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CONFIDENTIALCONFIDENTIAL

Technology Development Program: ElectroKinetic Reclamation Dewatering Technology

(EKR‐DT)

Status Report:

Process Optimisation Testing Program

May 25, 2017

EKS Inc. 60 Adelaide Street East

Toronto Ontario M5C 3E4

May 23, 2017 Process Optimisation Testing ‐ Status Report Page ii of 13

TABLE OF CONTENTS

1 BACKGROUND ....................................................................................................................................... 3

2 EXPERIMENTALSETUP ........................................................................................................................... 3

2.1 Lab Space ...................................................................................................................................... 3

2.2 Test Apparatus .............................................................................................................................. 4

2.3 Test Material ................................................................................................................................. 5

2.4 Monitoring System ........................................................................................................................ 5

2.4.1 Applied Power ............................................................................................................................... 5

2.4.2 Electric Field .................................................................................................................................. 7

2.4.3 Pore Pressure ................................................................................................................................ 7

2.4.4 Mudline Elevation ......................................................................................................................... 7

2.4.5 Supernatant Water Chemistry ...................................................................................................... 7

2.4.6 Core Samples................................................................................................................................. 7

2.4.7 Decommissioning .......................................................................................................................... 7

3 COMMISSIONING TEST ......................................................................................................................... 8

3.1 Purpose ......................................................................................................................................... 8

3.2 Limitations ..................................................................................................................................... 8

3.3 Test Configuration ......................................................................................................................... 9

3.4 Dewatering Behaviour .................................................................................................................. 9

3.5 Electrode Conservation ............................................................................................................... 10

3.6 Final % Solids ............................................................................................................................... 10

4 CONCLUSIONS ..................................................................................................................................... 12

4.1 Functionality of Apparatus .......................................................................................................... 12

4.2 Voltage Gradients ....................................................................................................................... 12

4.3 Applied Power Signature ............................................................................................................ 12

4.4 Management of Density Gradients ............................................................................................. 12

4.5 Anode Conservation .................................................................................................................... 12

4.6 Energy Consumption ................................................................................................................... 13

4.7 Maximum Dewatering Potential ................................................................................................. 13

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May 23, 2017 Process Optimisation Testing ‐ Status Report Page 3 of 13

1 BACKGROUND This status report provides an update of the EKR‐DT process optimisation testing program that is underway in London, Ontario. EKS has prepared a detailed research design document that lays out the tests that are being conducted and the research questions that each test is designed to address. This status report complements that research design document but does not delve into the technical foundations for each experiment. That information can be found in the research design document.

This status report provides interested parties with an update on the progress being made with the process optimisation testing program. The results provided in this report are preliminary and their interpretation will be refined as the results from other experiments are compiled and analysed.

2 EXPERIMENTAL SETUP EKS has set up a testing lab in collaboration with Western University. The testing lab is located within the City of London's Greenway Wastewater Treatment Plant. The facility is owned by the City of London and Western University. Access to this space was facilitated by the Southern Ontario Water Consortium. This section describes the lab and experimental setups.

2.1 LAB SPACE The lab has the capability of running four independent experiments simultaneously. Each test apparatus has its own power supply, instrumentation and data acquisition system. (Figures 1 and 2)

Figure 1‐ View of individual power control systems



Figure 2‐ View of test apparatus and video recording cameras

2.2 TEST APPARATUS Four identical test apparatus have been custom manufactured. Figure 3 shows an empty apparatus with a set of anodes installed.

The test apparatus have been designed to replicate the electric field and dimensional scaling factors associated with a commercial‐scale EKR‐DT system. A key design factor has been to create an electric field comparable to what can be expected at a commercial scale. A detailed research plan has been prepared that lays out how key research questions will be explored through the process optimisation testing program.

Each apparatus is independent of the others. Each includes: • A test cell including variable numbers of electrodes (maximum of five anodes), • A variable power supply unit (B&K Precision Multi‐range Programmable DC Power Supply,

Model 9206; design capacity: see Table 1) • Custom PCB units that control power on and off to individual electrodes plus polarity, • A tree of voltage probes, • A nest of micropiezometers, • Data acquisition units, • A computer running a LABView (www.ni.com/labview/) program. The LABView program

controls the applied voltage and manages the monitoring data.



Figure 3 ‐ Partially configured apparatus with instrumentation mounting posts

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Instrumentation Post

Table 1: Power supply system specifications

Max Voltage 150 V

Max Current 10 A

Max Power 600 W

2.3 TEST MATERIAL Shell Canada has supplied 2 m3 of centrifuge cake plus 1 m3 of virgin FFT (i.e. with no flocculants added). Initial characterisation of the material has been conducted (Table 2). Further characterisation is planned.

2.4 MONITORING SYSTEM Each apparatus is configured to collect various data over the course of each test. Further details are provided following.

2.4.1 APPLIED POWER The applied power for each test is recorded at regular short‐time intervals. The total current plus the current flowing through each electrode is recorded. The applied voltage is also recorded for the same time intervals.

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Table 2: Initial characterisation of FFT

Characteristic Test Material

Units CC#1 CC#2 VF#1

Supernatant ‐ pH 7.97 7.79 7.23

Supernatant ‐ conductivity 1,834 1,844 1,647 µS/cm

FFT ‐ % solids 40% 36% 35% kg/kg

Figure 4–Monitoring systems., b) voltage probes, c) piezometers, and d) mudline tracking

a) Power control and data collection system b) Voltage probe tree

c) Micropiezometer nest d) Mudline tracking



2.4.2 ELECTRIC FIELD One to three trees of voltage probes are centrally located (see Figure 3). The voltage probes are aligned vertically so that the voltage gradient at each layer in the FFT can be mapped as the dewatering process proceeds. The voltage probes readings are recorded at the same time interval as the applied power. The voltage probe data are stored in the applied power database.

2.4.3 PORE PRESSURE A nest of micropiezometers is attached to the central instrumentation mounting pole. The ends of the micropiezometers are aligned midway between each pair of voltage probes.

Water level readings for each micropiezometer are taken manually. The time interval between readings is tied to the test being conducted. The micropiezometers provide a measure of the local pore pressure.

2.4.4 MUDLINE ELEVATION The mudline elevation is regularly recorded along the transparent walls of the apparatus. The drop of the mudline during Stage 1 of the dewatering process is closely tied to the amount of water released and the increase in % solids resulting from the EKR‐DT process.

2.4.5 SUPERNATANT WATER CHEMISTRY A water cap is present over the FFT. Samples of the supernatant from the FFT are collected for each tote. These results are used to produce water cap water having a similar water chemistry profile as the supernatant.

At regular intervals over the course of the dewatering process, samples are drawn from the water cap and analysed. These samples are routinely analysed for:

• pH and • Conductivity.

More extensive characterisation of the water cap water chemistry will be conducted for some of the future tests.

2.4.6 CORE SAMPLES Core samples will be extracted over the course of the dewatering process. Each core will be sectioned and analysed for:

• Density/% solids and • pH

More extensive physical and chemical characterisation of the FFT will be conducted over the course of some of future tests.

2.4.7 DECOMMISSIONING At the end of each test, a systematic decommissioning protocol will be followed. This protocol is designed to provide a detailed 3D picture of the final physical and chemical state of the dewatered FFT mass. The dewatered FFT is vertically subdivided into sections (~ 12). Each section is subdivided into four horizontal layers. Each layer will be analysed for:



• Density/% solids, • Shear strength and • pH

More extensive physical and chemical characterisation of the dewatered FFT will be conducted for some tests. The nature of this characterisation will depend on the test that has been run.

The electrodes are removed after each test and are analysed to determine the pattern and total amount of corrosion that has occurred.

3 COMMISSIONING TEST EKS has conducted a commissioning test. The details of this test are reported following.

3.1 PURPOSE The primary purposes of the commissioning test were:

• To ensure the proper functioning of the experimental apparatus including the power supply and data recording systems, and

• To develop and refine the logistics of loading, running and cleaning out an apparatus for each experiment.

The commissioning test also provided an opportunity to gain initial insights into the dewatering behaviour of the FFT when the dewatering process is extended to higher % solids content (i.e. >55% solids). This initial understanding has proven to be valuable for designing, operating and interpreting the results of subsequent tests.

3.2 LIMITATIONS The commissioning test was initiated at the same time as the lab was being set up and the monitoring system was being installed. For that reason, not all of the monitoring systems were installed and operational for the commissioning test. Not having these monitoring data limited the precision with which the EKR‐DT process could be operated.

Additionally, the operation of the commissioning test was run using a basic applied power signature. This applied power signature was not optimised. As well, adjustments to the applied power signature were made over the course of the test without the benefit of the results of the later tests that are designed to optimise the operation of the process.

For these reasons, the results of the commissioning test provided in this report should be viewed strictly as preliminary and indicative. Definitely these results should not be interpreted as the final or definitive performance results for the EKR‐DT process. Process optimisation is expected to yield improvements in dewatering efficiency and predictability.



3.3 TEST CONFIGURATION Table 3 shows the basic test configuration used for the commissioning test.

Table 3: Commissioning test configuration

Configuration Element Setting

Water Cap 15 cm

Electrode Vertical Separation 30 cm

Initial Applied Voltage 7 V

Maximum Applied Voltage 16 V

3.4 DEWATERING BEHAVIOUR Overall, the observed water release rate declined over the course of the EKR‐DT process. The reasons for this declining water release pattern with a constant applied voltage are well understood and discussed extensively in the literature. EKS has consistently observed this pattern in past tests.

To offset this decline, the applied voltage was stepped up in small increments as dewatering slowed. With each increment in the applied voltage, the water release rate spiked and then slowly began to decline again. A key process control decision is determining when and by how much the applied voltage should be adjusted.

The current flowing through the system followed a similar pattern as the water release rate. The current declined over time as the dewatering process progressed. This decline is partly due to increasing electrical resistance as the density of the FFT increases. With each incremental increase in the applied voltage, the current spiked and then gradually declined.

These observations demonstrate that the rate of water release is highly responsive to changes in the applied power schedule. In other words, the dewatering rate of the EKR‐DT process is readily controlled by the operator through the regulation of the applied power.

The amount of energy required to release a unit of water (i.e. kWh/m3 of released water) varies over the dewatering process. This metric provides a good measure of the energy efficiency of the dewatering process. Less energy is required to remove water during Stage 1 of the dewatering process than during Stage 2.

Offsetting this trend is the amount of water needing to be released as the % solids of the FFT increase. Much less water needs to be released to go from 55% to 65% compared to going from 35% to 45% solids. For this reason, high densities can be achieved with reasonable energy consumption requirements even though the energy efficiency is less.

The general trend in energy efficiency as the applied power is adjusted is similar over the course of the dewatering process. Energy efficiency closely tracks the pattern of water release which is driven by the



applied power schedule. These results reveal that considerable potential exists for optimising process performance in terms of energy efficiency during both stages of the dewatering process.

3.5 ELECTRODE CONSERVATION Figure 4 shows a close‐up of one of the anodes from the commissioning test. No quantitative analysis of the condition of the electrodes has been conducted yet but some qualitative observations can be made.

Figure 5 ‐ Close‐up Photograph of Electrodes at the Start and End of the Commissioning Test

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Cathode Anode

Unlike other tests by EKS and results reported in the literature, the anodes were not encased in a highly consolidated mass of FFT at the end of the dewatering process. No evidence of local cementation and dehydration was present. The surface of the anodes did show evidence of some metal loss but the anodes appeared to be fully functional at the end of the test.

The rate of metal loss will be quantitatively determined to improve the capability to forecast anode corrosion rates with commercial applications.

These results are quite promising in terms of the commercial application of the technology. These results suggest that the primary factors potentially limiting the functional life of anodes at a commercial scale (i.e. excessive consolidation and dehydration) can be effectively managed through the power signature.

3.6 FINAL % SOLIDS Figures 5 and 6 show the distribution of the % solids at the end of Stages 1 and 2.

At the end of Stage 1, the average % solids was in the range of 50‐55%. This is the density at which FFT transforms from a slurry to a soil. This level of dewatering is comparable to what was achieved in the C‐FER test.

At the end of Stage 2, the overall average % solids was 63%. The average densities of the layers in the sections ranged from a low of 59% to over 70%. The highest densities were in the upper layers and the lowest in the bottom layer above the anodes.

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This densification pattern is the opposite of that commonly reported in the literature and observed in past tests by EKS. This change in the densification pattern is likely due to the modifications to the applied power schedule that were explored in the commissioning test. This schedule will be refined in future tests to maximise the uniformity of the densification process and to optimise energy efficiency.

4 CONCLUSIONS Following is a summary of the conclusions resulting from the commissioning test.

4.1 FUNCTIONALITY OF APPARATUS The test apparatus performed as designed. The experimental design of the process optimisation tests does not need to be modified to accommodate the capabilities of the apparatus. Instead, the experience with the commissioning test has resulted in some major insights that will improve the efficiency and reliability of future tests.

The protocols for handling the FFT, taking samples and decommissioning an apparatus after a test is complete have proven to be practical and to provide accurate results. Several refinements to these protocols will improve the accuracy of future testing data.

4.2 VOLTAGE GRADIENTS The test apparatus is scaled down from the commercial conceptual design. The voltage gradients were comparable to those expected with a commercial installation. These results demonstrate that significant dewatering of FFT is possible with these voltage gradients.

4.3 APPLIED POWER SIGNATURE The commissioning test was run using a refined version of the EKS patented power signature. This refined version yielded significant improvements in energy efficiency. That being said, preliminary analyses of the test results indicate that further improvements in energy efficiency are possible through refinements to the applied power signature at different points in the dewatering process.

4.4 MANAGEMENT OF DENSITY GRADIENTS A key factor driving the revisions to the power signature was avoiding rapid consolidation and subsequent dehydration locally around the anodes. The commissioning test results are promising in this regard. The results demonstrate that the density gradients that form during the EKR‐DT process can be effectively managed by prudent manipulations of the applied power. The results of future tests will allow refinement of the management of these density gradients.

4.5 ANODE CONSERVATION The anodes remained functional throughout the commissioning test. The rate of metal loss needs to be determined quantitatively but other causes for anode failure (e.g. rapid consolidation, dehydration, and gas formation) did not prevent dewatering from continuing even at high % solids.




4.6 ENERGY CONSUMPTION The energy consumption to dewater from 40% to about 63% solids was in the range of 22 kWh per dry tonne. During Stage 1 (i.e. 40% to 50% solids), the energy consumption was in the range of 10 kWh per dry tonne. For Stage 2 (i.e. 50% to 63% solids), the energy consumption was about 12 kWh per dry tonne.

This level of energy consumption is comparable to that reported by others. For example, Shang (2016) projected energy consumption for dewatering FFT in the range of 30 kWh/m3 of FFT.

4.7 MAXIMUM DEWATERING POTENTIAL The commissioning test results indicate that the EKR‐DT process is able to dewater in excess of 65% solids. The goal of future tests will be to achieve a consistently high density as uniformly and as energy efficiently as possible.

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