial products does not constitute endorsement or recommendation for use of
specific products. This report is not a NSF Certification of the specific product mentioned herein.
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Availability of Supporting Documents
Copies of the ETV Protocol for Equipment Verification Testing for Inactivation of
Microbiological Contaminants dated August 9, 1999, the Verification Statement, and the
Verification Report (NSF Report #00/16/EPADW395) are available from the following
sources:
(NOTE: Appendices are not included in the Verification Report. Appendices are
available from NSF upon request.)
1. Drinking Water Systems ETV Pilot Manager (order hard copy)
NSF International
P.O. Box 130140
Ann Arbor, Michigan 48113-0140
2. NSF web site: http://www.nsf.org/etv (electronic copy)
3. EPA web site: http://www.epa.gov/etv (electronic copy)
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September 2000
Environmental Technology Verification Report
On-Site Sodium Hypochlorite Generation System Used for
Disinfection in Drinking Water
ClorTec, a Division of Capital Controls
Model MC 100 On-Site Sodium Hypochlorite Generation System
Prepared for:
NSF International
Ann Arbor, Michigan 48105
Prepared by:
Gannett Fleming, Inc.
Harrisburg, Pennsylvania 17106-7100
Under a Cooperative Agreement with the U.S. Environmental Protection Agency
Jeffrey Q. Adams, Project Officer
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Notice
The U.S. Environmental Protection Agency (EPA) through its Office of Research and
Development has financially supported and collaborated with NSF International (NSF) under
Cooperative Agreement No. CR 824815. This verification effort was supported by Drinking
Water Treatment Systems Pilot operating under the Environmental Technology Verification
(ETV) Program. This document has been peer reviewed and reviewed by NSF and EPA and
recommended for public release.
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Foreword
The following is the final report on an Environmental Technology Verification (ETV) test
performed for the NSF International (NSF) and the United States Environmental Protection
Agency (EPA) by Gannett Fleming, Inc., in cooperation with ClorTec, a division of Capital
Controls. The test was conducted during March 8 through April 6, 2000 at the Hummelstown
Water Treatment Plant (WTP), Hummelstown, Pennsylvania.
Throughout its history, the EPA has evaluated the effectiveness of innovative technologies to
protect human health and the environment. A new EPA program, the Environmental
Technology Verification Program (ETV) has been instituted to verify the performance of
innovative technical solutions to environmental pollution or human health threats. ETV was
created to substantially accelerate the entrance of new environmental technologies into the
domestic and international marketplace. Verifiable, high quality data on the performance of new
technologies are made available to regulators, developers, consulting engineers, and those in the
public health and environmental protection industries. This encourages more rapid availability
of approaches to better protect the environment.
The EPA has partnered with NSF, an independent, not-for-profit testing and certification
organization dedicated to public health, safety and protection of the environment to verify
performance of small package drinking water systems that serve small communities under the
ETV Drinking Water Treatment Systems (DWTS) Pilot Project. A goal of verification testing is
to enhance and facilitate the acceptance of small package drinking water treatment equipment by
state drinking water regulatory officials and consulting engineers while reducing the need for
testing of equipment at each location where the equipment's use is contemplated. NSF will meet
this goal by working with manufacturers and NSF-qualified Field Testing Organizations (FTO)
to conduct verification testing under the approved protocols.
The ETV DWTS is being conducted by NSF with participation of manufacturers, under the
sponsorship of the EPA Office of Research and Development, National Risk Management
Research Laboratory, Water Supply and Water Resources Division, Cincinnati, Ohio. It is
important to note that verification of the equipment does not mean that the equipment is
"certified" by NSF or "accepted" by EPA. Rather, it recognizes that the performance of the
equipment has been determined and verified by these organizations for those conditions tested by
the FTO.
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Table of Contents
Section Page
Verification Statement VS-1
Title Page
Notice '
Foreword ii
Table of Contents h
Abbreviations and Acronyms vii
Acknowledgements
Chapter 1 Introduction
1.1 ETV Purpose and Program Operation
1.2 Testing Participants and Responsibilities
1.2.1 NSF Internati onal
1.2.2 Field Testing Organization
1.2.3 Manufacturer
1.2.4 Analytical Laboratory
1.2.5 U.S. Environmental Protection Agency
1.2.6 United Water Pennsylvania
1.3 Verification Testing Site
1.3.1 Source Water and Existing Treatment
1.3.2 Treated Water Discharge
1.3.3 Installation and Start-up
Chapter 2 Equipment Description and Operating Processes
2.1 Equipment Description
2.1.1 Brine Generation and Storage System
2.1.1.1 Softener
2.1.1.2 Cartridge Filters
2.1.1.3 Brine Bulk Saturator Tank
2.1.1.4 Brine Day Tank
2.1.1.5 Sodium Hypochlorite Storage Tanks
2.1.2 Sodium Hypochlorite Generator System
2.1.2.1 Electrolytic Cells
2.1.2.2 Brine Dilution System 1
2.1.3 PLC/OIT Control Cabinet 1
2.1.4 Power Supply/Rectifier 1
2.2 Equipment Operations 1
2.2.1 Brine Generation and Storage System 1
2.2.2 Sodium Hypochlorite Generator System 1
2.2.2.1 Cell Electrode Cleaning 1
2.2.3 PLC/OIT 1
2.2.4 Power Supply/Rectifier 1
2.3 Advantages and Disadvantages 1
2.3.1 Advantages of On-Site Sodium Hypochlorite Generation 1
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Table of Contents, continued
Section Page
2.3.1.1 Comparison of On-Site SHG and Commercially Available
Sodium Hypochlorite (12% to 15%) 14
2.3.1.2 Comparison of On-Site SHG and Gas Chlorine 14
2.3.2 Disadvantages On-Site of SHG. 15
Chapter 3 Methods and Procedures 16
3.1 Experimental Design 16
3.1.1 Objectives 16
3.1.1.1 Evaluation of Stated Equipment Performance Claim 16
3.1.1.2 Evaluation of Performance Relative to the EPA Safe Drinking
Water Regulatio ns 16
3.1.1.3 Evaluation of Equipment Performance Relative to Feed Water
Quality 16
3.1.1.4 Evaluation of Operational Requirements 17
3.1.1.5 Evaluation of Maintenance Requirements 17
3.1.2 Equipment Characteristics 17
3.1.2.1 Qualitative Factors 17
3.1.2.2 Quantitative F actors 18
3.1.3 Operating Parameters 18
3.2 Health and Safety Measures 19
3.2.1 Hydrogen Off-Gas 19
3.2.2 Electrode Cleaners 19
3.3 Communications, Logistics and Data Handling Protocol 19
3.3.1 Introduction 20
3.3.2 Objectives 20
3.3.3 Procedures 20
3.4 Recording Statistical Uncertainty. 20
3.5 Verification Testing Schedule 21
3.6 Verification Task Procedures 21
3.6.1 Task 1: Equipment Operation and Disinfectant Production Capabilities ....21
3.6.2 Task 2: Treated Water Quality 22
3.6.3 Task 3: Data Management 23
3.6.4 Task 4: Quality Assurance/Quality Control (QA/QC) 25
3.6.4.1 Turbidity 25
3.6.4.2 pH 25
3.6.4.3 Chlorine Residual 25
3.6.4.4 Temperature 26
3.6.4.5 Brine Dilution Water Flow. 26
3.6.4.6 Power 26
3.6.4.7 Softener Regeneration Wastewater Flow Rate 26
3.6.4.8 Diluted Brine Concentration 26
3.6.4.9 Equipment Tubing and Connections 26
3.6.4.10 Sodium Hypochlorite Metering Pumps 26
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Table of Contents, continued
Section Page
3.6.4.11 Chemical and Biological Samples Shipped Off-Site
for Analyses 27
3.6.4.11.1 Organic Parameters 27
3.6.4.11.2 Microbiological Parameters 27
3.6.4.11.3 Inorganic Parameters 27
Chapter 4 Results and Discussions 28
4.1 Introduction 28
4.2 Verification Task Results 28
4.2.1 Task 1: Equipment Operation and Disinfectant Production Capability 28
4.2.1.1 Range of Treated Water Flow Rates 28
4.2.1.2 Range of Chlorine Concentrations in Generator Stream 28
4.2.1.3 Range of Treated Water Chlorine Residuals 32
4.2.1.4 Softener Wastewater Characterization 32
4.2.1.5 Feed Stock Consumption 33
4.2.1.6 Power Consumption 33
4.2.2 Task 2: Water Quality 34
4.2.2.1 On-Site Analytical Results 34
4.2.2.2 Feed and Finished Water Testing Results 35
4.2.2.3 Microbiological Results 36
4.2.2.4 Disinfectant Byproducts 37
4.2.3 Task 3: Data Management 38
4.2.4 Task 4: Quality Assurance/Quality Control (QA/QC) 39
4.2.4.1 Turbidimeters 39
4.2.4.2 pH Meters 39
4.2.4.3 Chlorine Residual Analyzers 39
4.2.4.4 Generator Dilution Flow Meters 40
4.2.4.5 WTP Flow Meters 40
4.2.4.6 Microbac Laboratories 40
4.2.4.7 On-Site Inspection 40
4.3 System Operation 40
4.4 Maintenance 41
4.5 O&M Manual Revi ew 41
4.6 Costs 42
Chapter 5 References 43
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Table of Contents, continued
Tables Page
Table 1-1. Feed Water Quality 5
Table 3-1. Operational Parameter Monitoring and Data Collection Schedule 18
Table 3-2. Water Quality Sampling Schedule 23
Table 4-1. On-Site Chlorine and Brine Analyses 30
Table 4-2. Total Chlorine Analyses and Sodium Hypochlorite Feed Rates 32
Table 4-3. Softener Regenerant Wastewater Quality 33
Table 4-4. Daily Feed Stock Consumption 33
Table 4-5. Daily Power Consumption 34
Table 4-6. On-Site Water Quality Analyses 35
Table 4-7. Feed, Treated, and Softener Water Quality - Laboratory Analyses 35
Table 4-8. Weekly Feed Water Quality - Laboratory Analyses 36
Table 4-9. Weekly Treated Water Quality - Laboratory Analyses 36
Table 4-10. Daily Bacteria - Laboratory Analyses 37
Table 4-11. Organic Disinfectant Byproduct Analyses 37
Table 4-12. Inorganic Disinfectant Byproduct Analyses 37
Table 4-13. Simulated Distribution System Test Conditions 38
Table 4-14. On-Site SHG Feedstock Costs 42
Table 4-15. Chlorine Cost Comparison 42
Figures
Figure 2-1. Schematic of ClorTec Model MC100 Sodium Hypochlorite Generation System 7
Figure 4-1. ETV Treated Water Flow Rate 29
Figure 4-2. Hypochlorite Generator Chlorine Concentration 29
Figure 4-3. Hypochlorite Generator Chlorine and Sodium Chloride Concentrations 30
Figure 4-4. Sodium Chloride Concentration and Dilution Water Flow 31
Photographs
Photograph 2.1 - Brine Bulk Saturator Tank 8
Photograph 2.2 - Softener, PLC, Brine Day Tank and Hypochlorite Generator 9
Photograph 2.3 - Sodium Hypochlorite Generator 9
Photograph 2.4 - Power Supply/Rectifier 11
Appendices
Appendix A - Chart: Sodium Chloride Percent Solution, Specific Gravity and Temperature
Appendix B - On-Site Analytical and Sample Collection Procedures
Appendix C - Data Management Spreadsheets
Appendix D - Microbac Laboratories Lab Reports
Appendix E - SDS Procedures for DBPFT
Appendix F - Chemical Reagent Spec/MSDS Sheets
Appendix G - Instrumentation QA/QC Documentation
Appendix H - Sodium Chloride Spec/MSDS
Appendix I - Field Logbook
Appendix J - ClorTec MC Operator Interface PLC Manual
vii
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Abbreviations and Acronyms
A
Amp
AC
Alternating Current
ANOVA
Analysis of Variance
CAAA
Clean Air Act Amendment
CaC03
Calcium Carbonate
CFU
Colony Forming Unit
CI
Chlorine
cm
Centimeter
°C
Degrees Celsius
c.u.
Platinum-Cobalt Color Units
D
Depth
DBP
Disinfectant Byproduct
DBPFT
Disinfectant Byproduct Formation Testing
DC
Direct Current
EPA
Environmental Protection Agency
ETV
Environmental Technology Verification
°F
Degrees Fahrenheit
FAC
Free Available Chlorine
FRP
Fiberglass Reinforced Plastic
FOD
Field Operations Document
FTO
Field Testing Organization
gph
Gallons Per Hour
gpd
Gallons Per Day
gpm
Gallons Per Minute
H
Height
HAA5
Haloacetic Acids-5
HazMat
Hazardous Material
HC1
Hydrochloric Acid
HDPE
High Density Polyethylene
HPC
Heterotrophic Plate Count
HP
Horsepower
HZ
Hertz
ICR
Information Collection Rule
kWh
Kilowatt-hours
L
Liter
lb
Pound
LCD
Liquid Crystal Diode
LED
Liquid Emitting Diode
M
Mole
mA
milliAmp
MCL
Maximum Contaminant Level
mg/1
Milligram per Liter
ml
Milliliter
MPN
Most Probable Number
MSDS
Material Safety Data Sheets
viii
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NA
Not Analyzed
NaCl
Sodium Chloride
NaOCl
Sodium Hypochlorite
NaOH
Sodium Hydroxide
NEMA
National Electrical Manufacturers Association
nh3-n
Ammonia Nitrogen
NIST
National Institute of Standards and Technology
NOM
Natural Organic Matter
NPDES
National Pollution Discharge Elimination System
NR
Not Reported
NSF
NSF International (formerly known as National Sanitation Foundation)
NSR
No Softener Regeneration
NT
Not Tested
NTU
Nephlometric Turbidity Units
OIT
Operator Interface Terminal
O&M
Operation and Maintenance
OSHA
Occupational Safety and Health Administration
PADEP
Pennsylvania Department of Environmental Protection
PE
Professional Engineer
PLC
Programmable Logic Controller
PRV
Pressure Reducing Valve
PSM
Process Safety Management
PSI
Pounds per Square Inch
PVC
Poly Vinyl Chloride
QA/QC
Quality Assurance/Quality Control
QAPP
Quality Assurance Project Plan
RMP
Risk Management Plan
SCR
Speed Control Rheostat
SDS
Simulated Distribution System
SHG
Sodium Hypochlorite Generation
SM
Standard Methods
ss
Stainless Steel
TAC
Total Available Chlorine
TC
Total Coliform
IDS
Total Dissolved Solids
TOC
Total Organic Carbon
TTHM
Total Trihalomethane
UFC
Uniform Formation Conditions
UPS
Uninterruptible Power Supply
UVA
Ultraviolet Absorbance
UV254
Ultraviolet Absorbance @ 254 nanometers
Hg/1
microgram per liter
V
Volts
VDC
Volts Direct Current
VAC
Volts Alternating Current
W
Width
WTP
Water Treatment Plant
IX
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Acknowledgements
The Field Testing Organization, Gannett Fleming, Inc., was responsible for all elements in the
testing sequence, including collection of samples, calibration and verification of instruments,
data collection and analysis, data management, data interpretation and the preparation of this
report.
Gannett Fleming, Inc.
202 Senate Avenue
Camp Hill, PA 17011
Contact Person: Gene Koontz, Project Administrator
The laboratory selected for microbiological analysis and non-microbiological analytical work of
this study was:
Microbac Laboratories, Inc.
209 Senate Avenue
Camp Hill, PA 17011
Contact Person: Cheri Casari, Manager
The Manufacturer of the Equipment was:
ClorTec, a Division of Capital Controls (ClorTec)
1077 Dell Avenue, Suite A
Campbell, CA 95008
Contact Person: Greg Cibinski, Director of Engineering
Gannett Fleming, Inc., wishes to thank the following participants:
NSF International, especially Bruce Bartley, Project Manager, and Carol Becker, Environmental
Engineer, for providing guidance and program management.
The United Water Pennsylvania staff including Timothy K. McGarvey, Production
Superintendent; Rob Roth, Water Quality Manager; and Ron Artley, Assistant Production
Superintendent; provided operator training assistance and technical guidance. Dale Garrett,
George Hawthorne, Bill Reynolds, Tami Wilson, Bob Heineman, Matt Hobba and Phil Barley,
WTP operators, provided on-site monitoring, data collection and analytical assistance.
Greg Cibinski, Director of Engineering, for ClorTec, and Chester Parks, Sales Engineer of CP
Equipment Sales Company, provided technical and product expertise.
x
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Chapter 1
Introduction
1.1 ETV Purpose and Program Operation
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative or improved
environmental technologies through performance verification and dissemination of information.
The goal of the ETV program is to further environmental protection by substantially accelerating
the acceptance and use of improved and more cost-effective technologies. ETV seeks to achieve
this goal by providing high quality, peer reviewed data on technology performance to those
involved in the design, distribution, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; stakeholders
groups which consist of buyers, vendor organizations, and permitters; and with the full
participation of individual technology developers. The program evaluates the performance of
innovative technologies by developing test plans that are responsive to the needs of stakeholders,
conducting field or laboratory (as appropriate), collecting and analyzing data, and preparing peer
reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance
protocols to ensure that data of known and adequate quality are generated and that the results are
defensible.
NSF International (NSF) in cooperation with the EPA operates the Drinking Water Treatment
Systems (DWTS) Pilot, one of 12 technology areas under ETV. The DWTS Pilot evaluated the
performance of the ClorTec Model MC 100 system, which is an on-site sodium hypochlorite
generation (SHG) system used in package drinking water treatment system applications. The
performance claim evaluated during field testing of the system was that the system is capable of
producing sodium hypochlorite at a concentration of 0.8% ± 0.05%, from 99.1% purity sodium
chloride in 3.0% solution. This document provides the verification test results for the ClorTec
Model MC 100 system.
1.2 Testing Participants and Responsibilities
The ETV testing of the ClorTec Model MC 100 system was a cooperative effort between the
following participants:
NSF International
Gannett Fleming, Inc.
ClorTec, a Division of Capital Controls (ClorTec)
United Water Pennsylvania
U.S. Environmental Protection Agency
Microbac Laboratories, Inc.
The following is a brief description of each ETV participant and their roles and responsibilities.
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1.2.1 NSF International
NSF is a not-for-profit testing and certification organization dedicated to public health safety and
the protection of the environment. Founded in 1946 and located in Ann Arbor, Michigan, NSF
has been instrumental in the development of consensus standards for the protection of public
health and the environment. NSF also provides testing and certification services to ensure that
products bearing the NSF Name, Logo and/or Mark meet those standards. The EPA partnered
with the NSF to verify the performance of drinking water treatment systems through the EPA's
ETV Program.
NSF provided technical oversight of the verification testing. An inspection of the field analytical
and data gathering and recording procedures was conducted by NSF. NSF also provided review
of the Field Operations Document (FOD) and this report.
Contact Information
NSF International
789 N. Dixboro Rd.
Ann Arbor, MI 48105
Phone: 734-769-8010
Fax: 734-769-0109
Contact: Bruce Bartley, Project Manager
Email: Bartley@nsf.org
1.2.2 Field Testing Organization
Gannett Fleming, Inc., a consulting engineering company, conducted the verification testing of
the ClorTec Model MC 100 system. Gannett Fleming, Inc., is an NSF-qualified Field Testing
Organization (FTO) for the ETV Drinking Water Treatment Systems pilot project.
The FTO was responsible for conducting the verification testing for 30 calendar days. The FTO
provided all needed logistical support, established a communications network, and scheduled and
coordinated activities of all participants. The FTO was responsible for ensuring that the testing
location and feed water conditions were such that the verification testing could meet its stated
objectives. The FTO prepared the FOD, oversaw the pilot testing, managed, evaluated,
interpreted and reported on the data generated by the testing, as well as evaluated and reported
on the performance of the technology.
United Water Pennsylvania employees conducted the on-site analyses and data recording during
the testing. Oversight of the daily tests was provided by the FTO's Project Engineer and Project
Manager.
Contact Information:
Gannett Fleming, Inc.
202 Senate Avenue
Camp Hill, PA 17011
Gene Koontz, Project Administrator
gkoontz@gfnet.com
2
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1.2.3 Manufacturer
The treatment system is manufactured by ClorTec, a manufacturer of alternative chlorine
technologies for the municipal and industrial water and wastewater markets.
The manufacturer was responsible for supplying a field-ready on-site SHG system equipped with
all necessary components including treatment equipment, instrumentation and controls, and an
operations and maintenance manual. The manufacturer was responsible for providing logistical
and technical support as needed as well as providing technical assistance to the FTO during
operation and monitoring of the equipment undergoing field verification testing.
Contact Information:
ClorTec, a Division of Capital Controls
1077 Dell Avenue, Suite A
Campbell, CA 95008
Contact Person: Greg Cibinski, Director of Engineering
Email: Greg@ClorTec.com
1.2.4 A nalytical Laboratory
Full service environmental laboratory services were provided by Microbac Laboratories, Inc.
Microbac Laboratories is certified in the State of Pennsylvania for drinking water quality
analyses (PA DEP Certification No. 21-133).
Contact Information:
Microbac Laboratories, Inc.
209 Senate Avenue
Camp Hill, PA 17011
Contact Person: Cheri Casari, Laboratory Manager
Email: ccasari@gfnet.com
1.2.5 U.S. Environmental Protection Agency
The EPA through its Office of Research and Development has financially supported and
collaborated with NSF under Cooperative Agreement No. CR 824815. This verification effort
was supported by the Drinking Water Treatment Systems Pilot operating under the ETV
Program. This document has been peer reviewed and reviewed by NSF and EPA and
recommended for public release.
1.2.6 United Water Pennsylvania
The public water supplier United Water Pennsylvania provided staffing for monitoring, data
collection and on-site water quality analyses for the ETV.
3
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1.3 Verification Testing Site
The site selected for the verification testing is a surface water treatment plant (WTP) located
within the Borough of Hummelstown, approximately five miles east of Harrisburg,
Pennsylvania. The treatment plant, known as the Hummelstown WTP, is owned and operated by
United Water Pennsylvania. The main building of the treatment plant dates to the late 191
century, and was at one time a power generation station for the Borough. The chemical feed
room in this building is the location of the on-site SHG system. What is now WTP process
wastewater lagoons was originally a sluice for providing water to power a water wheel (since
removed) located inside the building. Since converting the building to a WTP additional
facilities have been added, including a filter building, clarifier and two finished water storage
tanks. The most recent addition, in November/December 1999, was the ClorTec Model MC 100
system.
1.3.1 Source Water and Existing Treatment
The treatment plant withdraws water from the adjacent Swatara Creek, its only source of supply.
The Swatara Creek Watershed encompasses an area of 483 square miles of primarily rural
flatlands consisting of mixed agricultural and wooded areas.
The water is pumped directly from Swatara Creek to the treatment plant, where pretreatment
chemicals (sodium hypochlorite, lime, and alum) are fed just prior to an in-line rapid mixer.
Following rapid mixing, the coagulated water flows to a solids contact clarifier for flocculation
and clarification. Clarified water flows to a set of four conventional dual media filters containing
anthracite and sand. The combined flow of the four filter effluents is chlorinated with sodium
hypochlorite prior to flowing to two above-ground finished water storage tanks.
The ClorTec Model MC 100 system is the source of chlorine for both pre and post chlorine at the
treatment plant, and both pre and post chlorine were fed during the verification test. However,
for ETV monitoring purposes, the post chlorine feed point was selected as the equipment
verification testing location. Therefore, all sample locations designated as feed water during the
ETV were from the combined filter effluent upstream of the post chlorine feed point. All feed
water monitoring samples were collected from a filter effluent sample pump located in the filter
building. The treated water monitoring samples were collected from the sample sink located in
the WTP operators lab. This water is a side stream of the water pumped from the finished water
storage tanks, and therefore has undergone post chlorination and contact time prior to
monitoring.
The summary of the feed water quality information is presented in Table 1-1.
4
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Table 1-1. FeedWater Quality
Total
Alkalinity
(mg/1)
Temperature
C°C)
PH
TDS(1)
(mg/1)
FAC
(mg/1)
Total
Coliform
(mpn/100 ml)
HPC
(cfu/lOOml)
True
Color
(C.U.)
uv254
(cm'1)
Ammonia
(mgNFh-N/l)
Turbidity
bench
(NTU)
Mean
28
11.4
7.00
139
0.36
<1
4
5
0.021
<0.10
0.067
Minimum
15
7.5
6.20
139
0.01
<1
0
5
0.017
<0.10
0.040
Maximum
37
15.1
7.60
139
1.38
<1
73
5
0.023
<0.10
0.100
Standard Deviation
11
1.9
0.32
0
0.24
0
16.5
0
0.003
0
0.017
95% Confididence
28 +
11.4 +
7.00 +
N/A
0.36 +
N/A
4 +
N/A
0.021 +
N/A
0.067 +
Interval
10.4
0.7
0.12
0.06
7.6
0.003
0.006
(1) One Analysis
"<1" was assigned a zero value for the purposes of calculating an average and standard deviation.
N/A = Not Applicable because standard deviation = 0.
1.3.2 Treated Water Discharge
The ClorTec Model MC 100 system at the treatment plant is a permanent installation that has
been granted an operating permit by the Pennsylvania Department of Environmental Protection
(PADEP) to treat raw and finished water. As such, there is no treated water discharge from the
on-site SHG. The softener regenerant wastewater flows to the WTP process wastewater lagoons.
1.3.3 Installation and Start-up
The SHG equipment was installed and started up (run to waste) in December of 1999. Following
the receipt of an operating permit from the PADEP in January of 2000, the SHG equipment was
placed on-line, replacing pre and post gas chlorinators as the source of chlorine. An initial
operations period spanning several months prior to the initiation of the ETV allowed United
Water Pennsylvania staff to optimize the equipment's operations and add system appurtenances
as required for the site-specific characteristics. In addition, initial operations provided "hands-
on" training for the WTP operators. Set points were established and entered into the PLC for
parameters such as high and low tank levels, which enabled automation of the batch system
operating mode.
It was determined during this period of operations that if the brine dilution water temperature
dropped much below 50°F, a sodium hypochlorite concentration of 0.8% was not attainable
regardless how much the amperage and voltage settings were increased within the power
supply/rectifier's range. Subsequently, United Water Pennsylvania staff installed an in-line
water heater that maintains an adjustable minimum dilution water temperature; the temperature is
monitored upstream and downstream of the in-line heater with in-line thermometers. This has
resolved the "cold dilution water" problem, enabling the SHG system to always have the
capacity of producing an 0.8% concentration of sodium hypochlorite within the rectifier power
supply's range.
5
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Chapter 2
Equipment Description and Operating Processes
2.1 Equipment Description
The equipment tested was the ClorTec Model MC 100 system. This system is designed to
produce a 0.8% sodium hypochlorite solution from a 3% sodium chloride solution using an
applied low voltage DC current. The actual concentration of sodium hypochlorite solution
generated is dependent on the temperature and salt concentration of the brine solution, and the
amperage and voltage applied.
The ClorTec Model MC 100 system is designed to produce up to 100 pounds per day (lbs/day)
of sodium hypochlorite as chlorine. The system configuration is modular and consists of three
major components: rack-mounted sodium hypochlorite generator; control cabinet, which houses
the programmable logic controller (PLC) and operator interface terminal (OIT); and power
supply/rectifier. In addition, a brine generation and storage system supplies the feedstock for the
generator. Figure 2-1 presents a schematic of the ClorTec Model MC 100 system and
appurtenances. The major components are described in more detail in the following sections.
2.1.1 Brine Generation and Storage System
The brine solution used for generating sodium hypochlorite is prepared using several stages of
dilution.
2.1.1.1 Softener
ClorTec requires that all brine dilution water be softened to remove minerals that may cause
scaling on the electrolytic plates. The following equipment produced softened water for the
ClorTec Model MC 100 system.
• Two Kinetico Model No. 60 ion exchange modules
° each module is rated for 8.0 gallons per minute (gpm) service flow
° maximum pressure drop: 15 pounds per square inch (psi)
° ion exchange capacity: 3772 grains of hardness per lb of salt
° useable gallons between regenerations: 1,200
2.1.1.2 Cartridge Filters
Cartridge filtration is recommended by ClorTec to prevent debris from fouling downstream
solenoid valves and the brine pump poppet valves. One cartidge filter is located just
downstream of the softener; the other cartridge filter is located just upstream of the brine day
tank influent.
• Cartridge filter porosity: 25 |j,m
6
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Figure 2—1 Schematic of Clortec Model MC100 Sodium Hypochlorite
Generation System and Appurtenances at United Water PA- Hummelstown WTP
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2.1.1.3 Brine Bulk Saturator Tank
The brine bulk saturator tank, which appears in Photograph 2.1,
functions to generate and store 30% brine solution.
• The tank, Beden-Baugh Products Inc. Brinemaster Salt Dissolver,
has the following specifications and appurtenances
o 40 ton salt capacity
o side shell - 16 ft
o diameter - 10 ft
o covered fiberglass reinforced plastic (FRP) tank with 72H
resin interior corrosion barrier
o 1.5 inch thick urethane insulation (bottom six feet of tank)
o 75 feet of heat tracing under insulation (Accutron CW-6,
temperature setting 50°F, 120 VAC)
o brine sight level indicator
o high/normal brine level probes with output signal to PLC
o motorized ball valve and solenoid valve controlled by
PLC (make-up water pipe)
o two inch salt transfer pipe
2.1.1.4 Brine Day Tank
One brine day tank serves as the primary supply of 30% brine for the SHG following transfer
from the saturator tank. The day tank has the following specifications and appurtenances:
• 55 gallon high density polyethylene (HDPE) tank
• tank equipped with ultrasonic level transmitter (Flowline Model LU20) with
output signal to PLC for control of brine supply from saturator tank
2.1.1.5 Sodium Hypochlorite Storage Tanks
The following tanks and appurtenances store the on-site generated sodium hypochlorite:
• two 1,400 gallon HDPE tanks
• each tank is equipped with an ultrasonic level transmitter (Flowline Model LU20)
with output signal to PLC for control of generator batch operation
2.1.2 Sodium Hypochlorite Generator System
The ClorTec Model MC 100 system consists of two electrolytic cells racked horizontally on top
of a steel cabinet which houses one bellows-type brine pump, one solenoid valve, and one
junction box. Mounted on the outside of the cabinet are one flow indicator/transmitter and flow
switch, one rotameter and flow control valve, and one pressure gauge.
f
•Jia
Photograph 2.1
Brine Bulk Saturator Tank
8
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System specifications are as follows:
• Output - 100 lb/day (as chlorine)
• Flow - 62.5 gallons per hour (gph)
(sodium hypochlorite)
• Electrolytic Cells - two @ 50
lb/day production capacity each
(as chlorine)
• Pressure Range - 30 psi to 70 psi
• Water consumption - 1,500 gallons
per day (gpd) Photograph 2.2
• Salt consumptioni - 350 11 v day Softener, PLC, Brine Day Tank and
• Power consumption — 250 kilowatt- Hypochlorite Generator
hours (kWh)/day alternating current
(AC)
• Required power supply - 480 volts (V),
3 phase
• Current draw - 16 amps AC
• Required circuit rating - 30 amps (A)
• Cabinet dimensions - 24 inch width (W) x 18 inch depth (D) x 72 inches height (H).
2.1.2.1 Electrolytic Cells
Each electrolytic cell consists of a 4 inch diameter clear
polyvinyl chloride (PVC) tube that contains an array of ten
pairs of flat-plate anode and cathode electrodes that are
uniformly spaced approximately 1/4 inch apart. The clear tube
allows for viewing the process and the electrode condition.
The cylindrical design permits access to the electrode array,
which can be removed as a single unit. Maximizing the surface
area of the plates lowers current density, resulting in longer
electrode life and lower cell temperature. The electrodes are
made of titanium with proprietary metal oxide and catalytic
precious metal coatings (ruthenium, iridium, platinum) for
electrical efficiency and longevity. Brine solution flows
through the plates where it is subjected to a low voltage direct
current (VDC) to produce sodium hypochlorite and the only
byproduct, hydrogen. The cells are designed for rapid
hydrogen separation to produce maximum gas lift at the
electrode surface and minimize calcification of the electrodes. Photograph 2.3
The cells are in series electrically and hydraulically, so that Sodium Hypochlorite
Cell No. 1 discharges to Cell No. 2. Hydrogen is vented from Generator
the effluent end of Cell No. 2 via a two-inch diameter flexible
hose connected to a PVC pipe which discharges outside the building.
There are two safety devices to protect the electrolytic cells: (1) a level transmitter monitors
the top cell's liquid level, which must be above the electrodes; and (2) a temperature
9
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transmitter monitors the lower cell's temperature, which must be below 122 degrees
Fahrenheit (°F). If either of these parameters is outside its specified limit, the PLC will shut
down the system.
There are three PVC ball valves with barbed tube connections at the base of the cabinet:
1) brine influent feed, 2) acid influent feed, and 3) electrolytic cell drainage.
2.1.2.2 Brine Dilution System
The generator cabinet houses a bellows-type pump that is factory set to deliver the 30% brine at
a flow rate of 0.1 gpm from the day tank to the dilution water blending tee located inside the
generator cabinet. Prior to blending, the softened dilution water is filtered through a 25 micron
cartridge filter, followed by pressure reduction from approximately 80 psi to 60 psi through a
pressure reducing valve (PRV). Prior to entering the SHG cabinet, the dilution water is heated,
as required, with an in-line heater (Controlled Energy Corp., 9500 watts, 240 volts) to maintain a
temperature above 50° F. The dilution water is then blended with the 30% brine at a flow rate of
1.0 gpm dilution water to 0.1 gpm of brine to develop an approximate 3.0% brine solution.
Three gauges are mounted on the front of the generator cabinet. Two gauges monitor dilution
water flow (a flow indicator/transmitter and a rotameter with needle valve), and one gauge
monitors dilution water pressure.
2.1.3 PLC/OIT Control Cabinet
The control cabinet consists of a 316 stainless steel (SS), National Electrical Manufacturers
Association (NEMA) 4X cabinet that houses all control and display functions for the SHG
system. Logic functions are at the PLC level where operating parameters are monitored,
corrected, scaled, reported, and controlled.
A PLC controller monitors and controls each aspect of the system's operation, including:
• Cell Safety Devices
• Rectifier Controls
• DC Amperage and Voltage
• Brine Bulk Saturator and Day Tank Levels
• Sodium Hypochlorite Storage Tank Levels
• Alarm Reset
• Alarm History
• Security Protection
• Hypochlorite Metering Pump Flow Pacing and Measuring
• Salt Usage Log
• Maintenance Log
The PLC has trending capability for five operating parameters:
• Sodium Hypochlorite Storage Tank Level
10
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• Dilution Water Flow Rate
• Chlorine Residual
• Rectifier Amperage
• Rectifier Voltage
The control cabinet also includes an OIT. The OIT provides the following functions:
• Operator Interface
• Alarm Viewer
• Communications Hub
• Data Input Screen
The OIT includes a touch sensitive screen to allow menu scrolling, selection and data entry.
The control system includes safety interlocks that will prevent SHG operation if any of the
following operating parameters fall outside their specified limits:
• Dilution water flow
• Cell high temperature
• Cell low level
• Transformer high temperature
• Cell over-voltage
• Automatic voltage and current regulation
• Hypochlorite storage tank high level
The control system will generate an alarm but will not shut down the SHG system on
hypochlorite storage tank low level.
An uninterruptible power supply (UPS) is housed in the control cabinet to provide constant
power to the PLC so that any fluctuations or brief losses of AC power will not affect the
system's controls. The UPS will provide constant power to the PLC for 15 minutes after
complete loss of 120 VAC power.
2.1.4 Power Supply/Rectifier
The rectifier provides constant current to the electrolytic cells
within specified voltage ranges. Rectifier operation is entirely
controlled by the PLC. The rectifier has the following features:
• 150 Amp Speed Control Rheostat (SCR) Thyristors
• Class H Insulation
• NEMA 1 Enclosure
• Frame Mounted
• PVC Enclosed
• Air Cooled Photograph 2.4
Power Supply/Rectifier
11
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• Emergency Stop
• DC Amp and Volt meters
• 3 Phase Motor Starter
• 4-20 milliAmp (mA) output of Volts and Amps
• Phase Monitoring
• Power and Fault Light
• 480 V Disconnect
The rectifier is compatible with all capacities of the ClorTec series of SHG systems. It has a
voltage range of 25 to 75 volts DC @180 amps.
2.2 Equipment Operations
2.2.1 Brine Generation and Storage System
Salt is conveyed to the brine bulk saturator tank by pneumatic transfer from a delivery truck via a
truck hose connection through a transfer pipe into the top of the tank. A 30% brine solution is
produced in the brine bulk saturator tank by dissolving a solar grade of sodium chloride (that
meets all specifications in ANSI/AWWA Standard B200-98) with WTP finished water that has
undergone softening and cartridge filtration. The brine level in the saturator tank is maintained
below the salt, which assures that a 30% brine concentration is maintained (approximate
solubility of sodium chloride above 50°F is 30%). A two level probe system maintains the brine
depth in the tank within a range set at the PLC by controlling the operation of a solenoid valve
on the softened water supply.
The thermostatically controlled electric heat tracing together with insulation around the bottom
six feet of the tank maintain a minimum water temperature inside the tank of 50°F.
An ion exchange softener treats all of the dilution water supplied to the brine saturator tank. The
softener automatically cycles into backwash, regeneration and rinse following the treatment of an
adjustable preset volume of water.
Brine levels in the brine day tank are measured by an ultrasonic level transmitter mounted on the
top of the tank. Refilling of the day tank occurs automatically; a solenoid valve on the discharge
pipe between the saturator tank and the day tank is controlled by adjustable high and low level
day tank settings in the PLC. When the brine depth drops to the low level setting, the solenoid
valve receives a signal to open, allowing the day tank to fill. When the brine fills to the high
level setting, the PLC controller sends a signal to the solenoid valve to close.
2.2.2 Sodium Hypochlorite Generator System
As stated previously, the 30% brine solution is blended with softened plant treated water at a
ratio of 1:10 (0.1 gpm brine to 1.0 gpm softened water) to produce a brine solution that is
approximately 3% in strength. After dilution, the 3% brine flows through two electrolytic cells
in series where a low voltage DC current from the rectifier is applied to generate approximately
12
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0.8. sodium hypochlorite, with hydrogen gas as a byproduct. The hydrogen is safely vented
outside the building via a two inch PVC pipe.
The SHG system operates in automatic batch mode, activated from a standby mode whenever the
level in either one or both of the sodium hypochlorite storage tanks reaches the adjustable low
level setting in the PLC, based on the tanks' ultrasonic level transmitter readings. The generator
will continue to operate until the sodium hypochlorite level in the storage tanks rises to the PLC
adjustable high level setting, as reported by the ultrasonic level transmitters. A flow
indicator/transmitter on the softened dilution water line sends a signal to the PLC, which will
shut down the generator if dilution water flow is out of range of parameter set points.
The electrolytic cells have two transmitters: one transmitter monitors temperature to protect the
electrodes from temperatures above 122°F; the other transmitter monitors the sodium
hypochlorite level to prevent exposure of the electrodes. Based on settings in the PLC, the
system will be shutdown if either of these conditions occur.
2.2.2.1 Cell Electrode Cleaning
When scaling on the electrodes results in not being able to generate approximately 0.8% sodium
hypochlorite within the specified voltage range, the generator should be taken off line for
cleaning. A weak acid such as muriatic acid is used for removing the scaling. The operator
should have eye and body protection in place before starting the cleaning procedure. The
procedure as presented in the MC Operator Interface PLC Manual is as follows:
1. Turn off the rectifier's disconnect
2. Drain the cells
3. Flush the cells with water by first closing the brine needle valve on the generator
cabinet, followed by filling the cells using the priming mode on the PLC to prime the
bellows pump (the cells should be filled and emptied a minimum of three times
before starting the acid wash)
4. Close the brine valve and open the acid valve on the generator cabinet
5. Connect a piece of 3/8 inch ID tubing to the acid tubing barb and place the other end
of the 3/8 inch tube into a one gallon container of the acid solution
6. Press Start on the PLC and the cell will begin to fill with the acid solution
7. Allow the cells to fill in priming mode to the top cell. Once the acid solution fills the
top cell, press Stop
8. If the cells are not cleaned, drain them and repeat the previous steps as necessary
9. Once the cells are clean, drain the solution
10. Flush the cell by repeating Step 4 with softened dilution water instead of acid
11. After flushing three times, open the brine valve and begin priming the cell
12. Once primed, turn on the rectifier disconnect
13. Press Start and the ClorTec system is back in production
14. Confirm proper voltage on the rectifier
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2.2.3 PLC/OIT
ThePLC-based control system monitors and controls each aspect of the ClorTec Model MC 100
system's operation by processing and reporting operating parameters including process flow,
tank levels, system status and alarm conditions.
The OIT provides the plant operator the capability to access system control settings, view alarms,
and review trending of operations data previously logged.
2.2.4 Power Supply/Rectifier
The rectifier converts AC current to DC current and applies it at a constant rate to the electrolytic
cells within a specified voltage range. The operation is completely controlled by the PLC.
2.3 Advantages and Disadvantages
2.3.1 Advantages of On-Site Sodium Hypochlorite Generation
2.3.1.1 Comparison of On-Site SHG and Commercially Available Sodium Hypochlorite (12% to
15%)
• Stability of sodium hypochlorite is dependent on the following:
hypochlorite concentration, storage temperature, time in storage, impurities in
solution and exposure to light. Decomposition of sodium hypochlorite affects
dosage and feed rate, and the production of undesirable byproducts such as
chlorate ions. Commercially available sodium hypochlorite is more susceptible to
decomposition than on-site SHG. Twelve percent sodium hypochlorite stored for
approximately 30 days under the best conditions will degrade to ten percent.
Since SHG is used almost immediately, it does not have the opportunity to
degrade.
• Commercially available sodium hypochlorite has a pH of 13; on-site SHG has a
pH of 9, and is therefore less likely to cause scaling of feed lines and fittings.
• Storage area requirements are reduced for SHG due to "on-demand" production.
• SHG, due to its low chlorine concentration, does not have the containment
requirements of commercially available sodium hypochlorite.
• Occupational Safety and Health Adminstration (OSHA) Process Safety
Management (PSM) is not required for SHG; commercially available sodium
hypochlorite requires PSM.
2.3.1.2 Comparison of On-Site SHG and Gas Chlorine
• Chlorine gas requires the handling of 150 lb. chlorine cylinders or ton containers;
SHG does not require handling of any containers.
• EPA Risk Management Plan (RMP) or OSHA Process Safety Management PSM
is not required for SHG; Chlorine gas requires EPA RMP and OSHA PSM.
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• Chlorine gas requires isolated containment of its storage and feed facilities; SHG
storage and feed facilities can be located in a common room with other
equipment.
• SHG does not have scrubber requirements, as is required with most gas chlorine
installations. Scrubbing for accidental leak remediation is mandated by the
Uniform Fire Code (Article 80) and EPA's Clean Air Act Amendment (CAAA)
Title III.
• Chlorine gas, at a pH < 1, can have a significant impact on the treated water pH;
SHG, at a pH = 9, has little, if any, impact on treated water quality.
2.3.2 Disadvantages of On-Site SHG
• Higher electrical power required for SHG than chlorine gas or commercially available
sodium hypochlorite.
• Larger capacity metering pumps required for SHG than for commercially available
sodium hypochlorite.
• Dilution water softening and minimum temperature is requirements for SHG.
• Production of hydrogen gas byproduct presents a potential explosive condition if the
SHG system is not properly designed for off-gas.
• Cell descaling is periodically required for SHG.
• Softener brine wastewater disposal is required for SHG.
• Cost of electrode replacement is a consideration for SHG, but not chlorine gas or
commercially available sodium hypochlorite.
• SHG storage area requirements, although less than for commercially available sodium
hypochlorite, are greater than for chlorine gas.
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Chapter 3
Methods and Procedures
3.1 Experimental Design
The experimental design of this verification study was developed to provide accurate information
regarding the performance of the ClorTec Model MC 100 system. Field operations, sampling,
and analytical methodologies were standardized as much as possible to validate collected data.
3.1.1 Objectives
The objectives of this verification testing were to evaluate the performance of ClorTec Model
MC 100 system, specifically relative to ClorTec's stated equipment performance claim and
relative to regulatory requirements. Impacts of feed water quality variations, operational
requirements and maintenance requirements were also evaluated. The details of these
evaluations are presented below.
3.1.1.1 Evaluation of Stated Equipment Performance Claim
ClorTec's stated performance claim was in terms of the concentration of sodium hypochlorite
generated. ClorTec claims their Model MC 100 system is capable of producing sodium
hypochlorite at a concentration of 0.8% ± 0.05% as chlorine, from a 3% brine solution
containing 99.1% pure sodium chloride. Evaluation of this claim was performed by conducting
twice daily analyses of the concentrated sodium hypochlorite generator stream using two
different analytical methods for total chlorine analysis. Once daily monitoring of the actual
sodium chloride concentration was conducted by measuring the specific gravity of the dilute
brine solution.
3.1.1.2 Evaluation of Performance Relative to the EPA Safe Drinking Water Regulations
The sodium hypochlorite generated on-site was evaluated in terms of its effectiveness for
inactivating Total Coliform and Heterotrophic Plate Counts. It was also evaluated for adequacy
of maintaining a chlorine residual in the WTP finished water storage tanks sufficient to achieve
1.0 log inactivation of Giardia cysts post filtration (EPA, 1989). Disinfectant byproducts that
have been selected for regulation under Stage 1 of the promulgated Disinfectant/Disinfectant
Byproduct Rule (D/DBPR) were analyzed to get a "snapshot" of disinfectant byproduct levels
using on-site SHG.
3.1.1.3 Evaluation of Equipment Performance Relative to Feed Water Quality
Water quality upstream of the post sodium hypochlorite feed point was evaluated relative to the
water quality downstream of this feed point to determine the impact of sodium hypochlorite
addition as a chlorine residual disinfectant. Other than chlorine residual, water quality upstream
and downstream of the feed point was not anticipated to vary significantly. A range of feed and
treated water quality parameters were analyzed at a frequency varying from twice daily to once
per test period.
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3.1.1.4 Evaluation of Operational Requirements
An overall evaluation of the operational requirements for the treatment system was undertaken as
part of this verification. The ClorTec's Operater Interface PLC Manual (O&M), and
experiences during the daily operations, were used to develop a subjective evaluation of the
operational requirements of the system.
3.1.1.5 Evaluation of Maintenance Requirements
ClorTec's O&M manual includes a section which presents the primary maintenance items and
the procedures to be followed. Those items that required maintenance during the 30 day ETV
test period have been evaluated.
3.1.2 Equipment Characteristics
3.1.2.1 Qualitative Factors
The following factors were defined by those personnel actually operating and monitoring the
equipment:
• Susceptibility to changes in environmental conditions. The equipment was
monitored to determine what conditions most affected ClorTec's performance
claims. The nature and frequency of the changes required to maintain the operating
conditions were used in the qualitative evaluation of the equipment.
• Operational reliability. Frequent equipment adjustments, particularly those that are
significant, would have indicated relatively lower reliability and higher susceptibility
to environmental conditions. Frequent adjustments would also indicate the degree of
operator experience that may be required. The affect of operator experience with the
ClorTec Model MC 100 system was also evaluated.
• Equipment installation. The degree of difficulty for equipment installation was
evaluated through discussions with the United Water Pennsylvania personnel who
performed the installation. As stated previously, the equipment used for the ETV
test is a permanent installation, and was installed approximately two months prior to
the initiation of testing. Equipment installation can add significantly to overall
project cost and impact the overall effectiveness of operations.
• Raw materials. The "raw materials" used in the process of generating sodium
hypochlorite were evaluated based on a review of "raw material" and equipment
specifications.
• Byproducts. The byproduct(s) of the on-site SHG process were identified and
evaluated in terms of handling and disposal of those byproduct(s), and levels of
specific byproduct(s) through reactions of the generated sodium hypochlorite with
the treated water.
• Equipment Safety. A review of the equipment O&M manual during the ETV testing
period included identification of specific interlocked safety features and precautions.
Some of these safety components were evaluated during the testing.
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3.1.2.2 Quantitative F actors
The following factors of normal ClorTec Model MC 100 system equipment operations were
quantified by various means in this Verification Testing Program:
• Power consumption. The amperage and voltage readings from the rectifier gauges and
PLC display were recorded daily.
• Salt consumption. Daily salt consumption was measured indirectly by daily recording of
softened water flow rate, the specific gravity of the diluted brine, and the daily recording
of the accumulative hours of sodium hypochlorite generation.
• Softened dilution water consumption. The dilution water flow rate, and hours of
generator operation provided a record of softened water consumption.
• Duration and frequency of sodium hypochlorite generation. The hours of generator
operation and sodium hypochlorite storage tank levels were recorded daily.
• Frequency of softener regeneration. The softener regenerations were noted and recorded
when they occurred.
• Estimated labor time for operation and maintenance. The time of operator attention was
recorded daily.
3.1.3 Operating Parameters
In addition to the daily water quality analyses, measurement of the ClorTec Model MC 100
equipment's physical parameters were also recorded on a daily basis. This includes monitoring
brine and sodium hypochlorite storage tank levels, dilution water flow rate, brine specific
gravity, dilution water and brine temperatures, and rectifier amperage and voltage readings.
Table 3-1 presents all of the ClorTec Model MC 100 system operating parameters that were
monitored and recorded during the ETV.
Table 3-1. Operational Parameter Monitoring and Data Collection Schedule
Monitoring
Parameter Frequency Monitoring Method
Feed water flow rate
Brine dilution water flow
Total chlorine concentration
in generator product
Rate of feed stock
consumption
Once per day
Twice per day (adjust
when 10% above or
below target)
Twice per day
Once per day
Sum of individual WTP filter
flow meters
SHG rotameter and PLC/OIT
display of converted signal
transmitted from the SHG
flow indicator
SM 4500-C1 B
SM 4500-C1 F
Record softened dilution water
flow, the specific gravity of
the diluted brine and daily
hours of generator operation.
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Table 3-1. Operational Parameter Monitoring and Data Collection Schedule (cont'd)
Parameter Monitoring Frequency Monitoring Method
Amperage & voltage
Once per day
Gauge readings
Diluted brine specific gravity
Once per day
Hydrometer and one liter
graduated cylinder
Brine remaining in day tank
Once per day
Liquid level and gallon
graduations on side of
tank
Hypochlorite remaining in
Once per day
Liquid level and 10 gallon
storage tanks
graduations on side of tank
Softener waste stream
Once during softener
Grab samples for lab
composition
regeneration
analysis
Softener waste stream flow rate
Twice during test period
Volumetric measurement
("Bucket and stopwatch")
Treated water flow rate
Twice per day
WTP finished water flow
meter
3.2 Health and Safety Measures
3.2.1 Hydrogen Off-Gas
The only byproduct formed during the generation of sodium hypochlorite with the ClorTec
system is hydrogen. The hydrogen gas is contained and vented outside the WTP building via
piping and leak-proof connections from both the generator and sodium hypochlorite storage
tanks. This eliminates the build-up of hydrogen gas in a confined space, which otherwise could
potentially lead to an explosion.
3.2.2 Electrode Cleaners
Cleaning of the generator electrode plates requires a relatively mild acid solution. Protective
clothing and eye protection are recommended when handling even mild acids. Specific
protective equipment recommendations and handling procedures provided in the O&M were
reviewed during the ETV testing period and appear to be adequate.
3.3 Communications, Logistics and Data Handling Protocol
It was essential that Gannett Fleming, as the FTO, coordinate lines of communication due to the
number of participants involved in the test program. Documentation of study events was
facilitated through the use of a logbook, photographs, data spreadsheets, and laboratory chain-of-
custody forms. Data handling is a critical component of any equipment evaluation or testing.
Care in handling data assures that the results are accurate and verifiable. Accurate sample
analysis is meaningless without verifying that the numbers being entered into spreadsheets and
reports are accurate, and that the results are statistically valid.
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3.3.1 Introduction
The data management system used in the verification testing program involved the use of both
custom computer spreadsheet software and manual recording methods for daily logging of
operational parameters. United Water Pennsylvania staff manually recorded daily operating
parameters in the field data logbook. On a weekly basis, designated United Water Pennsylvania
staff entered this data into custom prepared computer spreadsheets. Electronic copies of these
spreadsheets and paper copies of the logsheets were collected by Gannett Fleming personnel on a
weekly basis. Gannett Fleming personnel printed "hard copies" of the spreadsheets and
compared the data entries to the copied logsheet data. Laboratory water quality reports were
submitted to Gannett Fleming by Microbac Laboratories approximately every two weeks. The
laboratory results from these reports were checked, entered into computer spreadsheets and then
rechecked.
3.3.2 Objectives
There were two primary objectives related to data handling. The first objective was to establish
a viable structure for the recording and transmission of field testing data so that Gannett Fleming
would generate sufficient and reliable analytical data for verification purposes. The second
objective was to develop a statistical analysis of the data, as described in the EPA/NSF ETV
Protocol for Equipment Verification Testing for Inactivation of Microbiological Contaminants,
August 1999.
3.3.3 Procedures
Specific established data handling procedures were used for handling all aspects of the
verification data, photographs taken during the study for documentation, the use of chain-of-
custody forms, the gathering of on-line instrument measurements, entry of data into customized
computer spreadsheets, and methods of performing statistical analyses.
These procedures are presented in Section 3.8.3.
3.4 Recording Statistical Uncertainty
For the analytical data obtained during verification testing, 95 percent confidence intervals were
calculated by Gannett Fleming for selected water quality parameters. Water quality parameters
included chlorine residual (both free and total), pH, alkalinity, turbidity, UV254 and HPC.
The consistency and precision of water quality data can be evaluated with the use of the
confidence interval. A confidence interval describes a population range in which any individual
population measurement may exist with a specified percent confidence. The following formula
was employed for confidence interval calculation:
confidence interval = X + t. -1.1 - i. (S/ V«)
where: Xis the sample mean;
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S is the sample standard deviation;
n is the number independent measures included in the data set;
t is the Student's t distribution value with n-1 degrees of freedom; and
oc is the significance level, defined for 95% confidence as: 1 - 0.95 = 0.05.
According to the 95% confidence interval approach, the oc term is defined to have the value of
0.05, thus simplifying the equation for the 95% confidence interval in the following manner:
95% confidence interval = X + t. - 1,0.975
Results of these calculations are expressed as the sample mean plus or minus the width of the
95% confidence interval.
3.5 Verification Testing Schedule
Verification testing activities included equipment verification operations, sampling and analysis.
The test schedule was developed to encompass all of these activities.
The 30 day test was initiated on March 8, 2000, following the receipt of an operating permit by
United Water Pennsylvania for the ClorTec Model MC 100 system from the PADEP, and
completed April 6, 2000.
3.6 Verification Task Procedures
3.6.1 Task 1: Equipment Operation and Disinfectant Production Capabilities
During Task 1, Gannett Fleming evaluated equipment operations and determined the rates of
feed water flow and sodium hypochlorite production concentration for which the SHG system
was designed.
The following are the objectives of this task:
• Establish SHG equipment generation range.
• Define chlorine concentration range and species.
• Document feed water quality.
• Determine power and raw material consumption.
The protocol for start-up presented in Section 5 of ClorTec MC Series Operator Interface
Manual was used and evaluated for initial startup of the ClorTec Model MC 100 system.
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3.6.2 Task 2: Treated Water Quality
Water quality data was collected during the equipment operation test run of Task 1.
The objective of this task was to assess the impact on treated water quality of feeding sodium
hypochlorite generated on-site.
The following sources were characterized for water quality: Feed Water (WTP combined filter
effluent), Concentrated Sodium Hypochlorite Stream, (ClorTec Model MC 100 generated
sodium hypochlorite), Treated Water (WTP finished water) and Softener Regenerant
Wastewater. The feed water, concentrated sodium hypochlorite stream and treated water quality
were characterized by measurement of the parameters listed in Table 3-2. The characteristics of
the feed water are explicitly stated in reporting data from Task 1.
Samples were analyzed on- site, or off-site by Microbac Laboratories, Inc. EPA method numbers
and Standard Methods reference numbers are indicated on Table 3-2 for both the field and
laboratory analytical procedures. All laboratory samples were collected in appropriate
containers, with preservatives, as applicable, prepared by Microbac Laboratories. Chain-of-
custody forms accompanied all samples submitted to Microbac Laboratories.
The ClorTec Model MC 100 system at the Hummelstown WTP is used for both primary and
residual (distribution system) disinfection. Organic and inorganic disinfection byproduct (DBP)
analyses were conducted on an instantaneous basis for both primary and residual disinfection
samples. Samples collected for DBP analyses were collected at the same time as samples for pH,
alkalinity, UV254, turbidity, ammonia, true color, iron and manganese. This places other water
quality results in the context of the water quality parameters that may have an affect on DBP
concentrations.
SDS testing was performed once during steady-state operation of the ClorTec Model MC 100
system. SDS was used to estimate DBP formation in the distribution system including total
trihalomethanes (TTHM), haloacetic acids (HAA5), chlorite and chlorate. Since additional
dosing of the sodium hypochlorite is used for residual disinfection subsequent to primary
disinfection, the SDS method as specified in the EPA ICR Manual was performed by collecting a
sample of the sodium hypochlorite treated water, spiking it with an additional dose of sodium
hypochlorite disinfectant to achieve the Uniform Formation Conditions (UFC), chlorine residual,
and incubating the sample in the dark under UFC.
The following UFC was used for the SDS testing:
Incubation period of 24 + 1 hour
Incubation temperature of 20 + 1.0°C
Buffered pH of 8.0 + 0.2
24-hour chlorine residual of 1.0 + 0.4 mg/1
No comparison of DBP formation between alternate disinfectants was performed.
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Table 3-2. Water Quality Sampling Schedule
Parameter
Frequency
Source
Method
On-Site Analyses
PH
Temperature
Turbidity
Chlorine Disinfectant
Residual
Hydrogen Sulfide
Laboratory Analyses
Alkalinity
TDS
Ammonia Nitrogen
UVA
True Color
Iron
Manganese
Chloride
Bromide
Sodium
Total Coliform Bacteria
HPC
TTHM
HAA5
Chlorite
Chlorate
Daily Feed, Treated, Wastewater1-1 -1
Daily Feed, Treated, Wastewater1-1 -1
Daily Feed, Treated
Twice/Day Concentrated Sodium Hypochlorite Stream,
Feed, Treated, Wastewater1-1-1
Once/Day Feed
Weekly Feed, Treated, Wastewater1-1-1
1/Test Period Feed, Treated, Wastewater1-1-1
Weekly Feed, Treated
Weekly Feed, Treated
Weekly Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
5/Week Feed, Treated
5/Week Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
1/Test Period Feed, Treated
SM4500H+
SM2550B
SM2130B
4500 CI B
4500C1F
4500 CI G
Hach Field Test Kit
Model HS-C (Color chart/
Effervescence of H2S)
SM 2320 B
SM 2540 C
SM4500NHD
SM 5910
SM2120B
EPA 200.7
EPA 200.7
SM4500 C
EPA 300.0
EPA 200.7
SM 9223
EPA 600878017
EPA 524.2
SM 625 IB
EPA 300.0
EPA 300.0
DBP Formation Testing
TTHM
HAA5
Chlorite
Chlorate
1/Test Period Treated EPA 524.2
1/Test Period Treated SM6251 B
1/Test Period Treated EPA 300.0
1/Test Period Treated EPA 300.0
ujSoftener regenerate wastewater
^'Conditions for DBP Formation Testing preparation follow the UFC proposed in the Information Collection Rule.
3.6.3 Task 3: Data Management
The data management system used in the Verification Testing involved the use of custom
computer spreadsheets and a field data logbook.
The following were the objectives of this task:
• Establish a viable structure for the recording and transmission of field testing data by
Gannett Fleming such that sufficient and reliable data are generated for verification
purposes.
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• Develop a statistical analysis of the data as described in the EPA/NSF ETV Protocol For
Equipment Verification Testing of Microbiological Contaminant Inactivation, August
1999.
The field testing operators recorded all operating data and on-site water quality analyses by hand
on a daily daily basis in a field data logbook. The logbook is permanently bound with
consecutively numbered pages. The pages indicate the starting and ending dates that apply to
entries in the logbook. Each page of the logbook has an appropriate heading to avoid entry
omissions. All logbook entries were made in black ink, although permanent ink was not used
due to its tendency to "bleed through" the logbook pages. Corrections in the logbook were made
by placing one line through the erroneous information and initialing by the line. A comments
section was provided in the logbook for each test day to record any testing problems, issues, etc.
The original logbook was stored on site, and was photocopied once per week to provide a backup
record and for transfer of logbook data to Gannett Fleming. This data protocol not only eased
referencing the original data, but offered protection of the original records.
The electronic database for the project was set up in the form of custom-designed spreadsheets.
The spreadsheets are capable of storing and manipulating data for each monitored water quality
and operational parameter from each task, each sampling location, and each sampling time. All
data from the field data logbook was entered into the appropriate spreadsheets. Data entries for
all on-site operating data were conducted by the designated field testing operator. Following
data entry, each spreadsheet was printed out and the print-out was checked against the
handwritten data. Any corrections were noted on the hard copies and corrected on the screen,
and then a corrected version of the spreadsheet was printed out. Each step of the verification
process was initialed by the field testing operator performing the entry or verification step.
Following transmission of spreadsheets and copies of logbook sheets to Gannett Fleming, data
entries were rechecked by the Gannett Fleming project engineer.
Samples for off-site water quality analyses were collected and sent to Microbac Laboratories.
The data were tracked by use of the following abbreviations for the sample locations: feed water-
FW, treated water-TW, softener wastewater-SW. Data from Microbac Laboratories were
received and reviewed by Gannett Fleming. These data were entered into the appropriate lab
spreadsheets, corrected, and verified in the same manner as the field data.
Water quality data from grab sample analyses, collected according to the Water Quality
Sampling Schedule (Table 3-2) in Task 2, were evaluated for statistical uncertainty. For
example, Gannett Fleming calculated the mean values, standard deviations, and 95 percent
confidence intervals for grab sample data obtained during the Verification Testing as described
in the Protocol for Equipment Verification Testing of Microbiological Contaminant Inactivation,
August 1999. Statistical analysis can be carried out for water quality data obtained under a large
variety of testing conditions. The statistics developed will be helpful in demonstrating the
degree of reliability with which the sodium hypochlorite generation system can attain quality
goals.
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3.6.4 Task 4: Quality Assurance/Quality Control (QA/QC)
The objective of this task was to maintain strict QA/QC methods and procedures during the
ClorTec Model MC 100 system Verification Testing program. Maintenance of strict QA/QC
procedures was important in that if a question arises when analyzing or interpreting data, it will
be possible to verify exact conditions at the time of testing.
Equipment flow rates and associated signals were verified and verification recorded on a daily
basis. A twice-daily walk-through during testing was conducted to verify that each piece of
equipment or instrumentation was operating properly. On-line monitoring equipment, such as
flow meters, were checked to verify that the read-out matched with the actual measurement and
the signal being recorded was correct. The QA/QC items listed below were conducted in
addition to any specified QA/QC procedures required with the analytical methods listed on
Table 3-2.
3.6.4.1 Turbidity
• The four on-line filter effluent turbidimeters (feed water turbidity) and the treated water
turbidimeter were calibrated one time at the beginning of the test with formazin
solution (primary standard).
• The bench turbidimeter was calibrated one time at the beginning of test with formazin
solution at the following standards: 0.1 NTU, 0.5 NTU and 5.0 NTU.
• The bench turbidimeter was checked daily with secondary standards.
• The on-line turbidimeter readings were compared with the bench turbidimeter readings
for both feed water and treated water.
• The treated water on-line turbidimeter sample flow rate was checked daily; feed water
on-line turbidimeter sample flow rates were checked one time only, at the beginning of
the test, due to equipment accessibility problems.
3.6.4.2 pH
• The bench pH meter was calibrated daily with certified 7.0 and 10.0 buffer solutions.
The pH probe was stored in the appropriate solution, as defined in the instrumentation
manual.
• The on-line treated water pH meter was calibrated at the beginning of test; the on-line pH
probe was replaced on 3/13/00 and recalibrated; the on-line pH meter was recalibrated
again on 3/15/00.
• The on-line treated water pH readings were compared with bench pH analyses of treated
water.
3.6.4.3 Chlorine Residual
• The total chlorine analyses of the hypochlorite generator stream were conducted twice
daily with two different method analyses, SM 4500-C1 B and SM 4500-C1F.
• The twice daily on-line free chlorine readings of treated water were compared with
treated water grab samples analyzed for free chlorine.
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• The twice daily on-line free chlorine readings of feed water were compared with treated
water grab samples analyzed for free chlorine.
3.6.4.4 Temperature
• The on-line temperature readings of the treated water were compared with treated water
grab samples checked for temperature, using a NIST-traceable thermometer.
• The on-line temperature readings of the heated dilution water were compared with the
temperature of heated dilution water grab samples using a NIST-traceable thermometer.
3.6.4.5 Brine Dilution Water Flow
• The dilution water flow rate was measured continuously with two different instruments
mounted on the generator cabinet: 1) a rotometer reading in units of gpm, and 2) a sight
flow instrument that transmitted rpm to the PLC which converted this signal to milliliters
per minute. The flow rates from these instruments were recorded by hand at the same
time on a daily basis, (calibration with "bucket and stopwatch" was not done for either
instrument due to the difficulty involved in disconnecting plumbing).
• The treated water flow meter was calibrated once at the beginning of the test as indicated
in Appendix G.
3.6.4.6 Power
• The amp and volt readings were recorded from the PLC display daily, and compared to
local readings on gauges mounted on the rectifier.
3.6.4.7 Softener Regeneration Wastewater Flow Rate
• The softener wastewater flow rate was calculated based on the time of regeneration and
the collection of the wastewater in a polyethylene drum with gallon graduations.
3.6.4.8 Diluted Brine Concentration
• The brine solution diluted in the ratio of 1:10 with softened water was checked daily for
specific gravity and temperature using a hydrometer and NIST-traceable thermometer.
This information together with the chart in Appendix A was used to determine actual
diluted brine concentrations.
3.6.4.9 Equipment Tubing and Connections
• All tubing and connections were checked daily for leaks.
3.6.4.10 Sodium Hypochlorite Metering Pumps
• Prechlorine and post chlorine metering pumps were checked once daily for calibration
using "stopwatch and calibration tube".
26
-------
When results of the twice-daily, daily, bi-weekly and one time equipment monitoring indicated
possible questionable data results, the data was rejected and resampling occurred.
3.6.4.11 Chemical and Biological Samples Shipped Off-Site for Analyses
Microbac Laboratories was used for the analysis of off-site chemical and biological parameters.
As a Pennsylvania-certified laboratory for drinking water, it follows all preservation, delivery,
hold time and analytical procedures contained in either Standard Methods for the Examination of
Water and Waste Water, 18th or 19th Edition (1992, 1995) or Methods for Chemical Analysis of
Water and Wastes (1979). Sample collection was performed by either United Water
Pennsylvania operations staff or the Gannett Fleming engineer providing ETV supervision.
3.6.4.11.1 Organic Parameters. Organic parameters analyzed during the verification testing
were true color, UVA254, TTHM and HAA5. (Sample bottles left on-site for laboratory TOC
analysis were used by United Water Pennsylvania staff for non-ETV sampling and,
inadvertently, were not replaced; TOC samples were never collected). Samples for analysis of
true color and UVA254 were collected in glass bottles supplied by Microbac Laboratories and
hand-carried to the Laboratory by Gannett Fleming personnel immediately after collection. True
color and UVA254 samples were collected, preserved, held and analyzed in accordance with
Standard Methods 2120B and 5910, respectively. Storage time before analysis was minimized
in accordance with Standard Methods.
Samples for analysis of TTHM and HAA5 were collected in glass vials with teflon caps supplied
by Microbac Laboratories and hand-carried to the laboratory by Gannett Fleming after
completion of SDS testing. TTHM and HAA5 samples were collected, preserved and held in
accordance with EPA method 524.2 and Standard Method 625 IB, respectively.
3.6.4.11.2 Microbiological Parameters. Microbiological parameters analyzed during the
verification testing were Total Coliform and HPC. HPC and Total Coliform samples were
collected, held and analyzed according to procedures outlined in EPA Method 6008780017 and
Standard Method 9223, and hand-carried to the laboratory by a Microbac Laboratories
representative.
3.6.4.11.3 Inorganic Parameters. True color and UVA254 samples were collected, preserved,
held and analyzed in accordance with Standard Methods 2120B and 5910, respectively.
Inorganic chemical samples alkalinity, ammonia nitrogen, chloride and TDS were collected,
preserved and held in accordance with Standard Methods 2320B, 4500 NHD, 4500 C and 2540
C, respectively.
Inorganic chemical samples bromide, chlorate and chlorite were collected, preserved and held in
accordance with EPA Method 300.0.
Inorganic chemical samples iron, manganese and sodium were collected, preserved and held in
accordance with EPA Method 200.7.
27
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Chapter 4
Results and Discussions
4.1 Introduction
The ETV testing for the ClorTec MC 100 system was initiated on March 8, 2000 and concluded
on April 6, 2000.
The verification testing site was United Water Pennsylvania's Hummelstown WTP, located in
the Borough of Hummelstown, Pennsylvania. The equipment was located in the chemical room
of the WTP.
This section of the verification report presents the results of the testing and offers discussion of
the results. Results and discussions encompassed the concentration of sodium hypochlorite
generated, feed and treated water quality, and equipment characteristics. QA/QC procedures are
also presented in this section of the report.
4.2 Verification Task Results
4.2.1 Task 1: Equipment Operation and Disinfectant Production Capability
The SHG system operated in auto batch mode. Daily operations consisted of monitoring the
SHG system, conducting on-site water quality analyses, and recording equipment operating data.
Daily operating data recorded for the entire 30-day verification test are presented in Appendix C.
4.2.1.1 Range of Treated Water Flow Rates
The treated water flow varied between 1075 gpm and 1893 gpm over the 30-day test period, with
a mean of 1419 gpm. Treated water flow rates recorded twice daily are presented on Figure 4-1.
4.2.1.2 Range of Chlorine Concentrations in Generator Stream
The total chlorine concentration in the sodium hypochlorite generator stream was analyzed using
two different methods of chlorine analysis, Standard Methods (SM) 4500-C1 B and SM4500-C1
F. The generator stream average total chlorine concentration using either chlorine method was
essentially the same, 0.90% for SM4500-C1 B and 0.91% for SM4500-C1 F. Standard Method
4500-C1 F, which is the EPA-approved method required for this testing, had a slightly greater
total chlorine variability then occurred with SM4500-C1 B. A comparison of the daily results
from the two methods is presented on Figures 4-2 and 4-3. Table 4-1 presents a summary of the
results.
28
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WTP Finished Water Flow Meter - Twice Daily Readings
3/8/00 to 4/6/00
2000
1800
1600
? 1400
a
3 1200
« 1000
K
£ 800
600
400
200
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Figure 4-1. ETV Treated Water Flow Rate Flow Reading Number
ClorTec On-Site Sodium Hypochlorite Generation System
3/8/00 to 4/6/00
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
i.
©
CS
u
0)
c
o
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59
Sample Number*
.(i)
(1) Samples collected twice per day for total
chlorine analysis using two different methods,
SM4500-C1 B and SM 4500-C1 F
SM 4500-C1 B
SM 4500-C1 F
Figure 4-2. Hypochlorite Generator Chlorine Concentration
29
-------
The greater variability in results for SM4500-C1 F is probably due to the significant potential for
error in sample dilutions that are required as part of this procedure (see "Testing Procedures for
High Chlorine Concentrations" in Appendix B).
Table 4-1. On-Site Chlorine and Brine Analyses
Treated Water
Hypochlorite Generator
Brine
FAC
FAC
TAC
TAC
TAC
FA§1)
On-Line
FA§1)
FA§1)
Iodo(2)
NaCl
Temp.
(mg/1)
(mg/1)
(mg/1)
(%)
(%)
(%)
Sp. Gr.
(°C)
Mean
1.33
1.23
1.46
0.91
0.90
3.53
1.024
24
Minimum
1.05
1.00
1.00
0.80
0.78
3.04
1.020
18
Maximum
1.80
1.69
2.00
1.11
0.97
3.90
1.026
27
Standard Deviation
0.17
0.16
0.22
0.08
0.04
0.23
0.002
1.9
95% Confidence
1.33 +
1.23 +
1.46 +
0.91 +
0.90 +
3.53 +
1.024+
24 +
Interval
0.04
0.04
0.05
0.02
0.01
0.08
0.001
0.68
(1) FAS = Ferrous Ammonium Sulfate Titration (Standard Method 4500-C1 F)
(2) Iodo = Iodometric Titration (Standard Method 4500-C1 B)
FAC=Free Available Chlorine
TAC=Total Available Chlorine
The results of the total chlorine analyses of the hypochlorite generator stream using the two
chlorine analysis methods are compared to the diluted sodium chloride (NaCl) concentration in
percent on Figure 4-3. There appears to be a rough correlation between the sodium chloride
concentration and the chlorine concentration.
s
•e
o
2
u
=
o
ClorTec On-Site Sodium Hypochlorite Generation System
3/8/00 to 4/6/00
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
A A A
A A
A a A £ £ A_
&-A-
3.5 £
3 ;
2.5 -1
o
2 2
U
1.5 g
1
0.5
0
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58
Sample Number
¦s
o
-------
target range stated in the ClorTec MC Operator Interface PLC Manual of approximately 1.023
to 1.025. A NIST-traceable thermometer was used to measure the temperature of the brine. The
average brine temperature of 24°C (76°F) was in the acceptable range of greater than 50°F and
less than 80°F. These measurements were used with the chart in Appendix A to determine the
percent sodium chloride.
Figure 4-3 presents a trend of erratic but generally increasing sodium chloride concentrations;
the total chlorine levels in the concentrate stream generally correlated with this trend. If the
average generator chlorine concentration of 0.91% is adjusted by the target sodium chloride
concentration of 3.00% divided by the actual average sodium chloride concentration of 3.53%,
the average adjusted total chlorine concentration is 0.77%, which is within ClorTec's
performance claim. This assumes a linear relationship between sodium chloride concentration
and generator hypochlorite concentration, which cannot be determined from the data presented
on Figure 4-3. Since the dilution water flow of 1.0 gpm was generally confirmed with two
different flow meters, the bellows pump was probably delivering brine at a rate higher than the
0.1 gpm specified, producing sodium chloride and chlorine concentrations above the targeted
levels.
The percent sodium chloride concentration is compared to the dilution water flow rate on Figure
4-4.
¦o
o
2
U
¦s
o
-------
4.2.1.3 Range of Treated Water Chlorine Residuals
The mean values for free and total chlorine residual in the treated water using SM 4500-C1 F
were 1.32 mg/1 and 1.46 mg/1, as presented on Table 4-1. Free chlorine was greater than 90% of
total chlorine due to the majority of the chlorine demand having been removed and/or satisfied
with prechlorination, coagulation, clarification and filtration.
In addition to the bench analyses, treated water free chlorine was also monitored with an on-line
chlorine residual analyzer. Data from this instrument were recorded at the same time that grab
samples were collected for chlorine residual analysis. The average of recorded on-line analyses
was around 10% less than the grab sample analyses.
The WTP post sodium hypochlorite metering pump was manually adjusted to account for
changes in WTP flow and feed water quality in order to maintain a treated water free chlorine
residual between 1.0 mg/1 and 2.0 mg/1.
The minimum and maximum daily feed rates of post sodium hypochlorite during the test period,
presented on Table 4-2, were approximately 14 lbs/day and 39 lbs/day, respectively. Since the
SHG system supplies both the pre and post chlorine feed requirements, the system appears to be
adequately sized at 100 lbs/day, with 100% redundancy in the event that one of the two 50 lb/day
electrolytic cells should fail.
Table 4-2. Total Chlorine Analyses and Sodium Hypochlorite Feed Rates
WTP Post
Treated
Sodium
Feed
Water
Treated
Sodium Flypochlorite Generator
Flypochlorite
Water TAC
TAC
Water
TAC
Metering Pump
FAS(1)
FAS(1)
Flow
FAS(1)
Feed Rate
(mg/1)
(mg/1)
(spm)
(%)
(mg/1)
(ml/min)
Mean
0.51
1.46
1419
0.91
9,160
781
Minimum
0.08
1.14
1075
0.80
8,000
500
Maximum
1.58
2.00
1893
1.11
11,100
1210
Standard Deviation
0.29
0.22
346
0.08
748
189
95% Confidence Interval
0.51±0.07
1.46±0.05
1419± 124
0.91± .02
9160±265
781+68
TAC=Total Available Chlorine
(l)FAS=Ferrous Ammonium Sulfate Titration (SM4500-C1F)
N/A=Not Applicable because standard deviation=zero
4.2.1.4 Softener Wastewater Characterization
An ion exchange softener was used to treat dilution water for the brine saturator tank and water
used for dilution of the 30 percent brine solution. The softener required regeneration, and was
based on the volume of water softened. Regeneration was completely automated.
The frequency of softener regeneration and the consequent discharge of regenerant wastewater
was dependent on the daily operating time for the SHG system. If WTP production rate was at
the higher end of the range that occurred during the test period, daily softener regeneration was
required. Otherwise, softener regeneration occurred every two to three days. The water quality
of regenerant wastewater, presented on Table 4-3, was characterized as being of relatively low
pH, averaging less than 6.5, and low alkalinity, approximately 24 mg/1. This compares with the
unsoftened feed water pH of 7.0 and alkalinity of 30 mg/1. The result of the only analysis for
32
-------
TDS of the regenerant wastewater was 7,785 mg/1, an indication of very high dissolved mineral
concentration, in comparison with one unsoftened feed water sample TDS analysis of 139 mg/1.
Table 4-3. Softener Regenerant Wastewater Quality
Alkalinity
FAC
TAC
(mg/1
TDS
Bromide
Temp.
FA^2)
fa^2)
CaC03)
(mg/1)
(mg/1)
PH
(°C)
(mg/1)
(mg/1)
Mean
24
7,785
NA(1)
6.5
12.4
1.71
2.07
Minimum
17
7,785
NA
5.8
9.2
0.25
0.50
Maximum
31
7,785
NA
7.4
17.3
9.00
9.30
Standard Deviation
7.0
0
NA
0.41
2.16
2.05
2.39
95% Confidence Interval
24 + 8
N/A
NA
6.5 + 0.2
12.4+1.03
1.71 +0.95
2.07+1.10
(1)Bromide could not be analyzed due to masking by high chloride concentration.
(2)FAS=Ferrous Ammonium Sulfate Titration (Standard Method 4500-C1 F).
NA=Not Analyzed
N/A=Not Applicable because standard deviation=0
The softener regenerated at a flow rate of 2.85 gpm for approximately ten minutes to produce a
total regenerate wastewater volume of around 30 gallons per regeneration. Although the
concentration of TDS is very high, the volume of wastewater is insignificant relative to the
quantity of process wastewater in the WTP wastewater lagoons. Dilution in the lagoons should
result in a negligible increase in TDS in the lagoon NPDES discharge. Therefore, no special
handling of this regenerant wastewater is anticipated.
4.2.1.5 Feed Stock Consumption
Feed stock consisted of a solar grade salt and softened water used to dilute the salt into a brine
solution. An analysis of the salt used in the ETV test indicated it was 99.0% pure sodium
chloride; the calcium concentration was less than 0.23% (see Appendix H). The calcium
concentration is important due to the scaling effect it can have on the generator electrode plates.
Despite the low to moderate level of hardness in the feed water, the WTP treated water used for
brine dilution must be softened to minimize the calcium concentration. Table 4-4 presents a
summary of daily consumption of salt and softened water for the 30 day test period.
Table 4-4. Daily Feed Stock Consumption
Total
Generator
Softened
Operating Time
Water
Salt
(min)
(gpd)
(lbs)
Mean
790
842
247
Minimum
180
189
59
Maximum
1500
1681
481
Standard Deviation
280
299
91
95% Confidence Interval
790+119.6
842+131.7
247+37.9
4.2.1.6 Power Consumption
Power consumption was recorded daily for voltage and amperage, which was displayed locally
on the power supply/rectifier, and remotely on the PLC cabinet LCD screen. Summary data for
these recordings are presented on Table 4-5.
33
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Table 4-5. Daily Power Consumption
Amperage
Voltage
Rectifier
PLC
Rectifier
PLC
(amps-DC)
(amps-DC)
(volts)
(volts)
Mean
183
184
46
46
Minimum
170
183
45
45
Maximum
185
185
48
48
Standard Deviation
4.6
0.5
0.8
0.8
95% Confidence Interval
183+1.6
184+0.2
46+0.3
46+0.3
The Clor Tec MC Operator Interface Manual states that for Model MC 100 the voltage and
amperage should be approximately 48 volts and 185 amps. The average voltage and amperage
results during the ETV are within 4% and 2%, respectively, of these levels.
4.2.2 Task 2: Water Quality
As stated previously, the feed water treated by the SHG system was surface water that had
undergone prechlorination supplied by the same SHG system, followed by coagulation,
clarification and dual media granular filtration. As a result, the feed water turbidity was low,
averaging 0.06 NTU during the verification testing. A free chlorine residual was maintained in
the feed water, averaging 0.36 mg/1 during the test period. Due to the high quality filtered water
and the chlorine demand having been satisfied with prechlorination, the addition of post sodium
hypochlorite provided a free available chlorine residual for achieving compliance with CT
requirements under the EPA Surface Water Treatment Rule (SWTR), and provide a residual
disinfectant throughout the distribution system.
4.2.2.1 On-Site Analytical Results
Table 4-6 summarizes the results of on-site analytical testing for the 30 day verification test. The
only change in water quality of any significance between the feed water and treated water was
the concentration of chlorine. The addition of post sodium hypochlorite resulted in an average
total chlorine concentration of 1.46 mg/1, an increase of 0.95 mg/1 over feed water total chlorine
level. As stated previously, the treatment prior to post sodium hypochlorite either removed or
satisfied almost all of the chlorine demand, resulting in post chlorine being available largely as
free chlorine.
Sodium hypochlorite had no impact on the pH of the treated water due to the insignificant
quantity fed relative to the treated water flow.
Sodium hypochlorite had no effect on the turbidity level in the treated water. Turbidity averaged
0.06 NTU in both the feed and treated water.
Hydrogen sulfide was not detected in the feed water. The minimum method detection level was
0.1 mg/1.
34
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Table 4-6. On-Site Water Quality Analyses
Feed Water
^Filter Rnnm PnmneH Samnlftl
Turbidity
Bench Bench
Bench Temp. Bench On-line H2S
pH (°Q (NTU) (NTU) (mg/1)
On-line TAC
FAC FAS])
(mg/1) (mg/1)
Treated Water
("Finished Water - T.ah Sinlcl
Turbidity
On-
line
pH
Bench
Bench Temp.
PH (°C)
Bench
(NTU)
On-line FA&]) line FAS(1)
(NTU) (mg/1) (mg/1) (mg/1)
Hypochlorite
Generator
TAC
FAS-1' Iodo(2)
(%) (%)
Mean
Minimum
Maximum
Standard
Deviation
95%
Confidence
Interval
7.0
6.2
7.6
11.4
7.5
15.1
0.067
0.040
0.100
0.060
0.040
0.094
0.36 0.51
0.01 0.08
1.38 1.58
0.067+ 0.060+
0.24
0.36+
0.06
0.29
0.51 :
0.90
0.80
1.11
0.89
0.78
0.97
0.90+ 0.89+
0.02 0.01
(1)FAS=Ferrous Ammonium Sulfate Titration (Standard Method 4500-C1 F)
(2)Iodo=Iodometric Titration (Standard Method 4500-C1B)
FAC=Free Available Chlorine
TAC=Total Available Chlorine
N/A=Not Applicable because standard deviation=0
4.2.2.2 Feed and Finished Water Testing Results
Six inorganic contaminants commonly found in water supplies, presented on Table 4-7, were
analyzed in the feed water and treated water once during the test period. Iron, manganese and
bromide were below detection limits in both the feed water and treated water. TDS, sodium and
chloride were approximately 10 percent higher in the treated water relative to the feed water.
This is likely due to the addition of sodium hypochlorite to the feed water process. The TDS of
the softener wastewater was much higher than the feed water due to the removal and
concentration of dissolved minerals in the softener treatment process.
Table 4-7. Feed, Treated, and Softener Water Quality -
Laboratory Analyses
Feed Treated Softener
Parameter Water Water Wastewater
TDS (mg/1)
139
147
7,785
Iron (mg/1)
<0.03
<0.03
NA
Manganese (mg/1)
<0.01
<0.01
NA
Chloride (mg/1)
23.8
27
NA
Bromide (mg/1)
<0.02
<0.02
NA
Sodium (mg/1)
11.6
13.3
NA
NA=Not Analyzed
Tables 4-8 and 4-9 present the results of weekly feed water and treated water analyses for
alkalinity, ammonia, UV254 and true color. The presence of ammonia can have a significant
impact on disinfection due to the demand it places on chlorine. No ammonia was detected in
either the feed water or treated water.
The impact of feeding sodium hypochlorite on the alkalinity level was negligible. Feed water
and treated water alkalinity levels were essentially the same.
35
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Table 4-8. Weekly Feed Water Quality - Laboratory Analyses
Alkalinity Ammonia UV254 True Color
(mg/1 CaC03) (mg NH3-N/L) (cm1) (C.U.)
Mean 28 <0.10 0.021 5
Minimum 15 <0.10 0.017 5
Maximum 37 <0.10 0.023 5
Standard Deviation 11 0 0.003 0
95% Confidence Interval 28 + 10.41 N/A 0.021 + 0.003 N/A
N/A=Not Applicable because standard deviation=0
Table 4-9. Weekly Treated Water Quality - Laboratory Analyses
Alkalinity Ammonia UV254 True Color
(mg/lCaC03) (mg NH3-N/L) (cm1) (C.U.)
Mean
30
<0.10
0.020
5
Minimum
23
<0.10
0.016
5
Maximum
37
<0.10
0.023
5
Standard Deviation
7
0
0.003
0
95% Confidence Interval
30 + 7.12
N/A
0.020 + 0.003
N/A
N/A=Not Applicable because standard deviation=0
UV254 and true color are parameters commonly used as indicators of the relative concentration of
natural organic matter (NOM). UV254, in particular, is used to measure the humic portion of
NOM. The primary significance of NOM is as potential precursors to disinfection byproducts
(DBP) when combined with a disinfectant such as chlorine; the humic portion of NOM contains
the majority of the DBP precursors.
The levels of UV254 and true color were low, with no apparent difference between the feed water
and treated water.
4.2.2.3 Microbiological Results
Total coliform, indicator bacteria for potential fecal contamination, and heterotrophic plate count
(HPC), a general indicator for total bacterial levels, were sampled five days per week for the test
period. A summary of sampling results is presented on Table 4-10.
There were no positive indications for the presence of Total Coliform in either the feed water or
treated water.
Two feed water samples and three treated water samples were positive for HPC. United Water
Pennsylvania staff were contacted concerning these positive samples. A review of the WTP
operating records did not indicate any shutdown of the SHG or its metering pumps at the time of
HPC sampling. There is also no indication in the ETV field logbook of any shutdown of the
disinfection system. The most likely cause of the HPC positives is improper sampling technique,
i.e. contaminating the mouth of the sample bottles, perhaps through contact with the sampler's
hands.
36
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Table 4-10. Daily^ Bacteria - Laboratory Analyses
Feed Water
Treated Water
Total
Total
Coliform
HPC
Coliform
HPC
(mpn/100 ml)
(cfu/ml)
(mpn/100 ml)
(cfu/ml)
Mean
<1
4
<1
7
Minimum
<1
0
<1
0
Maximum
<1
73
<1
71
Standard Deviation
0
16.5
0
19.9
95% Confidence Interval
N/A
4 + 7.6
N/A
7 + 9.2
"<1" assigned a value of zero for purposes of statistical ca
(l)Samples collected 5 days per week.
culations.
4.2.2.4 Disinfectant Byproducts
Organic and inorganic disinfectant byproducts are presented on Table 4-11 and Table 4-12.
Table 4-11. Organic Disinfectant Byproduct Analyses
F eed W ater T reated W ater
Parameter (mg/1) (mg/1)
TTHM - Inst.
0.0140
0.0160
HAA5 - Inst.
0.0060
0.0187
TTHM - SDS
NT
0.0390
HAA5- SDS
NT
0.0277
Inst. =Instantaneous
SDS=Simulated Distribution System
NT=Not Tested
Table 4-12. Inorganic Disinfectant Byproduct Analyses
Feed Water Treated Water
Parameter (mg/1) (mg/1)
Chlorite-Inst.
<0.02
<0.02
Chlorate-Inst.
0.081
0.112
Chlorite-SDS
NT
<0.02
Chi orate-SDS
NT
0.262
Inst. =Instantaneous
SDS=Simulated Distribution System
NT=Not Tested
As indicated on Table 4-11, instantaneous analyses were conducted on both the feed water and
treated water samples for TTHM and HAA5. DBP levels were anticipated to be higher in the
treated water relative to the feed water due to the addition of post sodium hypochlorite and the
additional contact time in the WTP finished water storage. As expected, TTHM and HAA5
37
-------
levels were higher in the treated water TTHM levels increased slightly, whereas HAA5 levels
increased by a factor of three.
A portion of the treated water sample was subject to UFC, as defined under the EPA Information
Collection Rule, for the purpose of producing SDS samples under equivalent conditions. These
conditions resulted in a three-fold increase in TTHM and 30 percent increase in HAA5.
Table 4-12 presents the results for the inorganic DBP analyses, chlorite and chlorate. As with
the organic DBP, instantaneous samples were collected for the feed and treated water. The
promulgated D/DBPR has an MCL of 0.8 mg/1 for chlorite. Chlorite was not detected in either
sample. Chlorate was detected in both the feed water and treated water. SDS conditions resulted
in a doubling of the instantaneous chlorate level to 0.262 mg/1. There are presently no proposed
regulations for chlorate.
Actual SDS conditions that occurred during the testing are presented on Table 4-13.
The pH values are outside the UFC pH range due to poor buffering (low alkalinity) in the treated
water. Before the start of the incubation period, each bottle was adjusted to a pH of 8.0 with
caustic soda.
Table 4-13. Simulated Distribution System Test Conditions
Incubation
Chlorine
Incubation
Time
Chlorine
Residual
Temperature
Bottle No.
(hrs)
Dose (mg/1)
(mg/1)
(°C)
pH
1
24
0.0
0.64
20.8
7.6
2
24
0.3
0.95
20.8
7.6
3
24
0.6
0.82
20.7
7.3
Another disinfectant byproduct of ongoing concern with the use of on-site generation of sodium
hypochlorite is bromate. Bromate will be regulated under Stage 1 of the D/DBPR with an MCL
of 0.01 mg/1.
Although the ETV protocol did not require analysis of bromate, bromide, the precursor of
bromate, was required. No bromide was detected in either the feed water or treated water, or in
the chemical analysis of the sodium chloride used.
4.2.3 Task 3: Data Management
All on-site operating data other than chlorine analyses was entered into the field logbook daily;
chlorine analyses were analyzed and recorded twice daily.
Most corrections to logbook errors were made properly by first drawing one line through the
error and initializing beside it. Some errors had more than one line drawn through them. There
were a few data errors that had a line drawn through them but were not initialized.
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Data were entered into summary spreadsheets once a week by the designated United Water
Pennsyvania field testing operator. The spreadsheets were printed and checked versus the
logbook, but were not initialized by the field testing operator. The spreadsheets were either
emailed or faxed to Gannett Fleming. Gannett Fleming performed a check of all data collected
in the logbook and entered into the spreadsheets. Incorrect data in the spreadsheets were
corrected.
4.2.4 Task 4: Quality Assurance/Quality Control (QA/QC)
4.2.4.1 Turbidimeters
The treated water on-line turbidimeter sample flow rate was checked daily. The average sample
flow rate was 380 ml/min, within the manufacturer's specified range of 250 to 750 ml/min. Six
sample flow rate checks were less than 250 ml/min.
All on-line turbidimeter readings were checked twice daily versus bench turbidimeter readings of
grab sample. The average feed water bench turbidity readings were 0.07 NTU, 14% greater than
the on-line readings (0.06 NTU); this may have been due the bench turbidimeter cuvette glass
contributing to the turbidity readings.
The treated water grab and on-line turbidity readings, although not always identical, had the
same average and standard deviation.
4.2.4.2 pH Meters
The on-line treated water pH meter was compared with a bench pH meter that was calibrated
daily. There was a one percent difference in the average readings between these instruments.
4.2.4.3 Chlorine Residual Analyzers
The sample water for the on-line analyzer filled a container in a batch operation; there was no
sample flow rate to check.
Readings from the on-line analyzers were checked twice daily versus bench chlorine analyses.
For the treated water the on-line readings on average were 8% less than the bench analyses for
the treated water.
Two methods of chlorine analysis, SM 4500 Cl-B and SM 4500 Cl-F, were used to analyze the
hypochlorite stream for total chlorine. Using SM 4500-C1 F, the average total chlorine residual
was 1% higher than with SM 4500-C1 B; the standard deviation SM 4500-C1 F was greater than
with SM 4500-C1 B. This possibly indicates that SM 4500-C1 F may be more prone to error by
the analyst than SM 4500-C1 B.
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4.2.4.4 Generator Dilution Water Flow Meters
The two flow meters were not checked for calibration using the "bucket and stopwatch" method
due to difficulties in "breaking" the plumbing; the readings from these meters averaged within
3% of each other, which provided a level of confidence in the accuracy of their readings.
4.2.4.5 WTP Flow Meters
Copies of certificates of calibration for the WTP flow meters are found in Appendix C. A
comparison of flow readings for the sum of the four filter flow meters and the finished water
flow meter is presented in Appendix C. There is not always close agreement between these two
readings because the actual flows pumped from the finished water tanks relative to the flows into
the tanks was not always the same.
4.2.4.6 Microbac Laboratories
All Microbac Laboratories analyses followed either Standard Methods for the Examination of
Water and Waste Water, 18th or 19th Edition (1992, 1995) or Methods for Chemical Analysis of
Water and Wastes (1979) for sample collection, preservation, hold time and analytical
methodology.
4.2.4.7 On-Site Inspection
Ms. Carol Becker of NSF International performed an inspection of the Gannett Fleming ETV
program at Hummelstown, Pennsylvania on March 15, 2000. Several corrective actions were
discussed during the inspection and implemented as a result of the inspection.
4.3 System Operation
The SHG batch mode of operation was effectively controlled by the sodium hypochlorite storage
tank levels together with the PLC. When the liquid level dropped to the low level setpoint, the
SHG system was activated from standby mode to generate sodium hypochlorite. When the
liquid level rose to the high level setpoint, the SHG was deactivated, returning to standby mode.
The number of SHG continuous hours of operation was contingent on the raw water quality and
the WTP production, and varied from 3 hours to 25 hours with an average of 13 hours. The
hypochlorite metering pumps typically had to be adjusted manually several times daily to
account for these operating variables (there was no pacing system for the metering pumps).
The brine day tank was filled with 30% brine from the saturator tank in a batch mode of
operation. The day tank has a level transmitter that relays a 4-20 mA signal back to the PLC,
which converts the signal into a continuous reading of brine depth. This level was compared to
operator entered high and low day tank level setpoints. When the liquid level dropped to the low
level setpoint, the PLC controller activated the solenoid valve on the influent line to open,
allowing the brine to flow into the day tank. When the brine level in the day tank rose to the
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high level setpoint, the PLC controller deactivated the solenoid valve, stopping the flow of brine
from the saturator tank into the day tank.
A level probe system on the brine bulk saturator tank would normally maintain a water level that
at all times is contained within a heated/insulated portion of the tank, and above the normal level
probe. This assures that 30% brine concentration is maintained, the maximum solubility of
sodium chloride when the dilution temperature is maintained above 50°F. This system was not
operational during the ETV; the saturator tank had to be resupplied with softened water by
manually opening a 3-way ball valve to bypass the solenoid and motor-operated valves.
No adjustments were made to the SHG dilution water flow, voltage or amperage during the ETV
because these parameters and the brine specific gravity were within the ranges specified in the
ClorTec MC Operator Interface PLC Manual.
It is stated in the ClorTec MC Operator Interface PLC Manual that the bellows pump is factory
set. Therefore, no attempts were made to adjust the rate of this pump.
None of the safety lock-out features were tested since the FTO did not want to interfere with
normal WTP operations.
4.4 Maintenance
There were a few items that required maintenance during the ETV, none of which directly
involved the ClorTec MC 100 system:
• One of the two ion exchange (softener) cylinders developed a leak and was promptly
replaced by the manufacturer.
• The one inch feed line (black plastic) on the pre-hypochlorite metering pump developed a
pin hole leak.
• The treated water on-line pH probe required replacement.
The hypochlorite generator electrodes had started to develop a scale formation by the end of the
30-day test; scaling had not developed to the point of loss in generator efficiency, requiring acid
cleaning. (A loss in generator efficiency becomes evident when an increase in power is required
to maintain the same level of concentrated chlorine).
4.5 O&M Manual Review
The ClorTec MC Operator Interface PLC Manual was generally well organized. However, there
were inconsistencies and deficiencies found in different sections of the manual.
There is not a good explanation for what SHG equipment adjustments need to be made when the
hypochlorite concentrate stream is outside the target production concentration of 0.8% ± 0.05%
as chlorine. In Section 5 of the manual, MC System Startup, step 10 states that the Model MC
100 dilution water meter should be set at 1.0 gpm. Step 12 states that a sample should be
collected from the one inch product line to confirm the brine's density, which should be
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approximately 1.023 to 1.025. There is no discussion in this section or in the troubleshooting
section, Section 7, on what adjustments need to be made if the specific gravity or diluted sodium
chloride concentrations are outside of their target ranges, or if the concentrated hypochlorite
stream is not within ClorTec's stated performance claims.
In Section 4 under "Brine Tank", item 2, "a consistent 0.3% brine solution" is assumed to be
incorrect, and should read "a consistent 3.0% brine solution".
In Section 4 under "Plumbing", the second paragraph states that "the one inch union at the top of
the last cell carries the 0.8% sodium hypochlorite product and hydrogen byproduct". The
ClorTec Model MC 100 installation at the Hummelstown WTP had two lines connected on top
of the last cell, one dedicated for sodium hypochlorite transfer to storage tanks, and the other for
the venting of hydrogen outside the building.
In Section 2 under "Brine Saturator Tank", it states that the ClorTec MC Series system uses a
2,000 pound capacity H.D.P.E. salt brine storage tank, with the brine made up via the water float
valve positioned within a 6-inch protective chase allowing softened water to fill the tank. The
Hummelstown installation has separate tanks for brine generation and brine storage, and level
probe and level transmitter systems together with the PLC for controlling water supply influent
valves.
4.5 Costs
The ClorTec MC Operator Interface Manual states that the ClorTec process requires 3.5 pounds
of salt, 15 gallons of water and 2.5 kWh of electrical power to produce one pound of chlorine
equivalent. The following table presents the costs associated with each of these feedstock
components.
Table 4-14. On-Site SHG Feedstock Costs
Component
Unit Cost*
Total Cost
3.5 lbs of salt
$0.024/lb
$0,084
2.5 kWh
$0.074/kWh
$0,185
15 gallons potable water
$0.0027/gal
$0,041
1.0 Lb. Ch
$0,310
The table below presents a relative chemical cost comparison between liquid gas chlorine,
sodium hypochlorite delivered and on-site generated sodium hypochlorite.
Table 4-15. Chlorine Cost Comparison
One Lb Chlorine Chemical Costs
Unit Cost*
Liquid chlorine gas
$0.32/lb
Sodium Hypochlorite (bulk-15%)
$0.90/lb
On-site Sodium Hypochlorite Gen.
$0.31/15 gal.
*Costs from slide presentation by Timothy McGarvey of United Water Pennsylvania and Chester Parks of CP
Equipment Sales to AWWA-Pennsylvania Section Conference.
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Chapter 5
References
The following references were used in the preparation of this report:
APHA, AWWA, WEF. Standard Methods for the Examination of Water and Wastewater, 19th
Ed. 1995.
AWWARF. Compliance Guidance and Model Risk Management Program for Water Treatment
Plants. 1998
ClorTec MC Operator Interface Manual. 1999.
ClorTec MC PC Based Touchscreen Manual. 1999.
Connell, Gerald F. The Chlorination/Chloramination Handbook. AWWA 1996.
DEP Fact Sheet: Small Drinking Water Systems Technology Report On-Site Sodium
Hypochlorite Generation. Pennsylvania Department of Environmental Protection. January 2000.
National Primary Drinking Water Regulations: Disinfectant and Disinfection Byproducts.
Federal Register Volume 63, No. 241. December 1998.
EPA Guidance Manual for Compliance with the Filtration and Disinfection Requirements for
Public Water Systems using Surface Water Sources, 1989.
National Primary Drinking Water Regulations: Information Collection Rule. Federal Register
May 1996.
NSF International. Protocol for Equipment Verification Testing for Inactivation of
Microbiological Contaminants. August 1999.
USEPA Surface Water Treatment Rule (SWTR) - 54FR27486, June 29, 1989, EPA 1989b.
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