May 2000
NSF 00/07/EPADW395
Environmental Technology
Verification Report
Physical Removal of Cryptosporidium
oocysts and Giardia cysts in Drinking
Water
Aquasource North America
Ultrafiltration System Model A35
Pittsburgh, PA
Prepared by
®
NSF International
Under a Cooperative Agreement with
&EPA U.S. Environmental Protection Agency
etVElVElV
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THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
oEPA
PROGRAM ^
ET V
U.S. Environmental Protection Agency
NSF International
ETV Joint Verification Statement
TECHNOLOGY TYPE:
MEMBRANE FILTRATION USED IN PACKAGED
DRINKING WATER TREATMENT SYSTEMS
APPLICATION:
GIARDIA AND CRYPTOSPORIDIUM REMOVAL
TECHNOLOGY NAME:
TEST LOCATION:
MODEL A35 ULTRAFILTRATION SYSTEM
PITTSBURGH, PA
COMPANY:
AQUASOURCE NORTH AMERICA
ADDRESS:
2924 EMERYWOOD PARKWAY PHONE: (804)672-8160
RICHMOND, VA 23060 FAX: (804) 672-8135
WEB SITE:
http :\\www.infilcodegrem ont.com
EMAIL:
beamguardm@idi-online.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) program, one of 12 technology areas under ETV. The PDWTS program 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 Aquasource
North America Model A35 Ultrafiltration System. Gannett Fleming, Inc., an NSF-qualified field testing
organization (FTO), performed the verification testing.
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ABSTRACT
Verification testing of the Aquasource Ultrafiltration Treatment System Model A35 was conducted from
December 1 to December 31, 1998. The treatment system underwent microbial challenge testing on
January 22, 1999, and demonstrated a 5.5 logio removal of Giardia cysts and a 6.5 logio removal of
Cryptosporidium oocysts. Source water characteristics were: turbidity average 0.078 Nephlometric
Turbidity Units (NTU), pH 8.5, and temperature 8.0°C. During the thirty-day verification test, the system
was operated at a flux recommended by the manufacturer of 112 liter per square meter per hour (l/m2/h)
(65.9 gallon per square foot per day [gfd]) at 8.0°C which equates to 155 l/m2/h at 20 °C (91.2 gfd at
68°F). The average transmembrane pressure was 0.65 bar (b) (9.4 pounds per square inch [psi]). The feed
water recovery of the treatment system during the study was 94%. 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. The Aquasource UF membrane
is a hollow fiber made of cellulose acetate. It has a 0.02(.un nominal pore size and utilizes inside-out flow.
Water is applied under pressure to the inside of the hollow fiber membrane. The membrane consists of a
thin film acting as a sieve. The membrane is a physical barrier, providing removal of particulate
contaminants. Permeate (filtered water) is collected from the outside of the fiber and carried to the
permeate outlet.
The Aquasource Ultrafiltration Treatment System Model A35 system is a skid mounted, stand alone
system. The required connections are for the water supply, a sewer connection for the discharge of
backwash and chemical cleaning wastes and electrical service. The treatment system consists of two
membrane modules, supply pump, backwash reservoir and pump, chemical cleaning equipment and
necessary gauges and controls. The unit is equipped with a 200 (.un prefilter to remove large debris from
the feed water prior to introduction to the membranes. The treatment system is capable of operating in an
automatic mode with limited operator intervention.
For this test program, a dead end flow configuration was used. The particles that are removed from the
feed water clog the hollow fiber membrane. At a preset time, determined by raw water quality, the
treatment system was backwashed. This was accomplished by reversing the flow direction and forcing
the permeate back through the fibers from outside to inside. The permeate was chlorinated using a small
diaphragm pump which adds sodium hypochlorite to the permeate prior to backwash. During backwash,
the particles were removed and the backwash water was carried to waste.
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 with ferric chloride,
sedimentation, filtration, and disinfection using free chlorine 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 Giardia cysts and Cryptosporidium 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 8,720,000 of Giardia cysts and 91,770,000 of
Cryptosporidium oocysts were added to the feed water reservoir. The turbidity of the feed water was 0.09
NTU during the microbial 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 pilot unit.
The pump was operated at about 0.85 gallons per minute (gpm), (3.2 liter per minute) and was capable of
overcoming the pressure in the feed water line of the pilot unit. Samples of the permeate were collected
using a polypropylene wound filter with a nominal pore size of 1.0 (.un. One thousand liters (264 gallons)
of permeate 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. Backwash was delayed until the end of the collection period. Samples of the backwash
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.
The unit automatically operates in the filtration and backwash modes. All operational data, flows,
pressures, turbidity and particle counts were recorded on data logging software. Manual intervention was
required for chemical cleaning and to occasionally refill the tank of sodium hypochlorite used during
backwash. A representative of the manufacturer conducted daily checks of the system although this was
not necessary for operational control.
The flux selected by the manufacturer for the ETV study was 112 liter per square meter per hour (l/m2/h)
(65.9 gallon per square foot per day [gfd]) at 8.0°C which equates to 155 1 /m2/h at 20 °C (91.2 gfd at
68°F). 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 26.8 liter per minute (1pm) (7.09 gallon per day [gpm]).
The average feed pressure was 0.84 b (12 psi). The average filtrate pressure was 0.20 b (2.9 psi). The
amount of pressure lost as the water is filtered through the membrane is referred to as transmembrane
pressure (TMP). It is calculated by averaging the feed water pressure and the retentate pressure and
subtracting the filtrate pressure from that average. The average TMP for the system was 0.65 b (9.4 psi).
For this test program, a filtration cycle of 60 minutes was used. Every 60 minutes the system was
backwashed. Each backwash required 60 minutes to complete; 15 seconds for various valve operations
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and 45 seconds for the backwash itself. Approximately 25 gallons (95 liters) of permeate were used to
backwash the membranes.
The feed water recovery of the treatment system during the study was 94%. This figure was calculated by
comparing the amount of water needed to backwash the membranes to the total amount of water filtered
by 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
was used to calculate recovery of specific flux and the loss of original specific flux. Since the membrane
had not accumulated a significant amount of material that could not be removed with backwashing due to
the high quality of the feed water, the recovery of specific flux cleaning was negligible. Data from the
beginning of the thirty-day testing period and just prior to cleaning was used to calculate the loss of
original specific flux. The loss was 10 %.
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.
Water Quality Results
During the microbial challenge testing that occurred on January 22, 1999, the Aquasource Model A35 UF
System demonstrated a 5.5 logio removal of Giardia cysts and a 6.5 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 permeate that could be sampled, and the percent recovery of the
analytical methodology. There were no Giardia cysts or Cryptosporidium oocysts observed in the
permeate. During the microbial challenge testing, the feed water characteristics were: turbidity average
0.09 NTU, pH 8.2, temperature 1.7 °C.
During the thirty-day ETV operation of the Aquasource Model A35 UF System reductions were seen in
HPC, algae, turbidity and particle counts. HPC averaged 260 CFU/lOOml in the feed water and 11
CFU/lOOml in the permeate. Algae concentrations averaged 90 cells/ml in the feed water and five
cells/ml in the permeate. This reported average was the result of one cell observed in one of the four
samples with a level of detection of eight cells/ml. The presence of HPC and algae in the permeate may
have been due to the inability to completely disinfect the Tygon sample lines. The average turbidity
concentration in the feed water was 0.078 NTU and 0.022 NTU in the permeate. Particle counts were
reduced from an average of 86 total counts/ml in the feed water to an average 0.56 total counts/ml in the
permeate. A reduction in TSS of 0.075 mg/1 on average was observed. This represented a 50% reduction
in TSS, although given the low concentration of TSS in the feed water it may be hard to extrapolate this
percent removal to other locations. Total coliform reduction could not be demonstrated due to the
absence of total coliforms in the feed water and permeate throughout the test.
Temperature of the feed water during the thirty-day ETV study was somewhat variable with a high of
11.0°C, a low of 3.2°C, and an average of 8.0°C. The membrane pilot unit had little or no effect on total
alkalinity, total hardness, TDS, TOC and UVA254. The following table presents the water quality
reductions of the feed water and filtered water samples collected during the 30 days of operation:
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Feed Water Quality / Filtered Water Quality
Aquasource Model A35 UF Treatment System
Total
Particle
Coliforms
HPC
Algae
Turbidity
Counts
(cfu/100 ml) (cfu/100 ml)
(cells/ml)
(NTU)
(particles/ml)
Average1
0/0
260/11
90/5
0.078/0.022
86/0.56
Minimum1
0/0
70/2
40/<8
0.060/0.021
—
Maximum1
0/0
460/30
136/8
0.10/0.029
—
Std. Dev.1
0/0
160/13
39/2
0.011/0.0036
—
95% Confidence
N/A*
(103,417)/
(51,129)/
(0.073,0.081)/
Interval1
(0, 24)
(3,7)
(0.021,0.023)
1 - Concentration of feed water/concentration of filtered water.
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).
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. There was a failure of the system during the verification
testing. A solenoid valve on the backwash system of the prefilter stuck closed and caused the unit to
automatically shut down. The manufacturer's representative was notified and rectified the problem the
following day by manually exercising the valve. The unit was off line for slightly more than 27 hours.
The failure appeared to be caused by environmental conditions: freezing of the solenoid valve due to
extremely low temperatures in the trailer housing the treatment system. This was caused by a failure of
the enclosure's heating system. Changes were made in the method of heating the trailer in order to
prevent any more failures due to environmental conditions.
The Operating and Maintenance (O&M) Manual provided by Aquasource was available for review on-
site and was referenced occasionally during the testing. Particularly, the manual was consulted during the
cleaning procedure and to diagnose the alarm codes during the aforementioned system shutdown. The
manual was well organized and a valuable resource during the testing period.
Original Signed by
E. Timothy Oppelt
5/24/00
E. Timothy Oppelt Date
Director
National Risk Management Research Laboratory
Office of Research and Development
United States Environmental Protection Agency
Original Signed by
Tom Bruursema 5/31/00
Tom Bruursema Date
General Manager
Environmental and Research Services
NSF International
NOTICE: Verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. EPA and NSF make no
expressed or implied warranties as to the performance of the technology and do not certify that a
technology will always operate as verified. The end user is solely responsible for complying with
any and all applicable federal, state, and local requirements. Mention of corporate names, trade
names, or commercial products does not constitute endorsement or recommendation for use of
specific products. This report is not a NSF Certification of the specific product mentioned herein.
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Availability of Supporting Documents
Copies of the ETV Protocol for Equipment Verification Testing for 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
#00/07/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/etv (electronic copy)
3. EPA web site http: //www. epa. gov/etv (electronic copy)
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May 2000
Environmental Technology Verification Report
Physical Removal of Cryptosporidium oocysts and Giardia cysts in
Drinking Water
Aquasource North America Ultrafiltration System Model A35
Pittsburgh, PA
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
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Notice
The U.S. Environmental Protection Agency (EPA) through its Office of Research and
Development has financially supported and collaborated with NSF International (NSF) under
Cooperative Agreement No. CR 824815. This verification effort was supported by 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 (EPA) by Gannett Fleming, Inc., in cooperation with Aquasource North America. The
test was conducted during December of 1998 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 Environmental
Technology Verification Program (ETV) has been instituted to verify the performance of
innovative technical solutions to environmental pollution or human health threats. ETV was
created to substantially accelerate the entrance of new environmental technologies into the
domestic and international marketplace. Verifiable, high quality data on the performance of
new technologies is 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.
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Table of Contents
Section Page
ETV Joint 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 International 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 Pilot Effluent Discharge 5
Chapter 2: Equipment Description and Operating Processes 6
2.1 Equipment Description 6
2.2 Operating Process 11
2.2.1 Feed Water 11
2.2.2 Prefiltration 11
2.2.3 Filtration 11
2.2.4 Backwash/Reverse Flow 12
2.2.5 Chemical Cleaning 15
Chapter 3: Methods and Procedures 16
3.1 Experimental Design 16
3.1.1 Objectives 16
3.1.1.1 Evaluation of Stated Equipment Capabilities 16
3.1.1.2 Evaluation of Equipment Performance Relative to Water
Quality Regulations 16
3.1.1.3 Evaluation of Operational Requirements 17
3.1.1.4 Evaluation of Maintenance Requirements 17
3.1.2 Equipment Characteristics 17
3.2 Water Quality Consideration 17
3.3 Recording Data 18
3.3.1 Operational Data 18
3.3.2 Water Quality Data 18
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Table of Contents, continued
Section Page
3.4 Communications, Logistics and Data Handling Protocol 19
3.4.1 Introduction 19
3.4.2 Objectives 19
3.4.3 Procedures 19
3.4.3.1 Log Books 19
3.4.3.2 Photographs 20
3.4.3.3 Chain of Custody 20
3.4.3.4 Inline Measurements 20
3.4.3.5 Spreadsheets 20
3.4.3.6 Statistical Analysis 20
3.5 Recording Statistical Uncertainty 21
3.6 Verification Testing Schedule 21
3.7 Field Operations Procedures 21
3.7.1 Equipment Operations 22
3.7.1.1 Operations Manual 22
3.7.1.2 Analytical Equipment 22
3.7.2 Initial Operations 22
3.7.2.1 Flux 22
3.7.2.2 Transmembrane Pressure 23
3.7.2.3 Backwash 23
3.7.2.4 Percent Feed Water Recovery 24
3.8 Verification Task Procedures 24
3.8.1 Task 1: Membrane Flux and Operation 24
3.8.1.1 Filtration 25
3.8.1.2 Backwash 25
3.8.1.3 Chemical Cleaning 25
3.8.2 Task 2: Cleaning Efficiency 25
3.8.2.1 Analytical & Operational Data Collection Schedule 26
3.8.2.2 Cleaning Procedures 26
3.8.3 Task 3: Finished Water Quality 26
3.8.3.1 Sample Collection and Analysis Procedure 27
3.8.4 Task 4: Reporting of Maximum Membrane Pore Size 27
3.8.5 Task 5: Membrane Integrity Testing 27
3.8.5.1 Air Pressure Hold Test 28
3.8.5.2 Turbidity Reduction Monitoring 28
3.8.5.3 Particle Count Reduction Monitoring 28
3.8.6 Task 6: Microbial Removal 28
3.8.6.1 Feed Water Stock Preparation 29
3.8.6.2 Sample Collection Procedure 29
3.9 QA/QC Procedures 29
3.9.1 Daily QA/QC Verification Procedures 29
3.9.1.1 Inline Turbidimeter Flow Rate 30
3.9.1.2 Inline Particle Counter Flow Rate 30
3.9.1.3 Inline Turbidimeter Readout 30
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Table of Contents, continued
Section Page
3.9.2 Bi-Weekly QA/QC Verification Procedures 30
3.9.2.1 Inline Flow Meter Clean Out 30
3.9.2.2 Inline Flow Meter Flow Verification 30
3.9.3 Procedures for QA/QC Verifications at the Start of Each Testing
Period 31
3.9.3.1 Inline Turbidimeter 31
3.9.3.2 Pressure Gauges / Transmitters 31
3.9.3.3 Tubing 31
3.9.3.4 Inline Particle Counters 31
3.9.4 On-Site Analytical Methods 32
3.9.4.1 pH 32
3.9.4.2 Temperature 32
3.9.4.3 Residual Chlorine Analysis 32
3.9.4.4 Turbidity Analysis 33
3.9.5 Chemical and Biological Samples Shipped Off-Site for Analyses 33
3.9.5.1 Organic Parameters 33
3.9.5.2 Microbiological Parameters 34
3.9.5.3 Inorganic Parameters 34
Chapter 4: Results and Discussion 35
4.1 Introduction 35
4.2 Initial Operations Period Results 35
4.2.1 Flux 35
4.2.2 Transmembrane Pressure 35
4.2.3 Backwash Frequency 35
4.3 Verification Task Results and Discussion 36
4.3.1 Task 1: Membrane Flux and Operation 36
4.3.1.1 Transmembrane Pressure Results 36
4.3.1.2 Specific Flux Results 38
4.3.1.3 Cleaning Episodes 39
4.3.1.4 Percent F eed Water Recovery 39
4.3.2 Task 2: Cleaning Efficiency 39
4.3.2.1 Results of Cleaning Episodes 40
4.3.2.2 Calculation of Recovery of Specific Flux and Loss of
Original Specific Flux 40
4.3.2.3 Discussion of Results 41
4.3.3 Task 3: Finished Water Quality 42
4.3.3.1 Turbidity Results and Removal 43
4.3.3.2 Particle Count Results and Removal 45
4.3.3.3 Backwash Wastewater Testing Results 48
4.3.3.4 Total Suspended Solids Mass Balance 49
4.3.4 Task 4: Reporting of Maximum Membrane Pore Size 50
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Table of Contents, continued
Section Page
4.3.5 Task 5: Membrane Integrity Testing 51
4.3.5.1 Air Pressure Hold Test Results 51
4.3.5.2 Turbidity Reduction Monitoring 51
4.3.5.3 Particle Count Reduction Monitoring 52
4.3.6 Task 6: Microbial Removal 52
4.3.6.1 Feed Water Concentrations 52
4.3.6.2 Permeate Concentrations 53
4.3.6.3 Backwash Examination 54
4.3.6.4 Operational and Analytical Data Tables 54
4.3.6.5 Discussion of Results 56
4.4 Equipment Characteristics Results 56
4.4.1 Qualitative Factors 56
4.4.1.1 Susceptibility to Changes in Environmental Conditions 56
4.4.1.2 Operational Reliability 57
4.4.1.3 Equipment Safety 57
4.4.2 Quantitative Factors 58
4.4.2.1 Power Supply Requirements 58
4.4.2.2 Consumable Requirements 58
4.4.2.3 Waste Disposal 58
4.4.2.4 Length of Operating Cycle 59
4.5 QA/QC Results 59
4.5.1 Daily QA/QC Results 60
4.5.2 Bi-weekly QA/QC Verification Results 60
4.5.3 Results of QA/QC Verifications at the Start of Each Testing Period 61
4.5.4 Analytical Laboratory QA/QC 62
Chapter 5: References 63
Tables Page
Table 1-1 Aquasource UF Treatment System Model A35 Feed Water Quality 5
Table 3-1 Analytical Data Collection Schedule 18
Table 3-2 Operational Data Collection Schedule 18
Table 3-3 Analytical & Operational Data Collection Schedule - Chemical Cleaning 26
Table 4-1 Daily Unit Pressure Readings and Transmembrane Pressure 36
Table 4-2 Specific Flux 38
Table 4-3 Chemical and Physical Characteristics of Cleaning Solution 40
Table 4-4 Operational Parameter Results - Cleaning Procedure 40
Table 4-5 Feed Water Quality 42
Table 4-6 Finished Water Quality 42
Table 4-7 Turbidity Analyses Results and Removal 43
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Table of Contents, continued
Table Page
Table 4-8 Filtrate Turbidity Results - Four Hour In-Line Readings 44
Table 4-9 Feed Water Particle Counts 45
Table 4-10 Finished Water Particle Counts 46
Table 4-11 Daily Average Cumulative Particle Counts Feed and Finished Water,
Logio Particle Removal 46
Table 4-12 Daily Backwash Wastewater Testing Results - Summary 49
Table 4-13 Weekly Backwash Wastewater Testing Results 49
Table 4-14 Giardia and Cryptosporidium Stock Suspension Results by Hemocytometer
Counts 53
Table 4-15 Giardia and Cryptosporidium Stock Suspension Results by Microscopic
Examination 53
Table 4-16 Giardia and Cryptosporidium Challenge LogioRemoval Calculation 54
Table 4-17 Pressure Readings and Calculations During Microbial Removal Testing 55
Table 4-18 Specific Flux During Microbial Removal Testing 55
Table 4-19 Turbidity Analyses Results and Removal During Microbial Removal Testing.... 55
Table 4-20 Feed Water Particle Counts 1/22/1999 55
Table 4-21 Finished Water Particle Counts 1/22/1999 55
Table 4-22 Daily Backwash Wastewater Testing Results During Microbial
Removal Testing 56
Figure Page
Figure 2-1 Water Permeating Through the Fibers 6
Figure 2-2 Flow Path Through Fibers and Modules 6
Figure 2-3 Treatment System Equipment Schematic 8
Figure 2-4 Major Equipment Location 8
Figure 2-5 Flow Schematic 9
Figure 2-6 Dead-end Filtration Flow Path Schematic 12
Figure 2-7 Backwash of Top Head Flow Schematic 13
Figure 2-8 Backwash of Bottom Head Flow Schematic 13
Figure 2-9 Backwash of Both Heads Flow Schematic 14
Figure 2-10 Backwash of Recirculation Loop and Bottom Head Flow Schematic 14
Figure 2-11 Backwash of Prefilter 14
Figure 2-12 Chemical Cleaning Flow Schematic 15
Figure 4-1 Transmembrane Pressure vs. Time 37
Figure 4-2 Specific Flux Decline vs. Time 38
Figure 4-3 Four-Hour Permeate Turbidity 45
Figure 4-4 Four-Hour Feed Water Particle Counts 47
Figure 4-5 Four-Hour Permeate Particle Counts 47
Figure 4-6 Daily Average Logio Cumulative Particle Removal Graph 48
viii
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Table of Contents, continued
Photograph Page
Photograph 1. Aquasource Ultrafiltration System Model A3 5 showing piping, membrane
modules and prefilter 10
List of 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.
Pilot Plant Photos
K.
Field Operations Document
IX
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Abbreviations and Acronyms
ac
acre
A WW A
American Water Works Association
b
bar
CaC03
Calcium Carbonate
CCP
Composite Correction Program
cfu
colony forming unit
CIP
Clean in place
Cl2
Chlorine
°c
Degrees Celsius
DI
deionized
DOC
Dissolved Organic Carbon
EPA
U.S. Environmental Protection Agency
ESWTR
Enhanced Surface Water Treatment Rule
ETV
Environmental Technology Verification
°F
Degrees Fahrenheit
FOD
Field Operations Document
ft
feet
ft2
feet squared
FTO
Field Testing Organization
gfd
Gallon per square foot per day
gpm
Gallon per minute
hp
Horse Power
HPC
Heterotrophic Plate Count
hr
hour
ICR
Information Collection Rule
in
inch
kD
Kilo Daltons
L
Liters
lbs
pounds
1/h/m2
liter per hour per square meter
l/h/m2/b
liter per hour per square meter per bar
m
meter
MF
Microfiltration
MG
million gallon
MGD
million gallon per day
mg/L
milligram per liter
ml
milliliters
mm
millimeters
MSDS
Material Safety Data Sheets
N/A
Not Applicable
NIST
National Institute of Standards and Technology
NSF
NSF International (formerly known as National Sanitation Foundation)
nm
nanometers
NTU
Nephlometric Turbidity Units
x
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od
outside diameter
O&M
Operations and Maintenance
PADEP
Pennsylvania Department of Environmental Protection
PC
personal computer
PPE
Personal Protective Equipment
ppm
parts per million
psi
pounds per square inch
psid
pounds per square inch differential
PDWTS
Packaged Drinking Water Treatment System
PWSA
Pittsburgh Water and Sewer Authority
QA/QC
Quality Assurance / Quality Control
scfm
standard cubic feet per minute
SDI
Silt Density Index
SDWA
Safe Drinking Water Act
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 254nm
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:
Aquasource North America
2924 Emerywood Parkway
Richmond, VA 23060
Phone: (804) 756-7680
Contact Person: Mr. Michael F. McLaughlin, President
Gannett Fleming wishes to thank NSF International, especially Bruce Bartley, Project Manager,
Carol Becker and Kristie Wilhelm, Environmental Engineers, and Tina Beaugrand,
Microbiology Laboratory Auditor, 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.
Michael McLaughlin, President, Denis Vial, Technical Director, Johannes Nollen, Field
Engineer, and Miles Beamguard, Application Engineer of Aquasource North America are to be
commended for providing the treatment system and excellent technical and product expertise.
George Pitcairn, Manufacturers Representative for Ralph L. Stemler Inc. provided daily system
checks for Aquasource North America.
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 the Aquasource Ultrafiltration (UF) Treatment System
Model A35, which is a membrane filtration system used in package drinking water treatment
system applications. The performance claim evaluated during field testing of the Aquasource UF
Treatment System Model A35 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 Aquasource UF Treatment System Model A3 5.
1.2 Testing Participants and Responsibilities
The ETV testing of the Aquasource UF Treatment System Model A3 5 was a cooperative effort
between the following participants:
NSF International
Gannett Fleming, Inc.
Aquasource NA Corporation
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 audit of the field analytical and
data gathering and recording procedures was conducted. 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
Aquasource UF Treatment System Model A35. Gannett Fleming is a NSF-qualified Field
Testing Organization (FTO) for the Packaged Drinking Water Treatment System ETV pilot
project.
The FTO was responsible for conducting the verification testing for 30 calendar days. The FTO
provided all needed logistical support, established a communications network, and scheduled and
coordinated activities of all participants. The FTO was responsible for ensuring that the testing
location and feed water conditions were such that the verification testing could meet its stated
objectives. The FTO prepared the FOD, oversaw the pilot testing, managed, evaluated,
interpreted and reported on the data generated by the testing, as well as evaluated and reported
on the performance of the technology.
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.
2
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Contact Information:
Gannett Fleming, Inc.
P.O. Box 67100
Harrisburg, PA 17106-7100
Phone: 717-763-7211
Fax: 717-763-1808
Contact: Gene Koontz, Project Director
Email: gkoontz@gfnet.com
1.2.3 Manufacturer
The treatment system is manufactured by Aquasource North America a specialized subsidiary of
Infilco Degremont, Inc. (Richmond, Virginia) and Aquasource S.N.C. (Paris, France Aquasource
North America specializes in providing ultrafiltration membranes and systems to the water
industry.
The manufacturer was responsible for supplying a field-ready membrane filtration pilot 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 safety
devices to provide for automatic shut down of the pilot plant in the event of loss of feed water or
any other condition that would either damage the pilot 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 was automatically recorded
by the treatment system.
Contact Information:
Aquasource North America
2924 Emerywood Parkway
Richmond, VA 23060
Phone: (804) 672-8160
Fax:(804) 672-8135
Email: beamguard@idi-online.com
Contact Person: Miles Beamguard
1.2.4 Host and Analytical 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.
3
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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 microbial 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 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 Package Drinking Water Treatment Systems Pilot operating under the ETV
Program. This document has been peer reviewed and reviewed by NSF and EPA and
recommended for public release.
1.3 Verification Testing Site
The verification testing site was 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 in an enclosure located at the rear of the pumping station 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, lined 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 with ferric chloride, sedimentation, filtration,
and disinfection using free chlorine at PWSA's Aspinwall Treatment prior to being pumped to
the reservoir. The influent to the Aquasource UF Treatment System Model A3 5 was drawn from
the reservoir effluent lines. The effluent from the reservoir is not tested by PWSA and the
4
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Authority has little historical data regarding the quality of the reservoir water. 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. The performance
was evaluated during challenge seeding studies of Cryptosporidium oocysts and Giardia cysts.
During the study the feed water turbidity ranged from 0.060 to 0.10 Nephlometric Turbidity
Units (NTU) with an average of 0.078 NTU. pH was within the range of 8.3 to 8.6 with an
average of 8.5. Total Alkalinity as CaCC>3 ranged from 59 to 71 mg/1 with an average of 63 mg/1.
Average Hardness, as CaCC>3, was 154 mg/1 and ranged from 150 to 158 mg/1. TOC ranged
from 1.36 to 1.73 mg/1 with an average of 1.56 mg/1. UVA254 was 0.019 mg/1 on average, with a
range of 0.016 to 0.022 mg/1. TDS averaged 296 mg/1 and the range was 280 to 313 mg/1. TSS
averaged 0.016 mg/1 and ranged from non detectable to 0.30 mg/1. HPC ranged from 70 to 460
colony forming units (cfu)/ml and averaged 260 cfu/ml. No coliform bacteria were detected in
the feed water. Temperature averaged 8.0°C, ranging from 3.2°C to 11.0°C. The algae levels
during the verification testing averaged 90 cell/ml, with a range of 40 to 136 cells/ml. The above
information is presented in Table 1-1 below.
Table 1-1. Aquasource UF Treatment System Model A35 Feed Water Quality
Parameter
Total
Total
TDS
TSS
Total
HPC
TOC
UVA Algae
Turbidity
Alkalinity Hardness
Coliforms
as CaC03
as CaC03
(mg/1)
(mg/1)
(cfu/100
(cfu/100
(mg/1)
(cm-1) (cells/ml)
(NTU)
(mg/1)
(mg/1)
ml)
ml)
Average
63
154
296
0.16
0
260
1.56
0.019 90
0.078
Minimum
59
150
280
<0.05
0
70
1.36
0.016 40
0.060
Maximum
71
158
313
0.30
0
460
1.73
0.022 136
0.10
Std. Dev.
5.6
N/A
N/A
0.16
0
160
0.155
0.0028 39
0.011
95% Confid Int
(58,68)
N/A
N/A
(0.0069,
N/A1
(103,
(1.41,
(0.016, (51, 129)
(0.074,
0.32)
417)
1.72)
0.022)
0.082)
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. Per Statistical Methods for Environmental Pollution Monitoring. Richard O. Gilbert, Van Nostrand Reinhold, 1987.
1.3.2 Pilot Effluent Discharge
The effluent of the pilot treatment unit 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 the Aquasource Ultrafiltration System Model
A35. The membrane used in the A35 Treatment System is a hollow fiber ultrafiltration
membrane that is 0.93 millimeters (mm) in diameter (0.035 inch) and 1.30 meters (m) long
(4.3 feet). The membranes are made of cellulose acetate and have a nominal pore size in the
range of 10 to 20 nanometers (nm) with a molecular weight cutoff of approximately 180 Kilo
Daltons (kD) for 90% retention.
The membrane filters are contained in a fiberglass cylinder called the module. The modules used
in the A35 Treatment System are designated M1A35. The modules are vertically mounted on
the treatment skid. The filtration surface area provided in a module is approximately 7.2 m2
(77.4 ft2). The M1A35 module used in this treatment study contains 15,904 fibers arranged in
7 bundles, each bundle maintained in plastic netting. Figure 2-1 is a photograph of water
permeating through the fibers. Figure 2-2 is a pictorial representation of the flow path through
the individual fiber.
Figure 2-2. Flow path through fibers and modules
6
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The fibers are fastened on both ends with an epoxy resin glued to the fiberglass cylinder so there
is no contact in between the raw water inside the fibers and the treated water (permeate) outside
the fibers.
The raw water goes to the inside of each fiber via one of the heads of the module. Due to the
difference of pressure in between the inside and the outside of the fibers, water is driven through
the fibers. During filtration, the membrane retains the suspended solids, microorganisms and
organic macromolecules forming a cake on the inner side of the ultrafiltration membrane. The
process is called inside-out flow.
A summary of membrane characteristics as reported by the manufacturer is as follows:
Membrane classification ultrafiltration
Membrane material cellulose acetate
Membrane type hollow fiber
Membrane flow path inside out
Filtration mode dead end or cross flow
pH tolerance 4-8.5
Temperature tolerance 1 - 35° C (33 - 95° F)
The following major equipment components are provided on the A35 Treatment System's self
contained skid mounted unit:
One (1) feed pump,
One (1) pre-filter,
One (1) recirculation pump,
Two (2) AquasourceMlA35 ultrafiltration modules,
One (1) backwash pump,
One (1) filtrate tank,
One (1) air compressor,
One (1) sodium hypochlorite tank with one (1) metering pump.
One (1) control panel
The raw water tank is provided, separate of the skid mounted pilot unit.
The schematic in Figure 2-3 is a representation of all treatment system equipment and related
names. Figure 2-4 illustrates the location of the main equipment on the unit.
7
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CV x : Check valve EV x : Pneumatically actuated valve
FE : Flow element LSL x: Level switch low
MV x: Manually operated valve P x : Pump
TE : Temperature element
Figure 2-3. Treatment system equipment schematic
1 Filtrate tank
2 Allen Bradley Panel View 550,
3 Pumps VFDs,
4 Flow meters,
5 Emergency stop,
6 Manometers,
7 Pressure switch,
8 Sampling valves,
9 Sink,
10 Solenoid valves cabinet,
11 Modules
Figure 2-4. Major equipment location
8
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Figure 2-5 represents as a flow schematic of the Aquasource unit.
Purge Vi_
. Backwash
*-/ waste water
outlet
Raw water line
Treated water line
Recirculation loop
Backwash line
Backwash waste line
Detergent line
Treated
HlJ)* water
overflow
PAC
Chlorine
Figure 2-5. Flow schematic
The data plate affixed to the treatment system contains the following information.
a. Equipment name: Aquasource Pilot System
b. Model #: A35
c. Manufacturer: Aquasource; 2924 Emery wood Parkway; Richmond, VA 23060
d. Electrical requirements: 480Volts, 30 Amps, 3 phase
e. Serial number: #6
f. Warning and caution statements: N/A
g. Capacity or output rate: 10 gpm
According to the manufacturer, the treatment system is capable of handling feed water turbidity
up to 500 NTU. Turbidity challenge testing was not done during this verification so this feed
water limitation was not field verified. There are no documented upper limits for concentrations
of Giardia and Cryptosporidium in the feed water. The manufacturer's O&M manual states that
the membranes have a pH tolerance of 4 to 8.5 and a temperature tolerance of 1 to 35°C.
The following is a photograph of the A3 5 system on-site during testing.
9
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2.2 Operating Process
2.2.1 Feed Water
The feed water is pumped into the filtration loop by the feed pump. The feed pump provides the
pressure needed to drive the raw water through the fibers. In normal operation the feed flow is
equal to the instantaneous production flow, ensuring a constant production rate.
2.2.2 Prefiltration
A 200 |im raw water prefilter removes large particles prior to the feed flow entering the modules.
The prefilter protects the heads of the modules against clogging. Prefiltration is performed with
an automatic backwashed prefilter. Backwashing of the prefilter is done with permeate during
the backwash of the modules. No chlorine is added to the permeate during backwash of the
prefilter.
2.2.3 Filtration
The unit can operate in two modes:
- Cross flow filtration: The recirculation pump, installed on the skid-mounted unit, minimizes
clogging of the membrane by circulating feed water at a high velocity inside the fibers. This
mode is used only when the raw water contains a rather high concentration of suspended
solids, such as during spring runoff, winds or rainstorms, or with powdered activated carbon
(PAC) addition.
- Dead end filtration: The recirculation pump is stopped. This mode is used when the raw water
is low in suspended solids. In dead end filtration, raw water goes inside the lumen of the
fibers from the bottom head of the modules to the upper head with a decreasing velocity. This
mode is also called frontal filtration.
The unit was operated in dead-end filtration mode due to the low level of suspended solids in the
feed water at the test site.
The manufacturer reports that typically during filtration, the pressure drop across the module is
approximately 0.2 bar (b) («3 pound per square inch [psi]) at 20°C. The recommended
maximum transmembrane pressure is 0.8 b (« 12 psi). The permeate pressure can be as low as
0.2 b (« 3 psi). Thus, the maximum pressure at the bottom head of a module, which will allow
the unit to automatically switch from dead-end to recirculation, is about 1.1 b 16 psi).
Figure 2-6 is a schematic representation of the flow path in dead-end mode.
11
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Purge
outlet
Cleaning
fank
inlet
0_i
Recirculation
pump
Raw
Water
Tank
O
pump
-oOrri}^-0^
Concentrate/
side
Permeate
side
Backwash
waste water
outlet
Raw water line
Treated water line
G
backwash
pump
T reated
water
tank
T reated
l-O water
overflow
Figure 2-6. Dead-end filtration flow path schematic
2.2.4 Backwash/Reverse Flow
During normal operation, the A35 unit alternates between the filtration mode and the backwash
mode. These backwashes are called cycle backwashes (or automatic backwashes).
Periodically permeate is sent back under pressure in the reverse direction (backwash) to restore
the effectiveness of the membrane. Only chlorinated ultrafiltered water is used for backwash
purposes. A backwash pump, drawing water from the filtrate tank, provides the water for
backwash under pressure. Backwash is performed at a pressure of about 2.5 bar (^ 36 psig) at the
module permeate inlet. During the backwash, blow-down valves are opened to discharge the
concentrate stream (backwash wastewater) to waste. Following backwash, the filtration cycle
automatically resumes.
The backwash is automatically initiated after a preset filtration time. The frequency is dependent
on raw water quality, and will occur between every 20 minutes to three hours. For this
verification study a backwash frequency of 60 minutes was used due to the low amount of solids
in the feed water.
Backwash duration varies as a function of the water temperature and the clogging of the
membrane to maintain a constant volume sent through the fibers. The duration of the module's
backwash is usually set from 45 to 75 seconds. Forty-five seconds was the backwash duration
for the verification study. The total length of a backwash cycle which includes the necessary
valve operations is from 55 to 85 seconds and corresponds to the non-production duration. Sixty
seconds was the total length of the backwash cycle for the study.
During backwash, backwash water (permeate) is chlorinated to enhance backwash efficiency.
Chlorine is used as a disinfectant to protect the membrane against biological contamination on
the permeate side and as an oxidant for the organic matter. Sodium hypochlorite is added to the
backwash water (except during the backwash of the prefilter) at a concentration between 5 and
10 mg/L as free chlorine. Sodium hypochlorite concentration is adjusted as a function of the
backwash duration and the backwash frequency and to have at least 0.5 ppm of free chlorine in
the backwash wastewater.
12
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The following occurs sequentially during a cycle backwash:
1) Backwash of the top head of the modules.
2) Backwash of the bottom head of the modules.
3) Backwash of the both heads of the modules.
4) Backwash of the recirculation loop and bottom head.
5) Backwash of the prefilter.
6) Production resumes.
The cycle backwash steps are shown in Figures 2-7 through 2-10.
13
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Figure 2-9. Backwash of both heads flow schematic
Figure 2-10. Backwash of recirculation loop and bottom head flow schematic
^21 Chlorine
Figure 2-11. Backwash of prefilter
14
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2.2.5 Chemical Cleaning
Periodically, membrane cleaning is performed using a detergent-type cleaning solution. The
function of the cleaning solution is to loosen and/or dissolve fouling matter that has adhered to
the surface of the membrane or to the porous structure of the membrane. The frequency of
detergent cleaning depends on the raw water quality. The manufacturer reports that the cleaning
operation is performed about once a year for ground waters with occasional turbidity spikes. For
waters having higher TOC levels, cleaning may need to be more often. Cleaning was not
required due to loss of flux during the verification testing period but was performed at the end of
the thirty day testing as required by the ETV Protocol. The manufacturer estimated that the
cleaning interval would be approximately 3-6 months for the type of feed water used in this
verification testing period.
After preparing the cleaning solution in the detergent tank, the solution is circulated through the
membranes using the recirculation pump. After cleaning, the modules are rinsed with raw water.
Aquasource NA provides the detergents for the cleaning of the membranes. Three detergents
may be used. Ultrasil 43 (detergent and free chlorine) will remove organic fouling. Ultrasil 59
(detergent and complexing agent) will remove organic and mineral fouling. An acid based
detergent will remove iron and manganese fouling. Ultrasil 43 was used for pre-cleaning and
cleaning during the verification testing.
The manufacturer recommends that with organic and mineral fouling, a pre-cleaning with
Ultrasil 43, followed by a cleaning with Ultrasil 43, and a second cleaning with Ultrasil 59 are
performed. With iron and manganese fouling, the cleaning sequence is modified to cleaning with
the acid based detergent, followed by a cleaning with Ultrasil 43 or Ultrasil 59 depending on the
water quality. Figure 2-12 is a schematic representation of the chemical cleaning process.
Backwash Detergent line
Purge
waste water
outlet
/ Permeate
' side
a
lackwash
i pump
T reated
water
overflow
T reated
water
tank
PAC
Chlorine
Figure 2-12. Chemical cleaning flow schematic
15
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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. Adequate field analytical controls were in
place during the verification and allow valid conclusions to be drawn from the gathered data.
3.1.1 Objectives
The verification testing was undertaken to evaluate the performance of Aquasource
Ultrafiltration Treatment System Model A3 5. Specifically evaluated were the manufacturer's
stated equipment capabilities and equipment performance relative to water quality regulations.
Operational requirements and maintenance requirements of the system were also evaluated. The
details of each of these evaluations are discussed below.
3.1.1.1 Evaluation of Stated Equipment Capabilities
The Aquasource Ultrafiltration Treatment System Model A3 5 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. Giardia and Cryptosporidium removal
challenge testing was conducted to demonstrate acceptable protozoan removal capability.
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 finished water 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 finished water turbidity levels was not
verifiable due to the fact that the feed water already was in compliance with drinking water
turbidity regulations. Logio 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 (Aquasource NA 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
(Aquasource, 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. The
qualitative factors examined during verification testing were susceptibility to changes in
environmental conditions, operational reliability, and equipment safety. The quantitative factors
examined during verification testing were power supply requirements, consumable requirements,
waste disposal technique, and length of operating cycle. 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 Aquasource Pilot System Model A35. This treatment
unit operated at 155 liter per square meter per hour (l/m2/h) at 20°C (91.2 gallon per square foot
per day [gfd] at 68°F). Costs will increase with increasing flow.
3.2 Water Quality Consideration
Characterization of the treated water quality was the driving force behind the development of the
experimental design of the ETV. The water quality and microbial analyses which were
conducted were selected to demonstrate the treatment effectiveness of the manufacturer's
equipment. The feed and filtrate analytical parameters which were analyzed as part of the
testing and the sampling frequency are presented in Table 3-1.
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Table 3-1. Analytical Data Collection Schedule
Parameter
Frequency
Feed
Filtrate
Backwash Waste
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
1 (Backwash feed
0
1
Cleaning
water)
Laboratory Analytes
Total Alkalinity
Monthly
1
1
0
Total Flardness
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
Giardia and
Once during
3
Composite
0
Cryptosporidium
challenge testing
3.3 Recording Data
Operational and water quality data was recorded to document the results of the verification
testing.
3.3.1 Operational Data
Operational data was 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
Raw Flow 2/day
Feed Water Temperature 1/day
Electric Power Use 1/day
Influent module/vessel pressure 2/day
Effluent module/vessel pressure 2/day
Filtrate pressure 2/day
Filtrate flow 2/day
In addition to these parameters, data was collected during chemical cleaning and membrane
integrity testing. Operational data collected during these tasks is 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
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monthly laboratory analyses were recorded in laboratory log books and reported to the FTO on
separate laboratory report sheets. The data spreadsheets 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 log books, 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.
3.4.1 Introduction
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 was submitted to the FTO by PWSA Laboratory representatives, verified,
and entered into computer spreadsheets.
3.4.2 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 "A Protocol for
Equipment Verification Testing for Physical Removal of Microbiological and Particulate
Contaminants" (EPA/NSF. EPA/NSF ETV Protocol - Protocol for Equipment Verification
Testing for Physical Removal of Microbiological and Particulate Contamination, NSF, April,
1998).
3.4.3 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 on-line
measurements, entry of data into the customized spreadsheets, and the methods for performing
statistical analyses.
3.4.3.1 Log Books
Field log books were bound with numbered pages and labeled with 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.
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Errors had one line drawn through them and the line was initialed and dated. 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.
3.4.3.2 Photographs
All photographs were logged in the field logbook. These entries include time, date, direction,
subject of photo and the identity of the photographer.
3.4.3.3 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 audit
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.
3.4.3.4 Inline Measurements
Data from the computers recording the on-line measurements were copied to disk at least on a
weekly basis. This information was stored on site and at the FTO's office.
3.4.3.5 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.
3.4.3.6 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
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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 and total suspended and total dissolved solids. The equation used is:
95% confidence interval = X ± tn_j 0975 (S /4n)
where: X is the sample mean;
S is the sample standard deviation;
n is the number of independent measurements included in the data set; and
t is the Student's t distribution value with n-1 degrees of freedom;
Results of these calculations are expressed as the sample mean +/- the statistical variation.
3.6 Verification Testing Schedule
The verification testing commenced on December 1, 1998, with the initiation of daily testing.
The unit ran in normal mode (dead end flow, 155 l/m2/h at 20°C flux, 60-minute backwash
interval). Daily testing concluded on December 31. Data was logged for a total of 726 hours of
treatment system operation. Twenty-one hours of run time were lost due to a failure of the
treatment system. Loss of the heating system in the treatment system enclosure caused a
solenoid to freeze and the treatment system to automatically shut down on December 23.
Specialized tasks were not conducted until the conclusion of the daily testing for a variety of
reasons. Giardia and Cryptosporidium removal challenge testing was delayed until January 22,
1999 because of the unavailability of challenge organisms (i.e. of Giardia cysts and
Cryptosporidium oocysts).
The cleaning efficiency task was performed on February 16, 1999, due to unavailability of
manufacturer's field technicians to assist in the procedure until that time. Membrane integrity
testing was done on February 17, 18 after the conclusion of 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.
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3.7.1 Equipment Operations
The operating procedures used during the verification study were described in the Operations
Manual. (Appendix B) (Aquasource, 1998). Analytical procedures were described in equipment
operations manual and PWSA's Laboratory Quality Assurance Plan (Appendix F) (Pittsburgh
Water and Sewer Authority. Laboratory Quality Assurance Plan, January, 1997).
3.7.1.1 Operations Manual
The Operations Manual for the treatment system was housed on-site, attached to the Field
Operations Document, and attached to this report as Appendix B. Additionally, operating
procedures and equipment descriptions are 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 for chlorine analyses.
¦ An Ertco 1003-FC 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 1720D turbidimeter for filtrate turbidity and Met One PCX
particle counters for particle analysis.
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 the last week of September 1998 and was operated for two months to
establish the optimum treatment scheme prior to initiation of verification testing.
The major operating parameters examined during initial operations were flux, transmembrane
pressure, backwash 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 liter per square meter
per hour (l/m2/h) or gallon per square foot per day (gfd). The surface area of the membrane used
for the verification testing was 14.4 m2. It is customary to refer to flux normalized to 20°C or
68°F. Lower temperatures increase the viscosity of water and decrease the amount of permeate
that can be produced from a given area. The formula used to calculate the system flux is:
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Flux (in l/m2/h) = (Flow (gpm) * 3.785 l/gal*60 minutes/hour)/membrane area (m2)
Flux (in gfd) = (Flow (gpm) * 1440 minute/day)/ membrane area (ft2)
A manufacturer supplied coefficient, which is calculated from the temperature of the feed water,
was used to normalize the flux to 20°C (68°F). The formula used for the calculation is:
Coefficient = 1/(0.4122+(1.3558"° 04179*Water temperature))
The feed pressure to the membrane is adjusted to maintain the selected flux. This usually
requires an increase in feed pressure to maintain the selected flux. In order to take this change in
feed pressure into account, a parameter known as specific flux can be calculated. Specific flux is
calculated by dividing the flux of the system (as calculated above) by the transmembrane
pressure. The specific flux is expressed in liter per square meter per hour per bar at 20 °C (l/m2/h
/b at 20°C) or gallon per square foot per day per psi (gfd/psi at 68°F). By plotting the inverse of
specific flux, known as permeability, on to a semi log curve and extrapolating the trend line, an
estimation of the expected cleaning date can be made.
3.7.2.2 Transmembrane Pressure
The pressures of the feed water were recorded twice per day. Since the Aquasource unit feeds
water to the top and bottom of the vertically mounted filter columns, the pressure at the top and
bottom of the filter column is measured and recorded. The average of these two readings is used
as the feed pressure to the system. The filtrate pressure was recorded twice per day. The
amount of pressure lost as the water is filtered through the membrane is referred to as
transmembrane pressure (TMP).
3.7.2.3 Backwash
Backwashing of the filter is accomplished by forcing permeate under pressure in the reverse
direction through the hollow fiber membrane. This removes the particles that have been
deposited on the membrane and carries them to waste. Five percent sodium hypochlorite
(bleach) was added to the backwash water before it enters the membrane to enhance backwash
efficiency and prevent microbiological fouling of the filter. The target for the total chlorine
residual in the backwash waste was 5 mg/1 for the verification testing. The pilot automatically
initiates a backwash after a preset filtration time. Membranes used on feed waters with low
solids loading can operate with longer filtration cycles than those used on feed waters with
higher solids loading. The filtration interval was set initially to accommodate the quality of the
feed water. Adjustments to the backwash interval are made based on the maintenance of flux.
That is, if the backwash is not able to maintain flux at a particular level, the frequency of
backwashing is increased.
For this test program, a backwash interval of one minute every 60 minutes was used. Actual
backwash time of the membrane was 45 seconds, the other 15 seconds was for cessation of the
filtration cycle, valve operation and restart of the system. This backwash scenario was proven to
be appropriate for flux maintenance during the study. The unit used approximately 25 gallons of
permeate to backwash the membranes each cycle.
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The prefilter was backwashed as part of the membrane backwashing sequence. Prefilter
backwashing is the last portion of the system backwash. Permeate was passed through the
prefilter in the opposite direction of normal flow. Approximately 8% of the total backwash, or
two gallons in the case of this verification testing, is used to backwash the prefilter.
3.7.2.4 Percent Feed Water Recovery
In order to calculate the feed water recovery of the treatment system, the net production of the
unit is divided by the total production of the unit. Multiplying the average flow rate by the
filtration run time gives the total amount produced for the run. The net production is calculated
by subtracting the amount of permeate required to backwash the system from the total amount
produced. Dividing the net production by the total production and multiplying the result by 100
equals the percent water recovery of the system.
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 (EPA/NSF, 1998). The Verification Tasks were as
follows:
¦ Task 1 Membrane Flux and Operation
¦ Task 2 Cleaning Efficiency
¦ Task 3 Finished Water Quality
¦ Task 4 Reporting of Maximum Membrane Pore Size
¦ Task 5 Membrane Integrity Testing
¦ 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 raw water quality.
Standard operating parameters for filtration, backwash, 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 was collected according to the schedule presented in Table 3-2.
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3.8.1.1 Filtration
The flux selected by the manufacturer for the verification study was 155 l/m2/h at 20°C (91.2 gfd
at 68°F. The treatment unit adjusted flow as necessary to maintain this flux.
3.8.1.2 Backwash
The filtration cycle was 60 minutes for the verification study. The backwash required 60
seconds to complete; 15 seconds for system shutdown and various valve operations and 45
seconds for the backwash itself.
The interval between backwashes is determined based on the maintenance of flux. That is, if the
backwash frequency is not able to maintain flux at a particular level, it is increased. The
backwash frequency used during the study was capable of maintaining the flux selected for the
verification testing.
The procedure for backwashing is detailed in the O&M Manual and will not be presented here.
The normal backwash is an automatic function of the unit; the only adjustments which can be
made are to frequency, duration, and pressure. Procedures for making these adjustments are
detailed in the O&M Manual.
3.8.1.3 Chemical Cleaning
Chemical cleaning was to be instituted when the backwashing sequence was unable to restore the
specific flux to above 120 l/m2/h/b at 20°C (4.9 gfd/psi at 68°F). Due to the short duration of the
verification testing and high quality of the feed water, chemical cleaning was not dictated by
operational parameters; cleaning was conducted as per protocol requirements at the conclusion of
the verification test.
The procedure used to perform chemical cleaning is presented in the O&M Manual and Section
3.8.2 will not be presented here.
3.8.2 Task 2: Cleaning Efficiency
Cleaning efficiency procedures were identified in this task. The objectives of this task were to:
1. To evaluate the effectiveness of chemical cleaning for restoring finished water 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
backwashing sequence was unable to restore the specific flux to above 120 l/m2/h/b at 20 0 C (4.9
gfd/psi at 68°F). If chemical cleaning was not required during the testing, it was to be performed
at the conclusion of the 30-day period. The membranes were cleaned using manufacturer's
recommendations February 16, 1999.
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Prior to cleaning, the treatment system was operated at the conditions as described in Section
3.8.1. Operational data, including flow and pressure, were collected prior to cleaning. After
cleaning, the system was restarted and operated a sufficient period of time to establish post
cleaning, specific rate of flux recovery. Operational data, including flow and pressure, were
collected after cleaning. Table 3-3 details all the operational and analytical data collected before,
during, and following cleaning.
3.8.2.1 Analytical & Operational Data Collection Schedule
Data was collected before, during, and following cleaning according to Table 3-3.
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 backwash waste initial
1/episode
Visual observation of backwash waste final
1/episode
Flow of UF unit prior to cleaning
1/episode
Pressure 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
Pressure of UF unit after cleaning
1/episode
Temperature of UF unit after cleaning
1/episode
3.8.2.2 Cleaning Procedures
The procedure used to perform chemical cleaning is presented in the O&M Manual (Appendix
B).
3.8.3 Task 3: Finished Water Quality
Procedures for the collection and analysis of finished 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 performed, this
stated capability was not verified.
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Testing on finished water 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 3.8.3.1.
3.8.3.1 Sample Collection and Analysis Procedure
Finished water samples were collected and analyzed monthly for total alkalinity, total hardness,
and TDS. Weekly collection and analysis of finished water samples was performed for TSS,
total coliforms, HPC, TOC, UV absorbance, and algae. Collection and analysis of Giardia and
Cryptosporidium was conducted during the microbial removal challenge testing. 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 a
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
Protocol requires the reporting of the maximum membrane pore size by the manufacturer based
on recommendation by the Steering Committee.
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 (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.
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3.8.5.1 Air Pressure Hold Test
In order to conduct this test, it was necessary to remove the membrane vessel from the treatment
unit. The membrane unit filtrate side was drained. The membrane itself was fully wetted (i.e.
membrane pores were filled with water). The membrane was air pressurized up to 2.0 b (29 psi).
The filtrate side was sealed and the pressure decline rate was monitored using an air pressure
gauge. An intact membrane would be demonstrated by minimal pressure loss, i.e. 0.07 b (1.0 psi)
every 5 minutes. Air pressure loss was also compared to the loss that was obtained when testing
a compromised membrane. Pressure data was collected initially and then every two minutes
during the pressure hold test.
3.8.5.2 Turbidity Reduction Monitoring
Turbidity of feed and filtrate water was monitored continuously with in-line equipment. 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 0.078 NTU) showing a
90% reduction, 0.0078 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 source to finished water 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 86 total counts per ml) showing a 99.9% reduction was pushing the limits of the
instrumentation. Particle counts were measured continuously with in-line equipment.
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 producing
organisms. Most of these organisms are removed or rendered non-infectious through the use of
conventional treatment practices like sedimentation, filtration, and disinfection. Not all disease
producing 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 Cryptosporidium
oocysts. Participation in this task was optional. The manufacturer opted to participate in the
microbial removal challenge.
Microbial challenge testing took place on January 22, 1999. The procedures for the preparation
of the feed water stock, stock addition, sample collection and analysis, and calibration are
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presented below. Table 3-1 contains the parameters and frequency of analytical data collection.
Table 3-2 contains the parameters and frequency of operational data collection.
Procedures used for testing the effectiveness of the 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. Five two ml samples were taken from the feed water
reservoir. These samples were examined and the quantity of cysts and oocysts were determined.
This was used as a check of the replicate hemocytometer counts.
Source water concentrations were fed into the treatment system immediately before the
membrane vessels over approximately 60 minutes. Seeding began immediately after a backwash
cycle. The feed water stock reservoir was gently mixed during this process.
3.8.6.2 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 in the suspension. The feed suspension was
pumped into the feed water line immediately before the membrane vessels. 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 permeate
water were then passed through a 1 |im pore sized yarn wound filter at a rate of one gallon per
minute (3.785 liter per minute). Sample volumes of feed water, filtrate water and back
washwater 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 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.
3.9.1 Daily QA/QC Verification Procedures
Daily QA/QC procedures were performed on the on-line turbidimeter and inline particle counter
flow rates and inline turbidimeter readout.
29
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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 (0.066 - 0.20gpm).
The target flow rate was 500 ml/minute (0.13gpm). 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.
3.9.1.2 Inline Particle Counter Flow Rate
The flow rate for the feed water and filtrate inline particle counters was 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 (0.024 - 0.029 gpm). The target flow rate was 100 ml/minute (0.026 gpm). Care
was taken to maintain the flow rate between 95 ml/minute and 105 ml/minute (0.025 - 0.028
gpm). Changes to the flow rate were made by adjusting the level of the discharge from the
overflow weir. If adjustments to the flow rate were made they were noted in the operational /
analytical data logbook.
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 online 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. 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.
3.9.2.2 Inline Flow Meter Flow Verification
Verification of the readout of the feed, filtrate, and backwash 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 shutting off the feed water flow to the feed tank, drawing the
30
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tank down, measuring the amount of water drawn from the tank, and comparing it to the totalizer
reading. The filtrate meter was verified by dropping the level of the water in the filtrate tank,
allowing the tank to fill with filtrate, measuring the amount of water that entered the tank, and
comparing it to the totalizer reading. The backwash meter was verified by measuring the draw
down of the filtrate tank during backwash and comparing the amount used to the totalizer
reading.
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 meter adding weight to the meter and comparing the reading obtained to
the known amount of weight.
3.9.3.3 Tubing
The tubing and connections associated with the treatment system were inspected to verify that
they were clean and did not have any holes in them. Also, the tubing was inspected for
brittleness or any condition which could cause a failure.
3.9.3.4 Inline Particle Counters
Calibration of the particle counter is generally performed by the instrument manufacturer. The
calibration data was provided by the instrument manufacturer for entry into the software
calibration program. Once the calibration data was entered, it was verified using calibrated
mono-sized polymer microspheres. Microspheres of 5wm, lOwm and 15wm were used for
particle size verification. The following procedure was used for instrument calibration
verification:
¦ 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;
31
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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 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 were recorded.
3.9.4.2 Temperature
Readings for temperature were conducted in accordance with Standard Methods 2550. Raw
water temperatures were obtained once per day by submerging the thermometer in the feed water
reservoir. A National Institute of Standards and Technology (NIST) certified thermometer
having a range of - 1°C to +51°C (30°F to 120 °F), subdivided in 0.1°C (0.2 °F) 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 backwash waste according to Standard Methods
4500 CI G. The unit was received new (factory calibrated) and daily calibration was not
necessary.
32
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The backwash wastewater was collected, during backwash, twice per day. The entire amount of
wash water from a backwash was collected in a reservoir for analysis.
Dilution of the backwash waste (1ml of backwash waste to 5ml deionized (DI) water) was
necessary due to the high level of residual total chlorine.
Blanks for chlorine analyses were done by analyzing 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 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 backwash waste once a day. Performance evaluation samples were
analyzed during the testing period. Results of the duplicates and performance evaluation 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 UVA 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 UVA samples were collected, preserved, and held in accordance with
Standard Method 5010B. Storage time before analysis was minimized in accordance to
Standard Methods.
Analyses of the TOC samples were done according to methodology outlined in PWSA's QA
Plan which is based on Standard Methods 5310 C. Analyses of the UVA samples were done
according to methodology outlined in PWSA's QA Plan which is based on Standard Methods
5910 B.
33
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3.9.5.2 Microbiological Parameters
Microbiological parameters analyzed during the verification testing were Total Coliform, HPC,
Protozoa and Algae, Giardia and Cryptosporidium. 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 (34 °F - 41 °F) until initiation of analysis.
Algae samples were preserved with Lugol's solution after collection and stored at a temperature
of approximately 1-5°C (34 °F - 41 °F) 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 Methods 9222B. HPC analyses were conducted according to procedures presented in
PWSA's QA plan. These procedures are based on Standard Methods 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
Methods 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 (34 °F - 41 °F) 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 Methods 2540C. TSS analyses were conducted according
to Standard Methods 2540D.
34
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Chapter 4
Results and Discussions
4.1 Introduction
The verification testing was for the Aquasource Pilot System Model A3 5 manufactured by
Aquasource NA. Initial operations were conducted in September and November 1998 to
establish operating parameters for the system. The testing commenced on December 1, 1998 and
concluded its 30-day period on December 31, 1998. Microbial challenge testing was conducted
on January 22, 1999, chemical cleaning was performed on February 16, 1999, and membrane
integrity testing was performed on February 17 and 18, 1999.
This section of the verification report will present the results of the testing and offer discussion
of the results. Results and discussions of initial operations, equipment characteristics, membrane
flux and operation, cleaning efficiency, finished water quality, maximum membrane pore size,
membrane integrity testing, and microbial removal will be presented in this section. Also the
results of the daily, bi-weekly and initial QA/QC procedures will be presented in this section.
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 unit was on site the last week of September 1998 and was operated for two months during
the initial operations period to establish the optimum treatment scheme prior to initiation of
verification testing. The primary goals of the initial operations were to establish a flux rate, the
expected transmembrane pressure, backwash frequency appropriate for the feed water quality,
and the efficiency of the unit.
4.2.1 Flux
The flux was gradually increased from 101 l/m2/h at 20°C to 151 l/m2/h at 20°C (59.6 gfd at 68
°F to 89 gfd at 68 °F) 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 155 l/m2/h at 20°C (91.2 gfd at 68 °F). This was a flux of 112 l/m2/h at 8.0°C (65.9
gfd at 50°F). The initial specific flux was 250 l/m2/h/b at 20°C (10 gfd/psi at 68°F), 190 l/m2/h/b
at 9.9°C (110 gfd/psi at 50°F).
4.2.2 Transmembrane Pressure
The TMP during the initial operations period varied with the flux. TMP ranged from 0.33b to
0.83b (4.8 psi to 12 psi) during the initial operations period.
4.2.3 Backwash Frequency
During the initial operations period, backwash frequencies of 30 and 60 minutes were
investigated. Based on the results of the initial operations period, it was determined that a
35
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backwash interval of one minute every 60 minutes would be used during the verification testing.
Actual backwash time of the membrane was 45 seconds, the other 15 seconds was for cessation
of the filtration cycle, valve operation and restart of the system. This backwash scenario proved
to be appropriate for flux maintenance during the study. The unit used approximately 25 gallons
(95 liters) of permeate to backwash the membranes each cycle.
4.3 Verification Testing Results and Discussion
The results and discussions of membrane flux and operation, cleaning efficiency, finished 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, feed and filtrate pressures, backwash 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. The results of the
TMP and rate of specific flux decline are presented below. Date of chemical cleaning was
February 16, 1999. A calculation of the treatment unit efficiency is presented.
4.3.1.1 Transmembrane Pressure Results
Transmembrane pressure fluctuated from 0.58b to 0.76b (8.4 psi to 11 psi). The average TMP
during the testing was 0.65b (9.4 psi). Table 4-1 presents a summary of the daily unit pressure
readings and 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 Unit Pressure Readings and Transmembrane Pressure
Upper Vessel
Lower Vessel
Filtrate Pressure
T ransmembrane
Pressure
Pressure
Pressure
(psi)
(psi)
(psi)
(psi)
Average
12
13
2.9
9.4
Minimum
10
12
2.1
8.4
Maximum
14
15
3.6
11
Standard Deviation
0.69
0.63
0.36
0.53
95% Confidence Interval
(12,12)
(12,13)
(2.9, 3.0)
(9.2, 9.5)
36
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Transmembrane Pressure vs. Time
Run Time (Hours)
Figure 4-1. Transmembrane Pressure vs. Time
As depicted in Figure 4-1, the TMP tended to increase over the course of the verification testing.
The increase was not unexpected and seemed to indicate that the treatment system was capable
of operation at the selected flux and backwash protocol on this feed water.
The increase in TMP may be due to the accumulation of particles on the membrane surface. The
backwash 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 backwash 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. The feed
pressure increased as the time to the next backwash decreased. If the pressure and flow readings
were taken shortly after the completion of a backwash cycle, a lower TMP would result.
Likewise, if the readings were taken just prior to the initiation of a backwash cycle, a higher
TMP would result.
37
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There was a noticeable decrease in TMP between run time 485 hours and 555 hours. This may
have been related to the system shut down caused by the previously discussed failure of the
enclosure's heating system. Allowing the membranes to "relax" may have caused some of the
accumulated particles to be released from the membranes. There is no empirical evidence for
this supposition. Overall the increase in TMP during the 30-day testing period was slight. This
would seem to indicate that the selected flux and backwash protocol was appropriate for this feed
water quality.
4.3.1.2 Specific Flux Results
The specific flux of the treatment system was 240 l/h/m2/b at 20°C (10 gfd/psi at 68°F) on
average. The specific flux varied from a minimum of 220 l/m2/h/b at 20°C to 260 l/m2/h/b at
20°C (9.0 gfd/psi at 68°F to 11 gfd/psi at 68°F) during the testing. 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
(l/m2/h/b @20°C)
Average 240
Minimum 220
Maximum 260
Standard Deviation 7.2
Confidence Interval (240, 240)
Specific Flux vs. Time
260
255
250
245
240
» 235
230
225
220
® ^ <*> $ ^ ^ ^ ^ ^ ^
Run Time (Hours)
Figure 4-2. Specific Flux Decline vs. Time
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As depicted in Figure 4-2, specific flux 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 specific flux decline did not appear to be excessive
during the testing. There were two episodes of significant decline of specific flux decline. The
first occurrence was between run time 25 hours and 75 hours, when the flux declined from 260
l/m2/h/b at 20°C to 230 l/m2/h/b at 20°C. This correlates to increase in TMP during that time
frame. The increase of TMP may have been due, as previously discussed, to variations in the
time in the operational cycle when readings were taken. The second occurrence was on
December 21, there was a slight increase in TMP and a slight decrease in flux that combined to
create this reading.
4.3.1.3 Cleaning Episodes
Aquasource recommends that cleaning be instituted when the backwashing sequence is unable to
restore the specific flux to above 120 l/m2/h/b at 20°C (4.9 gfd/psi at 68°F). Due to the short
duration and high quality of the feed water, chemical cleaning was not required during the 30-
day test run. Cleaning was conducted as per ETV protocol requirements on February 16, 1999.
Results of that cleaning are presented in Section 4.3.2.
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 total water filtered. The following equation was used:
Percent feed water recovery = 100 * [Qp/Qf]
where: Qp = filtrate flow (gpd)
Qf = feed flow to membrane
Using the above equation the following calculation was performed:
Filtrate flow = flow (gpm) * minutes/day = filtrate flow (gpd)
Filtrate flow = 7.0 gpm* 1440 minute/day = 10080 gpd
Feed flow to membrane = filtrate flow + backwash volume
Feed flow = 10080 gpd + (25 gal/bw/hr * 24 hr/day) = 10680 gpd
Percent feed water recovery = 100 * [10080/10860] = 94%
4.3.2 Task 2: Cleaning Efficiency
Cleaning was conducted on February 16, 1999. The cleaning was a two-stage process consisting
of a pre-cleaning and cleaning step. The pre-cleaning consists of circulating the cleaning
solution through the membranes for 30 minutes; the cleaning step consists of circulating the
cleaning solution through the membranes for 45 minutes. A detailed description of the cleaning
process is presented in the manufacturer's O&M Manual (Appendix B).
39
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Data on the characteristics of the cleaning solution before, during, and after cleaning was
collected. Operational parameters were recorded before and after cleaning. The cleaning
solution data was used to characterize the cleaning solution and waste generated by cleaning of
the membranes. The operational data was 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.
Table 4-3. Chemical and Physical Characteristics of Cleaning Solution
Prewash
Second Wash
Parameter
unit
Result
Dup.
Result Dup.
pH of Cleaning Solution Initial
8.1
8.1
OO
OO
4^
pH of Cleaning Solution During Process
9.2
9.2
OO
OO
pH of Cleaning Solution Final
9.1
9.1
OO
OO
TDS of Cleaning Solution Initial
(mg/1)
110,558
96,698
TDS of Cleaning Solution During Process
(mg/1)
4,216
22,318
TDS of Cleaning Solution Final
(mg/1)
3,288
29,336
Turbidity of Cleaning Solution Initial
(NTU)
11.10
11.30
9.20 9.23
Turbidity of Cleaning Solution During Process
(NTU)
9.11
9.81
5.56 5.39
Turbidity of Cleaning Solution Final
(NTU)
8.40
8.42
2.88 3.00
Oxidant Residual Initial
(mg/1)
86
90
25 25
Oxidant Residual Final
(mg/1)
32
37
21 22
Visual Observation of Backwash Waste Initial
Clear, some air
Clear, some air
Visual Observation of Backwash Waste Final
Soapy, cloudy (air),
Soapy, no brown
slightly brownish cast
Table 4-4. Operational Parameter Results - Cleaning Procedure
Prewash
Second Wash
Parameter
Unit Time
Result
Result
Flow of UF Unit Prior to Cleaning
(gpm) 11:00
6.3
Pressure of UF Unit Prior to Cleaning (Upper)
(psi) 11:00
12
Pressure of UF Unit Prior to Cleaning (Lower)
(psi) 11:00
13
Pressure of UF Unit Prior to Cleaning (Filtrate)
(psi) 11:00
2.4
Temperature of UF Unit Prior to Cleaning
(°C) 11:00
3.7
3.7
Flow of UF Unit After Cleaning
(gpm) 13:37
6.3
Pressure of UF Unit After Cleaning (Upper)
(psi) 13:37
11
Pressure of UF Unit After Cleaning (Lower)
(psi) 13:37
13
Pressure of UF Unit After Cleaning (Filtrate)
(psi) 13:37
1.9
Temperature of UF Unit After Cleaning
(°C) 13:37
3.7
Recirculation Flow - during cleaning
(gpm)
30
30
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 X (1- (Jsf / Js;))
where: Jsf = Specific flux (gfd/psi, l/m2/h/b) at end of current run (final)
40
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Jsi = Specific flux (gfd/psi, l/m2/h/b) when the system was restarted after
completion of the cleaning procedure (initial)
The specific flux prior to the start of the cleaning process was: 220 l/m2/h/b at 20°C (9.0 gfd/psi
at 68°F). The specific flux when the system was restarted after the completion of the washing
procedure was 220 l/m2/h/b at 20°C (9.0 gfd/psi at 68°F).
Using these figures in the above equation resulted in a recovery of specific flux of -0.34%.
The following equation was used calculate the loss of original specific flux:
Loss of original specific flux = 100 X (1- (Js;/ Jsi0))
where: Jsi0 = Specific flux (gfd/psi, l/m2/h/b) at time zero point of membrane testing
The specific flux at time zero point of membrane testing was 250 l/m2/h/b at 20°C (10 gfd/psi at
68°F). The specific flux when the system was restarted after the completion of the washing
procedure was 220 l/m2/h/b at 20°C (9.0 gfd/psi at 68°F).
Using these figures in the above equation resulted in a loss of original specific flux of 12%.
4.3.2.3 Discussion of Results
Aquasource recommends that cleaning be instituted when the backwashing sequence is unable to
restore the specific flux to above 120 l/h/m2/bar at 20°C (4.9 gfd/psi at 68°F). Due to the short
duration and high quality of the feed water, chemical cleaning was not dictated by operational
parameters. However, a chemical cleaning is required by the ETV Protocol and was performed
on February 16, 1999.
The procedure used for chemical cleaning was well defined in the operations manual and
required minor manual effort. Loading of the detergent, mixing it into solution, and initiation of
the cleaning procedure required approximately two hours of effort by the operator.
The characterization of the cleaning wastewater indicated that the solution was moderately basic,
with a pH of 9.1 in the pre-cleaning waste and 8.6 in the final cleaning waste, had turbidity of not
exceeding 12 NTU, high TDS, with the final waste at nearly 30,000 mg/1, and total chlorine
residuals of 20 mg/1 to 30 mg/1. The wastewater during the pre-cleaning had a slight brown cast
and a "soapy" appearance.
Aquasource indicated that no hazardous material is present in the cleaning detergent. The
presence of hazardous materials in the wastewater would be dependent on the quality of the feed
water. Depending on local regulations, the waste stream may be able to be discharged to the
sanitary sewer system.
Examination of the operational data shows a slight recovery of specific flux. This may indicate
that the cleaning procedure was not capable of restoring membrane performance because of
irreversible fouling of the membrane or that this particular cleaning event was not effective.
41
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The loss of original specific flux was 12%. This may indicate that some irreversible degradation
of the membrane had occurred. However, given the poor performance of the cleaning
procedure's recovery of specific flux, it may again indicate that the cleaning event was not
effective.
4.3.3 Task 3: Finished Water 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 finished water 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.
Table 4-5. Feed Water Quality
Total
Total Total
Alkalinity Hardness Dissolved
Solids
Parameter
Total Total
Suspended Coliforms
Solids
HPC
TOC UVA Algae
Average
63
154
296
0.16
0
260
1.56
0.019
90
Minimum
59
150
280
<0.05
0
70
1.36
0.016
40
Maximum
71
158
313
0.30
0
460
1.73
0.022
136
Std. Dev.
5.6
N/A
N/A
0.16
0
160
0.155
0.0028
39
95%
(58,68)
N/A
N/A
(0.0069,
N/A1
(103,417)
(1.41,
(0.016,
(51, 129)
Confid Int
0.320
1.72)
0.022)
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. Finished Water Quality
Parameter
Total
Total
Total
Total
Total
HPC
TOC
UVA
Algae
Alkalinity Hardness
Dissolved
Suspended
Coliforms
Solids
Solids
(mg/1)
(mg/1)
(mg/1)
(mg/1)
(cfu/100 ml) (cfu/100 ml)
(mg/1)
(cm-1) (cells/ml)
Average
65
150
296
0.088
0
11
1.73
0.018
5
Minimum
60
146
271
<0.050
0
2
1.34
0.015
<8
Maximum
73
154
321
0.20
0
30
2.26
0.020
8
Std. Dev.
5.9
N/A
N/A
0.083
0
13
0.387
0.0021
2
95% Confid
(59,71)
N/A
N/A
(0.062,0.17)
N/A1
(0, 24)
(1.35,
(0.016,
(3, 7)
Int
2.11)
0.020)
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 and finished water
testing. Significant reductions were seen in HPC. HPC averaged 260 CFU/lOOml in the feed
water. Permeate HPC concentrations were 11 CFU/lOOml on average. This was likely due to the
42
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physical removal of the bacteria on the membrane surface. (The presence of HPC in the permeate
may have been due to the inability to completely disinfectant the Tygon sample lines.)
Algae concentrations were reduced. Feed water contained 90 cells/ml on average. Average
permeate algae concentrations were 5 cells/ml. The reported average finished water
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. (Permeate algae presence may have been
due to growth in the Tygon sample lines.)
A reduction of 0.072 mg/L TSS was observed on average. This represented approximately a
50% reduction in TSS; although given the low concentration of TSS in the feed water it may be
hard to extrapolate this percent removal to other locations.
The membrane pilot unit had little or no effect on the total alkalinity, total hardness, TDS, TOC,
and UVA254. This was not unexpected since these parameters are not present in the water as solid
constituents and are not amenable to reduction by physical straining.
Total coliform reduction could not be demonstrated due to the absence of total coliforms in the
feed water and permeate throughout the test.
Temperature of the feed water changed dramatically during the thirty day testing from a high of
11°C to a low of 3.2°C (52°F to 38 °F). The average temperature was 7.6°C (46°F).
4.3.3.1 Turbidity Results and Removal
Results of testing for turbidity in the feed and finished water 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 Tables 4-7 and 4-8. A complete data table is presented in
Appendix C. A graph of this data is presented as Figure 4-3.
Table 4-7. Turbidity Analyses Results and Removal
Sample
Feed (Bench Top)
Filtrate (In-line)
Parameter
Turbidity
Turbidity
Turbidity
Amount Removed
(duplicate)
(NTU)
(NTU)
(NTU)
(NTU)
Average
0.078
0.078
0.022
0.055
Minimum
0.060
0.050
0.021
0.039
Maximum
0.10
0.10
0.029
0.079
Standard Deviation
0.011
0.012
0.0036
0.011
95% Confidence Interval
(0.075,0.081)
(0.074, 0.082)
(0.021,0.023)
(0.051,0.059)
43
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Table 4-8. Filtrate Turbidity Results -
Parameter
Four Hour In-line Readings
Turbidity
(NTU)
Average
0.020
Minimum
0.015
Maximum
0.045
Standard Deviation
0.0036
95% Confidence Interval
(0.020, 0.021)
The turbidity of the permeate was very low throughout the duration of the verification testing.
The inline permeate turbidimeter readings averaged 0.022 NTU; the benchtop turbidimeter
readings averaged 0.045 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 finished water 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 online and
benchtop turbidimeter and the low level of turbidity in the permeate. 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 permeate 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 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 finished water with turbidities of less than 0.1 NTU.
Figure 4-3 shows the results of the four-hour permeate turbidity readings. Particle count
readings from run time 532 hours to 560 hours are not available due to a failure of the treatment
enclosure heating system. The loss of heat caused a solenoid valve that controlled flow to the
prefilter during backwash to freeze automatically shutting down the treatment unit.
44
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Permeate Turbidity vs. Time
Run Time (hours)
Figure 4-3. Four-Hour Permeate Turbidity
4.3.3.2 Particle Count Results and Removal
Particle count readings were taken on a continuous basis and recorded every 10 minutes.
Average particle count calculations were calculated from these readings. Average feed water
particle counts are presented in Table 4-9. Average finished water particle counts are presented
in Table 4-10. Daily average cumulative counts for feed and finished water and the logio particle
removals are presented in Table 4-11. A complete data table is presented in Appendix C.
Figures 4-4 and 4-5 depict results of four hour particle counts for feed water and permeate.
Figure 4-6 graphically depicts daily logio removals for cumulative particle counts.
Table 4-9. Feed Water Particle Counts
Size
2-3 |jm
3-5|jm
5-7|jm
7-lOpm
10-15|jm
>15|jm
Cumulative
Average
32
40
7.1
5.0
1.4
0.51
86
Minimum
3.0
4.0
0.55
0.60
0.025
0
N/A
Maximum
510
1200
510
830
660
480
N/A
Standard Deviation
14
23
8.0
13
10
7.4
N/A
95% Confidence
(31,32)
(39,40)
(6.9, 7.4)
(4.6, 5.4)
(1.1,1.7)
(0.30, 0.73)
N/A
Interval
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 above
readings were on average 22% lower than actual. See instrument QA/QC verification results in Section 4.5.3.
45
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Table 4-10. Finished Water Particle Counts
Size
2-3 |xm
3-5|jm
5-7|xm
7-lOpm
10-15|xm
>15|jm
Cumulative
Average
0.22
0.22
0.028
0.024
0.014
0.058
0.56
Minimum
0
0
0
0
0
0
N/A
Maximum
16
26
6.8
7.4
3.8
10
N/A
Standard Deviation
0.82
0.86
0.14
0.14
0.084
0.23
N/A
95% Confidence
(0.20, 0.24)
(0.19,0.24)
(0.024,
(0.020,
(0.012,
(0.051,
N/A
Interval
0.032)
0.028)
0.016)
0.065)
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 above
readings were on average 22% lower than actual. Due to extremely low results in the 10 (jm size range results of the 7-10 (jm
and 10-15 (jm the reliability of these counts should be considered questionable. See instrument QA/QC verification results in
Section 4.5.3.
Table 4-11. Daily Average Cumulative Particle Counts Feed and Finished Water, Logi0 Particle Removal
Date Permeate Feed Log i0 Removal
12/1/99
0.60
88
2.2
12/2/99
0.72
83
2.1
12/3/99
0.47
76
2.2
12/4/99
0.32
66
2.3
12/5/99
0.70
70
2.0
12/6/99
1.0
78
1.9
12/7/99
0.59
97
2.2
12/8/99
0.50
100
2.3
12/9/99
0.64
100
2.2
12/10/99
0.45
100
2.4
12/11/99
0.36
100
2.4
12/12/99
0.30
110
2.6
12/13/99
0.16
98
2.8
12/14/99
0.23
110
2.7
12/15/99
0.72
94
2.1
12/16/99
0.36
80
2.4
12/17/99
0.21
75
2.6
12/18/99
0.44
75
2.2
12/19/99
0.91
66
1.9
12/20/99
0.79
64
1.9
12/21/99
0.43
77
2.2
12/22/99
0.60
130
2.3
12/23/99
0.29
120
2.6
12/24/99
1.1
93
1.9
12/25/99
0.41
80
2.3
12/26/99
0.32
66
2.3
12/27/99
0.37
58
2.2
12/28/99
0.36
72
2.3
12/29/99
0.26
57
2.3
12/30/99
0.36
74
2.3
12/31/99
0.30
67
2.3
46
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Four Hour Feed Water Particle Counts vs. Time
O q> t?> ^ ^ ^ ^ ^ ^ ^J» ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ 41 # & $ & $> 41 ^ <$> &
Run Time (hours)
Figure 4-5. Four Hour Permeate Particle Counts
47
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Daily Average Log 10 Removal of Cumulative Particle Counts
vs. Date
3.0
°
> 1
E o
a;
o «
O)
re
2.0
1.5
O)
5 re
> I
< I
£ I
re o
D
0.5
0.0
^ ^ <&<&<&<&<&<&<&<&<&<&<&
J> J> J> ^ ^ ^ ^ ^ ^ ^ ^ ^
^ ^ ^ ^ ^ ^ ^
Date
Figure 4-6. Daily Average Logi0 Cumulative Particle Removal Graph
Particle counting of feed and finished water was conducted throughout the testing period. The
feed water cumulative counts averaged 86 particles per ml. The finished water cumulative
counts averaged 0.56 counts per ml. The average logio removal for the cumulative counts was
2.3.
The low particle counts for each size range in the filtrate water indicated good system
performance throughout the testing period. The treatment system demonstrated effective particle
removal.
4.3.3.3 Backwash Wastewater Testing Results
Daily and weekly testing was conducted on the backwash wastewater. The results of the testing
are listed in Table 4-13 and Table 4-14. A complete data table is presented in Appendix C.
48
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Table 4-12. Daily Backwash Wastewater Testing Results - Summary
Parameter
Turbidity
Turbidity (dup)
Chlorine Residual
Chlorine Residual (dup)
(NTU)
(NTU)
(mg/1)
(mg/1)
Average
0.66
0.67
5.48
5.51
Minimum
0.28
0.32
0.80
0.75
Maximum
1.6
1.63
7.50
7.50
Standard Deviation
0.35
0.33
1.2
1.2
95% Confidence Interval
(0.057, 0.075)
(0.55, 0.79)
(5.0, 5.9)
(5.0, 5.9)
Table 4-13 Weekly Backwash Wastewater Testing Results
Parameter
TSS
Total Coliforms
HPC
(mg/1)
(cfu/100 ml)
(cfu/100 ml)
Average
0.36
0
26
Minimum
0.050
0
6
Maximum
0.50
0
64
Standard Deviation
0.21
0
33
95% Confidence Interval
(0.16,0.57)
N/A
(0, 58)
N/A = Not applicable because standard deviation = 0.
The turbidity of the backwash waste was somewhat variable but averaged 0.66 NTU. The
chlorine residual was relatively consistent averaging 5.5 mg/1. TSS content in the backwash
waste was relatively consistent; indicating that the backwash procedure was removing some
particulate material. Total coliforms were absent in the backwash waste 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 finished water, and the amount in the backwash waste.
There is a portion of the TSS which will not be removed by backwashing and accumulates on the
membrane; the majority of this accumulated material is dissolved and removed by chemical
cleaning.
To calculate the amount of TSS in the treatment stream the following equation was:
lbs/day = Amount of TSS in mg/1 * ((8.341b/) / (mg/1 *MG))*Flow MG
Pounds of TSS in feed water:
Average feed water TSS (from Table 4-5) = 0.16 mg/1
Calculate the feed water flow in MG: (7.0 gpm) * (1440 min/day) = 10080 gal/day / (1,000,000
MG/gal) = 0.01008 MGD.
lbs/day = 0.16 mg/1 *((8.341b) / (mg/1 *MG))*0.01008MGD = 0.013 lbs/day
Pounds of TSS in finished water:
Average finished water TSS (from Table 4-6) = 0.088 mg/1
49
-------
Calculate the finished water flow in MG: (7.0 gpm)* (1440 min/day) = 10080 gal/day /
1,000,000 gal/ MG = 0.01008 MGD.
lbs/day = 0.088 mg/1 *((8.3 41b) / (mg/1 *MG))*0.01008MGD = 0.0074 lbs/day
Pounds of TSS in backwash wastewater:
Average wastewater TSS (from Table 4-13) = 0.36 mg/1
Calculate the amount of wastewater produced daily in MG: (25 gallons per backwash)* (24
backwashes per day) = 600 gallon per day / 1,000,000 gal/MG = 0.00060 MGD
lbs/day = 0.36 mg/1 *((8.341b) / (mg/1 *MG))*0.0006MGD = 0.0018 lbs/day
Pounds of TSS accumulating on membrane:
This value is the difference between the amount of TSS added to the membrane and the amount
of TSS removed during backwash. 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 backwash waste +
pounds of TSS accumulating on the membrane.
0.013 lbs/day TSS in influent = 0.0074 lbs/day TSS in effluent + 0.0018 lbs/day TSS in
backwash waste +0.0042 lbs/day accumulating on the membrane.
The TSS mass balance calculation would seem to indicate that the backwashing procedure was
not effective at removing the particulate material deposited on the membrane. According to the
calculation almost three times as much TSS was left on the membrane as was removed during
backwashing. 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 backwash water was higher than the
average of the weekly analyses indicated. The daily backwash waste 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 backwash
process.
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 180 kD (20 nm) and that 90% of the pores in their membrane are equal to or less
than 120 kD (10 nm). These results were generated through the use of AFNOR X45 103
Standard. This information is provided for informational purposes only. These results are
provided by the equipment manufacturer and were not verified during the ETV testing.
Appendix G contains a report from Aquasource in which the results of a number of different
50
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analytical methods are discussed. Appendix Three of the manufacturer's membrane pore size
report is the AFNOR X45 103 method.
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 February 17 and February 18, 1999. A
complete data table is presented in Appendix C.
4.3.5.1 Air Pressure Hold Test Results
The membrane vessel with the intact membrane was removed from the treatment unit and the
filtrate side was drained. The membrane itself was fully wetted (i.e. membrane pores were filled
with water). The membrane was air pressurized up to 2.00 b (29.0 psi). The filtrate side was
sealed and the pressure decline rate was monitored using an air pressure gauge.
At time zero the air pressure was 2.02 b (29.3 psi), after five minutes the air pressure was 2.00 b
(29.0 psi). At 10 minutes the air pressure inside the membrane was 1.98 b (28.7 psi), this
demonstrated that the membrane was intact. (An intact membrane would be expected to lose no
more than 0.07 b [1.02 psi] every five minutes.)
Air pressure loss was also compared to the loss that was obtained when testing a compromised
membrane. The membrane was intentionally compromised by removing the membrane vessel,
exposing the fibers themselves and severing a fiber.
At time zero the air pressure was 2.00 b (29.0 psi), after two minutes the air pressure was 0.63 b
(9.14 psi). At four minutes the air pressure inside the membrane was zero b (zero psi), this
demonstrated that the membrane was compromised.
4.3.5.2 Turbidity Reduction Monitoring
Turbidity of feed and filtrate water 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 0.078 NTU, showing a 90% reduction, 0.0078 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 two hours before the membrane was compromised averaged
0.023 NTU. The turbidity of the filtrate in the hour after the membrane was compromised was
0.022 NTU.
51
-------
Turbidity reduction monitoring between feed and finished water 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 source to finished water of 99.9% could demonstrate an intact
membrane. Due to the high quality of the feed water, the average cumulative feed water particle
counts were 86 total counts per ml, showing a 99.9% reduction was pushing the limits of the
instrumentation. 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.
The average cumulative particle count of the filtrate in the two hours before the membrane was
compromised was 2.2 counts/ml. The average cumulative particle count of the filtrate in the hour
after the membrane was compromised was 4.1 counts/ml.
Particle count reduction monitoring between feed and finished water was difficult due to high
quality of the feed water. The specified reduction from feed to finished to demonstrate an intact
membrane was 99.9%. The average particle count percent removal during the verification (with
the intact membrane) was 99.5%. Particle counts of the compromised membrane were 85%
higher than those produced by the intact membrane. This method of detecting a compromised
membrane may be useful as an indication of a compromised membrane but caution should be
used in relying on this method solely for a feed water with low particle count concentrations.
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 from source water to plant effluent of Giardia cysts and a 2 logio Cryptosporidium
oocysts. The Giardia and Cryptosporidium challenge took place on January 22, 1999. The
system operated at a manufacturer recommended flux of 153 l/m2/h at 20°C (90.4 gfd at 68°F)
and an average specific flux of 220 l/m2/h/b at 20°C (8.9 gfd/psi) during the Giardia and
Cryptosporidium removal challenge testing.
4.3.6.1 Feed Water Concentrations
During the Giardia and Cryptosporidium removal challenge testing the feed water had a pH of
8.2, a turbidity of 0.09 NTU, and a temperature of 1.7 °C. Based on the results of the replicate
hemocytometer counts, a total of 8,720,000 Giardia cysts and 91,770,000 Cryptosporidium
oocysts were added to 50 gallons of feed water in the feed water reservoir. This resulted in a
concentration of 174,400 Giardia cysts per gallon and 1,835,400 Cryptosporidium oocysts per
gallon in the feed water. The stock suspension of feed water and the cysts and oocysts was
constantly mixed using a drum mixer. A diaphragm pump was used to add the stock suspension
to the treatment unit. The pump was operated at about 0.85 gpm, (3.2 liter per minute) and was
52
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capable of overcoming the pressure in the feed water line of the pilot unit. The feed water from
the feed water reservoir was fed to the system for approximately 60 minutes.
As a QC check of the hemocytometer counts, a composite of the feed water was created from
five two-ml aliquots taken at five to ten minute intervals. Microscopic examination of the results
of this composite indicated 8,360,000 Giardia cysts and 82,270,000 Cryptosporidium oocysts.
These results were 4.1% and 10.3%, respectively, less, than the results obtained from the
hemocytometer counts. The hemocytometer counts were used to calculate the initial
concentration of the feed water per EPA protocols and due to the uncertain nature of sampling
and mixing of the suspension, which could render the composite sample results questionable.
The feed water results of the replicate hemocytometer counts are presented in Table 4-14. The
microscopic examination results of the composite sample are presented in Table 4-15. Bench
data sheets and report from the laboratory are enclosed in Appendix H.
Table 4-14. Giardia and Cryptosporidium Stock Suspension Results by Hemocytometer Counts
Giardia Cysts Cryptosporidium Oocysts
Average count (oocysts or cysts/0.0001 ml)
109
1,311
Standard Deviation
17
74
95% Confidence Interval
(97, 121)
(1,238, 1,384)
Total cysts and oocysts added to feed water
8,720,000
91,770,000
reservoir (8 ml of Giardia stock suspension,
7 ml Cryptosporidium)
Feed Water Amount Confidence Interval
(7,760,000, 9,680,000)
(86,660,000, 96,880,000)
Table 4-15. Giardia and Cryptosporidium Stock Suspension Results by Microscopic Examination
Giardia Cysts Cryptosporidium Oocysts
Presumptive count (oocysts or cysts/ml) 44 433
Total cysts and oocysts added to feed 8,360,000 82,270,000
water reservoir
4.3.6.2 Permeate Concentrations
No Giardia cysts or Cryptosporidium oocysts were identified in the permeate as shown by the
absence of cysts and oocysts on the 1 |im yarn wound capture filter. These results demonstrated
a 5.5 logio removal of Giardia cysts and a 6.5 logio removal of Cryptosporidium oocysts using
the hemocytometer counts of the feed water. During the Giardia and Cryptosporidium removal
challenge testing, the filtrate had a turbidity of 0.022 NTU and an average cumulative particle
counts of 1.8 counts/ml.
The logio removal of Giardia cysts or Cryptosporidium oocysts was calculated by first dividing
the amount of permeate sampled by the total amount of permeate filtered by the system. In this
case, one gallon per minute was filtered through the sampling filter compared to seven gallons
per minute of permeate produced by the treatment system. 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. This number was converted to its logio
53
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equivalent. The percent recovery of the test method at the PWSA laboratory is 25%, this means
that the lowest number of cyst or oocysts that could be detected is four. That is, if four cysts or
oocysts were in the permeate one of them would be detected. This number, four, was also
converted to its logio equivalent. The final log removal calculation was made by subtracting the
logio of the number of cysts added to the sampling filter less the logio of the number of cysts
trapped on the sampling filter, in this case zero, and then subtracting the logio of the number
four. Table 4-16 presents the concentrations and the logio removal calculations of the Giardia
cysts and Cryptosporidium oocysts.
Table 4-16. Giardia and Cryptosporidium Challenge Logio Removal Calculation
Giardia Cyst Removal Cryptosporidium Oocyst Removal
Cysts/oocysts in Feed Reservoir (from Table 4-14)
8,720,000
91,770,000
Cysts/oocysts Added to Capture Filter (The total number of
cysts/oocysts in Feed Reservoir multiplied by 14.3% because
the system was pumping at 7gpm and sampled at Igpm.
Effectively, only 14.3% of the total cysts/oocysts added could
have been detected on the capture filter.)
1,245,000
13,100,000
Log10 of Cysts/oocysts Added to Capture Filter
6.1
7.1
Log10 of Method Recovery (PWSA laboratory method recovery
is 25%, i.e. 1 in 4.)
0.60
0.60
Log10 Removal (Difference of Logio °f Cysts/oocysts Added to
Capture Filter and LogI0 of Method Recovery)
5.5
6.5
4.3.6.3 Backwash 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 backwashing
procedure was capable of removing the protozoans from the membrane system. Five hundred ml
of the backwash waste was 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 4-17
and 4-18. 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 4-19 4-20, and 4-21. Backwash
of the system was delayed, as per protocol requirements, until after the challenge testing was
completed. Samples of backwash water before and after the challenge were collected and
analyzed. Results of these analyses are presented in Table 4-22.
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Table 4-17. Pressure Readings and Calculations During Microbial Removal Testing
Upper Vessel Lower Vessel Filtrate Pressure Transmembrane
Pressure Pressure Pressure
Date Time (psi) (psi) (psi) (psi)
1/22/99 11:40 13 15 3.2 118
1/22/99 12:28 12 13 3.0 9.7
1/22/99 14:00 11 12 2.1 9.8
Table 4-18. Specific Flux During Microbial Removal Testing
Specific Flux
Date Time (l/m2/h/b (aj20°C)
1/22/99 11:40 210
1/22/99 12:28 230
1/22/99 14:00 220
Table 4-19. Turbidity Analyses Results and Removal During Microbial Removal Testing
Feed Filtrate
Turbidity Turbidity Turbidity Amount Removed
(duplicate)
Date Tune (NTU) (NTU) (NTU) (NTU)
1/22/99 12:10 0.090 0.080 0.022 0.068
1/22/99 14^05 0.090 N/A N/A N/A
N/A = Not applicable. Only one sample per day required by protocol.
Note: Feed water turbidity sampled prior to injection of challenge feed solution.
Table 4-20. Feed Water Particle Counts 1/22/1999
Size
2-3 |jm
3-5|jm
5-7|jm
7-10|jm
10-15|jm
>15|jm
Cumulative
Average
35
39
5.9
4.5
1.3
0.62
86
Minimum
0
0
0
0
0
0
N/A
Maximum
67
86
8.1
6.5
2.0
1.8
N/A
Std Dev
9.0
11
0.36
1.1
0.37
0.36
N/A
Confid Int
(32, 36)
(36,42)
(5.5, 6.3)
(4.2, 4.7)
(1.2, 1.4)
(0.53, 0.72)
N/A
N/A = Not Applicable. Statistical measurements on cumulative data do not generate meaningful data.
Note: Feed water particle counts sampled prior to injection of challenge feed solution.
Table 4-21. Finished Water Particle Counts 1/22/1999
Size
2-3 |jm
3-5|jm
5-7|jm
7-10|jm
10-15|jm
>15|jm
Cumulative
Average
0.44
0.91
0.12
0.098
0.048
0.14
1.8
Minimum
0
0
0
0
0
0
N/A
Maximum
7.7
19
1.5
1.5
0.57
1.4
N/A
Std Dev
1.1
3.0
0.037
0.24
0.10
0.25
N/A
Confid Int
(0.14,0.74)
(0.14, 1.7)
(0.035,0.16) (0.035,0.16) (0.021,0.074) (0.071,0.20)
N/A
N/A = Not Applicable. Statistical measurements on cumulative data do not generate meaningful data.
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Table 4-22. Daily Backwash Wastewater Testing Results During Microbial Removal Testing
Turbidity Turbidity (dup) Chlorine Residual Chlorine Residual (dup)
Date Time (NTU) (NTU) (mg/1) (mg/1)
1/22/99 15:30 2.30 2.06 3.25 3.35
1/22/99 16:30 2A1 N/A N/A N/A
N/A = Not applicable. Only one sample per day required by protocol.
Testing of the feed, finished and backwash water 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 permeate. The membranes
appeared to successfully remove all of the Giardia cysts and Cryptosporidium oocysts
introduced into the treatment system. Since the percent 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 5.5 logio removal of
Giardia cysts and a 6.5 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 limited by the amount of the parasites which were present in the stock
feed solution, the percentage of the permeate that could be sampled and the percent recovery of
the analytical methodology. Higher feed concentrations, percentage of permeate 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.
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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 a trailer and is not exposed to the elements, opportunities
for environmental upsets were limited. Failure of environmental controls in the treatment system
enclosure did occur during the test period and caused a system shut down. This was not a failure
of the treatment system; the heating system of the unit's enclosure failed causing an automatic
solenoid valve controlling the flow of backwash water to the prefilter to fail. This resulted in an
automatic system shut down. Restoration of heat to the enclosure and exercising of the solenoid
allowed the system to be restarted. The unit was offline for slightly more than 27 hours.
4.4.1.2 Operational Reliability
During the verification test the unit operated in the automatic mode. An automatic system shut
down occurred on December 23 when the enclosure's heating system failed as described earlier.
Restoration of heat to the enclosure and exercising of the solenoid allowed the system to be
restarted. The restoration of heat and restart of the system was not completed until December 24
and testing recommenced.
Manual operation was required for chemical cleaning of the system and to refill the container of
sodium hypochlorite used to supply chlorine to the backwash water. A representative of the
manufacturer visited the site daily primarily to download and transmit data from the PCs. While
on-site, the representative also visually checked the system.
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 and pressurized water.
The electrical service was connected according to local code requirements and did not represent
an unusual safety risk. The water pressure inside the treatment system was relatively low and
did not represent an unusual safety risk.
The sodium hypochlorite used for membrane backwashing 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 cleaning chemical Ultrasil 43 is a fine powder containing detergent and chlorine. The
powdery nature and chemical make-up of this substance could cause irritation to the nose and
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throat if it was accidentally released into the air. The use of appropriate PPE minimizes the risk
of exposure to this substance. The detergent in the Ultrasil 43 could produce slippery conditions
if accidentally spilled and mixed with water. The prompt and proper clean up of spills minimizes
the hazards associated with this chemical.
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 Aquasource Pilot System Model A35 operating at 155 l/m2/h at
20°C (91.2 gfd at 68°C). Costs will vary if the system is operated at different flux rates.
4.4.2.1 Power Supply Requirements
The unit was operated with 480V 3 phase 60Hz service with 20 Amp current as required by the
O&M manual. Daily power consumption of the treatment unit was determined by reading a
dedicated electric meter. The electric meter was installed by a certified electrician according to
the local electric code.
It became apparent after the first few days that the meter was not operating properly; it was
actually reading lower each day. It was determined that the electric meter was running
backwards. Due to the short duration of the study and the inability of the electric contractor to
respond in a timely manner it was not possible to change the meter before the end of the study.
According to information obtained from the meter manufacturer, the meter reading was not
accurate and can not be used for the purpose of this study.
4.4.2.2 Consumable Requirements
Consumable commodities included sodium hypochlorite and Ultrasil 43, which was the cleaning
chemical used during the verification testing. Sodium hypochlorite was added to the permeate
used for backwashing. The total chlorine residual in the backwash waste was 5.5 mg/1. This
level of chlorine residual required approximately 1 gallon of 12.5% sodium hypochlorite per
month. Each stage of the two-stage chemical cleaning episode requires 2.7 lbs. of Ultrasil 43
and about 10 gallons of permeate to dissolve the detergent.
4.4.2.3 Waste Disposal
The wastes generated by the treatment system were backwash water 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 600 gpd of backwash water during
verification testing.
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The backwash waste was finished water, 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 backwash waste was 0.36 mg/1. The range of TSS concentration was from
0.05mg/l to 0.50 mg/1. The chlorine concentration in the backwash wastewater averaged 5.51
mg/1 and ranged from 0.75 mg/1 to 7.50 mg/1. A complete presentation of the backwash waste
water data is included in Appendix C.
The chemical cleaning wastes contained dissolved solids, a surfactant, and a chlorine residual.
The concentration of the dissolved solids in the precleaning wastes was 3,288 mg/1. The second
cleaning wastes contained 29,336 mg/1. The residual chlorine in the precleaning waste was 32
mg/1 in the second cleaning waste the residual chlorine was 25 mg/1. The pH of the precleaning
wastes was 8.1; the pH of the second cleaning waste was 8.4. The concentration of the surfactant
in the cleaning wastes was not determined.
The microbial challenge utilized formalin fixed Giardia cysts and Cryptosporidium oocysts. The
backwash waste from the challenge test was collected, chlorinated, and stored for 3 days prior to
discharge.
4.4.2.4 Length of Operating Cycle
There were two "operating cycles" to be considered; the filtration cycle and the interval between
chemical cleaning. The lengths of these operating cycles are site specific and determined by the
manufacturer after evaluation of the feed water quality. These cycle lengths are easily field
adjustable if necessary; no adjustments were required for this verification.
The filtration cycle is the length of time between system backwashes. The interval between
backwashes is made based on the maintenance of flux. That is, if the backwash is not able to
maintain flux at a particular level, the frequency of backwashing is increased. The filtration
cycle was 60 minutes for the verification study. The backwash required 60 seconds to complete,
which included 15 seconds for system shutdown and various valve operations and 45 seconds for
the backwash itself.
The interval between chemical cleaning was not readily apparent due to the short duration of the
study and the high quality of the feed water. The treatment system did not reach the termination
criteria for initiation of chemical cleaning. Aquasource recommends that cleaning be done when
the specific flux reaches 120 l/m2/h/b at 20°C (4.9 gfd/psi at 68°F). The specific flux should
never be allowed to reach 100 l/m2/h/b at 20°C (4.1 gfd/psi at 68°F). Based on feed water quality
at the test site, the initial operations experience, and verification testing results, the manufacturer
estimated that the cleaning interval would be about three months at this site.
4.5 QA/QC Results
The daily, bi-weekly, initial, and the analytical laboratory QA/QC verification results are
presented below.
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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 filtrate turbidimeter flow rate averaged 503 ml/minute. To determine the flow rate of
the inline filtrate turbidimeter the flow was measured using a graduated cylinder and stop watch.
The maximum rate measured during the testing was 534 ml/minute; the minimum was 354
ml/minute. The acceptable range of flows as specified by the manufacturer is 250 ml/minute to
750 ml/minute. No adjustment of the flow rate was required during the verification testing.
The readout from the inline turbidimeter averaged 0.023 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 online and benchtop turbidimeter and the
low level of turbidity in the permeate. The benchtop turbidimeter uses a glass cuvette to hold the
sample; this cuvette can present some optical difficulties for the benchtop turbidimeter. The
online turbidimeter has no cuvette to present a possible interference with the optics of the
instrument. The low level of turbidity in the permeate also can create analytical difficulties,
particularly for the benchtop. Manufacturer's specifications state that stray light interference is
less than 0.02. 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 98 ml/minute. To determine the flow rate of
the inline feed water turbidimeter the flow rate was measured using a graduated cylinder and
stop watch. The maximum flow rate measured was 103 ml/minute; the minimum was 93
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 12 times during the verification study.
The finished water particle counter flow rate averaged 98 ml/minute. The flow rate was
measured using a graduated cylinder and stop watch. The maximum flow rate measured was 104
ml/minute; the minimum was 95 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 11 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 and finished water.
The flow meter readout was verified during the testing. The readout was compared to the results
obtained from the actual amount measured using a graduated cylinder and stopwatch. The
acceptable range of accuracy for the feed, finished and backwash meters was +/- 10%. The feed
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water meter readout averaged 1.75% higher than actual according to the results obtained during
the flow verification. The finished water meter readout averaged 3.85% higher than actual
according to the results obtained during the flow verification. The backwash meter readout
averaged 2.00% lower than actual according to the results obtained during the flow verification.
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.
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 upper membrane, lower membrane and filtrate pressure gauges were checked prior to the
start of testing. Dead weights of 5,10, 15, 20, 30, and 40 pounds were used. The upper
membrane pressure gauge averaged 4.9 psi (0.34b), 9.9 psi (0.68b), 14.9 psi (1.03b), 19.9 psi
(1.37b), 29.9 psi (2.06b), and 39.8 psi (2.74b) when tested with the above weights. The lower
membrane pressure gauge averaged 4.9 psi (0.34b), 9.85 psi (0.68b), 14.75 psi (1.02b), 19.75 psi
(1.36b), 29.55 psi (2.04b), and 39.45 psi (2.72b) when tested with the above weights. The filtrate
pressure gauge averaged 5.7 psi (0.39b), 10.67 psi (0.74b), 15.67 psi (1.08b), 20.57 psi (1.42b),
30.57 psi (2.11b), and 40.2 psi (2.77b) 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 |im, 10 |im, and
15 |im sized particles.
The feed water particle counter showed an average response for the 5 |im size of 1,552.24
counts/ml; the 10 |im size showed an average response of 1467.24 counts/ ml; the 15 |im size
showed an average response of 1654.41 counts/ ml. This corresponds to a difference of 22%,
27%), and 17% 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
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procedure. The average percent difference for the three standards used was 22%. The readings
for feed water particle counts obtained during the verification testing should be increased by 22%
to account for the low response of the feed water particle counter.
The finished water particle counter showed an average response for the 5 |im size of 1,699.55
counts/ml; the 10 |im size showed an average response of 629.85 counts/ ml; the 15 |im size
showed an average response of 1644.97 counts/ ml. This corresponds to a difference of 15%,
69%, and 18% respectively in particle counts. These results were outside of the generally
recognized range of +/- 10 %. 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
average percent difference for the 5 |im and 15 jam standards was 16%. The readings for
finished water particle counts in the 2-7 |im and the >15 |im obtained during the verification
testing should be increased by 16% to account for the low response of the finished water particle
counts. Due to extremely low results in the 10 |im size range the reliability of the 7-10 |im and
10-15 |im 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 Analytical Laboratory QA/QC
Samples for analyses conducted on feed and finished water 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 finished water is recorded and kept on file at the PWSAs 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.
Aquasource - Operations & Maintenance Manual - Pilot # 6. Aquasource NA, August, 1998.
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, EPA1991b.
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, EPA1989b.
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.
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