August 2000
NSF 00/06/EPADW395
Environmental Technology
Verification Report
Physical Removal of Cryptosporidium
oocysts and Giardia cysts in Drinking
Water
ZENON
ZeeWeed® ZW-500 Ultrafiltration
Membrane System
Pittsburgh, PA
Prepared by
NSF International
Under a Cooperative Agreement with
&EHV U.S. Environmental Protection Agency
eiVetVeiV
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
¦SERA ETV^ ©
U.S. Environmental Protection Agency NSF International
ETV Joint Verification Statement I
TECHNOLOGY TYPE:
MEMBRANE FILTRATION USED IN PACKAGED DRINKING
WATER TREATMENT SYSTEMS
APPLICATION:
GIARDIA AND CRYPTOSPORIDIUM REMOVAL IN
PITTSBURGH, PENNSYLVANIA
TECHNOLOGY NAME:
ZEEWEED® ZW-500 ULTRAFILTRATION SYSTEM
COMPANY:
ZENON ENVIRONMENTAL INC.
ZENON MUNICIPAL SYSTEMS
ADDRESS:
3239 DUNDAS STREET WEST
OAKVILLE, ONTARIO L6M 4B2
CANADA
PHONE: (905)465 3030
FAX: (905) 465 3050
WEB SITE:
http:Wwww.zenonenv.com
EMAIL:
gbest@zenonenv.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 Package Drinking Water Treatment
Systems (PDWTS) pilot, one of 12 technology areas under ETV. The PDWTS pilot recently evaluated
the performance of a membrane filtration system used in package drinking water treatment system
applications. This verification statement provides a summary of the test results for the ZENON
00/06/EPADW395 Hie accompanying notice is an integral part of this verification statement. August 2000
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Environmental Inc. ZeeWeed® ZW-500 UF Drinking Water System. Gannett Fleming, Inc., an NSF-
qualified field testing organization (FTO), performed the verification testing.
ABSTRACT
Verification testing of the ZENON Environmental Inc. ZeeWeed® ZW-500 UF Drinking Water System
was conducted from February 6 to March 7, 1999. The treatment system underwent Giardia and
Cryptosporidium removal challenge testing on March 2, 1999, and demonstrated a 5.3 logio removal of
Giardia cysts and a 6.4 logio removal of Cryptosporidium oocysts. Source water characteristics were:
turbidity average 0.09 Nephlometric Turbidity Units (NTU), pH 7.8, and temperature 3.8°C. During the
thirty-day verification test, the system was operated at a flux recommended by the manufacturer of 53
gallons per square foot per day (gfd) at 39°F (3.8°C) (91 liters per meter squared per hour [l/m2/h]) which
equates to 94 gfd at 68°F (169 l/m2/h at 20°C). The average transmembrane pressure was 7.5 pounds per
square inch (psi) (0.52 bar [b]). The feed water recovery of the treatment system during the study was
95%. Chemical cleaning of the treatment system was conducted as part of the verification testing.
TECHNOLOGY DESCRIPTION
Ultrafiltration (UF) processes are generally used to remove microbial contaminants such as Giardia and
Cryptosporidium and other particulate contaminants from drinking water. UF is generally capable of
removing particle sizes as small as 0.01 pirn The Zenon OCP ultrafiltration membrane is a hollow fiber
made of a proprietary polymeric compound. It has a 0.03 pim nominal pore size and utilizes outside-in
flow. A vacuum is applied to the inside of the hollow fiber membrane drawing the feed water into the
lumen of the fiber. The membrane is a mechanical barrier, providing removal of particulate contaminants.
Filtrate is collected from the inside of the fiber and drawn to the filtrate outlet.
The ZeeWeed® ZW-500 is a stand alone system. The only required connections are for the water supply,
a sewer connection for the discharge of bleed waste water and chemical cleaning wastes and electrical
service. The treatment system consists of one membrane module and reservoir, a filtrate (vacuum) pump,
an air blower, chemical cleaning equipment and necessary gauges and controls. The treatment system is
capable of operating in an automatic mode with limited operator intervention.
For this test program filtrate was drawn from both the top and bottom of each hollow fiber. The filtrate
pump was used to pull feed water through the membrane. Particulate material which is removed from the
membrane surface through air agitation and periodic back pulsing is constantly removed from the system
using a peristaltic bleed pump.
VERIFICATION TESTING DESCRIPTION
Test Site
The verification testing site was the Pittsburgh Water and Sewer Authority's (PWSA's) open air Highland
Reservoir No. 1, Pittsburgh, Pennsylvania. The source water for the verification testing was treated
surface water drawn from the Allegheny River. It underwent coagulation, sedimentation, filtration, and
disinfection at PWSA's Aspinwall Treatment Plant prior to being pumped to the Highland Reservoir No.
1. The influent to the treatment unit was drawn from the reservoir effluent lines. The verification testing
was limited to the performance of the equipment to remove Cryptosporidium oocysts and Giardia cysts,
because the source water was obtained from an open reservoir.
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Methods and Procedures
All field analyses (i.e. pH, turbidity, chlorine residual, temperature) were conducted daily using portable
field equipment according to Standard Methods for the Examination of Water and Waste Water, 18th Ed.,
(APHA, et. al., 1992). Likewise, Standard Methods, 18th Ed., (APHA, 1992) and Methods for Chemical
Analysis of Water and Wastes (EPA, 1979) were used for analyses conducted in PWSA's laboratory.
These analyses included total alkalinity, total hardness, total organic carbon (TOC), dissolved organic
carbon (DOC), total dissolved solids (TDS), total suspended solids (TSS), algae (number and species),
Ultraviolet Absorbance at 254 nanometers (UVA254), total coliform, and heterotrophic plate counts
(HPC). Total alkalinity, total hardness and TDS analyses were conducted monthly. All other laboratory
parameters were analyzed weekly.
Microbial challenge was performed using formalin-fixed Giardia lamblia cysts and Cryptosporidium
parvum oocysts. Procedures developed by EPA for use during the Information Collection Rule (ICR)
were employed for the identification and enumeration of Giardia cysts and Cryptosporidium oocysts
(EPA, ICR Microbial Laboratory Manual, EPA, April 1996). The protozoans were added to a fifty (50)
gallon (190 liter) drum. This drum was filled with the feed water. A total of 8,625,000 Giardia cysts and
109,643,000 Cryptosporidium oocysts were added to the feed water reservoir. The turbidity of the feed
water was 0.12 NTU during the Giardia and Cryptosporidium removal challenge testing. This stock
suspension was constantly mixed using a drum mixer. A diaphragm pump was used to add the
protozoans to the membranes on the treatment unit. The pump was operated at about 0.85 gallons per
minute (gpm) (3.2 liter per minute [1pm]). Samples of the filtrate were collected using a polypropylene
wound filter with a nominal pore size of 1.0 pim. One thousand liters (264 gallons) of filtrate water was
filtered through the sampling vessel at one gpm (3.8 liter per minute). In addition, aliquots of the stock
suspension were collected and analyzed to calculate concentrations of the microbes in the feed water.
Samples of the bleed water were collected and analyzed to verify that the parasites were added to the
system and removed by the filters.
VERIFICATION OF PERFORMANCE
System Operation
The treatment system was fully automated and capable of normal operations without manual intervention.
All operational data, flows, vacuum, turbidity and particle counts are recorded on data logging software.
Manual intervention is required for chemical cleaning. For this test program filtrate was drawn from both
the top and bottom of each hollow fiber. The filtrate pump was used to pull feed water through the
membrane.
The system was operated at a flux recommended by the manufacturer of 53 gfd at 39 °F (3.8°C) (91
l/nf/h) which equates to 94 gfd at 68 °F (169 l/m2/h at 20°C). The flow rate was recorded twice per day
and the water temperature was recorded once per day. The flow rate of the treatment system averaged 9.4
gpm (36 1pm) and ranged from 7.6 to 14 gpm (29 to 53 1pm).
The average vacuum applied to the system was -7.5 psi (-0.52 b). Since the membranes are immersed in a
tank at atmospheric pressure the absolute value of the vacuum applied to the system is equivalent to the
transmembrane pressure (TMP) of the unit. The average TMP for the system was 7.5 psi (0.52 b).
In order to minimize the amount of particulate material accumulating on the surface of the fibers, air is
constantly introduced into the system to gently agitate the fibers. An airflow of 7.5 standard cubic feet
per minute (scfm) was used during the verification testing. This agitation tends to remove particles
adhering to the fibers. In order to remove particles not eliminated by the air agitation, flow is periodically
reversed through the fibers. This is referred to as back pulsing. The back pulsing was done every 10
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VS-iii
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minutes for 20 seconds. A backpulse of one and a half to two times the filtrate flux is generally used to
ensure the most effective removal particulate material. Chlorine was added to the back pulse water at a
level of approximately 4 to 6 mg/1. The particulate material which is removed from the membrane
surface through air agitation and periodic back pulsing is constantly removed from the system using a
peristaltic bleed pump.
The feed water recovery of the treatment system during the study was 95%. This figure was calculated by
comparing the amount of water bled from the system to the total amount of water introduced into the
system.
The effectiveness of the chemical cleaning process was measured by the recovery of specific flux and loss
of original specific flux. Chemical cleaning was conducted at the end of the test period as required by the
ETV Protocol for Equipment Verification Testing for Physical Removal of Microbiological and
Particulate Contamination (EPA/NSF April, 1998). Data collected before and after the chemical cleaning
were used to calculate recovery of specific flux and the loss of original specific flux. The chemical
cleaning recovered 57% of the specific flux. Data from when the membranes were placed into service
and just after cleaning were used to calculate the loss of original specific flux. The loss of original
specific flux was 32%.
System integrity was demonstrated as required by the ETV protocol. Tests were conducted on an intact
membrane system and on one that had been intentionally compromised. The air pressure hold test
detected a compromised membrane after it was intentionally compromised.
Water Quality Results
During the Giardia and Cryptosporidium removal challenge testing that occurred on March 2, 1999, the
ZeeWeed® ZW-500 system demonstrated a 5.3 logio removal of Giardia cysts and a 6.4 logio removal of
Cryptosporidium oocysts. The logio removals were limited by the amount of the parasites which were
present in the stock feed solution, the percentage of the filtrate that could be sampled, and the percent
recovery of the analytical methodology. There were no Giardia cysts or Cryptosporidium oocysts
observed in the filtrate. During the challenge testing, the feed water characteristics were: turbidity
average 0.12 NTU, pH 7.8, temperature 3.6 °C.
During the thirty-day ETV operation of the ZeeWeed® ZW-500 system, treatment reductions were seen
in heterotrophic plate counts (HPC), algae, turbidity, and particle counts. HPC concentrations averaged
179 cfu/100 ml in the feed water and 6 cfu/100 ml in the filtrate. The presence of HPC in the filtrate may
have been due to inadequate disinfection of the Tygon tubing used for water sampling. Algae
concentrations averaged 18 cells/ml in the feed water and <8 cells/ml in the filtrate. The turbidity
concentration in the feed water was 0.09 NTU and 0.03 NTU in the filtrate. The treatment system
reduced feed water particle counts from an average of 64 total counts per ml to an average of 0.70 total
counts per ml in the filtrate. Total coliform reduction could not be demonstrated due to the absence of
total coliforms in the feed water and filtrate throughout the test. The following table presents the water
quality reductions of the feed water and filtrate samples collected during the 30 days of operation:
00/06/EPADW395 The accompanying notice is an integral part of this verification statement. August 2000
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Feed Water Quality / Filtrate Water Quality
ZENON ZeeWeed® ZW 500 Drinking Water Treatment System
Total Coliforms
HPC
Algae
Turbidity
Particle Counts
(cfu/100 ml)
(cfu/100 ml)
(cells/ml)
(NTU)
(particles/ml)
Average1
0/0
179/6
18/<8
0.09/0.03
64/0.70
Minimum1
0/0
94/2
8/<8
0.06/0.02
—
Maximum1
0/0
308/18
24/8
0.13/0.04
—
Standard Deviation1
0/0
92/8
8/2
0.02/0.004
—
95% Confidence Interval1
N/A/
(89,268)/
(10,26)/
(0.08, 0.09)/
N/A
(0,14)
(<8, <8)
(0.02, 0.03)
1 - Concentration of feed water/concentration of filtrate.
N/A = Not Applicable because standard deviation = 0
— = Statistical measurements on cumulative data not calculated.
Note: Calculated averages for less than results (<) utilize half of the Level of Detection (Gilbert, 1987).
Temperature of the feed water during the thirty-day ETV study was fairly stable with a high of 40.1°F
(4.5°C), a low of 37.9°F (3.3°C), and an average of 38.8°F (3.8°C). The treatment system unit had little or
no effect on dissolved constituents such as total alkalinity, total hardness, TOC, TDS, and UVA254.
Operation and Maintenance Results
Maintenance requirements on the treatment system did not appear to be significant but were difficult to
quantify due to the short duration of the study. The only interruption of the process occurred due to a
power failure at the pumping station. After power was restored to the pumping station the treatment
system was restarted and placed back into service.
The Operating and Maintenance (O&M) Manual provided by ZENON Environmental was available for
review on-site and was referenced occasionally during the testing. Particularly, the manual was consulted
during the cleaning procedure. The manual was well organized and a valuable resource during the testing
period.
Original Signed by
E. Timothy Oppelt
8/28/00
Original Signed by
Tom Bruursema
8/31/00
E. Timothy Oppelt Date
Director
National Risk Management Research Laboratory
Office of Research and Development
United States Environmental Protection Agency
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.
00/06/EPADW395 The accompanying notice is an integral part of this verification statement. August 2000
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Availability of Supporting Documents
Copies of the ETV Protocol for Equipment Verification Testing for Physical Removal of
Microbiological and Particulate Contaminants dated April 20, 1998 and revised May 14,
1999, the Verification Statement, and the Verification Report (NSF Report
#00/06/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)
00/06/EPADW395 The accompanying notice is an integral part of this verification statement. August 2000
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August 2000
Environmental Technology Verification Report
Physical Removal of Cryptosporidium Oocysts and
Giardia Cysts in Drinking Water
ZENON Environmental Inc.
ZeeWeed® ZW-500 Ultrafiltration System
Prepared for:
NSF International
Ann Arbor, Michigan 48105
Prepared by:
Gannett Fleming
Harrisburg, PA 17106
Under a cooperative agreement with the U.S. Environmental Protection Agency
Jeffrey Q. Adams, Project Officer
National Risk Management Research Laboratory
United States 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 Package
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 (USEPA) by Gannett Fleming, Inc., in cooperation with ZENON Environmental Inc.
The test was conducted during February and March 1999 at the New Highland Pump Station,
Pittsburgh Water and Sewer Authority, Pittsburgh, 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 ETV Program, 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
Package Drinking Water Treatment Systems (PDWTS) ETV 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 PDWTS 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.
Ill
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Table of Contents
Section Page
Verification Statement VS-i
Title Page i
Notice ii
Foreword iii
Table of Contents iv
Abbreviations and Acronyms x
Acknowledgements xii
Chapter 1 Introduction 1
1.1 ETV Purpose and Program Operation 1
1.2 Testing Participants and Responsibilities 1
1.2.1 NSF Internati onal 2
1.2.2 Gannett Fleming, Inc 2
1.2.3 Manufacturer 3
1.2.4 Host and Analytical Laboratory 3
1.2.5 U.S. Environmental Protection Agency 4
1.3 Verification Testing Site 4
1.3.1 Source Water 4
1.3.2 Effluent Di scharge 5
Chapter 2 Equipment Description and Operating Processes 6
2.1 Equipment Description 6
2.1.1 Membrane Fiber Characteristics 6
2.1.2 Major Equipment Components 6
2.1.3 Data Plate 7
2.1.4 System Photograph 7
2.2 Operating Process 8
2.2.1 Feed Water 8
2.2.2 Prefiltration 8
2.2.3 Filtration 8
2.2.4 Air Agitation/Backpulsing 9
2.2.5 Chemical Cleaning 10
Chapter 3 Methods and Procedures 11
3.1 Experimental Design 11
3.1.1 Objectives 11
3.1.1.1 Evaluation of Stated Equipment Capabilities 11
3.1.1.2 Evaluation of Equipment Performance Relative to Water Quality
Regulations 11
3.1.1.3 Evaluation of Operational Requirements 12
3.1.1.4 Evaluation of Maintenance Requirements 12
3.1.2 Equipment Characteristics 12
3.1.2.1 Qualitative Factors 12
3.1.2.2 Quantitative Factors 12
IV
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Table of Contents, continued
Section Page
3.1.2.3 Cost Factors 12
3.2 Water Quality Consideration 12
3.2.1 ETV Objective 13
3.2.2 Feed Water Quality 13
3.2.3 Filtrate Quality 13
3.3 Recording Data 14
3.3.1 Operational Data 14
3.3.2 Water Quality Data 14
3.4 Communications, Logistics and Data Handling Protocol 14
3.4.1 Objectives 15
3.4.2 Procedures 15
3.4.2.1 Log Books 15
3.4.2.2 Photographs 15
3.4.2.3 Chain of Custody 16
3.4.2.4 Inline Measurements 16
3.4.2.5 Spreadsheets 16
3.4.2.6 Statistical Analysis 16
3.5 Recording Statistical Uncertainty. 16
3.6 Verification Testing Schedule 17
3.7 Field Operations Procedures 17
3.7.1 Equipment Operations 17
3.7.1.1 Operations Manual 17
3.7.1.2 Analytical Equipment 17
3.7.2 Initial Operations 18
3.7.2.1 Flux 18
3.7.2.2 Transmembrane Pressure 18
3.7.2.3 Air Agitation/Backpulsing 19
3.7.2.4 Percent Feed Water Recovery 19
3.8 Verification Task Procedures 19
3.8.1 Task 1: Membrane Flux and Operation 20
3.8.1.1 Filtration 20
3.8.1.2 Air Agitation/Backpulsing 20
3.8.1.3 Chemical Cleaning 21
3.8.2 Task 2: Cleaning Efficiency 21
3.8.2.1 Cleaning Procedures 22
3.8.3 Task 3: Filtrate Quality. 22
3.8.3.1 Sample Collection and Analysis Procedure 23
3.8.4 Task 4: Reporting of Maximum Membrane Pore Size 23
3.8.5 Task 5: Membrane Integrity Testing 23
3.8.5.1 Air Pressure Hold Test 23
3.8.5.2 Turbidity Reduction Monitoring 24
3.8.5.3 Particle Count Reduction Monitoring 24
3.8.6 Task 6: Microbial Removal 24
3.8.6.1 Feed Water Stock Preparation 25
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Table of Contents, continued
Section Page
3.8.6.2 Stock Addition Procedure 25
3.8.6.3 Sample Collection Procedure 25
3.9 QA/QC Procedures 25
3.9.1 Daily QA/QC Verification Procedures 26
3.9.1.1 Inline Turbidimeter Flow Rate 26
3.9.1.2 Inline Particle Counter Flow Rate 26
3.9.1.3 Inline Turbidimeter Readout 26
3.9.2 Bi-Weekly QA/QC Verification Procedures 26
3.9.2.1 Inline Flow Meter Clean Out 26
3.9.2.2 Inline Flow Meter Flow Verification 27
3.9.3 Procedures for QA/QC Verifications at the Start of Each Testing Period 27
3.9.3.1 Inline Turbidimeter 27
3.9.3.2 Pressure Gauges / Transmitters 27
3.9.3.3 Tubing 27
3.9.3.4 Inline Particle Counters 27
3.9.4 On-Site Analytical Methods 28
3.9.4.1 pH 28
3.9.4.2 Temperature 28
3.9.4.3 Residual Chlorine Analysis 28
3.9.4.4 Turbidity Analysis 29
3.9.5 Chemical and Biological Samples Shipped Off-Site for Analyses 29
3.9.5.1 Organic Parameters 29
3.9.5.2 Microbiological Parameters 29
3.9.5.3 Inorganic Parameters 30
Chapter 4 Results and Discussion 31
4.1 Introduction 31
4.2 Initial Operations Period Results 31
4.2.1 Flux 31
4.2.2 Transmembrane Pressure 31
4.2.3 Backpul se Frequency 32
4.3 Verification Testing Results and Discussion 32
4.3.1 Task 1: Membrane Flux and Operation 32
4.3.1.1 Transmembrane Pressure Results 32
4.3.1.2 Specific Flux Results 34
4.3.1.3 Cleaning Episodes 35
4.3.1.4 Percent Feed Water Recovery 36
4.3.2 Task 2: Cleaning Efficiency 36
4.3.2.1 Results of Cleaning Episodes 36
4.3.2.2 Calculation of Recovery of Specific Flux and Loss of Original Specific
Flux 37
4.3.2.3 Discussion of Results 38
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Table of Contents, continued
Section Page
4.3.3 Task 3: Filtrate Quality. 38
4.3.3.1 Turbidity Results and Removal 40
4.3.3.2 Particle Count Results and Removal 41
4.3.3.3 Bleed Wastewater Testing Results 44
4.3.3.4 Total Suspended Solids Mass Balance 45
4.3.4 Task 4: Reporting of Maximum Membrane Pore Size 46
4.3.5 Task 5: Membrane Integrity Testing 47
4.3.5.1 Air Pressure Hold Test Results 47
4.3.5.2 Turbidity Reduction Monitoring 47
4.3.5.3 Particle Count Reduction Monitoring 47
4.3.6 Task 6: Microbial Removal 48
4.3.6.1 Feed Water Concentrations 48
4.3.6.2 Filtrate Concentrations 49
4.3.6.3 Bleed Wastewater Examination 50
4.3.6.4 Operational and Analytical Data Tables 50
4.3.6.5 Discussion of Results 52
4.4 Equipment Characteristics Results 52
4.4.1 Qualitative Factors 52
4.4.1.1 Susceptibility to Changes in Environmental Conditions 52
4.4.1.2 Operational Reliability 53
4.4.1.3 Equipment Safety 53
4.4.2 Quantitative Factors 53
4.4.2.1 Power Supply Requirements 53
4.4.2.2 Consumable Requirements 54
4.4.2.3 Waste Disposal 54
4.4.2.4 Length of Operating Cycle 55
4.5 QA/QC Results 55
4.5.1 Daily QA/QC Results 55
4.5.2 Bi-weekly QA/QC Verification Results 56
4.5.3 Results of QA/QC Verifications at the Start of Each Testing Period 56
4.5.4 On-Site Analytical QA Results 58
4.5.4.1 pH 58
4.5.4.2 Temperature 58
4.5.4.3 Residual Chlorine 58
4.5.4.4 Turbidity 59
4.5.5 Analytical Laboratory QA/QC 59
Chapter 5 References 60
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Table of Contents, continued
Tables Page
Table 1-1 - Feed Water Quality. 5
Table 3-1 - Analytical Data Collection Schedule 13
Table 3-2 - Operational Data Collection Schedule 14
Table 3-3 - Analytical & Operational Data Collection Schedule - Chemical Cleaning 22
Table 4-1 - Daily Transmembrane Pressure Results 32
Table 4-2 - Specific Flux 34
Table 4-3 - Chemical and Physical Characteristics of Cleaning Solution 37
Table 4-4 - Operational Parameter Results - Cleaning Procedure 37
Table 4-5 - Feed Water Testing Results 39
Table 4-6 - Filtrate Testing Results 39
Table 4-7 - Turbidity Analyses Results and Removal 40
Table 4-8 - Feed Water Particle Counts 41
Table 4-9 - Filtrate Particle Counts 41
Table 4-10 - Daily Average Cumulative Particle Counts - Feed Water and Filtrate,
Logio Particle Removal 42
Table 4-11 - Daily Bleed Wastewater Testing Results - Summary. 44
Table 4-12 - Weekly Bleed Wastewater Testing Results 45
Table 4-13 - Giardia and Cryptosporidium Stock Suspension Results by
Hemocytometer Counts 49
Table 4-14 - Feed Water Reservoir Concentrations of Giardia and Cryptosporidium by
Microscopic Examination 49
Table 4-15 - Giardia and Cryptosporidium Challenge Logio Removal Calculation 50
Table 4-16 - Transmembrane Pressure Readings During Microbial Removal Testing 51
Table 4-17 - Specific Flux During Microbial Removal Testing 51
Table 4-18 - Turbidity Analyses Results and Removal During Microbial Removal Testing 51
Table 4-19 - Feed Water Particle Counts 3/2/1999 51
Table 4-20 - Filtrate Particle Counts 3/2/1999 51
Table 4-21 - Daily Bleed Wastewater Testing Results During Microbial Removal Testing 51
Figures
Figure 2-1 - Flow Path During the Filtration Cycle 9
Figure 2-2 - Flow Path During the Backpulse Cycle 10
Figure 4-1 - Transmembrane Pressure vs. Time 33
Figure 4-2 - Specific Flux Decline vs. Time 35
Figure 4-3 - Four Hour Feed Water Particle Counts 43
Figure 4-4 - Four Hour Filtrate Particle Counts 43
Figure 4-5 - Daily Average Logio Cumulative Particle Removal 44
Photographs
Photograph 1 - The ZENON Environmental Inc. ZeeWeed® ZW-500 Drinking Water System
showing control, panel process tank, bleed pump and ancillary equipment 8
vm
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Appendices
A. Laboratory Approval Statements
B. Manufacturer's Operation and Maintenance Manual
C. Data Spreadsheets
D. Data Log Book
E. Laboratory Chain of Custody Forms
F. PWSA Laboratory QA/QC Plan
G. Manufacturer's Membrane Pore Size Report
H. Laboratory Reports and Giardia and Cryptosporidium Challenge Bench Sheets
I. Particle Counter Information
J. Package Plant Photos
K. Field Operations Document
IX
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Abbreviations and Acronyms
ac
b
CaC03
cfu
CIP
Cl2
°c
DI
EPA
ESWTR
ETV
°F
FOD
ft
ft2
FTO
gfd
gpm
Hp
HPC
ICR
kwh
L
lbs
lpm
m
MG
MGD
mg/1
ml
N/A
NIST
NSF
nm
NTU
O&M
PADEP
PC
PPE
psi
PDWTS
PWSA
acre
bar
Calcium Carbonate
Colony forming unit
Clean in place
Chlorine
Degrees Celsius
Deionized
Environmental Protection Agency
Enhanced Surface Water Treatment Rule
Environmental Technology Verification
Degrees Fahrenheit
Field Operations Document
Foot
Feet Squared
Field Testing Organization
Gallon per square foot per day
Gallon per minute
Horse Power
Heterotrophic Plate Count
Information Collection Rule
kilowatt hour
Liters
Pounds
liter per minute
meter
million gallon
million gallon per day
milligram per liter
milliliters
Not Applicable
National Institute of Standards and Technology
NSF International (formerly known as National
Sanitation Foundation)
nanometers
Nephlometric Turbidity Units
Operations and Maintenance
Pennsylvania Department of Environmental
Protection
personal computer
Personal Protective Equipment
pounds per square inch
Packaged Drinking Water Treatment System
Pittsburgh Water and Sewer Authority
X
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QA/QC Quality Assurance / Quality Control
scfm standard cubic feet per minute
SWTR Surface Water Treatment Rule
TDS Total Dissolved Solids
TMP Transmembrane pressure
TOC Total Organic Carbon
TSS Total Suspended Solids
UF Ultrafiltration
|im Micron
UVA254 Ultraviolet Absorbance at 254 nm
XI
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ACKNOWLEDGMENTS
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.
P.O. Box 67100
Harrisburg, PA 17106-7100
Phone: 717-763-7211
Contact Person: Mr. Gene Koontz
The laboratory selected for microbiological analysis and non-microbiological, analytical work of
this study was:
Pittsburgh Water and Sewer Authority
900 Freeport Road
Pittsburgh, PA 15238
Phone: 412-782-7552
Contact Person: Mr. Stanley States, Ph.D., Director of Analytical Services
The Manufacturer of the Equipment was:
ZENON Environmental Inc.
ZENON Municipal Systems
3239 Dundas Street West
Oakville, Ontario L6M 4B2 Canada
Phone: 905-465-3030
Contacts: Graham Best/Drinking Water Process Mgr., Doreen Benson/Pilot Project Mgr.
Gannett Fleming wishes to thank the participants in this test, especially Bruce Bartley, Project
Manager, Carol Becker and Kristie Wilhelm, Environmental Engineers, and Tina Beaugrand,
Microbiology Laboratory Auditor of NSF International for providing guidance and program
management.
The Pittsburgh Water and Sewer Authority staff including Dr. Stanley States, Director of
Analytical Services, Raymond Wisloski, Water Treatment Plant Manager, Chester Grassi,
Assistant Plant Manager, and Mickey Schuering, Water Treatment Technician provided
invaluable analytical and operational assistance.
Steve Watzek, Manager/Business Development, Graham Best, Drinking Water Process Manager,
Doreen Benson, Pilot Project Manager are to be commended for providing the treatment system
and excellent technical and product expertise. Mike Fishbaugh provided daily onsite system
checkout and readings of the treatment unit.
Xll
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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 Package Drinking Water
Treatment Systems (PDWTS) program, one of 12 technology areas under ETV. The PDWTS
program evaluated the performance of the ZENON Environmental Inc. ZeeWeed® ZW-500
Ultrafiltration (UF) Drinking Water System manufactured by ZENON Environmental Inc, which
is a membrane filtration system used in package drinking water treatment system applications.
The performance claim evaluated during field testing of the ZeeWeed® ZW-500 system was that
the system is capable of a minimum 3 logio removal of Giardia cysts and 2 logio removal of
Cryptosporidium oocysts. This document provides the verification test results for the ZENON
Environmental Inc. ZeeWeed® ZW-500 UF Drinking Water System.
1.2 Testing Participants and Responsibilities
The ETV testing of the ZeeWeed® ZW-500 System was a cooperative effort between the
following participants:
NSF International
Gannett Fleming, Inc.
Zenon Environmental Inc.
Pittsburgh Water and Sewer Authority
U.S. Environmental Protection Agency
The following is a brief description of each ETV participant and their roles and responsibilities.
1
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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 package drinking water treatment systems through the
EPA's ETV Program.
NSF provided technical oversight of the verification testing. An onsite 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 Gannett Fleming, Inc.
Gannett Fleming, Inc., a consulting engineering firm, conducted the verification testing of the
ZeeWeed® ZW-500 system. Gannett Fleming is a NSF-qualified Field Testing Organization
(FTO) for the ETV PDWTS 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 verification 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.
FTO employees conducted the onsite analyses and data recording during the testing. Oversight
of the daily tests was provided by the FTO's Project Manager and Project Director.
Contact Information:
Gannett Fleming, Inc.
P.O. Box 67100
Harrisburg, PA 17106-7100
Phone: 717-763-7211
Fax: 717-763-1808
2
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Contact: Gene Koontz, Project Director
Email: gkoontz@gfnet.com
1.2.3 Manufacturer
The treatment system is manufactured by ZENON Environmental Inc., a developer and
manufacturer of membrane technologies for water treatment, wastewater treatment, and water
reuse. ZENON Environmental Inc. is based in Burlington, Ontario.
The manufacturer was responsible for supplying a field-ready UF membrane filtration package
plant equipped with all necessary components including treatment equipment, instrumentation
and controls and an operations and maintenance manual. The unit was capable of continuous,
safe 24 hour per day operation with minimal operator attention. The unit was equipped with
protective devices to provide for automatic shut down of the package plant in the event of loss of
feed water or any other condition that would either damage the package plant or render data
generated by the unit to be not reliable. 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.
Representatives of the manufacturer were utilized to conduct chemical clean in place (CIP),
membrane integrity testing and examined daily operational data that were automatically recorded
by the treatment system.
Contact Information:
ZENON Environmental Inc.
ZENON Municipal Systems
3239 Dundas Street West
Oakville, Ontario L6M 4B2 Canada
Phone: 905-465-3030
Contacts: Graham Best/Drinking Water Process Mgr.
Email: gbest@zenonenv.com
1.2.4 Host and A nalytical Laboratory
The verification testing was hosted by the Pittsburgh Water and Sewer Authority (PWSA).
PWSA serves water to over 500,000 people from its 120 million gallon per day (MGD) surface
water treatment plant located in the Aspinwall section of the City of Pittsburgh. PWSA was
interested in examining the use of membrane filtration to treat water which had been stored in its
Highland Reservoir No. 1, an open finished water reservoir.
PWSA's laboratory provided collection and analytical services for Total Alkalinity, Total
Hardness, Total Dissolved Solids (TDS), Total Suspended solids (TSS), Total Coliforms,
Heterotrophic Plate Count (HPC), Total Organic Carbon (TOC), Ultraviolet Absorbance at 254
nanometers (nm) (UVA254), and Algae. In addition, PWSA supplied operational support and
analytical services for the Giardia and Cryptosporidium removal testing. PWSA's laboratory is
certified by the Pennsylvania Department of Environmental Protection (PADEP) for analysis of
Microbiological, Inorganic, and Organic compounds in water. Additionally, the laboratory has
3
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received Protozoa Laboratory Approval from the EPA under the Information Collection Rule
(ICR) Program. Copies of the Laboratory Approval Statements are attached in Appendix A.
Contact Information:
Pittsburgh Water and Sewer Authority
900 Freeport Road
Pittsburgh, PA 15238
Phone: 412-782-7552
Fax: 412-782-7564
Contact: Stanley States, Ph.D. Director of Analytical Services
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 PDWTS Pilot operating under the ETV Program. This document has been
peer reviewed and reviewed by NSF and EPA and recommended for public release.
1.3 Verification Testing Site
The verification testing was conducted at the PWSA's Highland Reservoir No. 1. The physical
location of the treatment unit was the New Highland Pumping Station at the corner of North
Negley Avenue and Mellon Terrace in the Highland Park section of the City of Pittsburgh,
Pennsylvania. The treatment unit was housed in the pumping station itself and received its feed
water from the influent lines of the pumping station.
1.3.1 Source Water
The source water for the verification testing was finished drinking water that was stored in
PWSA's open Highland Reservoir No. 1. The reservoir is 18 acres (ac) with an average depth of
20 feet (ft) and contains 120 million gallons (MG) of water. The water that is stored in Highland
Reservoir No. 1 is treated surface water drawn from the Allegheny River. The water stored in
the reservoir has undergone coagulation, sedimentation, filtration, and disinfection at PWSA's
Aspinwall Treatment prior to being pumped to the reservoir. The influent to the ZeeWeed®
ZW-500 system was drawn from the reservoir effluent lines. The effluent from the reservoir is
not tested by PWSA and the Authority has little historical data regarding the quality of the
reservoir water.
During the study the feed water turbidity ranged from 0.06 to 0.14 NTU with an average of 0.09
NTU. pH was within the range of 7.7 to 8.1 with an average of 7.8. Total alkalinity as calcium
carbonate (CaCCb) ranged from 37 to 43 milligrams per liter (mg/1) with an average of 39 mg/1.
Average hardness, as CaCC>3, was 103 mg/1 and ranged from 98 to 108 mg/1. TOC ranged from
1.66 to 2.02 mg/1 with an average of 1.89 mg/1. All of the samples analyzed for UVA254 yielded
results of 0.020 cm"1. TDS averaged 229 mg/1 and the range was 176 to 300 mg/1. TSS averaged
0.29 mg/1 and ranged from non detectable to 1.00 mg/1. HPC ranged from 94 to 308 colony
forming units (cfu) per milliliter (ml) and averaged 179 cfu/ml. No coliform bacteria were
detected in the feed water. Temperature averaged 3.8 degrees Celsius (°C), ranging from 3.3°C
4
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to 4.5°C. The algae levels during the verification testing averaged 18 cells/ml, with a range of 8
to 24 cells/ml. The above information is presented in Table 1-1 below.
Table 1-1. Feed Water Quality
Parameter
Total
Total
TDS
TSS
Total
HPC
TOC
UVA
Algae
Turbidity
Alkalinity Hardness
Coliforms
(mg/1 as
CaC03)
(mg/1 as
CaC03)
(mg/1)
(mg/1)
(cfu/100
ml)
(cfu/100
ml)
(mg/1)
(cm-1)
(cells/ml)
(NTU)
Average
39
103
229
0.29
0
179
1.89
0.020
18
0.09
Minimum
37
98
176
<0.05
0
94
1.66
0.020
8
0.06
Maximum
43
108
300
1.00
0
308
2.02
0.020
24
0.14
Std. Dev.
2.6
N/A
60.8
0.48
0
92
0.163
0.000
8
0.02
95% Confid Int
(36, 42)
N/A
(169,
289)
(0, 0.75)
N/A1
(89, 269)
(2.13,
2.50)
N/A1
(10,26)
(0.08, 0.09)
N/A1 = Not Applicable because standard deviation = 0
Note: Calculated averages for less than results (<) utilize half of the Level of Detection (0.05 mg/1) or 0.025 mg/1 in these
calculations. Per Statistical Methods for Environmental Pollution Monitoring. Richard O. Gilbert, Van Nostrand Reinhold, 1987.
1.3.2 Effluent Discharge
The effluent of the treatment unit, (i.e. the filtrate, bleed waste, and chemical cleaning waste)
was piped to an existing catch basin that is part of the PWSA sanitary sewer collection system.
No discharge permits were required.
5
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Chapter 2
Equipment Description and Operating Processes
2.1 Equipment Description
The equipment tested in this ETV program was ZENON Environmental Inc. ZeeWeed®
ZW-500 UF Drinking Water System. A ZW-500 ZeeWeed® membrane cassette was used in the
treatment system. OCP is the manufacturer's designation for their drinking water membrane.
The membrane cassette was immersed in a ZeeWeed® tank. This process tank was constructed
of stainless steel and had a 185 gallon (700 liter) mean operating volume. The membrane
cassette was 6.6 ft. x 2.5 ft x 0.7 ft (2.0 m x 0.75 m x 0.2 m) (L x H x W). This provided a
filtration surface area of 253 feet squared (ft2) (23.5 in2). The fibers contain thousands of pores.
The pore size was 0.1 micron («m) absolute, 0.03 um nominal in diameter. This correlates to
approximately 120 Kilo Dalton (absolute), 100 Kilo Dalton (nominal) molecular weight cutoff
rating.
As previously mentioned the membrane cassette was immersed in the process tank. The process
tank and necessary ancillary equipment were mounted on the treatment skid.
The individual fibers were potted (attached) top and bottom in epoxy. The epoxy potting ensures
that no feed water may enter the filtrate side of the treatment system without having passed
through the membrane. Water was drawn into the fiber interior core via the pores.
Contaminants, which cannot pass through the pores, remain exterior to the filter module as
reject. Water which passes through the membrane exits as clean filtrate.
2.1.1 Membrane Fiber Characteristics
A summary of membrane characteristics as reported by the manufacturer is as follows:
Membrane classification Ultrafiltration
Membrane material Proprietary Polymer
Membrane type hollow fiber
Membrane flow path outside in
Filtration mode Once through / constant waste bleed
pH tolerance 5-9 (operational), 2-10.5 (cleaning)
Temperature tolerance 1 - 40° C (33 - 95° F)
2.1.2 Major Equipment Components
The following major equipment components are provided on the ZeeWeed® ZW-500 System:
• Stainless steel ZeeWeed® tank (185 US gallons mean operating volume).
• Polypropylene CIP tank (20 US gallons operating volume).
• Becker DT 4.40, 2 Horsepower (Hp), Carbon Vane Blower (P 3 - air supply for membranes).
• Service Filtration GNOK Series Self-priming Centrifugal Pump (P 4 -filtrate pump).
6
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• Goulds NPE, 1 Hp, Centrifugal Pump (P 2 - sprayer pump).
• Feed Solenoid Valve - An one inch pneumatic (air actuated, normally closed) ball valve.
Ancillary equipment that was used with the treatment system:
• Masterflex I/P Peristaltic Bleed Pump (P 05).
• 1" normally closed air actuated pneumatic ball valve.
• An electrical transformer.
• 4 Hp air compressor.
The individual components are interconnected with the necessary piping, valving, wiring, and
controls. The membranes, influent, effluent, vacuum, and air piping are assembled into a
cassette that is partially submerged into the process tank.
2.1.3 Data Plate
The data plate affixed to the treatment system contains the following information:
a. Equipment name: ZENON Environmental Inc. ZeeWeed® ZW-500 UF Drinking Water
System
b. Membrane Model #: ZW-500
c. Manufacturer: ZENON Environmental Inc. 845 Harrington Court, Burlington, Ontario
d. Electrical requirements: 230 V, 60 Amps, 60 Hertz, single phase
e. Serial number: FS 102
f Warning and caution statements: High Voltage Inside
g. Capacity or output rate: 2 to 15 US gallons per minute (gpm)
2.1.4 System Photograph
A photograph of the ZeeWeed® ZW-500 System used for the ETV testing is included in this
section of the report. Photograph 1 shows the layout of the unit and the location of various
pieces of equipment including the control panel, process tank, bleed pump and ancillary
equipment.
7
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Photograph 1. The ZENON Environmental Inc. ZeeWeed® ZW-500 UF Drinking Water System showing control panel,
process tank, bleed pump and ancillary equipment.
2.2 Operating Process
2.2.1 Feed Water
The feed water flows from Highland No. 1 Reservoir to the booster pumps in the New Highland
booster station the influent to the treatment system is drawn from discharge of the booster station
pumps. An air actuated solenoid valve controls the level of the feed water in the process tank.
2.2.2 Prefiltration
There is no prefiltration equipment utilized on the treatment system.
2.2.3 Filtration
During the filtration cycle, feed water enters the process tank. The filtrate pump is placed down
stream of the membrane cassette. The placement of the membranes on the suction side of the
filtrate pump creates a vacuum inside the membrane fibers. The vacuum pulls the feed water
through the membrane fibers creating the flow through the system. During normal operation the
8
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vacuum is applied to the top and bottom head of the membrane cassette, allowing flow from both
heads of the cassette. Figure 2-1 illustrates the flow path during normal operation.
2.2.4 Air Agitation/Backpulsing
As water is filtered through the membrane surface, a film of rejected particulates accumulates on
the surface of the fibers. The filtrate flow is gradually impeded as particles accumulate on the
surface of the membrane. The treatment system utilizes two methods to control this particulate
accumulation. Air is introduced to the bottom of the process tank on a continuous basis. This air
agitates the outer surface of the membrane loosening any particles that adhere to the membrane
surface. Periodically, the system undergoes a "backpulse". Backpulsing is the reversal of flow
through the membrane fibers. This flow reversal forcefully removes particles which have tightly
adhered to the membrane fibers. The frequency and duration of the back pulse is adjustable and
is determined by the feed water quality and the ability to maintain the desired flux rate.
Backpulsing is accomplished by operating pneumatic valves, drawing filtrate from the CIP tank,
and reversing the flow through the membrane fibers. A peristaltic pump is used to constantly
remove a small portion of the water from the process tank. This pump is referred to as the bleed
pump. Particulate material that is loosened from the membrane by air agitation or backpulsing is
removed from the process tank by the bleed pump.
To aid in cleaning the membrane fibers, chlorine is added to the back pulse water. Sodium
hypochlorite dosing can be done using a small chemical metering pump. During the verification
testing calcium hypochlorite tablets were placed into the CIP tank. The use of the hypochlorite
tablets resulted in a free chlorine residual in the backpulse water of 4-6 mg/1.
The reject removed by the bleed pump was discharged to an existing sewer. Figure 2-2
illustrates the flow path during backpulsing.
9
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2.2.5 Chemical Cleaning
Air agitation and back pulsing are not totally effective at removing particulate material from the
membrane surface. These procedures must be augmented by occasional chemical cleaning. This
procedure is referred to as Clean-In-Place (CIP). The required cleaning frequency is determined
by the flow rate of the treatment system and the contaminant level in the feed water. The
frequency of cleaning for this feed water is estimated to be between one and three months.
The CIP process was done manually using a full tank soak cleaning procedure. This was done
by draining the process tank and refilling it with clean water. (In this case water from the pump
station was used.) The soak water was dosed with 255 mg/1 of chlorine. The membranes were
soaked in this solution overnight (18 hours). The chlorine soak was followed by a citric acid
soak. The process tank was drained and refilled with clean water. A 650 mg/1 solution of citric
acid was created by adding citric acid to the process tank. The membranes were soaked in this
solution for four hours. Following the cleaning procedure the system is drained, rinsed, refilled
and production resumed.
10
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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 treatment system. The impact of field operations as they relate
to data validity was minimized, as much as possible, through the use of standard sampling and
analytical methodology. Due to the unpredictability of environmental conditions and mechanical
equipment performance, this document should not be viewed in the same light as scientific
research conducted in a controlled laboratory setting.
3.1.1 Objectives
The verification testing was undertaken to evaluate the performance of the ZENON
Environmental Inc. ZeeWeed® ZW-500 UF Drinking Water System. Specifically evaluated
were the manufacturer's stated equipment capabilities and equipment performance relative to
water quality regulations. Also evaluated were the operational requirements and maintenance
requirements of the system. The details of each of these evaluations are discussed below.
3.1.1.1 Evaluation of Stated Equipment Capabilities
The ZeeWeed® ZW-500 system was tested to show that it was capable of providing a minimum
3 logio removal of Giardia cysts and 2 logio removal of Cryptosporidium oocysts from the
source water and consistently producing water with a turbidity of less than 0.1 Nephlometric
Turbidity Units (NTU). Giardia and Cryptosporidium removal challenge testing was conducted
to demonstrate acceptable protozoan removal capability. Since turbidity challenge testing was
not done during the course of the study and the turbidity of the feed water was quite low,
turbidity removal capabilities were not verified during the course of the testing.
3.1.1.2 Evaluation of Equipment Performance Relative to Water Quality Regulations
Drinking water regulations require, for filtration plants treating surface water, a minimum of 3
logio removal/inactivation of Giardia cysts from feed to finished waters, that finished water
turbidity at no time exceeds 5 NTU and that at least 95% of the daily finished water turbidity
samples be less than 0.5 NTU (EPA, Surface Water Treatment Rule [SWTR], 1989). Recently
promulgated rules have modified the SWTR to include a lower turbidity standard, less than 0.3
NTU in 95% of the daily filtrate turbidity samples, and a requirement to provide a 2 logio
removal of Cryptosporidium oocysts (EPA, Enhanced Surface Water Treatment Rule [ESWTR],
1999). Both these rules grant the "log removal credit" if the treatment facility achieves the
required turbidity levels.
The treatment system's ability to achieve required filtrate turbidity levels was not verifiable due
to the fact that the feed water already was in compliance with drinking water turbidity
regulations. Log removal for Giardia cysts and Cryptosporidium oocysts was quantified using
microbial removal challenge testing although there is no provision for this type of testing in the
regulations.
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3.1.1.3 Evaluation of Operational Requirements
An overall evaluation of the operational requirements for the treatment system was undertaken as
part of the verification. This evaluation was qualitative in nature. The manufacturer's
Operations and Maintenance (O&M) manual (Panel View Standard ZeeWeed® Pilot System
Manual August, 1998) and experiences during the daily operation were used to develop a
subjective judgement of the operational requirements of the system. The O&M manual is
attached to this report as Appendix B.
3.1.1.4 Evaluation of Maintenance Requirements
Verification testing also evaluated the maintenance requirements of the treatment system. Not
all of the system's maintenance requirements were necessary due to the short duration of the
testing cycle. The O&M manual details various maintenance activities and their frequencies
(ZENON, 1998). This information, as well as experience with common pieces of equipment
(i.e. pumps, valves etc.) was used to evaluate the maintenance requirements of the treatment
system.
3.1.2 Equipment Characteristics
The qualitative, quantitative and cost factors of the tested equipment were identified, in so far as
possible, during the verification testing. The relatively short duration of the testing cycle creates
difficulty in reliably identifying some of the qualitative, quantitative and cost factors.
3.1.2.1 Qualitative Factors
The qualitative factors examined during verification testing were susceptibility to changes in
environmental conditions, operational reliability, and equipment safety.
3.1.2.2 Quantitative Factors
The quantitative factors examined during verification testing were power supply requirements,
consumable requirements, waste disposal technique, and length of operating cycle.
3.1.2.3 Cost Factors
The cost factors examined during verification testing were power supply, consumables, and
waste disposal. It is important to note that the figures discussed here are for the ZeeWeed®
ZW-500 system. This treatment unit operated at 53 gfd at 3.8°C (91 l/m2/h) which equates to 94
gfd at 68 degrees Fahrenheit (°F) (170 l/m2/h at 20°C). Costs will increase with increasing flow.
3.2 Water Quality Consideration
The focus of the ETV program is the verification that the tested treatment systems are capable of
achieving their stated equipment capabilities. These capabilities invariably refer to the
production of water meeting specific quality goals. In order to evaluate the effectiveness of the
12
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treatment system, it is necessary to know the objective of the study and the quality of the water
before and after treatment.
3.2.1 ETV Objective
The overall objective of the ETV program is to facilitate the deployment of innovative
technologies through performance verification and information dissemination. Specifically, this
ETV study was undertaken to demonstrate that the ZeeWeed® ZW-500 system was capable of
providing a minimum 3 logio removal of Giardia cysts and 2 logio Cryptosporidium oocysts
from source water to plant effluent and consistently producing water with a turbidity of less than
0.1 NTU.
3.2.2 Feed Water Quality
The source water for the verification testing of the ZeeWeed® ZW-500 system was from the
open-air Highland Reservoir No. 1. The reservoir is 18 acres with an average depth of 20 ft and
contains 120 MG of water. The water that is stored in Highland Reservoir No. 1 is treated
surface water drawn from the Allegheny River. It has undergone coagulation, sedimentation,
filtration, and disinfection at PWSA's Aspinwall Treatment Plant prior to being pumped to the
Highland No. 1 reservoir. The influent to the ZeeWeed® ZW-500 system was drawn from the
reservoir effluent lines. The effluent from the reservoir is not tested by PWSA and the Authority
has little historical data regarding the quality of the reservoir water.
The parameters which were analyzed as part of the testing and the sampling frequency are
presented in Table 3-1.
Table 3-1. Analytical Data Collection Schedule
Bleed Waste
Parameter
Frequency
Feed
Filtrate
(Reject)
Onsite Analytes
Temperature
Daily
1
0
0
pH
Daily
1
0
0
Turbidity
Daily
2
Continuous
2
Particle Counts
Daily
Continuous
Continuous
0
Chlorine Residual
During Cleaning
1 (Backpulse feed
0
1
water)
Laboratory Analytes
Total Alkalinity
Monthly
1
1
0
Total Hardness
Monthly
1
1
0
TDS
Monthly
1
1
0
TSS
Weekly
1
1
1
Total Coliforms
Weekly
1
1
1
HPC
Weekly
1
1
0
TOC
Weekly
1
1
0
UVA
Weekly
1
1
0
Algae
Weekly
1
1
0
3.2.3 Filtrate Quality
Characterization of the filtrate quality of the system was the driving force behind the
development of the experimental design of the ETV. The water quality and microbial analyses
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were selected to demonstrate the treatment effectiveness of the manufacturer's equipment.
Filtrate analyses and their frequencies are listed in Table 3-1 above.
In addition to analyses of total coliform and HPC, analyses for Giardia cysts and
Cryptosporidium oocysts were conducted during the microbial removal phase of the evaluation.
These analyses were conducted using procedures developed by EPA for use during the ICR for
the identification and enumeration of Giardia cysts and Cryptosporidium oocysts (EPA, April
1996).
3.3 Recording Data
Operational and water quality data were recorded to document the results of the verification
testing.
3.3.1 Operational Data
Operational data were read and recorded for each day of the testing cycle. The operational
parameters and frequency of readings are listed in Table 3-2 below.
Table 3-2. Operational Data Collection Schedule
Parameter
Frequency
Feed flow
2/day
Feed water temperature
1/day
Electric power use
1/day
Filtrate applied vacuum
2/day
Filtrate flow
2/day
In addition to these parameters, data were collected during chemical cleaning and membrane
integrity testing. Operational data collected during these tasks are discussed in Sections 3.8.2
and 3.8.5.
3.3.2 Water Quality Data
Table 3-1 lists the daily, weekly, and monthly water quality samples that were collected. The
results of the daily on-site analyses were recorded in the operations log book. The weekly and
monthly laboratory analyses were recorded in laboratory log books and reported to the FTO on
separate laboratory report sheets. The data spreadsheets to which the above data were entered
are attached to this report as Appendix C.
3.4 Communications, Logistics and Data Handling Protocol
With the number of verification participants involved in the study it was important for the FTO
to coordinate communication between all parties. Documentation of study events was facilitated
through the use of logbooks, photographs, data sheets and 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 are being entered into spreadsheets and reports accurately and that the
results are statistically valid.
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The data management system used in the verification testing program involved the use of
computer spreadsheet software and manual recording methods for recording operational
parameters for the membrane filtration equipment on a daily basis. Weekly and monthly water
quality testing data were submitted to the FTO by PWSA Laboratory representatives, verified,
and entered into computer spreadsheets.
3.4.1 Objectives
There were two primary objectives of the data handling portion of the study. One objective was
to establish a viable structure for the recording and transmission of field testing data such that the
FTO provides sufficient and reliable operational data for the NSF for verification purposes. A
second objective was to develop a statistical analysis of the data, as described in the "EPA/NSF
ETV Protocol for Equipment Verification Testing for Physical Removal of Microbiological and
Particulate Contaminants" (EPA/NSF 1998).
3.4.2 Procedures
The data handling procedures were used for all aspects of the verification test. Procedures
existed for the use of the log books used for recording the operational data, the documentation of
photographs taken during the study, the use of chains of custody forms, the gathering of inline
measurements, entry of data into the customized spreadsheets, and the methods for performing
statistical analyses.
3.4.2.1 Log Books
Field log books were bound with numbered pages and labeled with the project name. The log
book is attached to this report as Appendix D. Log books were used to record equipment
operating data. Each line of the page was dated and initialed by the individual responsible for
the entries. Errors had one line drawn through them and the line was initialed and dated.
Although the FTO attempted to initial and date each page and individual line entries review of
the log book at the conclusion of testing indicated that in a few instances the entries had not been
initialed. Field testing operators recorded data and calculations by hand in laboratory notebooks.
Daily measurements were recorded on specially prepared data log sheets. The laboratory
notebook was photocopied weekly. The original notebooks were stored on-site; the photocopied
sheets were stored at the office of the FTO. This procedure eased referencing the original data
and offered protection of the original record of results. Treatment unit operating logs included a
description of the membrane filtration equipment (description of test runs, names of visitors,
description of any problems or issues, etc); such descriptions were provided in addition to
experimental calculations and other items.
3.4.2.2 Photographs
All photographs were logged in the field log book. These entries include time, date, direction,
subject of the photo and the identity of the photographer.
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3.4.2.3 Chain of Custody
Samples which were collected by PWSA representatives and hand delivered to the laboratory
were logged into the laboratory's sample record upon arrival at the laboratory. During an
inspection by NSF representatives, the use of chain of custody forms was requested. Subsequent
samples were collected and hand delivered to the laboratory accompanied by chain of custody
forms. The chain of custody forms are included in Appendix E.
3.4.2.4 Inline Measurements
Data from the computers recording the inline measurements were copied to disk at least on a
weekly basis. This information was stored on site and at the FTO's office.
3.4.2.5 Spreadsheets
The database for the project was set up in the form of custom-designed spreadsheets. The
spreadsheets are capable of storing and manipulating each monitored water quality and
operational parameter from each task, each sampling location, and each sampling time. All data
from the laboratory notebooks and data log sheets were entered into the appropriate spreadsheet.
Data entry into the spreadsheets was conducted at the FTO's office by designated operators. All
recorded calculations were also checked at this time. Following data entry, the spreadsheet was
printed out and the printout was checked against the handwritten data sheet. 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 or engineer performing the entry or verification step. Spreadsheet printouts are
included in Appendix C of this report.
3.4.2.6 Statistical Analysis
Water quality data developed from grab samples collected during filter runs, the operational data
recorded in the logbook, and the inline data were analyzed for statistical uncertainty. The FTO
calculated the average, minimum, maximum, standard deviation, and the 95% confidence
intervals. The statistics developed are helpful in demonstrating the degree of reliability with
which water treatment equipment can attain quality goals.
3.5 Recording Statistical Uncertainty
The FTO calculated a 95% confidence interval for selected water quality parameters. These
calculations were also carried out on data from inline monitors and for grab samples of turbidity,
total coliform, HPC, TOC, total suspended and total dissolved solids. The equation used is:
95% confidence interval = X ± tn_j 0 975 (s/a/^)
where: X is the sample mean;
S is the sample standard deviation;
n is the number of independent measurements included in the data set;
t is the Student's t distribution value with n-1 degrees of freedom;
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Results of these calculations are expressed as the sample mean +/- the statistical variation.
3.6 Verification Testing Schedule
The verification testing commenced on February 6, 1999 with the initiation of daily testing. The
unit ran in normal mode (53 gfd at 39°F [91 l/m2/h at 3.8°C] which equates to 94 gfd at 68°F
[169 l/m2/h at 20°C] constant air flow, back pulse 20 seconds every 10 minutes). Daily testing
concluded on March 7.
Giardia and Cryptosporidium removal challenge testing was conducted March 2, 1999.
The cleaning efficiency task was performed on April 15 & 16, 1999. Membrane integrity testing
was done on April 15 prior to the cleaning evaluation.
3.7 Field Operations Procedures
In order to assure data validity, NSF Verification Testing Plan procedures were followed. This
ensured the accurate documentation of both water quality and equipment performance. Strict
adherence to these procedures resulted in verifiable performance of equipment.
3.7.1 Equipment Operations
The operating procedures for the ZeeWeed® ZW-500 system are described in the Operations
Manual (Appendix B) (ZENON, 1998). Analytical procedures are described in PWSA's
Laboratory Quality Assurance Plan (Appendix F) (PWSA 1997).
3.7.1.1 Operations Manual
The Operations Manual for the treatment system was housed on-site and is attached to this report
as Appendix B. Additionally, operating procedures and equipment descriptions were described
in detail in Chapter 2 of this report.
3.7.1.2 Analytical Equipment
The following analytical equipment was used during the verification testing:
¦ A Fisher Accumet Model AP61 portable pH meter was used for pH analyses.
¦ A Hach 21 OOP portable turbidimeter was used for turbidity analyses.
¦ A Hach Pocket Colorimeter was used for chlorine analyses.
¦ An Ertco 1003-FC National Institute of Standards and Technology (NIST) traceable
thermometer was used for temperature analyses. The thermometer had a range -1 to 51°C
with scale divisions of 0.1°C.
The treatment unit used a Hach 1720C turbidimeter for filtrate turbidity and Met One PCX
particle counters for particle analysis.
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3.7.2 Initial Operations
Initial operations allowed the equipment manufacturer to refine the unit's operating procedures
and to make operational adjustments as needed to successfully treat the source water.
Information gathered during system start up and optimization would have been used to refine the
FOD, if necessary. No adjustment to the FOD was necessary as a result of the initial operations.
The unit was on site from September of 1998 conducting pilot testing for the PWSA. The
treatment system was operated until the start of the verification testing to establish the optimum
treatment scheme.
The major operating parameters examined during initial operations were flux, transmembrane
pressure, backpulse frequency, and the efficiency of the treatment unit.
3.7.2.1 Flux
Production capacity of a membrane system is usually expressed as flux. Flux is the water flow
rate through the membrane divided by the surface area of the membrane. Flux is calculated from
the flow rate and membrane surface area and it is typically expressed as gallon per square foot
per day (gfd) or liter per hour per square meter (l/m2/h). The surface area of the membrane used
for the verification testing was 253 ft2 (23.5 in2). It is customary to refer to flux normalized to
68°F or 20°C. Lower temperatures increase the viscosity of water and decrease the amount of
filtrate that can be produced from a given area. The formula used to calculate the system flux is:
Flux (in gfd) = (Flow (gpm) * 1440 minute/day)/ membrane area (ft2)
Flux (in 1/m /h) = (Flow (gpm) * 3.785 l/gal*60 minutes/hour)/membrane area (m2)
A manufacturer-supplied coefficient, which is calculated from the temperature of the feed water,
was used to normalize the flux to 68°F (20°C). The formula used for the calculation for water
temperatures less than 68°F (20°C) is:
Coefficient = L035(20-Watertemperature(qc))
The coefficient is then multiplied by the flux to obtain the flux normalized to 68°F (20°C).
Flux (at uncorrected water temperature)* Coefficient = Flux (normalized to 68°F (20°C)).
The vacuum applied to the membrane is adjusted to maintain the selected flux. Maintaining the
selected flux usually requires an increase in the vacuum. In order to take this change in vacuum
into account, a parameter known as specific flux can be calculated. Specific flux is calculated by
dividing the flux of the system by the transmembrane pressure (TMP). The specific flux is
expressed in gfd per pounds per square inch (psi) at 20°C.
3.7.2.2 Transmembrane Pressure
The vacuum applied to the membrane was recorded twice per day. Since the membranes are
immersed in a tank at atmospheric pressure, the absolute value of the vacuum applied to the
system is equivalent to the TMP of the unit.
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3.7.2.3 Air Agitation/Backpulsing
As water is filtered through the membrane surface, a film of rejected particulates accumulates on
the surface of the fibers. The filtrate flow is gradually impeded as particles accumulate on the
surface of the membrane. The treatment system utilizes two methods to control this particulate
accumulation. Air is introduced to the bottom of the process tank on a continuous basis. This air
agitates the outer surface of the membrane loosening any particles that adhere to the membrane
surface. Periodically, the system undergoes a "backpulse". Backpulsing is the reversal of flow
through the membrane fibers. This flow reversal forcefully removes particles which have tightly
adhered to the membrane fibers. Backpulsing is accomplished by operating pneumatic valves,
drawing filtrate from the CIP tank, and reversing the flow through the membrane fibers. The
manufacturer recommends that the backpulse flux be 1.5 to two times the filtrate flux.
Backpulsing was done for 20 seconds every 10 minutes. A peristaltic pump is used to constantly
remove a small portion of the water from the process tank. This pump is referred to as the bleed
pump. Particulate material that is loosened from membrane by air agitation or backpulsing is
removed from the process tank by the bleed pump.
To aid in cleaning the membrane fibers, chlorine is added to the backpulse water. Sodium
hypochlorite dosing can be done using a small chemical metering pump. During the 30 day test
calcium hypochlorite tablets were placed into the CIP tank. The use of the hypochlorite tablets
resulted in a free chlorine residual in the backpulse water of 4-6 mg/1.
The wastewater removed by the bleed pump was discharged to an existing sewer.
3.7.3.4 Percent Feed Water Recovery
The percent feed water recovery of the treatment system was calculated by comparing the net
production to the amount of wastewater bled from the system. The process tank was filled
through the use of a solenoid valve. The valve would open when the tank level dropped to a
predetermined point; the tank would then refill and the solenoid valve would close. This 'fill and
drain' cycle caused the feed water flows recorded daily to be quite erratic and generally higher
than the average feed water flow of the system. Since the bleed flow and the filtrate flow were
constant these two values were added together to calculate the feed water flow. Therefore the
percent feed water recovery of the system was calculated by dividing the filtrate flow by the sum
of the filtrate and bleed flows and multiplying that result by 100.
3.8 Verification Task Procedures
The procedures for each task of the verification testing were developed in accordance with the
requirements in the EPA/NSF ETV Protocol (NSF, 1998). The Verification Tasks were as
follows:
¦ Task 1 - Membrane Flux and Operation
¦ Task 2 - Cleaning Efficiency
¦ Task 3 - Filtrate Quality
¦ Task 4 - Reporting of Maximum Membrane Pore Size
¦ Task 5 - Membrane Integrity Testing
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¦ Task 6 - Microbial Removal
Detailed descriptions of each task are provided in the following sections.
3.8.1 Task 1: Membrane Flux and Operation
Membrane flux and operational characteristics were identified in this task. The purpose of this
evaluation was to quantify operational characteristics of the UF equipment. Information
regarding this task was collected throughout the length of the 30-day verification study.
The objectives of this task were to:
1. Establish appropriate operational parameters;
2. Demonstrate the product water recovery achieved;
3. Monitor the rate of flux decline over extended operation; and
4. Monitor feed water quality.
Standard operating parameters for filtration, backpulse, and chemical cleaning were established
through the use of the manufacturer's O&M Manual and the initial operations of the treatment
system. After establishment of these parameters, the unit was operated under those conditions.
Operational data were collected according to the schedule presented in Table 3-2.
3.8.1.1 Filtration
The flux selected for the verification study was 94 gfd at 68°F (169 l/m2/h at 20°C).
3.8.1.2 Air Agitation/Backpulsing
As previously discussed, the treatment system utilized air agitation and backpulsing to remove
particles from the membrane surface.
Air agitation consisted of introduction of 7.5 standard cubic feet per minute (scfm) of air on a
continuous basis. The air flow agitated the surface of the fibers and caused some of the particles
adhering to fibers to be removed.
In order to remove particles not eliminated by the air agitation, flow is periodically reversed
through the fibers. This is referred to as backpulsing. The backpulsing was done every 10
minutes for 20 seconds.
Backpulsing is accomplished by operating pneumatic valves, drawing filtrate from the CIP tank,
and reversing the flow through the membrane fibers.
The interval between backpulses is determined based on the ability of the unit to maintain stable
operating conditions. That is, if the backpulse frequency and duration are not able to maintain a
stable flow and TMP over the short term, they are increased. The backpulse frequency and
duration used during the study were capable of maintaining a stable operating conditions.
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Particulate material that is loosened from the membrane by air agitation or backpulsing is
removed from the process tank by the bleed pump. The bleed pump is a peristaltic pump that
constantly bleeds a small portion of the water from the process tank.
3.8.1.3 Chemical Cleaning
The manufacturer generally recommends that chemical cleaning be instituted when the system
TMP approaches 8 psi. The manufacturer indicated that depending on the feed water quality and
verification testing results the TMP can be allowed to reach 12 psi. The latter criterion was
recommended for use during the verification testing.
The cleaning was a two-stage process consisting of soaking the membrane in a chlorine solution
and then soaking the membrane in a citric acid solution. The concentrations of the solutions and
soak times were determined by the manufacturer. The results of the cleaning were evaluated by
the manufacturer and a standard procedure for the concentrations of the solutions and soak times
were established for the site.
For the verification testing the full tank soak cleaning procedure was used. The procedure was
done manually. It consisted of draining the process tank and refilling it with clean water. (In
this case water from the pump station was used.) The clean soak water was dosed with 255 mg/1
of chlorine. The membranes were soaked in this solution overnight (18 hours). The chlorine
soak was followed by a citric acid soak. The process tank was drained and refilled with clean
water. A 650 mg/1 solution of citric acid was created by adding citric acid to the process tank.
The membranes were soaked in this solution for four hours. Following the cleaning procedure
the system was drained, rinsed, and flushed. The system was then refilled and production
resumed.
The procedure used to perform chemical cleaning and alternate cleaning procedures are
presented in detail in the O&M Manual.
3.8.2 Task 2: Cleaning Efficiency
Cleaning efficiency procedures were identified in this task. The objectives of this task were to:
1. Evaluate the effectiveness of chemical cleaning for restoring filtrate productivity to the
membrane system.
2. Confirm manufacturer's cleaning practices are sufficient to restore membrane productivity.
Chemical cleaning, if required during the testing period, was to be instituted when the air
agitation and backpulsing were unable to maintain system TMP <12 psi. If chemical cleaning
was not required during the testing, it was to be performed at the conclusion of the 30-day
period. Although the system did not reach a 12 psi TMP during the 30 day test, the system was
cleaned per protocol requirements on April 15-16, 1999. The membranes were cleaned using
manufacturer's recommendations.
Prior to cleaning, the treatment system was operated at the conditions as described in Section
3.8.1. Operational data, including flow and vacuum, were collected prior to cleaning. After
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cleaning, the system was restarted and operated for a sufficient period of time to establish post-
cleaning specific rate of flux recovery. Operational data, including flow and vacuum, were
collected after cleaning. Table 3-3 details all the operational and analytical data collected before,
during and following cleaning.
Table 3-3. Analytical & Operational Data Collection Schedule - Chemical Cleaning
Parameter Frequency
pH of cleaning solution initial
1/episode
pH of cleaning solution during process
1/episode
pH of cleaning solution final
1/episode
TDS of cleaning solution initial
1/episode
TDS of cleaning solution during process
1/episode
TDS of cleaning solution final
1/episode
Turbidity of cleaning solution initial
1/episode
Turbidity of cleaning solution during process
1/episode
Turbidity of cleaning solution final
1/episode
Oxidant residual initial
1/episode
Oxidant residual final
1/episode
Visual observation of bleed waste initial
1/episode
Visual observation of bleed waste final
1/episode
Flow of UF unit prior to cleaning
1/episode
Vacuum of UF unit prior to cleaning
1/episode
Temperature of UF unit prior to cleaning
1/episode
Flow of UF unit after cleaning
1/episode
Vacuum of UF unit after cleaning
1/episode
Temperature of UF unit after cleaning
1/episode
3.8.2.1 Cleaning Procedures
The procedure used to perform chemical cleaning is presented in the O&M Manual (Appendix
B).
The chemical cleaning process consisted of soaking the membranes in a 255 mg/1 solution of
chlorine, draining the tank, soaking the membranes in 650 mg/1 citric acid solution, draining the
tank, rinsing the membranes, and flushing the system.
3.8.3 Task 3: Filtrate Quality
Procedures for the collection and analysis of filtrate water quality samples are identified in this
task. The purpose of this task was to demonstrate whether the manufacturer's stated treatment
goals are attainable. The goal of this portion of the ETV was to demonstrate the treatment unit's
ability to consistently produce water with a turbidity of less than 0.1 NTU and comply with
current and future regulations in the SWTR and ESWTR as they apply to filtration. Since the
feed water was consistently less than 0.1 NTU and a turbidity challenge was not conducted, this
stated treatment goal was not verifiable.
Testing on filtrate was conducted throughout the length of the 30-day run. Procedures for
sample collection and analysis, analytical equipment operation, analytical equipment calibration
and calibration results are discussed in Section 3.8.1.3.
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3.8.3.1 Sample Collection and Analysis Procedure
Filtrate samples were collected and analyzed monthly for total alkalinity, total hardness, and
TDS. Weekly collection and analysis of filtrate samples was performed for TSS, total coliforms,
HPC, TOC, UV absorbance, and algae. A summary of the sampling schedule is presented in
Table 3-1.
Sample collection and analysis was performed according to procedures adapted from Standard
Methods (APHA et. al., 1992) and Methods for Chemical Analysis of Water and Wastes (EPA,
March, 1979).
3.8.4 Task 4: Reporting of Maximum Membrane Pore Size
Determination of the maximum membrane pore size was to be done to assess the UF unit's
ability to sieve particles of particular sizes. The FTO was to conduct a bubble point test, air
pressure hold test, diffusive air flow test, or sonic wave sensing on the type of membrane in use
during the verification study. The test was to be conducted by a state or EPA certified
laboratory. Due to the extremely high cost of this test and the reliability of data available from
membrane manufacturers, the ETV Steering Committee modified this requirement. The 1999
ETV Protocol Revision requires the reporting of the maximum membrane pore size by the
manufacturer based on recommendation by the Steering Committee (EPA/NSF 1999).
The manufacturer requested a waiver to permit the reporting of maximum membrane pore size in
lieu of maximum pore size determination. This waiver was granted based on the modified
Protocol requirement (EPA/NSF 1999).
3.8.5 Task 5: Membrane Integrity Testing
Procedures for the testing of membrane integrity are identified in this task. The experimental
objective of this task was to assess the membrane's integrity through the use of an air pressure
hold test, turbidity reduction monitoring and particle count reduction monitoring. Membranes
provide a physical barrier against the passage of particles and most types of microbial
contamination. If the membrane is compromised, that is not intact, this barrier is lost. It is
important to be able to detect when a membrane is compromised.
The three procedures, air pressure hold test, turbidity reduction monitoring, and particle count
reduction monitoring, were conducted on intact and compromised membranes. The tests were
conducted prior to and after the intentional breaking of a fiber.
3.8.5.1 Air Pressure Hold Test
The manufacturer provided the following procedure to be used in conducting the air pressure
hold test:
1. Membrane pores must be wet and air bubbles removed (make sure no bubbles are in filtrate
flow meter).
2. Make sure the process tank level is at the set level determined by the project manager (or
owner) (all pressure hold tests must be done at the same operating level).
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3. Shut off the system (filtrate pump and the blower air).
4. Close valves to isolate the membrane.
5. Make sure the pressure regulator is in the closed position before opening the air intake valve
(do not allow a pressure >7 psi on the membranes).
6. Open the air intake and slowly open the pressure regulator to a pressure of 4 psi.
7. Hold the pressure at 4 psi for three minutes to flush water out of the membrane lumens.
8. Keep adjusting the pressure regulator until the pressure on the round pressure gauge
stabilizes at 4 psi for at least 30 seconds.
9. Close hand valve to hold the air in the membrane.
10. Record the pressure decay over 2 minutes.
An intact membrane would be expected to lose no more than 1 psi every two minutes.
3.8.5.2 Turbidity Reduction Monitoring
Turbidity of feed water and filtrate was monitored. An intact membrane would be expected to
show a 90% reduction in turbidity from feed to filtrate. Due to the high quality of the feed water
(the average feed turbidity was 0.09 NTU) showing a 90% reduction, 0.009 NTU, was beyond
the capability of the turbidimeters. Filtrate turbidity between an intact and a compromised
membrane was compared. An increase of 100 % was used as an indication of a compromised
membrane.
3.8.5.3 Particle Count Reduction Monitoring
Particle count reductions from feed water to filtrate of 99.9% would demonstrate an intact
membrane. Due to the high quality of the feed water (the average cumulative feed water particle
counts were 64 total counts per ml) showing a 99.9% reduction was beyond the limits of the
instrumentation. Particles counts were monitored continuously and the differences between
filtrate particle counts from an intact and a compromised membrane were compared. An
increase of 100% was used as an indication of a compromised membrane.
3.8.6 Task 6: Microbial Removal
The primary goal of water treatment is to provide water that is free of disease-causing organisms.
Most of these organisms are traditionally removed or rendered non-infectious through the use of
conventional treatment practices like sedimentation, filtration, and disinfection. Not all disease-
causing organisms are reliably removed by these conventional processes. Membrane filtration
offers the advantage of providing a physical barrier against the passage of two of these
organisms, Giardia and Cryptosporidium.
The purpose of this task was to demonstrate the treatment unit's ability to provide a minimum 3
logio removal from source water to plant effluent of Giardia cysts and 2 logio removal of
Cryptosporidium oocysts. Participation in this task was optional. The manufacturer opted to
participate in the microbial removal challenge.
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Giardia and Cryptosporidium removal challenge testing took place on March 2, 1999. The
procedures for the preparation of the feed water stock, stock addition, sample collection and
analysis, and calibration are presented below.
Procedures for the testing the effectiveness of treatment system in removing Giardia cysts and
Cryptosporidium oocysts are identified in this section. The testing schedule, the experimental
objectives, procedures, and data collection schedule are discussed below.
3.8.6.1 Feed Water Stock Preparation
Challenge organisms were concentrated stock suspensions of formalin-fixed Giardia lamblia
cysts and formalin-fixed Cryptosporidium parvum oocysts. The suspensions were added to a
reservoir using a pipette as that reservoir was being filled with 50 gallons of feed water. A
cocktail of both protozoans was added to the same feed water reservoir and fed simultaneously to
the treatment system. The concentration of the organisms was determined from the stock
suspensions by replicate hemocytometer counts. Five two-ml samples were taken from the feed
water reservoir. These samples were examined and the quantity of cysts and oocysts was
determined. This was used as a check of the replicate hemocytometer counts.
3.8.6.2 Stock Addition Procedure
Source water concentrations were fed into the treatment system immediately before the process
tank over approximately 60 minutes. The feed water stock reservoir was gently mixed during
this process.
3.8.6.3 Sample Collection Procedure
After the suspension was prepared and before the initiation of filtration, samples were collected
to establish the initial titer of the microorganisms. The feed suspension was pumped into the
feed water line immediately before the process tank. Once filtration had begun, the operational
parameters, as presented in Table 3-2, were recorded. Daily analytical testing as presented in
Table 3-1 was conducted. One thousand liters (264 gallons) of filtrate were then passed through
a \um pore sized yarn wound filter at a rate of one gallon per minute (3.785 liter per minute).
Sample volumes of feed water, filtrate and backwash water were recorded. Samples were
processed and analyzed by PWSA's EPA-qualified laboratory according to EPA protocols (EPA,
April, 1996). A minimum of three replicates of the filtered water sample were analyzed.
3.9 QA/QC Procedures
Maintenance of strict Quality Assurance/Quality Control (QA/QC) procedures is important, in
that if a question arises when analyzing or interpreting data collected for a given experiment, it
will be possible to verify exact conditions at the time of testing. The following QA/QC
procedures were utilized during the verification testing.
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3.9.1 Daily QA/QC Verification Procedures
Daily QA/QC procedures were performed on the inline turbidimeter and inline particle counter
flow rates and inline turbidimeter readout.
3.9.1.1 Inline Turbidimeter Flow Rate
The inline turbidimeter flow rate was verified volumetrically over a specific time. Effluent from
the unit was collected into a graduated cylinder while being timed. Acceptable flow rates, as
specified by the manufacturer, ranged from 250 ml/minute to 750 ml/minute. The target flow
rate was 500 ml/minute. Adjustments to the flow rate were made by adjusting the valve
controlling flow to the unit. Fine adjustments to the flow rate were difficult to make. If
adjustments to the flow rate were made they were noted in the operational/analytical data
notebook by including the flow rate prior to adjustment in parenthesis next to the description of
what adjustment was made.
3.9.1.2 Inline Particle Counter Flow Rate
The flow rates for the feed water and filtrate inline particle counters were verified volumetrically
over a specific time. Effluent from the units was collected into a graduated cylinder while being
timed. Acceptable flow rates, as specified by the manufacturer, ranged from 90 ml/minute to
110 ml/minute. The target flow rate was 100 ml/minute. Care was taken to maintain the flow
rate between 95 ml/minute and 105 ml/minute. Flow rate to the particle counter was controlled
by an integral overflow weir. Adjusting the height of the overflow weir altered the flow rate
through the particle counter. If adjustments to the flow rate were made they were noted in the
operational/analytical data logbook by including the flow rate prior to adjustment in parenthesis
next to the description of what adjustment was made.
3.9.1.3 Inline Turbidimeter Readout
Inline turbidimeter readings were checked against a properly calibrated bench model. Samples
of the filtrate were collected and analyzed on a calibrated bench turbidimeter. The readout of the
bench model and the inline turbidimeter were recorded. Exact agreement between the two
turbidimeters is not likely due to the differences in the analytical techniques of the two
instruments.
3.9.2 Bi-Weekly QA/QC Verification Procedures
Bi-weekly QA/QC procedures were performed on the inline flow meter. The meter was checked
to determine if cleaning was necessary and verification of flow was performed.
3.9.2.1 Inline Flow Meter Clean Out
Examination of the inline flow meters indicated that clean out was not required during the
verification testing. This was due to the short duration of the study and the high quality of the
feed water.
26
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3.9.2.2 Inline Flow Meter Flow Verification
Verification of the readout of feed flow and the filtrate flow meters was conducted bi-weekly
during the testing period. This was done by taking the difference in the totalizer reading over a
specific period of time and comparing it to a volume collected over the same time period. The
feed meter was verified by collecting the entire volume of feed water over a timed period and
comparing the amount collected to the totalizer readings. The filtrate meter was verified by
collecting the entire volume of filtrate over a timed period and comparing the amount collected
to the totalizer readings.
3.9.3 Procedures for QA/QC Verifications at the Start of Each Testing Period
Verifications of the inline turbidimeter, pressure gauges/transmitters, tubing, and particle
counters were conducted. These verification procedures follow.
3.9.3.1 Inline Turbidimeter
The inline turbidimeter reservoir was cleaned by removing the plug from the bottom of the unit
and allowing the body to drain. The body of the unit was then flushed with water. The unit was
recalibrated following manufacturer's recommendations.
3.9.3.2 Pressure Gauges / Transmitters
Pressure gauge readouts were compared to the display on the control screen, although the
readings taken directly from the gauges were entered into the operational/analytical data log
book. Pressure gauge readings were verified through the use of a dead test meter. Procedures
for the use of the meter were included with the meter. Generally, the procedure consisted of
placing the gauge on the dead test meter, adding weight to the meter, and comparing the reading
obtained to the known amount of weight. The "pressure" gauge used on the treatment system
was actually a vacuum/pressure gauge. The pressure side of the gauge was verified using the
dead test meter.
3.9.3.3 Tubing
The tubing and connections associated with the treatment system were inspected to verify that
they were clean and in good condition.
3.9.3.4 Inline Particle Counters
Calibration of the particle counter is generally performed by the instrument manufacturer. The
calibration data were provided by the instrument manufacturer for entry into the software
calibration program. Once the calibration data were entered, it was verified by the FTO using
calibrated mono-sized polymer microspheres. Microspheres of 5 «m, 10 um and 15 um were
used for particle size verification. The following procedure was used for instrument calibration:
¦ Analyze the particle concentration in the dilution water;
¦ Add an aliquot of the microsphere solution to the dilution water to obtain a final
particle concentration of 2,000 particles per ml;
27
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¦ Analyze a suspension of each particle size separately to determine that the peak
particle concentration coincides with the diameter of particles added to the dilution
water;
¦ Prepare a cocktail containing all three microsphere solutions to obtain a final particle
concentration of approximately 2,000 particles per ml of each particle size; and
¦ Analyze this cocktail to determine that the particle counter output contains peaks for
all the particle sizes.
3.9.4 On-Site Analytical Methods
Procedures for daily calibration, duplicate analysis, and performance evaluation for pH,
temperature, residual chlorine, and turbidity are discussed in the following sections.
3.9.4.1 pH
Analysis for pH was performed according to Standard Methods 4500-H . A two-point
calibration of the pH meter was performed each day the instrument was in use. Certified pH
buffers in the expected range were used. After the calibration, a third buffer was used to check
linearity. The values of the two buffers used for calibration, the efficiency of the probe
(calculated from the values of the two buffers), and the value of the third buffer used as a check
were recorded in the logbook.
pH measurements do not lend themselves to "blank" analyses. Duplicates were run once a day.
Performance evaluation samples were analyzed during the testing period. Results of the
duplicates and performance evaluation samples were recorded.
3.9.4.2 Temperature
Readings for temperature were conducted in accordance with Standard Methods 2550. Feed
water temperatures were obtained once per day by submerging the thermometer in the feed water
reservoir. A NIST certified thermometer having a range of - 1°C to +51°C, subdivided in 0.1°C
increments, was used for all temperature readings.
Temperature measurements do not lend themselves to "blank" analyses. Duplicates were run on
every sample. The temperature of the feed water was not recorded until two like readings were
obtained, indicating that the thermometer had stabilized. Two equivalent readings were
considered to be duplicate analyses.
3.9.4.3 Residual Chlorine Analysis
Chlorine residual analyses were taken on the bleed waste according to Standard Methods 4500
CI G. The unit was received new (factory calibrated) and daily calibration was not necessary.
The bleed wastewater was collected and analyzed twice per day.
28
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Blanks for chlorine analyses were done by analyzing deionized (DI) water daily. Duplicates
were run once a day. Performance evaluation samples were analyzed during the testing period.
Results of the duplicates and performance evaluation samples were recorded.
3.9.4.4 Turbidity Analysis
Turbidity analyses were performed according to Standard Methods 2130. The bench-top
turbidimeter was calibrated at the beginning of verification test and on a weekly basis using
primary turbidity standards according to manufacturer's recommendations. Primary turbidity
standards of 0.1, 0.5 and 5.0 NTU were checked after calibration to verify instrument
performance. Deviation of more than 10% of the true value of the primary standards indicated
that recalibration or corrective action should be undertaken on the turbidimeter. Secondary
standards were used on a daily basis to verify calibration.
Blanks for turbidity analyses were done by analyzing DI water daily. Duplicates were run on
feed water turbidity and bleed waste once a day. Performance evaluation samples were analyzed
during the testing period. Results of the duplicates and performance evaluation samples were
recorded.
3.9.5 Chemical and Biological Samples Shipped Off-Site for Analyses
PWSA's in-house laboratory was used for the analysis of chemical and biological parameters.
PWSA's QA Plan outlines sample collection and preservation methods (PWSA 1997) (Appendix
F). Sample collection was done by representatives of PWSA.
3.9.5.1 Organic Parameters
Organic parameters analyzed during the verification testing were TOC and UVA254-
Samples for analysis of TOC and UVA254 were collected in glass bottles supplied by the PWSA
laboratory and hand carried to the laboratory by a PWSA representative immediately after
collection. TOC and UVA254 samples were collected, preserved, and held in accordance with
Standard Method 5010B. Storage time before analysis was minimized in accordance to
Standard Methods.
Analysis of the TOC samples were done according to methodology outlined in PWSA's QA Plan
which is based on Standard Methods 5310 C. Analysis of the UVA samples were done
according to methodology outlined in PWSA's QA Plan which is based on Standard Methods
5910 B.
3.9.5.2 Microbiological Parameters
Microbiological parameters analyzed during the verification testing were Total Coliform, HPC,
protozoa and algae.
29
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Microbiological samples were collected according to procedures outlined in PWSA's QA Plan
and hand delivered to the laboratory by a PWSA representative immediately following
collection. Samples were processed for analysis by the PWSA laboratory within the time
specified for the relevant analytical method. The laboratory kept the samples refrigerated at 1-5°
C until initiation of analysis.
Algae samples were preserved with Lugol's solution after collection and stored at a temperature
of approximately 1-5° C until counted.
Algae samples were analyzed according to Standard Method 10200 F. Total coliforms were
analyzed using procedures presented in PWSA's QA Plan. These procedures are based on
Standard Method 9222B. HPC analyses were conducted according to procedures presented in
PWSA's QA plan. These procedures are based on Standard Method 9215D. Protozoans were
analyzed using procedures developed by EPA for use during the Information Collection Rule
(EPA, 1996).
3.9.5.3 Inorganic Parameters
Inorganic parameters analyzed during the verification testing were Total Alkalinity, Total
Hardness, TDS, and TSS.
Inorganic chemical samples were collected, preserved and held in accordance with Standard
Method 301 OB. Particular attention was paid to the sources of contamination as outlined in
Standard Method 3010C. The samples were hand delivered to the laboratory by a representative
of PWSA immediately following collection. The laboratory kept the samples at approximately
1-5° C until initiation of analysis.
Total alkalinity analyses were conducted according to Method 150.1 (EPA, 1979). Total
Hardness analyses were conducted according to Method 130.2 (EPA, 1979). TDS analyses
were conducted according to Standard Method 2540C. TSS analyses were conducted according
to Standard Method 2540D.
30
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Chapter 4
Results and Discussions
4.1 Introduction
The verification testing for the ZENON Environmental Inc. ZeeWeed® ZW-500 UF Drinking
Water System which occurred at the PWSA's Highland Reservoir No. 1 site in Pittsburgh,
Pennsylvania, commenced on February 6, 1999 and concluded its 30-day period on March 7,
1999. Giardia and Cryptosporidium challenge testing was conducted on March 2, 1999,
chemical cleaning was performed on April 15 and 16, 1999, and membrane integrity testing was
performed on April 15, 1999.
This section of the verification report presents the results of the testing and offers a discussion of
the results. Results and discussions of the following are included: initial operations, equipment
characteristics, membrane flux and operation, cleaning efficiency, filtrate quality, maximum
membrane pore size, membrane integrity testing, Giardia and Cryptosporidium removal, and
QA/QC.
4.2 Initial Operations Period Results
An initial operations period allowed the equipment manufacturer to refine the unit's operating
procedures and to make operational adjustments as needed to successfully treat the source water.
The primary goals of the initial operations period were to establish a flux rate, the expected
transmembrane pressure, backpulse frequency appropriate for the feed water quality, and the
efficiency of the unit. The unit was on site in September of 1998 until the end of ETV testing
and was operated to establish the optimum treatment scheme prior to initiation of verification
testing.
4.2.1 Flux
Flux rates from 22 to 110 gfd at 68°F (37 to 190 l/m2/h at 20°C) were examined during the initial
operations period. Based on the data collected during the initial operations period, the
manufacturer determined that the treatment unit would be capable of operating at 94 gfd at 68°F
(169 l/m2/h at 20°C) (which equates to 53 gfd at 39°F [91 l/m2/h at 3.8°C]). This corresponds to
an initial specific flux of 20 gfd/psi at 68°F (482 l/m2/h/b at 20°C), or 11 gfd/psi at 39°F (278
l/m2/h/b at 3.8°C).
4.2.2 Transmembrane Pressure
The TMP during the initial operations period varied with the flux. TMP ranged from 0.9 psi to
9.6 psi (0.06 bar [b] to 0.7 b) during the initial operations period.
31
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4.2.3 Backpulse Frequency
During the initial operations period, backpulse frequencies of 10 and 15 minutes were
investigated. The duration of the backpulse was varied from 7.5 to 20 seconds. Based on the
results of the initial operations period, it was determined that a backpulse of 20 seconds would
occur every 10 minutes. Solids were removed from the system through the means of a bleed
pump. The bleed pump constantly bled a small quantity of the feed water from the process tank.
The bleed pump flow was constant. The bleed pump operated at 1,750 ml per minute throughout
the verification testing.
4.3 Verification Testing Results and Discussion
The results and discussions of membrane flux and operation, cleaning efficiency, filtrate water
quality, reporting of maximum membrane pore size, membrane integrity testing, and microbial
removal tasks of the verification testing are presented below.
4.3.1 Task 1: Membrane Flux and Operation
The parameters of flow, filtrate pressures, backpulse frequency and volumes, and the feed water
temperature were used to establish membrane flux and operational characteristics. TMP and rate
of specific flux decline were established from these parameters and are presented in Table 4-1
and 4-2 respectively. Date of chemical cleaning was April 15-16, 1999. A calculation of the
percent feed water recovery is presented.
4.3.1.1 Transmembrane Pressure Results
Transmembrane pressure fluctuated from 6.4 psi to 8.9 psi during the 30 day testing. The
average TMP during the testing was 7.5 psi. Table 4-1 presents a summary of the TMP. Figure
4-1 presents a graph of daily TMP results. A complete tabular summary of the data is presented
in Appendix C.
Table 4-1. Daily Transmembrane Pressure Results
Transmembrane Pressure
(psi)
Average
7.5
Minimum
6.4
Maximum
8.9
Standard Deviation
0.66
95% Confidence Interval
(7.3, 7.7)
32
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As depicted in Figure 4-1, the TMP increased slightly over the course of the verification testing.
This slight increase was not unexpected and seemed to indicate that the treatment system was
capable of operation at the selected flux and backpulse protocol on this feed water.
The increase in TMP may be due to the accumulation of particles on the membrane surface. The
backpulse protocol may not have removed all of the particulate material from the membrane.
Another possibility is that there was some accumulation of algae or bacteria on the membrane.
(The addition of chlorine to the backpulse water is intended to control the accumulation of these
substances.) An accumulation of material on the membrane would, most likely, cause an
increase in TMP in the system by limiting the available membrane surface area.
The TMP fluctuated somewhat from day to day with subsequent day's readings sometimes being
lower than the previous day's results. This would seem to argue against the accumulation of
material on the membrane. But examination of the overall TMP trend clearly shows an increase
with time. The explanation of why TMP sometimes decreased from day to day may be due to
the fact that the operational readings were taken at various times in the operational cycle.
Vacuum applied to the membrane increased as the time to the next backpulse decreased. If the
pressure and flow readings were taken shortly after the completion of a backpulse cycle, a lower
TMP would result. Likewise if the readings were taken just prior to the initiation of a backpulse
cycle, a higher TMP would result.
33
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There was a noticeable decrease in TMP between run time hours 553 to 578. Although this
decrease occurred during challenge testing, no changes in system operation were instituted in
relation to the challenge test. The reason for this decrease is unknown although it may be due to
the slightly variable flow rate observed during the testing. As the flow rate changed from reading
to reading the TMP would also slightly change. There was a noticeable increase in TMP from
run time hours 578 to 599. There was an increase in system flux between run time hours 553 to
576. The flux increased from 53 to 77 gfd (90 to 130 l/m2/h). The manufacturer has suggested
that this sudden increase in flux accelerated the fouling of the membrane, resulting in the
increased TMP.
The cleaning conducted on April 15 and 16 decreased the TMP from 8.8 psi to 4.4 psi.
Overall the increase in TMP during the 30-day testing period was slight. This would seem to
indicate that the selected flux and backpulse protocol was appropriate for this feed water quality.
4.3.1.2 Specific Flux Results
The specific flux of the treatment system was 13 gfd/psi at 68°F (330 l/m2/h/b at 20°C) on
average. The specific flux varied from a minimum of 11 gfd/psi at 20°C to 25 gfd/psi at 68°F
(264 l/mVh/b to 621 l/m2/h/b at 20°C) during the 30 day testing period. Table 4-2 presents a
summary of the specific flux of the treatment system. Figure 4-2 presents a graph of daily
specific flux results.
Table 4-2. Specific Flux
Specific Flux
(gfd/psi @20°C)
Average
13
Minimum
11
Maximum
25
Standard Deviation
2.3
Confidence Interval
(12, 13)
34
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As depicted in Figure 4-2, specific flux slightly declined over the course of the verification
testing. The specific flux is a function of the flux and the TMP of the system. As the TMP of
the system increases the specific flux declines. The decrease in specific flux during the testing
period was due to the increase in TMP. The specific flux decline did not appear to be excessive
during the testing.
There were five instances of a slight decrease or an increase and then a decrease of the specific
flux. These were at run time one hour, at run time 123 hour, at run time 167 hour, at run time
314 hour, and at run time 576 hour. The reason for these variations can be traced to a fluctuation
in the instantaneous flow through the system. In each instance the filtrate flow of the system
increased from near the average of 9.4 gpm to a value between 10.4 gpm and 14.2 gpm. The
reading on the filtrate flow meter was somewhat variable during the testing. These variations
were of very short duration, typically lasting less than one minute. It would seem that these
increases were transient in nature and not indicative of true long term system performance.
4.3.1.3 Cleaning Episodes
The membranes were cleaned as per protocol requirements using manufacturer's
recommendations on April 15 - 16, 1999. Results of that cleaning are presented in Section 4.3.2.
35
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4.3.1.4 Percent Feed Water Recovery
The percent feed water recovery of the treatment system was calculated by comparing the net
production to the amount of wastewater bled from the system. The process tank was filled
through the use of a solenoid valve. The valve would open when the tank level dropped to a
predetermined point; the tank would then refill and the solenoid valve would close. This caused
the feed water flows recorded daily to be quite erratic and generally higher than the average feed
water flow of the system. Since the bleed flow and the filtrate flow were constant these two
values were added together to calculate the feed water flow. Therefore the percent feed water
recovery of the system was calculated by dividing the filtrate flow by the sum of the filtrate and
bleed flows. The following equation was used:
Percent Feed Water Recovery = ((FF/(FF + BWF))*100
where: FF = filtrate flow
BWF = Bleed wastewater flow
Using the above equation the following calculation was performed:
Filtrate flow = flow (gpm) * minutes/day = filtrate flow (gpd)
Filtrate flow = 9.4 gpm* 1440 minutes/day = 13536 gpd
Feed flow to membrane = filtrate flow + bleed wastewater flow
Feed flow = 13536 gpd + ((1750 ml/min * (1 gal/3785ml) * 1440 min/day)) = 14202 gpd
Percent feed water recovery = 100 * [13536/ 14202] = 95%
4.3.2 Task 2: Cleaning Efficiency
Cleaning was conducted April 15-16, 1999. Data on the characteristics of the cleaning solution
before, during, and after cleaning were collected. Operational parameters were recorded before
and after cleaning. The cleaning solution data were used to characterize the cleaning solution
and waste generated by cleaning of the membranes. The operational data were collected to
facilitate the calculation of the recovery of specific flux and the loss of original specific flux.
4.3.2.1 Results of Cleaning Episodes
Table 4-3 below presents the chemical and physical characteristics of the cleaning solution.
Table 4-4 presents the results of the operational parameters collected before, during, and after the
cleaning procedure.
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Table 4-3. Chemical and Physical Characteristics of Cleaning Solution
Chlorine Cleaning
Citric Acid Cleaning
Parameter
Unit
Result
Dup.
Result Dup.
pH of Cleaning Solution Initial
9.1
9.1
2.6 2.6
pH of Cleaning Solution During Process
9.0
9.0
2.6 2.6
pH of Cleaning Solution Final
8.9
8.9
2.7 2.7
TDS of Cleaning Solution Initial
(mg/1)
680
1342
TDS of Cleaning Solution During Process
(mg/1)
798
1392
TDS of Cleaning Solution Final
(mg/1)
622
1020
Turbidity of Cleaning Solution Initial
(NTU)
1.32
1.36
0.86 0.87
Turbidity of Cleaning Solution During Process
(NTU)
0.88
0.79
0.92 0.96
Turbidity of Cleaning Solution Final
(NTU)
0.99
1.02
1.52 1.60
Chlorine Residual Initial
(mg/1)
198
190
-
Chlorine Residual Final
(mg/1)
121
114
-
Visual Observation of Cleaning Waste Initial
clear
clear
Visual Observation of Cleaning Waste Final
clear
clear
Table 4-4. Operational Parameter Results - Cleaning Procedure
Chlorine Cleaning Citric Acid Cleaning
Parameter
Unit Time
Result
Result
Flow of UF Unit Prior to Cleaning
(gpm) 14:30
8.6
Vacuum Applied to UF Unit Prior to Cleaning
(psi) 14:30
-8.8
Temperature of UF Unit Prior to Cleaning
(°C) 14:30
12.3
Flow of UF Unit After Cleaning
(gpm) 16:00
9.9
Vacuum Applied to UF Unit After to Cleaning
(psi) 16:00
-4.4
Temperature of UF Unit After Cleaning
(°C) 16:00
12.0
4.3.2.2 Calculation of Recovery of Specific Flux and Loss of Original Specific Flux
The following equation was used to calculate the recovery of specific flux:
Recovery of specific flux = 100*(1- (Jsf / Js;))
where: Jsf = Specific flux (gfd/psi) at end of current run (final)
Js; = Specific flux (gfd/psi) when the system was restarted after completion of the
cleaning procedure (initial)
The specific flux prior to the start of the cleaning process was 7.3 gfd/psi at 68°F. The specific
flux when the system was restarted after the completion of the cleaning procedure was 17 gfd/psi
at 68°F.
Using these fluxes in the above equation resulted in a recovery of specific flux of 57%.
The following equation was used to calculate the loss of original specific flux:
Loss of original specific flux = 100*(1- (Js, / Js;0))
where: Jsi0 = Specific flux (gfd/psi) at time zero point of membrane testing
The specific flux at time zero point of membrane testing was 25 gfd/psi at 68°F. The specific
flux when the system was restarted after the completion of the cleaning procedure was 17 gfd/psi
at 68°F.
Using these fluxes in the above equation resulted in a loss of original specific flux of 32%.
37
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4.3.2.3 Discussion of Results
ZENON generally recommends that cleaning be instituted when the TMP approaches and does
not stabilize at less than or equal to 8 psi. The manufacturer indicates that this TMP cut off value
is site-specific and determined by the feed water quality at the test site. The TMP cutoff used
for this verification testing was 12 psi.
The procedure used for chemical cleaning was defined in the operations manual and required
some manual effort. Mixing the cleaning agents into solution, and initiation of the cleaning
procedure required approximately four hours of effort by the operator.
The chlorine cleaning solution waste had a pH of 8.9, a turbidity of 0.99 NTU, and a TDS of 622
mg/1. The total chlorine residual of the chlorine cleaning solution waste was 121 mg/1. The
citric acid cleaning solution wastewater indicated that the solution was acidic, with a pH of 2.7.
The citric acid cleaning waste had a turbidity of 1.52 NTU and a TDS of 1020 mg/1. No chlorine
was used in conjunction with the citric acid solution. Both the chlorine cleaning solution waste
and the citric acid cleaning solution waste were clear.
The cleaning solutions are mixed from 12.5% NaOCl and 100% citric acid. Care must be taken
when handling these materials to avoid injury. Although the stock chemicals from which the
cleaning solutions are mixed can cause personal injury, there are no hazardous materials present
in the waste from the cleaning procedures. The presence of hazardous materials in the
wastewater would be dependent on the quality of the feed water. Local regulations allowed the
waste stream to be discharged to the sanitary sewer system.
Examination of the operational data and the recovery of specific flux showed that the cleaning
procedure did restore 57% of the specific flux to the treatment system. This indicated that the
cleaning procedure was capable of restoring some of the membrane performance.
The loss of original specific flux was 32%. This may indicate that some irreversible fouling of
the membrane had occurred. However, it may also indicate that the cleaning event was not
completely effective.
4.3.3 Task 3: Filtrate Quality
The results of the testing of the feed water for Total Alkalinity, Total Hardness, TDS, TSS, Total
Coliforms, HPC, TOC, UVA254, and Algae are presented in Table 4-5. The results of the testing
of the filtrate for Total Alkalinity, Total Hardness, TDS, TSS, Total Coliforms, HPC, TOC,
UVA254, and algae are presented in Table 4-6. A complete data table is presented in Appendix C.
38
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Table 4-5. Feed Water Testing Results
Parameter
Total
Total
TDS
TSS
Total
HPC
TOC
UVA
Algae
Alkalinity Hardness
Coliforms
(mg/1 as
CaC03)
(mg/1 as
CaC03)
(mg/1)
(mg/1)
(cfu/100 ml)
(cfu/100
ml)
(mg/1)
(cnf1)
(cells/ml)
Average
39
103
229
0.29
0
179
1.89
0.02
18
Minimum
37
98
176
<0.05
0
94
1.66
0.02
8
Maximum
43
108
300
1.0
0
308
2.02
0.02
24
Std. Dev.
2.6
N/A
60.8
0.48
0
92
0.163
0.00
8
95%
Confid Int
(37,42)
N/A
(169, 288)
(0, 0.75)
N/A1
(89, 268)
(1.73,
2.05)
N/A1
(10,26)
N/A = Not applicable because the sample size (n) was 2.
N/A1 = Not applicable because standard deviation = 0
Note: Calculated averages for less than results (<) utilize half of the Level of Detection (0.05 mg/1) or 0.025 mg/1 in these
calculations (Gilbert, 1987).
Table 4-6. Filtrate Testing Results
Parameter
Total
Total
TDS
TSS
Total
HPC
TOC
UVA
Algae
Alkalinity Hardness
Coliforms
(mg/1) as
CaC03
(mg/1) as
CaC03
(mg/1)
(mg/1)
(cfu/100 ml)
(cfu/100
ml)
(mg/1)
(cm4)
(cells/ml)
Average
39
99
236
0.10
0
6
2.17
0.02
<8
Minimum
38
94
150
<0.05
0
2
2.01
0.02
<8
Maximum
41
104
313
0.40
0
18
2.40
0.02
8
Std. Dev.
1.4
N/A
87.0
0.20
0
8.0
0.185
0.00
2
95% Confid
Int
(38, 40)
N/A
(150,321)
(0,0.30)
N/A1
(0, 14)
(1.99,
2.35)
N/A1
(<8, <8)
N/A = Not applicable because the sample size (n) was 2.
N/A1 = Not applicable because standard deviation = 0
Note: Calculated averages for less than results (<) utilize half of the Level of Detection (0.05 mg/1) or 0.025 mg/1 in these
calculations (Gilbert, 1987).
The following observations were made after examination of the results of feed water and filtrate
testing.
Reductions were seen in HPC. HPC averaged 179 cfu/lOOml in the feed water. Filtrate HPC
concentrations were 6 cfu/lOOml on average. (The presence of HPC in the filtrate may have
been due to the inability to completely disinfect the Tygon sample lines.)
Algae concentrations were reduced. Feed water contained 18 cells/ml on average. Average
filtrate algae concentrations were 5 cells/ml. The reported average filtrate concentration was the
result of one cell observed in one of the four samples with a level of detection of 8 cells/ml. The
removal of algae through the system was likely due to the physical removal of the algae cells on
the membrane surface. (Filtrate algae presence may have been due to growth in the Tygon
sample lines.)
Removal in TSS was observed; a reduction of 0.19 mg/1 on average.
The treatment system had little or no effect on the total alkalinity, and total hardness. This was
expected as these parameters are dissolved in solution and will pass through UF membranes.
39
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TOC and UVA254 were not well removed from the feed water. In fact, the average TOC in the
filtrate was slightly higher than the TOC in the feed water. Examination of the confidence
intervals of the results of the two sets of analyses indicates that the difference did not represent a
statistically significant increase. The equivalent nature of the feed water and filtrate TOC results
indicate that the bulk of the TOC in the feed water is dissolved in solution.
Total coliform reduction could not be demonstrated due to the absence of total coliforms in the
feed water and filtrate throughout the test.
Temperature of the feed water was fairly stable during the thirty day testing from a high of 4.5°C
to a low of 3.3°C (40°F to 38 °F). The average temperature was 3.8°C (39 °F).
4.3.3.1 Turbidity Results and Removal
Results of testing for turbidity in the feed water and filtrate were examined to verify the stated
turbidity treatment ability. Since the feed water turbidity was consistently less than 0.1 NTU and
a turbidity challenge was not conducted this stated treatment goal was not verifiable. A
summary of the results is presented in Table 4-7. A complete data table is presented in Appendix
C.
Table 4-7. Turbidity Analyses Results and Removal
Sample
Feed (bench top)
Filtrate (inline)
Parameter
Turbidity
Turbidity
Turbidity
Amount Removed
(duplicate)
(NTU)
(NTU)
(NTU)
(NTU)
Average
0.09
0.09
0.03
0.06
Minimum
0.06
0.06
0.02
0.03
Maximum
0.14
0.13
0.04
0.10
Standard Deviation
0.02
0.02
0.004
0.02
95% Confidence Interval
(0.08, 0.09)
(0.08,0.10)
(0.02, 0.03)
(0.05,0.07)
Due to a problem with the data logging program used on the treatment system the inline filtrate
turbidity data were not accurately recorded. The 10 minute readings from February 6 to
February 23 were recorded by the data logger as -0.002 NTU. The data logger failed on
February 24 and did not begin recording data until March 12. Due to these difficulties four hour
turbidity data can not be presented.
The turbidity of the filtrate was very low throughout the duration of the verification testing. The
inline filtrate turbidimeter readings averaged 0.03 NTU; the benchtop turbidimeter readings
averaged 0.04 NTU. While this may initially appear to be a significant difference, it is most
likely due to the low level of turbidity in the feed and filtrate and the differences in methodology
of the two pieces of analytical equipment. The discrepancy between these two results can be
explained by differences in the analytical techniques between the inline and benchtop
turbidimeter and the low level of turbidity in the filtrate. The benchtop turbidimeter uses a glass
cuvette to hold the sample; this cuvette can present some optical difficulties for the benchtop
turbidimeter. The inline turbidimeter has no cuvette to present a possible interference with the
optics of the instrument. The low level of turbidity in the filtrate also can create analytical
difficulties, particularly for the benchtop. Manufacturer's specifications state that stray light
interference is less than 0.02 NTU. Stray light interference approaching this level at the low
40
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turbidity levels tested could account for the differences in the readings. The low level of
turbidity in the feed water does not allow for conclusions to be drawn regarding the unit's ability
to produce filtrate with turbidities of less than 0.1 NTU.
4.3.3.2 Particle Count Results and Removal
Average feed water particle counts are presented in Table 4-8. Average filtrate particle counts
are presented in Table 4-9. Daily average cumulative counts for feed water and filtrate and the
logio particle removals are presented in Table 4-10. A complete data table is presented in
Appendix C. Figures 4-3 and 4-4 depict results of four hour particle counts for feed water and
filtrate. Figure 4-5 graphically depicts daily logio removals for cumulative particle counts.
Table 4-8.
Feed Water Particle Counts
2-3 jum 3-5 jum
5-7 jum
Size
7-10 jum
10-15 ftm
>15 jum
Cumulative
Average
7.1
43
7.1
5.5
1.4
0.62
64
Minimum
0
0
0
0
0
0
N/A
Maximum
22
130
22
21
8.6
10
N/A
Std. Dev.
3.9
24
3.9
2.5
0.68
0.42
N/A
95%
(6.9, 7.2)
(42, 44)
(6.9, 7.2)
(5.4,5.6)
(1.4, 1.4)
(0.60, 0.64)
N/A
Confid Int
N/A = Not Applicable. Statistical measurements on cumulative data do not generate meaningful data.
Note: Due to results obtained during the QA/QC task involving verification of the calibration of the particle counters, the 15/mi
readings were 16% lower than actual. Due to extremely low results in the 5 jum and 10 jum size range, the reliability of the 2-3
jum, 3-5 jum, 5-7 (im and 7-10 jum particle counts should be considered questionable. See instrument QA/QC verification results
in Section 4.5.3.
Table 4-9.
Filtrate Particle Counts
2-3 jum 3-5 jum
5-7 jum
Size
7-10 jum
10-15 jum
>15 jum
Cumulative
Average
0.33
0.13
0.06
0.05
0.02
0.10
0.70
Minimum
0
0
0
0
0
0
N/A
Maximum
41
6.0
6.0
6.0
2.5
2.4
N/A
Std. Dev.
1.2
0.21
0.21
0.18
0.07
0.19
N/A
95%
(0.28, 0.38)
(0.12,0.14)
(0.05, 0.07)
(0.04, 0.06)
(0.02, 0.02)
(0.01,0.11)
N/A
Confid Int
N/A = Not Applicable. Statistical measurements on cumulative data do not generate meaningful data.
Note: Due to results obtained during the QA/QC task involving verification of the calibration of the particle counters, the 15 jum
readings were 18% lower than actual. Due to extremely low results in the 5 jum and 10 jum size range, the reliability of the 2-3
jum, 3-5 jum, 5-7 jum and 7-10 jum particle counts should be considered questionable. See instrument QA/QC verification results
in Section 4.5.3.
41
-------
Table 4-10. Daily Average Cumulative Particle Counts - Feed Water and Filtrate, Log 10 Particle Removal
Date
Feed
Filtrate
Log10 Removal
2/6/1999
88
1.4
1.8
2/7/1999
80
1.2
1.8
2/8/1999
82
1.0
1.9
2/9/1999
82
0.92
2.0
2/10/1999
67
0.71
2.0
2/11/1999
62
0.75
1.9
2/12/1999
113
0.68
2.2
2/13/1999
95
0.53
2.2
2/15/1999
79
0.48
2.2
2/16/1999
76
0.51
2.2
2/17/1999
82
0.53
2.2
2/18/1999
58
0.62
2.0
2/19/1999
63
0.48
2.1
2/20/1999
49
0.40
2.1
2/21/1999
49
0.57
1.9
2/22/1999
42
0.53
1.9
2/23/1999
45
0.69
1.8
2/24/1999
50
0.46
2.0
2/25/1999
108
1.0
2.0
2/26/1999
54
0.71
1.9
2/27/1999
51
1.2
1.6
2/28/1999
94
1.1
1.9
3/1/1999
102
0.63
2.2
3/2/1999
107
0.41
2.4
3/3/1999
132
1.3
2.0
3/4/1999
168
2.5
1.8
3/5/1999
164
0.55
2.5
3/6/1999
194
0.39
2.7
3/7/1999
180
0.36
2.7
42
-------
Feed Water 4 Hour Particle Counts vs. Time
120
Run Time (hours)
Figure 4-3. Four Hour Feed Water Particle Counts
Filtrate 4 Hour Particle Counts vs. Time
161
1.4 1 L
1.2
J ImwTWTiTfftTTMiwmfVEVJIVJIVVtftfJVVVlJRIVfcJffiJJVJVVIVIVVJJmfVVIPVJVMHVVTnlJtrlVVItrnTi ifHrnUVVWPIVJIVJJNtflVJWVVJV
^ d?> bP A*"^ Os®
^ ^ K°
-------
Particle counting of feed water and filtrate was conducted throughout the testing period. The
feed water cumulative counts averaged 64 particles per ml. The filtrate cumulative counts
averaged 0.70 counts per ml. The average logio removal for the cumulative counts was 2.1.
Daily Average Log10 Removal of Cumulative Particle Counts vs. Time
3.UU
0)
>
13
3
£ 2.50
3
o
0
15 » 2 00"
> c
0 D
£ o
o o
Q£ r
o <5
-J a.
0 100
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rc
0)
< 0.50
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0.00 "T
.<$> .<#> .<#> .<$> .<#> .<$> .<#> .<$> .<$> .<#> .<$> .£#> .<#> ,c£>
^ ^ ^ * * *
Date
Figure 4-5. Daily Average Logio Cumulative Particle Removal
The low particle counts for each size range in the filtrate indicated good system performance
throughout the testing period. The treatment system seems to be an effective removal
mechanism for particle removal. However, given the poor results of the particle counter
calibration check (see Section 4.5.3), caution should be used when drawing inferences about
particle removal.
4.3.3.3 Bleed Wastewater Testing Results
Daily and weekly testing was conducted on the water bled from the bottom of the process tank.
The results of the testing are listed in Table 4-11 and Table 4-12. A complete data table is
presented in Appendix C.
Table 4-11. Daily Bleed Wastewater Testing Results - Summary
Parameter
Turbidity
Turbidity (dup) Chlorine Residual
Chlorine Residual (dup)
(NTU)
(NTU) (mg/1)
(mg/1)
Average
0.76
0.76 0.72
0.71
Minimum
0.35
0.38 0.53
0.49
Maximum
1.66
1.19 0.99
0.97
Standard Deviation
0.29
0.25 0.10
0.10
95% Confidence Interval
(0.69, 0.83)
(0.67,0.85) (0.68,0.76)
(0.68, 0.76)
44
-------
Table 4-12. Weekly Bleed Wastewater Testing Results
Parameter
TSS
Total Coliforms
HPC
(mg/1)
(cfu/100 ml)
(cfu/100 ml)
Average
0.43
0
22
Minimum
0.20
0
12
Maximum
0.80
0
40
Standard Deviation
0.26
0
13
95% Confidence Interval
(0.17,0.68)
N/A
(9, 35)
N/A = Not applicable because standard deviation = 0
The turbidity of the bleed wastewater averaged 0.76 NTU. The chlorine averaged 0.72 mg/1.
TSS content in the waste was somewhat variable; but the backpulse procedure appeared to be
removing some particulate material. Total coliforms were absent in the bleed wastewater but
HPC was observed.
4.3.3.4 Total Suspended Solids Mass Balance
The mass balance of TSS was calculated from the amount of suspended solids entering the
treatment system, the amount in the filtrate, and the amount in the bleed wastewater. There is a
portion of the TSS which will not be removed by backpulsing and accumulates on the
membrane; the majority of this accumulated material is presumably dissolved and removed by
chemical cleaning.
To calculate the amount of TSS in the treatment stream the following equation was used:
Pounds/day (lbs/day) = Amount of TSS in mg/1 * [(8.341b) / (mg/1 *MG)]*Flow MGD
Pounds of TSS in feed water:
Average feed water TSS (from Table 4-5) = 0.29 mg/1
Calculate the feed water flow in MG: (9.9 gpm) * (1440 min/day) = 14256 gal/day / (1,000,000
gal/MG) = 0.01426 MGD.
lbs/day = 0.29 mg/1 *[(8.341b) / (mg/1 *MG)*( 0.01426 MGD)] = 0.035 lbs/day
Pounds of TSS in filtrate:
Average filtrate TSS (from Table 4-6) = 0.10 mg/1
Calculate the filtrate flow in MG: (9.4 gpm)* (1440 min/day) = 13536 gal/day / (1,000,000
gal/MG) = 0.01354 MGD.
lbs/day = 0.10 mg/1 *[(8.341b) / (mg/1 *MG)*( 0.01354 MGD)] = 0.011 lbs/day
Pounds of TSS in bleed wastewater:
Average wastewater TSS (from Table 4-12) = 0.43 mg/1
Calculate the amount of bleed wastewater produced daily in MG:
(1750 ml/minute)/(3785 ml/gallon) = 0.462 gpm
45
-------
(0.462 gpm*1400 minute/day) = 666 gallons per day
665 gallons per day / (1,000,000 gal/MG) = 0.000666 MGD
lbs/day = 0.43 mg/l*[(8.341b) / (mg/1 *MG)*0.000666 MGD] = 0.0024 lbs/day
Pounds of TSS accumulating on membrane:
This figure is the difference between the amount of TSS added to the membrane and the amount
of TSS removed during continuous bleed. The majority of this portion of the TSS is removed
during the chemical cleaning process. The amount of TSS in the cleaning waste is not
quantifiable due to the nature of the solids in the waste (i.e. TDS).
The TSS mass balance equals:
Pounds of TSS in influent = pounds of TSS in effluent + pounds of TSS in bleed waste + pounds
of TSS accumulating on the membrane.
0.035 lbs/day TSS in influent = 0.011 lbs/day TSS in effluent + 0.0024 lbs/day TSS in bleed
waste +0.022 lbs/day accumulating on the membrane.
The TSS mass balance calculation would seem to indicate that the backpulsing procedure was
not effective at removing the particulate material deposited on the membrane. According to the
calculation, twice as much TSS was left on the membrane as was removed during backpulsing.
It would seem that if this were actually occurring that the system TMP would have increased
more significantly during the test period and that the recovery of specific flux after chemical
cleaning would have been greater than what was seen during the verification testing. A more
likely explanation is that the TSS in the bleed wastewater was higher than the average of the
weekly analyses indicated. The daily bleed wastewater turbidity readings were quite variable.
This variability and the limited number of TSS samples taken from the wastewater may have
allowed under estimation of the TSS removed during the backpulse process. The results could
be a function of the relatively low levels of TSS in the feed water. The laboratory uses Standard
Method 2540 D. According to the Standard Methods in the Precision Section of the method, the
standard deviation at 15 mg/1 was 5.2 mg/1, a coefficient of variation of 33%. At higher
concentrations, the coefficient of variation decreases, 10 % at 242 mg/1. (APHA et al., 1992).
There is a relative lack of precision with Standard Method 2540 D at low levels and low levels
were seen in the testing. The laboratory was contacted and reported that at the low levels tested
the method is very poor at generating meaningful results.
4.3.4 Task 4: Reporting of Maximum Membrane Pore Size
The manufacturer reports that the membrane used during the verification testing has a maximum
pore size of 0.1 |im and that 90% of the pores in their membrane are equal to or less than 0.03
|im. These results were generated through the use of ASTM Method F316 Standard Test
Methods for Pore Size Characterization of Membrane Filters by Bubble Point and Mean Flow
Pore Test. These results were provided by the manufacturer and were not verified during the
ETV testing. Appendix G contains the manufacturer's statement confirming this information.
46
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4.3.5 Task 5: Membrane Integrity Testing
Membranes provide a physical barrier against the passage of particles and most types of
microbial contamination. If the membrane is compromised, that is not intact, this barrier is lost.
It is important to be able to detect when a membrane is compromised. Methods for detecting a
compromised membrane are air pressure hold test, turbidity reduction monitoring, and particle
count reduction monitoring. These tests were run on an intact membrane and one that had been
intentionally compromised. Testing was conducted April 15, 1999. A complete data table is
presented in Appendix C.
4.3.5.1 Air Pressure Hold Test Results
At time zero, during testing of the intact membrane the air pressure was 4.00 psi (0.276 b). After
three minutes the air pressure was 3.97 psi (0.274 b). This demonstrated that the membrane was
intact. (According to the manufacturer, an intact membrane would be expected to lose no more
than 1 psi every two minutes).
Air pressure loss was also compared to the loss that was obtained when testing a compromised
membrane. The membrane was intentionally compromised by severing a fiber.
At time zero the air pressure was 4.00 psi (0.276 b). After two minutes the air pressure was 2.00
psi (0.138 b). This demonstrated that the membrane was compromised.
4.3.5.2 Turbidity Reduction Monitoring
Turbidity of feed water and filtrate was monitored. An intact membrane would be expected to
show a 90% reduction in turbidity from feed to filtrate. Due to the high quality of the feed water
(the average feed turbidity was 0.09 NTU) showing a 90% reduction, 0.009 NTU, was beyond
the capability of the turbidimeters. Filtrate turbidity between an intact and a compromised
membrane was compared. An increase of 100% was used as an indication of a compromised
membrane. The turbidity in the filtrate in the 8 hours before the membrane was compromised
averaged 0.022 NTU. The turbidity of the filtrate in the two hours after the membrane was
compromised was 0.027 NTU.
Turbidity reduction monitoring between feed water and filtrate was not possible due to the low
feed water turbidity level. The filtrate turbidity produced by an intact membrane was not
significantly different than the filtrate turbidity produced by a compromised membrane.
Comparison of the filtrate turbidity between intact and compromised membranes was not a
reliable way to detect a compromised membrane for the low turbidity feed water at the test site.
4.3.5.3 Particle Count Reduction Monitoring
Particle count reductions from feed water to filtrate of 99.9% would demonstrate an intact
membrane. The average cumulative feed water particle counts were 64 total counts per ml,
showing a 99.9% reduction was beyond the limits of the instrumentation. Differences between
47
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filtrate particle counts from an intact and a compromised membrane were compared. An
increase of 100% was used as an indication of a compromised membrane.
Due to a problem with the data logging program used on the treatment system, the inline filtrate
particle count data were not accurately recorded during the hour the system was run with the
broken fiber. This failure does not allow for evaluation of particle counting as a method for
detecting a compromised membrane.
4.3.6 Task 6: Microbial Removal
The purpose of this task was to demonstrate the treatment unit's ability to provide a minimum 3
logio removal of Giardia cysts and a 2 logio removal of Cryptosporidium oocysts from the feed
water. The Giardia and Cryptosporidium challenge took place on March 2, 1999. The system
operated at a manufacturer-recommended flux of 110 gfd at 68°F (190 l/m2/h at 20°C) and an
average specific flux of 12 gfd/psi (300 l/m2/h/b at 20°C) during the Giardia and
Cryptosporidium removal challenge testing. The results of the testing are summarized in the
laboratory report enclosed in Appendix H.
4.3.6.1 Feed Water Concentrations
During the Giardia and Cryptosporidium removal challenge testing the feed water had a pH of
7.8, a turbidity of 0.12 NTU, and a temperature of 3,6°C.
Three replicate hemocytometer counts were performed on the stock solutions. The average of
these replicate counts were then used to calculate stock concentrations. The average stock
solutions contained 1.15 x 106 and 1.32 x 107 (oo)cysts per milliliter for Giardia and
Cryptosporidium, respectively.
Fifty gallons of feed water were then spiked with 7.5 mis and 8.3 mis of the Giardia and
Cryptosporidium stock suspensions, respectively. As presented in Table 4-13, a total of
8,625,000 Giardia cysts and 109,643,000 Cryptosporidium oocysts were added to the 50 gallons
of feed water. This resulted in a theoretical concentration of 276,000 Giardia cysts and
2,192,860 Cryptosporidium oocysts per gallon of feed water. The spiked feed water containing
the cysts and oocysts was constantly mixed using a drum mixer. A diaphragm pump was used to
add the spiked feed water to the treatment unit. The pump was operated at about 0.85 8pm (3.2
liter per minute). The stock solution from the feed water reservoir was fed to the system for
approximately 60 minutes.
As a QC check, five two-ml aliquots were taken from the spiked feed water reservoir at five to
ten minute intervals. A composite of these five aliquots was prepared. A microscopic
examination of this composite showed concentrations of 48 and 560 (oo)cysts per milliliter for
Giardia and Cryptosporidium, respectively, in the 50 gallons of spiked feed water. Therefore,
multiplying these results by the total volume (50 gallons or 190,000 mis), 9,126,000 Giardia
cysts and 106,400,000 Cryptosporidium oocysts had been added to the feed water reservoir (see
Table 4-14). These results are 5.8% greater and 3.0% less, respectively than the results based on
the hemocytometer counts of the stock solutions and milliliters of stock added.
48
-------
To assess log removals, the hemocytometer counts presented in Table 4-13 were used rather than
the results in Table 4-14. This is because the concentrations of the stock solution were
determined per EPA protocols and also due to the uncertain nature of sampling and mixing of the
spiked feed water solution, which could render the composite sample results questionable.
Bench data sheets and report from the laboratory are enclosed in Appendix H.
Table 4-13. Giardia and Cryptosporidium Stock Suspension Results by Hemocytometer Counts
Giardia Cysts Cryptosporidium Oocysts
Average count (oocysts or cysts/0.0001 ml)
115
1,321
Standard Deviation
11
26
95% Confidence Interval
(105, 126)
(1,295, 1,346)
Total cysts and oocysts added to feed water
8,625,000
109,643,000
reservoir (7.5 mis of Giardia stock
suspension, 8.3 mis Cryptosporidium)
Feed Water Amount Confidence Interval
(7,877,974; 9,422,026)
(107,543,144; 111,527,523)
Table 4-14. Feed Water Reservoir Concentrations of Giardia and Cryptosporidium by Microscopic Examination
Giardia Cysts Cryptosporidium Oocysts
Presumptive count (oocysts or cysts/ml) 48 560
Total cysts and oocysts added to feed 9,126,000 106,400,000
water reservoir
4.3.6.2 Filtrate Concentrations
The filtrate was sampled as described in the EPA's ICR Method for detecting Giardia Cysts and
Cryptosporidium Oocysts (EPA, 1996). No Giardia cysts or Cryptosporidium oocysts were
identified in the filtrate as shown by the absence of cysts and oocysts on the 1 |im nominal
porosity, yarn-wound capture filter.
The logio removal of Giardia cysts and Cryptosporidium oocysts was calculated as follows.
1. The amount of filtrate sampled was divided by the total amount of filtrate filtered by the
system. In this case, one gallon per minute was filtered through the sampling filter
compared to ten gallons per minute of filtrate produced by the treatment system, with a
result of 0.1.
2. This result was applied to the total amount of cysts added to the treatment system and
used to calculate the total amount of cysts which could have been trapped on the
sampling filter. In this case 0.1 times the results presented in Table 4-13.
3. This result of Step 2 above was then converted to its logio equivalent.
4. The percent recovery of the ICR test method at the PWSA laboratory is 25%; this means
that the lowest number of cysts or oocysts that could be detected is four. That is, if four
cysts or oocysts were in the filtrate, one of them would be detected. This number, four,
was also converted to its logio equivalent.
5. The final log removal calculation was made by subtracting the logio of the number four
from the logio number of cysts added to the sampling filter (Step 3 above). Table 4-15
49
-------
presents the concentrations and the logo removal calculations of the Giardia cysts and
Cryptosporidium oocysts.
Based on this procedure for calculating log removals, these results demonstrated a 5.3 logio
removal of Giardia cysts and a 6.4 logio removal of Cryptosporidium oocysts.
During the Giardia and Cryptosporidium removal challenge testing, the filtrate had a turbidity of
0.028 NTU and an average cumulative particle counts of 0.31 counts/ml.
Table 4-15. Giardia and Cryptosporidium Challenge Logi0Removal Calculation
Giardia Cyst Removal Cryptosporidium
Oocyst Removal
Cysts/oocysts in Feed Reservoir (from Table 4-13) 8,625,000 109,643,000
Cysts/oocysts added to capture Filter (The total number of 862,500 10,964,300
cysts/oocysts in Feed Reservoir multiplied by 10% because the
system was pumping at 10 gpm and sampled at Igpm.
Effectively, only 10% of the total cysts/oocysts added could
have been detected on the capture filter.)
Log10 of cysts/oocysts added to capture filter 5.9 7.0
Log10 of method recovery (PWSA laboratory method recovery 0.60 0.60
is 25%, i.e. 1 in 4.)
Log10 removal (difference of logio of cysts/oocysts added to 5.3 6.4
capture filter and losm of method recovery)
4.3.6.3 Bleed Wastewater Examination
Examination of the wastewater was conducted to assure that the protozoans were added to the
membrane system, the organisms were removed by the membrane and that the backpulsing
procedure was capable of removing the protozoans from the membrane system. Five hundred ml
of the bleed wastewater were collected and examined. Both Giardia cysts and Cryptosporidium
oocysts were observed in the sample. Quantification of the numbers of each organism in the
sample was not done.
4.3.6.4 Operational and Analytical Data Tables
The operation of the treatment system was monitored during the challenge testing. Pressure
readings and flow rates were recorded. Results of these readings are presented in Tables 4-16
and 4-17. Turbidity and particle count readings were taken during the challenge testing.
Samples for feed water turbidity and particle counts were collected upstream of the point where
the Giardia cysts and Cryptosporidium oocysts were added to the feed water stream. Results of
the turbidity and particle count readings are presented in Tables 4-18, 4-19, and 4-20. Samples
of bleed wastewater before and after the challenge were collected and analyzed. Results of these
analyses are presented in Table 4-21.
50
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Table 4-16. Transmembrane Pressure Readings During Microbial Removal Testing
Transmembrane Pressure
Date Time (psi)
3/2/99 11:40 7.4
3/2/99 13:00 7.0
Table 4-17. Specific Flux During Microbial Removal Testing
Specific Flux
Date Time (gfd/psi @20°C)
3/2/99 11:40 19
3/2/99 13:00 12
Table 4-18. Turbidity Analyses Results and Removal During Microbial Removal Testing
Feed Filtrate
Turbidity Turbidity Turbidity Amount Removed
(duplicate)
Date Time (NTU) (NTU) (NTU) (NTU)
3/2/99 11:20 0.12 0.13 0.030 0.093
3/2/99 m5 OH N/A N/A N/A
N/A = Not applicable. Only one sample per day required by protocol.
Note: Feed turbidity sampled prior to injection of challenge feed solution.
Table 4-19. Feed Water Particle Counts 3/2/99
Size
2-3 jum 3-5 jum 5-7 jum 7-10 jum 10-15 jum >15 jum Cumulative
Average
6.5
43
6.5
5.8
1.5
0.67
64
Minimum
0
0
0
0
0
0
N/A
Maximum
8.7
54
8.7
7.3
2.1
3.6
N/A
StdDev
0.83
4.9
0.83
0.78
0.27
0.41
N/A
95% Confid
(4.9, 8.2)
(34, 53)
(4.9, 8.2)
(4.3, 7.4)
(0.99,2.1)
(0,1.5)
N/A
Int
N/A = Not Applicable. Statistical measurements on cumulative data do not generate meaningful data.
Note: Due to results obtained during the QA/QC task involving verification of the calibration of the particle counters, the \ 5fim
readings were 16% lower than actual. Due to extremely low results in the 5 jum and 10 jum size range, the reliability of the 2-3
jum, 3-5 jum, 5-7 (im and 7-10 jum particle counts should be considered questionable. See instrument QA/QC verification results
in Section 4.5.3.
Feed particle counts sampled prior to injection of challenge feed solution.
Table 4-20. Filtrate Particle Counts 3/2/99
Size
2-3 jum 3-5 jum 5-7 jum 7-10 jum 10-15 jum >15 jum Cumulative
Average
0.14
0.03
0.03
0.03
0.02
0.07
0.31
Minimum
0.03
0
0
0
0
0
N/A
Maximum
0.30
0.13
0.10
0.13
0.10
0.63
N/A
StdDev
0.06
0.03
0.03
0.03
0.02
0.09
N/A
95% Confid
(0.022, 0.26)
(0, 0.087)
(0, 0.081)
(0, 0.087)
(0, 0.063)
(0, 0.25)
N/A
Int
N/A = Not Applicable. Statistical measurements on cumulative data do not generate meaningful data.
Note: Due to results obtained during the QA/QC task involving verification of the calibration of the particle counters, the 15 jum
readings were 18% lower than actual. Due to extremely low results in the 5 jum and 10 jum size range, the reliability of the 2-3
jum, 3-5 jum, 5-7 jum and 7-10 jum particle counts should be considered questionable. See instrument QA/QC verification results
in Section 4.5.3.
Table 4-21. Daily Bleed Wastewater Testing Results During Microbial Removal Testing
Turbidity Turbidity (dup) Chlorine Residual Chlorine Residual (dup)
Date Time (NTU) (NTU) (mg/1) (mg/1)
3/2/99 11:15 1.17 1.19 0.70 0.67
3/2/99 13:10 1.08
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Testing of the feed, filtrate, and bleed wastewater for Total Alkalinity, Total Hardness, TDS,
TSS, Total Coliforms, HPC, TOC, UVA was not conducted during the challenge testing
procedure.
4.3.6.5 Discussion of Results
No Giardia cysts or Cryptosporidium oocysts were observed in the filtrate. The membranes
appeared to successfully remove all of the Giardia cysts and Cryptosporidium oocysts
introduced into the treatment system. Since the recovery of the analytical method is 25% there is
a slight possibility that some cysts or oocysts passed through the membrane and were not
identified during analysis. Nevertheless, the treatment system provided 5.3 logio removal of
Giardia cysts and 6.4 logio removal of Cryptosporidium oocysts. These results indicate that the
treatment system would be capable of successfully complying with the current protozoan
removal requirements of the SWTR and ESWTR, if used on this source water. The current
provisions are 3 logio removal of Giardia cysts and 2 logio removal of Cryptosporidium oocysts
as stated in Section 3.1.1.2.
The logio removals were controlled by the amount of the parasites which were present in the
stock feed solution, the percentage of the filtrate that could be sampled and the percent recovery
of the analytical methodology. Higher feed concentrations, percentage of filtrate examined and
percent recovery of the analytical methods may yield higher logio removals.
4.4 Equipment Characteristics Results
The qualitative, quantitative and cost factors of the tested equipment were identified during
verification testing, in so far as possible. The results of these three factors are limited due to the
relatively short duration of the testing cycle.
4.4.1 Qualitative Factors
Qualitative factors that were examined during the verification testing were the susceptibility of
the equipment to changes in environmental conditions, operational reliability, and equipment
safety.
4.4.1.1 Susceptibility to Changes in Environmental Conditions
Changes in environmental conditions that cause degradation in feed water quality can have an
impact on the treatment system. The short duration of the testing cycle and the stable nature of
the feed water minimized the opportunity for significant changes in environmental conditions.
As previously stated, the reservoir water was treated (coagulated, flocculated, settled, filtered,
and disinfected) surface water that had been pumped from PWSA's Aspinwall treatment plant.
The fact that the feed water was finished drinking water stored in an open reservoir limited the
opportunity for significant changes in feed water quality. No environmental upsets significant
enough to affect feed water quality occurred during testing. Since the treatment unit was housed
in the pumping station and was not exposed to the elements, opportunities for environmental
upsets were limited.
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4.4.1.2 Operational Reliability
During the verification test, the unit operated in the automatic mode. Manual operation was
required for chemical cleaning of the system. A representative of the manufacturer visited the
site daily to visually inspect the system, record operating parameters, and enter the operational
data into a personal computer (PC). This data was transmitted to the manufacturer who would
review the data and make any operational changes that were necessary. No significant
operational changes were necessary throughout the verification testing.
4.4.1.3 Equipment Safety
Evaluation of equipment safety was conducted as part of the verification testing. Evaluation of
the safety of the treatment system was done by examination of the components of the system and
identification of hazards associated with these components. A judgement as to the safety of the
treatment system was made from these evaluations.
There are safety hazards associated with high voltage electrical service. The electrical service
was connected according to local code requirements and did not represent an unusual safety risk.
The calcium hypochlorite used for membrane backpulsing created a safety concern. The use of
appropriate personal protective equipment (PPE) minimizes the risk of exposure when handling
the chemical. The prompt and proper clean up of spills also minimizes the hazards associated
with this chemical.
The stock chemicals from which the cleaning chemicals are mixed, citric acid and sodium
hypochlorite, are hazardous chemicals. The use of appropriate PPE minimizes the risk of
exposure to the stock chemicals while the dilution is being made. The prompt and proper clean
up of spills minimizes the hazards associated with these chemicals.
No injuries or accidents occurred during the testing.
4.4.2 Quantitative Factors
Quantitative factors that were examined during verification testing were power supply
requirements, consumable requirements, waste disposal technique, and length of operating cycle.
Cost factors for the above items are discussed where applicable. It is important to note that the
figures discussed here are for the ZeeWeed® ZW-500 system operating at 94 gfd at 68°F (170
l/m2/h at 20°C). Costs will vary if the system is operated at different flux rates.
4.4.2.1 Power Supply Requirements
The treatment unit's electrical requirements were 230 V, 60 Hertz, 60 Amps, single phase
current. Daily power consumption was determined by reading a dedicated electric meter. The
electric meter was installed by a certified electrician according to the local electric code.
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The unit used an average of 77 kilowatt hours (kwh) per day. The highest recorded daily usage
was 98 kwh; the minimum daily usage was 59 kwh. The differences in these readings can most
likely be explained by the differences in elapsed time between the daily readings. The electric
meter readings were taken daily but not necessarily exactly 24 hours after the previous readings.
The 59 kwh consumption was calculated from readings which were taken 22 hours apart. The 98
kwh consumption was calculated from readings taken 28 hours apart. There was also some
extrapolation of the meter readings done. If the arm of the last dial was between two numbers
the lower number was recorded.
4.4.2.2 Consumable Requirements
Consumable commodities included calcium hypochlorite and the cleaning chemicals, citric acid
and sodium hypochlorite. Calcium hypochlorite was added to the filtrate used for backpulsing.
The total chlorine residual in the backpulse waste was 0.72 mg/1. This level of chlorine residual
required approximately 1 lb. calcium hypochlorite per month. The chemical cleaning episode
requires one gallon of sodium hypochlorite and about one lb (455 g) citric acid. Each of these
chemicals is added to approximately 185 gallons of clean water in the process tank.
4.4.2.3 Waste Disposal
The wastes generated by the treatment system were bleed wastewater and the chemical cleaning
wastes. The microbial challenge testing also generated wastes during the verification testing.
All of these wastes were disposed of to an existing catch basin that was connected to PWSA's
sewerage system. The unit produced approximately 666 gpd of bleed wastewater during
verification testing.
The chlorine cleaning waste had a pH of 8.9, a turbidity of 0.99 NTU, and a TDS of 622 mg/1.
The total chlorine residual of the chlorine cleaning waste was 121 mg/1. The chlorine cleaning
waste was clear in appearance. The characterization of the citric acid cleaning waste indicated
that the solution was acidic, with a pH of 2.7. The citric acid cleaning waste had a turbidity of
1.52 NTU and a TDS of 1020 mg/1. The citric acid cleaning waste was clear in appearance.
The bleed wastewater was feed water, filtrate, residual chlorine and solids removed from the
membrane; it required no treatment prior to discharge to the sewers. The average concentration
of TSS in the bleed waste was 0.43 mg/1. The range of TSS concentration was from 0.20 mg/1 to
0.80 mg/1. The chlorine residual in the bleed wastewater averaged 0.72 mg/1 and ranged from
0.53 mg/1 to 0.99 mg/1. A complete presentation of the bleed wastewater data is included in
Appendix C.
The microbial challenge utilized formalin fixed Giardia cysts and Cryptosporidium oocysts. The
backpulse waste from the challenge test was collected, chlorinated, and stored for 3 days prior to
discharge.
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4.4.2.4 Length of Operating Cycle
The operating cycle to be considered was the interval between chemical cleanings. The length of
this operating cycle is site-specific and determined by the manufacturer after evaluation of the
feed water quality. The cycle lengths are easily field adjustable if necessary; no adjustments
were required for this verification.
The interval between chemical cleaning is estimated to be 30 days for the Pittsburgh test site.
For the Pittsburgh test site, ZENON recommended that cleaning be done when the air agitation
and backpulsing were unable to maintain system TMP <12 psi. The manufacturer estimates that
interval between chemical cleanings would be four weeks when the feed water temperature is
less than 10° C and may be extended to eight week periods when the feed water temperature is
greater than or equal to 10°C.
4.5 QA/QC Results
The daily, bi-weekly, initial, on-site, and the analytical laboratory QA/QC verification results are
presented below.
4.5.1 Daily QA/QC Results
Daily readings for the inline turbidimeter flow rate and readout and inline particle counter flow
rate QA/QC results were taken and recorded.
The inline feed water turbidimeter flow rate averaged 452 ml/minute. The flow rate was
measured using a graduated cylinder and stop watch. The maximum rate measured, during the
testing was in excess of 1000 ml/minute; the minimum was 0 ml/minute. These flows were
immediately adjusted to return them to the acceptable flow range. The acceptable range of flows
as specified by the manufacturer is 250 ml/minute to 750 ml/minute. The flow rate required
adjustment on six of the 30 days of testing.
The readout from the inline feed water turbidimeter averaged 0.060 NTU; the average from the
benchtop turbidimeter was 0.09 NTU. The discrepancy between these two results can be
explained by differences in the analytical techniques between the inline and benchtop
turbidimeter and the low level of turbidity in the feed water. The benchtop turbidimeter uses a
glass cuvette to hold the sample; this cuvette can present some optical difficulties for the
benchtop turbidimeter. The inline turbidimeter has no cuvette to present a possible interference
with the optics of the instrument. The low level of turbidity in the feed water also can create
analytical difficulties, particularly for the benchtop turbidimeter. Manufacturer's specifications
state that stray light interference is less than 0.02 NTU. Stray light interference approaching this
level at the low turbidity levels tested could account for the differences in the readings.
The inline filtrate turbidimeter flow rate averaged 477 ml/minute. The flow rate was measured
using a graduated cylinder and stop watch. The maximum rate measured during the testing was
850 ml/minute; the minimum was 0 ml/minute. The acceptable range of flows as specified by
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the manufacturer is 250 ml/minute to 750 ml/minute. The flow rate required adjustment on three
of the 30 days of testing.
The readout from the inline filtrate turbidimeter averaged 0.027 NTU; the average from the
benchtop turbidimeter was 0.04 NTU. The discrepancy between these two results can be
explained by differences in the analytical techniques between the inline and benchtop
turbidimeter and the low level of turbidity in the filtrate. The benchtop turbidimeter uses a glass
cuvette to hold the sample; this cuvette can present some optical difficulties for the benchtop
turbidimeter. The inline turbidimeter has no cuvette to present a possible interference with the
optics of the instrument. The low level of turbidity in the filtrate also can create analytical
difficulties, particularly for the benchtop turbidimeter. Manufacturer's specifications state that
stray light interference is less than 0.02 NTU. Stray light interference approaching this level at
the low turbidity levels tested could account for the differences in the readings.
The feed water particle counter flow rate averaged 97 ml/minute. The flow rate was measured
using a graduated cylinder and stop watch. The maximum flow rate measured was 101
ml/minute; the minimum was 85 ml/minute. The target flow rate specified by the manufacturer
is 100 ml/minute. Efforts were made to keep the flow rate between 95 ml/minute to 105
ml/minute. Adjustments to the flow rate were required four times during the verification study.
The filtrate particle counter flow rate averaged 95.4 ml/minute. The flow rate was measured
using a graduated cylinder and stop watch. The maximum flow rate measured was 100
ml/minute; the minimum was 88 ml/minute. The target flow rate specified by the manufacturer
is 100 ml/minute. Efforts were made to keep the flow rate between 95 ml/minute to 105
ml/minute. Adjustments to the flow rate were required five times during the verification study.
4.5.2 Bi-weekly QA/QC Verification Results
Every two weeks checks were made on the inline flow meters; the meters were cleaned out if
necessary and the flow readouts were verified.
The flow meters were inspected. Clean out of the meters was not necessary due to the high
quality of the feed water and filtrate.
The flow meter read out was verified during the testing. The acceptable range of accuracy for
the feed and filtrate meters was +/- 10%. The filtrate water meter readout averaged 3.4% higher
than actual according to the results obtained during the flow verification. The feed water meter
readout averaged 4.5% higher than actual according to the results obtained during the flow
verification. The treatment system did not have a backpulse meter.
4.5.3 Results of QA/QC Verifications at the Start of Each Testing Period
At the start of the testing period, the inline turbidimeter was cleaned out and recalibrated, the
pressure gauges/transmitters readouts were verified, the tubing was inspected, and the inline
particle counter calibration was checked.
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The inline turbidimeter reservoir was drained and cleaned and the unit was recalibrated
according to manufacturer's recommendations. No corrective action was required as a result of
these activities.
The filtrate pressure/vacuum gauge was checked prior to the start of testing. This was the only
pressure gauge on the treatment unit. Dead weights of 5, 10, and 15 pounds were used. The
filtrate pressure gauge averaged 5.1 psi, 9.9 psi, 15.0 psi when tested with the above weights.
These results were considered satisfactory.
The tubing used on the treatment system was inspected prior to the initiation of testing. The
tubing was in good condition and replacement was not necessary.
The calibration of the inline particle counters was checked. The cocktail of microspheres was
prepared to give an initial concentration of 2,000 particles/ml for each of the 5 «m, 10 «m, and
15 //m sized particles.
The feed water particle counter showed an average response for the 5 um size of 834 counts/ml;
the 10 um size showed an average response of 834 counts/ml; the 15 um size showed an average
response of 1684 counts/ml. This corresponds to a difference of 58%, 58%, and 16%
respectively in particle counts. These results were outside of the generally recognized range of
+/- 10%). The manufacturer of the particle counters was contacted to determine what corrective
action could be utilized to rectify this low response. The technical representative indicated that
unit would have to have been returned to the factory for recalibration. The representative
indicated that the lead time for this service was in excess of one month. Due to the short
duration of the testing schedule and the treatment system manufacturer's time constraints this
was not a feasible option. The technical representative indicated that the calibration procedure
consisted of adjusting the "threshold" of the unit. This consists of adjusting the output of the unit
to match the concentration of the standard being analyzed. The representative indicated that this
"threshold" adjustment is analogous to increasing the readout of the unit by the percent
differences obtained during the calibration check procedure. The percent difference for the
15«m standard used was 16%>. The readings for 15 um feed water particle counts obtained
during the verification testing should be increased by 16%> to account for the low response of the
15 |im size range of the feed water particle counter. Due to extremely low results in the 5 um
and 10 //m size range the reliability of the 2-3 //m, 3-5 //m, 5-7 //m and 7-10 //m particle counts
should be considered questionable.
The filtrate particle counter showed an average response for the 5 um size of 899 counts/ml; the
10 um size showed an average response of 1061 counts/ml; the 15 um size showed an average
response of 1,636 counts/ml. This corresponds to a difference of 55%, 47%, and 18%
respectively in particle counts. These results were outside of the generally recognized range of
+/- 10%). The manufacturer of the particle counters was contacted to determine what corrective
action could be utilized to rectify this low response. The technical representative indicated that
unit would have to have been returned to the factory for recalibration. As was the case with the
feed water particle counter the long lead time for recalibration by the manufacturer precluded
recalibration of the instrument. The percent difference for the 15 um standard used was 18%.
The readings for 15 um feed water particle counts obtained during the verification testing should
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be increased by 18% to account for the low response of the 15 um size range of the filtrate
particle counter. Due to extremely low results in the 5 um and 10 um size range the reliability of
the 2-3 //m, 3-5 //m, 5-7 //m and 7-10 //m particle counts should be considered questionable.
The particle counters used during the testing were Met-One PCX models. The units had
capabilities of measuring particles as small as 2 |im and a coincidence error of less than 10%.
Particle counter model, serial number, calibration certificate, and calculation of coincidence error
are included in Appendix I.
4.5.4 On-Site Analytical QA Results
QA procedures for pH, temperature, residual chlorine, and turbidity included daily calibration,
duplicate analysis, and performance evaluation. Results for the above procedures for each of the
parameters are discussed in the following sections.
4.5.4.1 pH
QA results for pH analyses included a daily calibration, duplicate analysis, and performance
evaluation sample analysis. A two-point calibration of the pH meter was performed each day the
instrument was in use. Certified pH buffers in the expected range were used. After the
calibration, a third buffer was used to check linearity. The values of the two buffers used for
calibration, the efficiency of the probe (calculated from the values of the two buffers), and the
value of the third buffer used as a check were recorded in the logbook. The acceptable range for
the instrument linearity was 95 -105%. All daily calibrations yielded an acceptable linearity
result. Acceptable duplicate results were +/- 0.1 pH unit. All duplicate analyses were
acceptable. Results obtained from the analysis of the performance evaluation sample were
compared to the certified value reported by the sample manufacturer. The pH obtained from the
field analysis was 6.02. The certified pH value of the sample was 6.00 with an acceptable range
of 5.80 to 6.20. Appendix C contains the results from the duplicate pH analyses.
4.5.4.2 Temperature
QA results for temperature analysis consisted of daily duplicate analysis. The acceptable range
of the duplicate results was +/- 0.1°C. All duplicate analyses were acceptable. Appendix C
contains the results from the duplicate temperature analyses.
4.5.4.3 Residual Chlorine
QA results for residual chlorine analyses consisted of duplicate analysis and performance
evaluation sample analysis. The acceptable range for duplicate analyses was +/- 0.1 mg/1. All
duplicate analyses were acceptable. Results obtained from the analysis of the performance
evaluation sample were compared to the certified value reported by the sample manufacturer.
The residual chlorine obtained from the field analysis was 2.02 mg/1. The certified value of the
sample was 2.15 mg/1 with an acceptable range of 1.61 to 2.27 mg/1. Appendix C contains the
results from the duplicate chlorine analyses.
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4.5.4.4 Turbidity
QA results for the turbidity analyses consisted of a weekly calibration, daily calibration check,
duplicate analysis, and performance evaluation sample analysis. The weekly calibration was
conducted according to manufacturer's recommendations and the results checked against third
party primary calibration standards. After the weekly calibration, secondary standards were
analyzed and the results were used to assign an acceptable range to the secondary standards. The
secondary standards were utilized for the daily calibration check. The results of the analysis of
the secondary standards were compared to the acceptable range established during the weekly
calibration. If the results were outside of the acceptable range the instrument was recalibrated.
All weekly calibrations and daily calibration checks were acceptable. Duplicate analyses were
conducted daily on the feed water and the bleed water. The acceptable range for duplicate
analyses was +/- 10%. All duplicate analyses were acceptable. Results obtained from the
analysis of the performance evaluation sample were compared to the certified value reported by
the sample manufacturer. The turbidity obtained from the field analysis was 2.04 NTU. The
certified value of the sample was 1.76 NTU with an acceptable range of 1.50 to 2.06 NTU.
Appendix C contains the results from the duplicate turbidity analyses.
4.5.5 Analytical Laboratory QA/QC
Samples for analyses conducted on feed and filtrate are listed in Table 3-1. QA/QC procedures
are based on Standard Methods, 18th Ed., (APHA, 1992) and Methods for Chemical Analysis of
Water and Wastes, (EPA 1979).
The laboratory participated in the ICR laboratory approval program sponsored by the EPA.
QA/QC results from this program as they relate to microbial testing are attached in Appendix H.
The analyses conducted as part of this program include samples with unknown amounts Giardia
cysts and Cryptosporidium oocysts. These samples were analyzed and the results submitted to
EPA for evaluation. These blind QA/QC samples were analyzed for 18 months as part of the
ICR lab program and served as the QA/QC component of the microbial testing for the
verification testing. Results of these QA/QC samples indicate that the controls in place were
adequate to render the data obtained from the challenge testing acceptable.
Calibration and QA/QC results of the analytical instrumentation used to conduct the analyses
listed in Table 3-1 on filtrate is recorded and kept on file at the PWSA's laboratory. All QA/QC
results for the analytical instrumentation indicate that adequate controls were in place to render
the data obtained acceptable.
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Chapter 5
References
The following references were used in the preparation of this report:
American Public Health Association, American Water Works Association, Water Environment
Federation. Standard Methods for the Examination of Water and Wastewater, APHA.
AWWA, WEF, 18th Ed., 1992.
American Water Works Association. Partnership for Safe Drinking Water Web Page, AWWA ,
July, 1999.
Gilbert, Richard O., Statistical Methods for Environmental Pollution Monitoring, Van Nostrand
Rheinhold, 1987.
Pittsburgh Water and Sewer Authority. Laboratory Quality Assurance Plan, Non Published,
January, 1997.
U.S. Environmental Protection Agency. Enhanced Surface Water Treatment Rule (ESWTR) - 40
CFR Parts 9, 141 and 142, EPA, February 16, 1999.
U.S. Environmental Protection Agency. Information Collection Rule (ICR) Microbial Laboratory
Manual, EPA, April 1996.
U.S. Environmental Protection Agency. Methods for Chemical Analysis of Water and Wastes,
EPA 600/479-020, March, 1979.
U.S. Environmental Protection Agency. Optimizing Water Treatment Plant Performance Using
the Composite Correction Program. EPA/625/6-91/027, EPA 1991b.
U.S. Environmental Protection Agency. Partnership for Safe Drinking Water Web Page, EPA,
July, 1999.
U.S. Environmental Protection Agency. Surface Water Treatment Rule (SWTR) - 54 FR 27486
June 29, 1989, EPA 1989b.
U.S. Environmental Protection Agency/NSF International. ETV Protocol - Protocol for
Equipment Verification Testing for Physical Removal of Microbiological and Particulate
Contamination, EPA/NSF, April, 1998.
U.S. Environmental Protection Agency /NSF International. ETV Protocol - Protocol for
Equipment Verification Testing for Physical Removal of Microbiological and Particulate
Contamination, EPA/NSF, February, 1999.
Zenon Environmental Inc.- Standard Operating Procedures For a Standard ZeeWeed Pilot
System, August, 1998.
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