10/6/2019 Steve Wait Director of Sales IDE Technologies 5050 Avenida Encinas Carlsbad, California 92008 Hello Steve, Thank you for sending your membrane to Avista Technologies for evaluation. Attached please find the autopsy reports for Filmtec ECO Pro-400 membrane serial numbers T5209566 (Position#1) and T5209558 (Position #7). I have reviewed this report and have the following comments:

Element SN T5209566 (Position #1)

• The element produced 64.3% of normal flow, rejection of 99.1% and DP of 8 psi.

• No physical damage was identified during the external or internal examination.

• Black rubber-like shavings were visible on the scroll end.

• Brown-colored foulant was detected on the membrane surfaces. The foulant was identified as bioslime and microorganisms.

• RoClean P111 (2% by weight in RO/DI water, heated to approximately 35 degrees Celsius and circulated for 8 hours) was able to remove the bulk of the visual foulant and restore flow to the membrane.

Element SN T5209558 (position #7)

• The element produced 77.2% of normal flow, rejection of 99.3% and DP of 6 psi.

• No physical damage was identified during the external or internal examination.

• Black rubber-like shavings were visible on the scroll end.

• Brown-colored foulant was detected on the membrane surfaces. The foulant was 85% bioslime and microorganisms. The remaining portion of the foulant was contributed by calcium phosphate found in the feed spacer contact points.

• RoClean P111 (2% by weight in RO/DI water, heated to approximately 35 degrees Celsius and circulated for 8 hours) was able to remove the bulk of the visual foulant and restore flow to the membrane.

Discussion Since 2018 Avista Technologies has supported IDE’s Pismo Beach pilot study. Avista has provided multiple autopsies at different phases of the project. A summary of the autopsies completed to date is noted in the table below:

Serial Number

T3976097 T3976130 T3400779 T3400789 T4657921 T4658181 T5220907 T5220923 T5209566 T5209558

Element 1st Stg Lead 1st Stg Last 2nd Stg Lead 2nd Stg Tail 1st Stg Lead 1st Stg Tail 2nd Stg Lead 2nd Stg Tail 1st Stg Lead 2nd Stg Tail

WO# 053018-6 053018-6 053018-6 053018-6 100418-1 100418-1 100418-1 100418-1 073119-2 073119-2

Element Flow

3.75 3.14 1.26 1.21 5.87 5.75 1.26 1.11 4.31 5.17

% from Normal

47.5% 39.7% 81.3% 78.1% 74.3% 72.8% 81.3% 71.6% 64.3% 77.2%

Weight 32 33 8 7 32 33 7 7 33 31

DP (psi) 7 7 4 3 6 5 3 3 8 6

LOI (%) 94.9% 97.0% 93.6% 95.3% 91.3% 91.6% 91.9% 82.3% 96.0% 84.0%

Foulant

Organic (bioslime, bacteria,

funji, micro-organisms)

Organic (bioslime, bacteria,

fungi, micro-organisms)

Organic (bioslime, bacteria,

fungi, micro-organisms)

Organic (bioslime, bacteria,

fungi, micro-organisms)

Organic (bio-slime,

notable micro-

organisms)

Organic (bio-slime,

notable micro-

organisms)

Organic (bio-slime,

notable micro-

organisms)

82% organic, 18%

inorganic composed of

calcium phosphate,

iron and aluminum

Organic (bio-slime, heavy presence of

micro-organisms)

84% organic, 16%

inorganic composed of

calcium phosphate and some

metals

CIP Contact

Time 6 6 6 6 2 2 2 2 8 8

From the table above, it is noted that the bulk of the foulant material is organic in nature. Although the inorganic content was slightly higher on the tail element from the autopsies completed under WO#100418-1 and WO#073119-2, the bulk of the foulant is organic. When comparing the cleaning studies, it is noted that the middle set of autopsies (WO#100418-1) required the least contact time (2 hours), while the initial and last set of autopsies required 6 and 8 hours of contact time, respectively. This indicates a more challenging fouling layer with the longer contact time. Regardless of the set, RoClean P111 was recommended as the cleaner of choice for the Pismo Beach pilot. Additionally, we recommend the review the CIP procedures to establish a proper cleaning schedule and standard operating procedure. Thanks again for permitting our organization to evaluate your membrane. We appreciate your business. Kind regards,

Lee Durham Technical Services Director Avista Technologies

Membrane Autopsy Report

Completed for:

IDE Americas, Inc. Pismo Beach, CA

Serial Number T5209566

Position #1 10/07/2019 WO#073119-2

1

Executive Summary .............................................................................................................................................. 2

Initial Element Test .............................................................................................................................................. 3

Element Weight ......................................................................................................................................................3

Full Element Wet Test .............................................................................................................................................3

Integrity Test ...........................................................................................................................................................4

Membrane Construction Diagrams ....................................................................................................................... 5

External Inspection .............................................................................................................................................. 6

Fiberglass Casing.....................................................................................................................................................6

Brine Seal ................................................................................................................................................................6

Permeate Tube ........................................................................................................................................................6

Anti-Telescoping Devices (ATDs) .............................................................................................................................7

Internal Inspection ............................................................................................................................................... 8

Scroll Ends ...............................................................................................................................................................8

Membrane Surface..................................................................................................................................................9

Feed Spacers ........................................................................................................................................................ 11

Glue Lines ............................................................................................................................................................. 12

Permeate Carriers and Membrane Backing ......................................................................................................... 12

Foulant Analysis ................................................................................................................................................. 13

Foulant Density Measurement and Composition Testing ..................................................................................... 13

Microbiological Analysis ....................................................................................................................................... 14

Acid Testing .......................................................................................................................................................... 15

Zeta Potential Testing .......................................................................................................................................... 15

Fourier Transform Infrared Spectroscopy Analysis ............................................................................................... 16

Energy Dispersive Spectroscopy (EDS) Analysis .................................................................................................... 17

Scanning Electron Microscope (SEM) Imaging ..................................................................................................... 18

Chromatic Elemental ImagingSM (CEISM) ............................................................................................................... 19

Organic Luminescence Microscopy (OLM) ........................................................................................................... 21

Flat Sheet Performance and Cleaning Study........................................................................................................ 23

Testing for Flat Sheet Damage ............................................................................................................................ 25

Fujiwara Testing ................................................................................................................................................... 25

Certification by Laboratory ................................................................................................................................. 26

Table of Contents

2

Executive Summary

Background IDE Technologies, Inc. provided two (2) Filmtec ECO PRO-400 reverse osmosis (RO) elements from Pismo Beach to Avista Technologies for full membrane autopsies. Element Serial Number (SN) T5209566 was indicated as Position #1 and SN T5209558 was indicated as Position #7. The remainder of this report pertains to SN T5209566 (Position #1).

Initial Element Testing The element produced 64.3% of normal flow, lower than normal rejection (99.1%) and a differential pressure of 8 psi. The element passed integrity testing, indicating that there was no damage to the internal components of the spiral wound element.

External Inspection The external components, fiberglass casing, permeate tube, anti-telescoping devices (ATD) and brine seal were in good condition even though foulant was observed on some of the components (casing and ATD).

Internal Inspection The scroll ends were in good mechanical condition; however, a black colored rubbery material was identified on the feed (brine seal) scroll end. A layer of smooth, brown-colored foulant was coating the exposed membrane surfaces. Smooth textured foulant indicates the presence of organics. An odor (biological) was also noted during the dissection process. Foulant was also observed on the feed spacers but the internal components (feed spacer, glue lines, permeate spacers) were in good mechanical condition.

Foulant Analysis Moisture content of the foulant material was 12%. Organic content of the foulant was 96.0%, indicating that the foulant was nearly completely organic. Dry foulant density on the membrane surface was measured at 0.09 mg/cm2. Microscope analysis of foulant removed from the membrane detected bioslime and a heavy presence of microorganisms in the foulant. Additionally, Fourier Transform Infrared (FT-IR) detected bands associated with biological material (proteins and carbohydrates). Energy Dispersive Spectroscopy (EDS) analysis only identified trace amounts of calcium as the inorganic material on the membrane. Chromatic Elemental ImagingSM (CEISM) confirmed that the membrane surface was covered with bioslime and microorganisms (represented by carbon). Additional testing with Organic Luminescence Microscopy (OLM) identified high concentrations of both live and dead bacteria colonies, scattered patches of proteins and a more even layer of lipids (hydrophobic organics) across the membrane.

Based on the foulant analysis it was determined that the membrane was biofouled.

Flat Sheet Performance and Cleaning Study Cleaning the flat sheet with RoClean P111 (2% by weight in RO/DI water, heated to approximately 35 degrees Celsius and circulated) for eight hours restored water and salt passage within the manufacturers specified range.

Flat Sheet Damage Fujiwara testing for the presence of halogens (e.g. chlorine) in the membrane structure was negative.

3

Initial Element Test

Element Weight All elements are weighed prior to autopsy as weight is often indicative of the degree of fouling. New eight-inch elements weigh approximately 30 to 35 pounds. Additionally, elements in excess of 50 pounds cannot be wet tested.

SN T5209566 weighed 33 pounds.

Full Element Wet Test Test results were normalized to the manufacturer’s published test conditions.

Filmtec ECO PRO-400 Flow

(gpm) Rejection

(%) Pressure Drop

(psi)

SN T5209566 4.31 99.1 8

Manufacturer’s Specifications 6.70 to 9.10 99.4 to 99.7 ≤15

Element wet testing

4

Integrity Test Integrity testing is performed to identify mechanical damage to the internal components of the spiral wound element. In this test, a vacuum of approximately 20 inches Mercury (in. Hg) is applied to the permeate side of the membrane and the membrane is then sealed. The vacuum is monitored for a duration of 120 seconds. Any loss of vacuum indicates the presence of damage; however, losses of over 35% of the vacuum within the 120 second period suggests severe physical damage.

The element passed integrity testing.

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Integrity Test Results for SN T5209566

Vacuum

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5

Membrane Construction Diagrams

6

External Inspection

Fiberglass Casing The purpose of the fiberglass casing is to ensure that the various membrane components are held in their correct position for optimum performance. Damage to the casing can be an indication of rough handling or damage from excessive differential pressure across the element from heavy fouling.

Green-colored foulant was observed on the casing towards the feed end (brine seal end) of the element but the casing was in good mechanical condition.

Fiberglass casing of SN T5209566

Brine Seal The brine seal is used to seal against the inside diameter of the pressure vessels and the outside diameter of the membrane to ensure that all the feed water passes through the element. Feed water passing on the exterior of the element can result in higher pressures, which can cause cracking of the fiberglass casing.

The brine seal was in good mechanical condition and free of foulant

Permeate Tube The permeate tube is a pipe that is located at the center of the element. It contains lines of holes and is bonded to each membrane leaf, allowing permeate water to travel from the leaves into the permeate tube to be collected. Damage to the ends of the permeate tube can lead to o-ring failures, causing bypass of feed or concentrate water into the permeate stream. Cracking of the permeate tube can also result in permeate contamination.

The permeate tube was in good mechanical condition.

7

Anti-Telescoping Devices (ATDs) The function of the ATDs is to stabilize the components of the element. This helps to prevent shifting of the internal mechanical components under pressure, also known as telescoping. Telescoping may still occur if pressures exceed the manufacturer’s specifications.

Both ATDs were absent of notable damages. The concentrate ATD did have some black material on the surfaces.

Feed (left) and concentrate (right) ATDs of SN T5209566

8

Internal Inspection

Scroll Ends The ends of the element are called scroll ends. They are examined for the presence of foulant debris and mechanical damage (e.g. gapping, feed spacer extrusion). The presence of foulant on the scroll ends can cause elevated delta pressures while gapping and feed spacer extrusion indicate uneven hydraulics (high flow/low flow regions). In addition, each scroll end is examined for telescoping, the gradual axial shift of the membrane leaves from the outer diameter of the element towards the permeate tube. Telescoping is often caused by the development of high differential pressure (greater than the manufacturer’s specification) across the element or when pressure is applied too quickly, causing a water hammer effect.

Black, rubbery foulant material was observed around the feed scroll end closest to the permeate tube. Additionally, brown-colored foulant material was present on both scroll ends. Despite the fouling, the scroll ends were in good mechanical condition.

Feed (left) and concentrate (right) scroll ends of SN T5209566

9

Membrane Surface New membrane surfaces are uniform and shiny. Foulant can often be detected through visual examination; however, membrane appearance can be misleading as some foulants are not visible. The presence of foulant on the membrane surface can cause elevated delta pressure, loss in flow and damage if the foulant is abrasive. Additionally, the membrane surface is inspected for damage such as delamination. Delamination is the lifting of the thin-film membrane from the support layer and often occurs due to a positive pressure on the permeate side of the element.

A layer of smooth, brown-colored foulant was coating the exposed membrane surfaces. Smooth textured foulant is usually an indicator that organics are present. The foulant material was scrapeable. A slight odor (biological was also noted during dissection.

Exposed membrane surface of SN T5209566

Exposed membrane surface from feed end of SN T5209566

10

Image of scraped foulant

11

Feed Spacers The feed spacer is a plastic net material designed to separate the membrane leaves, forming a flow path, and to promote turbulence within the feed water channels. Foulant blocking the feed channels causes more resistance for the feed water flowing through the element and results in higher than normal delta pressures.

The feed spacer was in good mechanical condition although some brown-colored foulant was observed on the surfaces.

Image of feed spacer in SN T5209566

Stereoscope image of feed spacer in SN T5209566

12

Glue Lines Membrane leaves are glued on three sides to separate the feed and permeate streams. The glue lines are inspected for specific damage, including glue flaps and pouching. Glue flaps refer to excess inactive membrane material located closest to the ends of the element. Flaps found on the feed end of the element can flare during operation, blocking the feed channels on the scroll end, potentially causing increased differential pressure. Pouching of the glue line, which is often a result of delamination, allows feed water to pass through the inactive membrane at the glue line, contaminating the permeate stream.

The glue lines were in good mechanical condition.

Permeate Carriers and Membrane Backing The permeate carriers provide a path for permeate water to flow towards the permeate tube, which minimizes permeate-side pressure losses. New permeate carriers and membrane backing are uniform in color. Foulant found on the permeate side of the membrane leaves indicates contamination of the permeate stream.

The permeate carriers and membrane backings were clear of visible contamination.

13

Foulant Analysis

Foulant Density Measurement and Composition Testing A sample collected from a known area of the membrane surface is weighed before and after drying to determine the foulant density (reported as dry foulant density – mg/cm2) and moisture content of the sample. Different types of foulant materials exhibit higher moisture contents. Relative water concentrations greater than 95% indicate an extremely hydrated, biological material. Alternatively, scales (crystalline material) typically contain very little moisture. The organic content of the dehydrated material is then measured through loss on ignition (LOI) testing. If the organic content of the total solids is greater than 65%, it is considered primarily organic.

The dry foulant density of SN T5209558 was measured as 0.09 mg/cm2. The moisture and organic content are displayed in the graphs below.

12%

88%

Moisture Content

Water Sample

96%

4%Organic Content

Organic Inorganic

14

Microbiological Analysis This analysis is performed to identify microbiological components of the foulant removed from the membrane surface. Foulant samples are stained and examined with a light microscope at 1000x using an oil immersion lens. Gram positive bacteria are stained purple while Gram negative bacteria are stained pink.

Foulant removed from the membrane contained amorphous organic material (e.g. bio-slime).and significant microbiological material including Gram positive and negative bacteria, algae, fungi, yeast and shelled microorganisms.

Light microscope images (1000x) of foulant scraped from SN T5209566

15

Acid Testing Acid testing is used to determine the presence of carbonates and metals on the membrane surface. In this test, several drops of dilute hydrochloric acid (HCl) were placed on the foulant surfaces. Effervescing indicates the presence of carbonates while a color change is associated with the presence of metals.

Acid testing was negative for the presence of carbonates and metals.

Zeta Potential Testing The zeta potential is the charge that resides at the double layer boundary of colloids. Most naturally occurring colloids are negatively charged. If an excess of coagulant is present, the charge of the colloids switches from negative to positive. As such, zeta potential testing is used to determine if coagulant is being overfed. Two grams of wet foulant is required for this test.

The foulant material of SN T5209566 had a zeta potential of -18.1 mV indicating there was no coagulant on the membrane surface.

Image based on diagram from Particle Characterization Laboratories, Inc.

16

Fourier Transform Infrared Spectroscopy Analysis Fourier Transform Infrared Spectroscopy (FT-IR) is an analytical technique used to identify functional groups (specific groups of atoms or bonds within molecules). Infrared radiation passes through a sample, with some of the radiation absorbed and some transmitted. A measurement and interpretation of this data produces a spectrum which can then be compared and matched to the known spectra for functional groups based on the wavenumber at which bands appear and their respective shapes (e.g. sharp, broad, strong, weak).

FT-IR spectrum of foulant removed from the membrane surface detected a strong double peak at around the 1650-1500 cm-1 range is which is indicative of the presence of proteins (e.g. amino acids from microorganisms). Additionally, a broader peak was observed at approximately 1000 cm-1 wavenumber, which is due to carbohydrates (polysaccharides). The absorbance signal from the proteins was higher than the carbohydrates.

FT-IR spectral image of foulant removed from the membrane surface of SN T5209566

Proteins

Carbohydrates

17

Energy Dispersive Spectroscopy (EDS) Analysis Energy Dispersive Spectroscopy analysis is used to determine the relative concentration of elements present in a sample. EDS analysis is performed on a dry membrane sample. The element sulfur is at least in part associated with the membrane support material (polysulfone) rather than a foulant layer. Avista’s analysis of new membranes typically detects between 5.00 and 7.00 weight percentage. Relative concentrations below 5.00 percent indicate the presence of a foulant layer masking the membrane surface.

EDS analysis only identified trace amounts of calcium as the inorganic elements present on the membrane surface. The carbon weight percentage was attributed to the membrane materials themselves and organics. The sulfur weight percentage (4.01%) indicates a masking of the membrane surface by the foulant layer.

Elements SN T5209566

Weight Percent (wt%)

Carbon 83.53

Oxygen 12.35

Sulfur 4.01

Calcium 0.11

18

Scanning Electron Microscope (SEM) Imaging SEM imaging is performed on the membrane surface to observe the topography of the foulant material. Foulant morphology can be an indicator of the type of foulant.

SEM images displayed a layering of material with a smooth topography (associated with organics) coating the surface of the membrane. Few random particles were also visible under the SEM across the membrane.

SEM image (150x) of the membrane surface of SN T5209566

Close-up SEM image (5000x) of the membrane surface of SN T5209566

19

Chromatic Elemental ImagingSM (CEISM) CEI is a high-resolution imaging technique used to determine the spatial distribution of elements in a foulant sample. Each element is assigned a color (shown in a legend on the bottom left corner of the CEI image) and the colors correspond to the location of the elements in the sample. An element’s color intensity is associated with its concentration in the sample (i.e. elements present with higher relative concentrations are displayed with greater color intensity in the image). Additionally, a blending of colors signifies a compound (material composed of more than one element such as calcium carbonate).

CEI image (1500x) of the membrane surface

20

CEISM confirmed that the membrane surface was coated with organic material as a high carbon content (dark blue) was observed where the organics were present. Microorganisms were visible in the organic slime layer. The membrane surface, represented by sulfur (red), was visible through areas where the foulant material had cracked after drying.

CEI image (1500x) of the membrane surface with labels

21

Organic Luminescence Microscopy (OLM) Organic Luminescence Microscopy (OLM) is an analytical method using specialized filters and focused emitted photons to identify individual microorganisms, plant material, carbohydrates, and proteins and how they interact in three-dimensional space. Each component type in the biofilm layer is designated a color to determine how each component interacts with each other in the wet bio matrix on the membrane surface.

Organic luminescence microscopy of the membrane surface identified high concentrations of both live (green) and dead (red) bacteria colonies. Additionally, scattered patches of proteins (1st image - dark blue) were detected within the biofilm. Lipids (hydrophobic organics - 2nd image - blue) were observed throughout the bio layer. The microorganisms colonies and lipids were relatively uniform across the bio layer.

Luminescence image of the membrane surface

22

Luminescence microscopy on membrane surface

23

Flat Sheet Performance and Cleaning Study

To evaluate flat sheet performance, membrane samples harvested from the full element are tested for permeability and salt passage. The raw flow and conductivity measurements from the test are used to calculate the permeability and salt passage constants, which are independent of pressure, temperature and salt content of the feed stream. The permeability constant is measured in cm/s/atm and the salt passage constant in cm/s. Discrepancies between the flat sheet and full element performance can indicate the presence of mechanical damage.

The flat sheet samples are then cleaned with various Avista chemicals to determine the most effective cleaner combinations and contact times. Cleaner efficacy is based on overall improvement in permeability and salt passage constant as well as visual foulant removal.

The table below shows performance data for the optimum cleaning. Flat sheet samples were cleaned with RoClean P111 (2% by weight in RO/DI water, heated to approximately 35 degrees Celsius and circulated) for eight hours.

SN T5209566 Permeability Constant Salt Passage Constant

Baseline 0.85E-05

63% of Normal 16.8E-06

172% of Normal

Post RoClean P111 1.68E-04 Normal

8.17E-06 Normal

Manufacturer’s Specifications 1.35 to 1.82E-04

Normal Range 4.86 to 9.75E-06

Normal Range

Note: testing conducted using dechlorinated San Marcos, CA water

>200%

Pre-CleanPost-Clean

0% 25% 50% 75% 100% 125% 150% 175% 200%

Permeability (% of Normal)

>200%

Pre-CleanPost-Clean

100% 125% 150% 175% 200%

Salt Passage (% of Normal)

24

Pre-Clean

Post Clean

25

Testing for Flat Sheet Damage

Fujiwara Testing Fujiwara testing is a qualitative analysis which determines if a polyamide (PA) thin-film membrane has been exposed to an oxidizing halogen, such as chlorine, bromine, or iodine. A color change does not occur if the membranes has not been exposed to halogens. Common symptoms of halogen oxidation include increased flow and loss in permeate quality.

Fujiwara testing was negative for the presence of halogens (e.g. chlorine) in the membrane structure.

Example of a negative Fujiwara color change

26

Certification by Laboratory

Report Number Report Content Element Serial Number Report Date

WO#073119-2 Standard Spiral Autopsy T5209558 T5209566

October 7th, 2019

We the undersigned being the technical specialists in membrane autopsy and related testing procedures and protocol for Avista Technologies certify to the best of our knowledge and belief that the tests listed in this report have been conducted following Avista’s standard testing practices and that the results are accurate and complete.

By signing this certificate neither the laboratory employees nor their employer makes any warranty, expressed or implied, concerning the cleaning study results.

Date: 10/07/2019

Signed:

Megan Lee Laboratory Services Manager

Arnell Abad Laboratory Services Chemist

Membrane Autopsy Report

Completed for:

IDE Americas, Inc. Pismo Beach, CA

Serial Number T5209558

Position #7 10/07/2019 WO#073119-2

1

Executive Summary .............................................................................................................................................. 2

Initial Element Test .............................................................................................................................................. 3

Element Weight ......................................................................................................................................................3

Full Element Wet Test .............................................................................................................................................3

Integrity Test ...........................................................................................................................................................4

Membrane Construction Diagrams ....................................................................................................................... 5

External Inspection .............................................................................................................................................. 6

Fiberglass Casing.....................................................................................................................................................6

Brine Seal ................................................................................................................................................................6

Permeate Tube ........................................................................................................................................................6

Anti-Telescoping Devices (ATDs) .............................................................................................................................7

Internal Inspection ............................................................................................................................................... 8

Scroll Ends ...............................................................................................................................................................8

Membrane Surface..................................................................................................................................................9

Feed Spacers ........................................................................................................................................................ 11

Glue Lines ............................................................................................................................................................. 12

Permeate Carriers and Membrane Backing ......................................................................................................... 12

Foulant Analysis ................................................................................................................................................. 13

Foulant Density Measurement and Composition Testing ..................................................................................... 13

Microbiological Analysis ....................................................................................................................................... 14

Acid Testing .......................................................................................................................................................... 15

Zeta Potential Testing .......................................................................................................................................... 15

Fourier Transform Infrared Spectroscopy Analysis ............................................................................................... 16

Energy Dispersive Spectroscopy (EDS) Analysis .................................................................................................... 17

Scanning Electron Microscope (SEM) Imaging ..................................................................................................... 18

Chromatic Elemental ImagingSM (CEISM) ............................................................................................................... 19

Organic Luminescence Microscopy (OLM) ........................................................................................................... 21

Flat Sheet Performance and Cleaning Study........................................................................................................ 23

Testing for Flat Sheet Damage ............................................................................................................................ 25

Fujiwara Testing ................................................................................................................................................... 25

Certification by Laboratory ................................................................................................................................. 26

Table of Contents

2

Executive Summary

Background IDE Americas, Inc. provided two (2) Filmtec ECO PRO-400 reverse osmosis (RO) elements from Pismo Beach to Avista Technologies for full membrane autopsies. Element Serial Number (SN) T5209566 was indicated as Position #1 and SN T5209558 was indicated as Position #7. The remainder of this report pertains to SN T5209558 (Position #7).

Initial Element Testing The full element produced 77.2% of normal flow, lower than normal rejection (99.3%) and a differential pressure of 6 psi during wet testing. The element passed integrity testing, indicating that there was no damage to the internal components of the spiral wound element.

External Inspection The external components (fiberglass casing, brine seal, anti-telescoping devices (ATDs) and permeate tube) were free of mechanical damage.

Internal Inspection Both scroll ends were in good mechanical condition. However black-colored rubber shavings were visible on the feed scroll end (brine seal end). The exposed membrane surfaces were coated with a smooth layer of brown-colored foulant material. Smooth textured foulant indicates the presence of organics. Additionally, a biological odor was noted during dissection of the element. The feed spacers were lightly fouled but in good mechanical condition. The remaining internal components (glue lines, permeate carriers and membrane backings) were clear of visible defects, damages and contamination.

Foulant Analysis Moisture content of the foulant material was approximately 85%. Organic content of the foulant material was 84%, indicating the bulk of the foulant was composed of organic material. Dry foulant density on the membrane surface was measured at 0.02 mg/cm2. Microscope analysis of the foulant identified a significant amount of bioslime and microorganisms. Fourier Transform Infrared (FT-IR) spectroscopy also detected bands associated with organics (proteins and carbohydrates) as well as phosphorous containing compounds. Energy Dispersive Spectroscopy (EDS) analysis identified calcium, phosphorus and silicon as the primary foreign inorganic elements present on the membrane surface. Chromatic Elemental ImagingSM (CEISM) showed significant organic fouling across the membrane with calcium phosphate and silica deposits in the feed spacer contact points. Additional testing with, Organic Luminescence Microscopy (OLM) identified high concentrations of live bacteria, dead bacteria, and lipids (hydrophobic organics) across the membrane. The biological foulant pattern was relatively even. Random patches of protein patches were also detected throughout the bio layer.

Based on the foulant analysis it was determined that the membrane was mainly biofouled with calcium phosphate and silica deposits in the feed spacer contact points. .

Flat Sheet Performance and Cleaning Study Cleaning the flat sheet with RoClean P111 (2% by weight in RO/DI water, heated to approximately 35 degrees Celsius and circulated) for eight hours restored water and salt passage within the manufacturers specified range.

Flat Sheet Damage Fujiwara testing for the presence of halogens (e.g. chlorine) in the membrane structure was negative.

3

Initial Element Test

Element Weight All elements are weighed prior to autopsy as weight is often indicative of the degree of fouling. New eight-inch elements weigh approximately 30 to 35 pounds. Additionally, elements in excess of 50 pounds cannot be wet tested.

SN T5209558 weighed 31 pounds.

Full Element Wet Test Test results were normalized to the manufacturer’s published test conditions.

Filmtec ECO PRO-400 Flow

(gpm) Rejection

(%) Pressure Drop

(psi)

SN T5209558 5.17 99.3 6

Manufacturer’s Specifications 6.70 to 9.10 99.4 to 99.7 ≤15

Element wet testing

4

Integrity Test Integrity testing is performed to identify mechanical damage to the internal components of the spiral wound element. In this test, a vacuum of approximately 20 inches Mercury (in. Hg) is applied to the permeate side of the membrane and the membrane is then sealed. The vacuum is monitored for a duration of 120 seconds. Any loss of vacuum indicates the presence of damage; however, losses of over 35% of the vacuum within the 120 second period suggests severe physical damage.

The element passed integrity testing.

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Membrane Construction Diagrams

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External Inspection

Fiberglass Casing The purpose of the fiberglass casing is to ensure that the various membrane components are held in their correct position for optimum performance. Damage to the casing can be an indication of rough handling or damage from excessive differential pressure across the element from heavy fouling.

Although green and brown-colored foulant was present on the casing it was in good mechanical condition.

Fiberglass casing of SN T5209558

Brine Seal The brine seal is used to seal against the inside diameter of the pressure vessels and the outside diameter of the membrane to ensure that all the feed water passes through the element. Feed water passing on the exterior of the element can result in higher pressures, which can cause cracking of the fiberglass casing.

The brine seal was in good mechanical condition.

Permeate Tube The permeate tube is a pipe that is located at the center of the element. It contains lines of holes and is bonded to each membrane leaf, allowing permeate water to travel from the leaves into the permeate tube to be collected. Damage to the ends of the permeate tube can lead to o-ring failures, causing bypass of feed or concentrate water into the permeate stream. Cracking of the permeate tube can also result in permeate contamination.

The permeate tube was in good mechanical condition.

7

Anti-Telescoping Devices (ATDs) The function of the ATDs is to stabilize the components of the element. This helps to prevent shifting of the internal mechanical components under pressure, also known as telescoping. Telescoping may still occur if pressures exceed the manufacturer’s specifications.

The ATDs were in good mechanical condition even though black and brown-colored foulant was observed on the surfaces.

Feed (left) and concentrate (right) ATDs of SN T5209558

8

Internal Inspection

Scroll Ends The ends of the element are called scroll ends. They are examined for the presence of foulant debris and mechanical damage (e.g. gapping, feed spacer extrusion). The presence of foulant on the scroll ends can cause elevated delta pressures while gapping and feed spacer extrusion indicate uneven hydraulics (high flow/low flow regions). In addition, each scroll end is examined for telescoping, the gradual axial shift of the membrane leaves from the outer diameter of the element towards the permeate tube. Telescoping is often caused by the development of high differential pressure (greater than the manufacturer’s specification) across the element or when pressure is applied too quickly, causing a water hammer effect.

Both scroll ends were in good mechanical condition. However, black-colored, rubbery material was detected on the feed end (brine seal end0 of the element. Additionally, brown colored foulant was observed on both scroll ends.

Feed (left) and concentrate (right) scroll ends of SN T5209558

9

Membrane Surface New membrane surfaces are uniform and shiny. Foulant can often be detected through visual examination; however, membrane appearance can be misleading as some foulants are not visible. The presence of foulant on the membrane surface can cause elevated delta pressure, loss in flow and damage if the foulant is abrasive. Additionally, the membrane surface is inspected for damage such as delamination. Delamination is the lifting of the thin-film membrane from the support layer and often occurs due to a positive pressure on the permeate side of the element.

The exposed membrane surfaces were coated with brown-colored foulant material. The foulant had a smooth texture indicative of organics. Beneath the foulant layer, obvious signs of physical damage to the membrane surface were not immediately apparent. Additionally, a biological odor was noted during dissection.

Exposed membrane surface of SN T5209558

Exposed membrane surface from feed end of SN T5209558

10

Image of scraped foulant

11

Feed Spacers The feed spacer is a plastic net material designed to separate the membrane leaves, forming a flow path, and to promote turbulence within the feed water channels. Foulant blocking the feed channels causes more resistance for the feed water flowing through the element and results in higher than normal delta pressures.

The feed spacers were in good mechanical condition . Minimal foulant was observed on the surfaces.

Feed spacer of SN T5209558

Stereoscope image of feed spacer in SN T5209566

12

Glue Lines Membrane leaves are glued on three sides to separate the feed and permeate streams. The glue lines are inspected for specific damage, including glue flaps and pouching. Glue flaps refer to excess inactive membrane material located closest to the ends of the element. Flaps found on the feed end of the element can flare during operation, blocking the feed channels on the scroll end, potentially causing increased differential pressure. Pouching of the glue line, which is often a result of delamination, allows feed water to pass through the inactive membrane at the glue line, contaminating the permeate stream.

The glue lines were in good mechanical condition

Permeate Carriers and Membrane Backing The permeate carriers provide a path for permeate water to flow towards the permeate tube, which minimizes permeate-side pressure losses. New permeate carriers and membrane backing are uniform in color. Foulant found on the permeate side of the membrane leaves indicates contamination of the permeate stream.

The permeate carriers and membrane backings absent of visible foulant.

13

Foulant Analysis

Foulant Density Measurement and Composition Testing A sample collected from a known area of the membrane surface is weighed before and after drying to determine the foulant density (reported as dry foulant density – mg/cm2) and moisture content of the sample. Different types of foulant materials exhibit higher moisture contents. Relative water concentrations greater than 95% indicate an extremely hydrated, biological material. Alternatively, scales (crystalline material) typically contain very little moisture. The organic content of the dehydrated material is then measured through loss on ignition (LOI) testing. If the organic content of the total solids is greater than 65%, it is considered primarily organic.

The dry foulant density of SN T5209558 was measured as 0.02 mg/cm2. The moisture and organic content are displayed in the graphs below.

85%

15%

Moisture Content

Water Sample

84%

16%

Organic Content

Organic Inorganic

14

Microbiological Analysis This analysis is performed to identify microbiological components of the foulant removed from the membrane surface. Foulant samples are stained and examined with a light microscope at 1000x using an oil immersion lens. Gram positive bacteria are stained purple while Gram negative bacteria are stained pink.

Microscope analysis of foulant removed from the membrane identified amorphous organic material (e.g. bio-slime) and significant microbiological material (Gram positive and negative bacteria, algae, fungi, yeast) in the foulant.

Light microscope images (1000x) of foulant scraped from SN T5209566

15

Acid Testing Acid testing is used to determine the presence of carbonates and metals on the membrane surface. In this test, several drops of dilute hydrochloric acid (HCl) were placed on the foulant surfaces. Effervescing indicates the presence of carbonates while a color change is associated with the presence of metals.

Acid testing produced no reaction, indicating the absence of carbonates and metals.

Zeta Potential Testing The zeta potential is the charge that resides at the double layer boundary of colloids. Most naturally occurring colloids are negatively charged. If an excess of coagulant is present, the charge of the colloids switches from negative to positive. As such, zeta potential testing is used to determine if coagulant is being overfed. Two grams of wet foulant is required for this test.

The foulant material of SN T5209566 had a zeta potential of -20.5 mV indicating there was no coagulant on the membrane surface.

Image based on diagram from Particle Characterization Laboratories, Inc.

16

Fourier Transform Infrared Spectroscopy Analysis Fourier Transform Infrared Spectroscopy (FT-IR) is an analytical technique used to identify functional groups (specific groups of atoms or bonds within molecules). Infrared radiation passes through a sample, with some of the radiation absorbed and some transmitted. A measurement and interpretation of this data produces a spectrum which can then be compared and matched to the known spectra for functional groups based on the wavenumber at which bands appear and their respective shapes (e.g. sharp, broad, strong, weak).

FT-IR spectrum of foulant removed from the membrane surfaces identified double peaks between 1650 and 1500 cm-1 and a stronger peak at 1000 cm-1 which are associated with proteins (e.g. amino acids from microorganisms) and carbohydrates (e.g. polysaccharides), respectively. Additionally, the split peak at 1000 cm-1 indicates the presence of phosphorous containing compounds (i.e. calcium phosphate).

FT-IR spectral image of foulant removed from the membrane surface of SN T5209558

Calcium phosphate

Carbohydrate

Proteins

17

Energy Dispersive Spectroscopy (EDS) Analysis Energy Dispersive Spectroscopy analysis is used to determine the relative concentration of elements present in a sample. EDS analysis is performed on a dry membrane sample. The element sulfur is at least in part associated with the membrane support material (polysulfone) rather than a foulant layer. Avista’s analysis of new membranes typically detects between 5.00 and 7.00 weight percentage. Relative concentrations below 5.00 percent indicate the presence of a foulant layer masking the membrane surface.

EDS analysis identified calcium, phosphorus and silicon as the primary foreign inorganic elements present on the membrane surface. Additionally, trace amounts of magnesium, aluminum and sodium were detected. The carbon weight percentage is predominantly contributed by the membrane materials; however, it can also be from foreign organics. The sulfur weight percentage indicates a partial masking of the membrane surface.

Elements SN T5209558

Weight Percent (wt%)

Carbon 71.25

Oxygen 19.76

Sulfur 4.67

Calcium 1.66

Phosphorus 1.09

Silicon 0.99

Magnesium 0.28

Aluminum 0.16

Sodium 0.14

18

Scanning Electron Microscope (SEM) Imaging SEM imaging is performed on the membrane surface to observe the topography of the foulant material. Foulant morphology can be an indicator of the type of foulant.

SEM imaging (150x) displayed a smooth layer of material across the membrane indicating the presence of organics. Granular material was also visible in the feed spacer contact points.

SEM image (150x) of the membrane surface of SN T5209558

Close-up SEM image (5000x) of the membrane surface of SN T5209558

Feed Spacer Contact Point

19

Chromatic Elemental ImagingSM (CEISM) CEI is a high-resolution imaging technique used to determine the spatial distribution of elements in a foulant sample. Each element is assigned a color (shown in a legend on the bottom left corner of the CEI image) and the colors correspond to the location of the elements in the sample. An element’s color intensity is associated with its concentration in the sample (i.e. elements present with higher relative concentrations are displayed with greater color intensity in the image). Additionally, a blending of colors signifies a compound (material composed of more than one element such as calcium carbonate).

CEI image (1500x) of the membrane surface

20

CEISM confirmed the presence of organics on the membrane surface by displaying carbon (dark blue) in the smooth deposits. Microorganisms were also visible in the smooth organic layer. The inorganic material in the feed spacer contact points was identified as calcium phosphate (green-blue) and colloidal silica (yellow).

CEI image (1500x) of the membrane surface with labels

21

Organic Luminescence Microscopy (OLM) Organic Luminescence Microscopy (OLM) is an analytical method using specialized filters and focused emitted photons to identify individual microorganisms, plant material, carbohydrates, and proteins and how they interact in three-dimensional space. Each component type in the biofilm layer is designated a color to determine how each component interacts with each other in the wet bio matrix on the membrane surface.

Organic luminescence Microscopy of the membrane surface identified high concentrations of live (green) bacteria, dead (red) bacteria, and lipids (hydrophobic organics - 2nd image - blue) across the membrane. The bacteria colonies and lipids were relatively evenly distributed. Random patches of protein patches were also detected throughout the bio layer.

Luminescence image of the membrane surface

22

Luminescence microscopy on membrane surface

23

Flat Sheet Performance and Cleaning Study

To evaluate flat sheet performance, membrane samples harvested from the full element are tested for permeability and salt passage. The raw flow and conductivity measurements from the test are used to calculate the permeability and salt passage constants, which are independent of pressure, temperature and salt content of the feed stream. The permeability constant is measured in cm/s/atm and the salt passage constant in cm/s. Discrepancies between the flat sheet and full element performance can indicate the presence of mechanical damage.

The flat sheet samples are then cleaned with various Avista chemicals to determine the most effective cleaner combinations and contact times. Cleaner efficacy is based on overall improvement in permeability and salt passage constant as well as visual foulant removal.

The table below shows performance data for the optimum cleaning. Flat sheet samples were cleaned with RoClean P111 (2% by weight in RO/DI water, heated to approximately 35 degrees Celsius and circulated) for six hours.

SN T5209558 Permeability Constant Salt Passage Constant

Baseline 1.04E-05

77% of Normal 11.5E-06

118% of Normal

Post-Clean 1.80E-04 Normal

6.87E-06 Normal

Manufacturer’s Specifications 1.35 to 1.82E-04

Normal Range 4.86 to 9.75E-06

Normal Range

Note: testing conducted using dechlorinated San Marcos, CA water

>200%

Pre-CleanPost-Clean

0% 25% 50% 75% 100% 125% 150% 175% 200%

Permeability (% of Normal)

>200%

Pre-CleanPost-Clean

100% 125% 150% 175% 200%

Salt Passage (% of Normal)

24

Pre-clean flat sheet

Post-clean flat sheet

25

Testing for Flat Sheet Damage

Fujiwara Testing Fujiwara testing is a qualitative analysis which determines if a polyamide (PA) thin-film membrane has been exposed to an oxidizing halogen, such as chlorine, bromine, or iodine. A color change does not occur if the membranes has not been exposed to halogens. Common symptoms of halogen oxidation include increased flow and loss in permeate quality.

Fujiwara testing was negative for the presence of halogens (e.g. chlorine) in the membrane structure.

Example of a negative Fujiwara color change

26

Certification by Laboratory

Report Number Report Content Element Serial Number Report Date

WO#073119-2 Standard Spiral Autopsy T5209558 T5209566

October 7th, 2019

We the undersigned being the technical specialists in membrane autopsy and related testing procedures and protocol for Avista Technologies certify to the best of our knowledge and belief that the tests listed in this report have been conducted following Avista’s standard testing practices and that the results are accurate and complete.

By signing this certificate neither the laboratory employees nor their employer makes any warranty, expressed or implied, concerning the cleaning study results.

Date: 10/07/2019

Signed:

Megan Lee Laboratory Services Manager

Arnell Abad Laboratory Services Chemist