An Innovative Treatment Method for Brines from
Coal Seam Gas Production
Jim Lozier, P.E.
CH2M HILL
Background

Australia has significant
coal seam gas reserves
– Located in Queensland and New
South Wales
– EDR of 935B m3
– 150-year reserve life at current
extraction rate of 5.6B m3

Graphic courtesy of Global Water intelligence
Extraction rates are
increasing with significant
investment in wells,
pipelines, and planned
liquid natural gas (LNG)
facilities
Background


Extraction of CSG results in co-extraction of significant
volumes of (produced or associated) water
Produced water quality
–
–
–
–
TDS: 200 to >10,000 mg/L (Study water TDS = ~2,500 mg/L)
Major ions: Na, Cl, HCO3/CO3
Minor ions: Ca, Mg, SO4
Trace metals, low levels of nutrients and moderate levels of SiO2
Graphics courtesy of Global Water intelligence
Background

Produced Water Regulations
– must be used beneficially
– where BU is not possible, treat and dispose to ensure env. protection
– recent ban on use of evap ponds, dams and basins for ‘treatment’

Produced Water Treatment
– Focus is on TDS removal

Typical Water Treatment Process
Brine pond
Storage Pond
Produced Water
from Wellfields
MF
WAC IX
RO
MVR BC
TSS removal
Ca, Mg removal
TDS removal
Brine volume
reduction
Produced Water Treatment Challenge and
Opportunity

Challenge
– MF/WAC IX/RO converts 85-90% of produced water to quality suitable
for beneficial use
– Ability to achieve higher recoveries and significantly lower brine
volumes constrained by silica supersaturation and scaling, increasing
the need for capital and energy intensive use of mechanical vapor
recompression brine concentrators

Opportunity
– Utilize innovative process to stabilize brine by removing silica, allowing
maximum use of energy efficient RO process for additional brine
volume reduction
– Achieving sufficient brine volume reduction can allow the use of deep
well injection, thereby avoiding costly evaporators and brine storage
ponds
MAX-RO Process Schematic
Silica precipitation
Solids removal
Hardness removal
CERAMIC UF
UNIT
WAC IX
REGENS*
SLUDGE ELUTRIATION
AND DEWATERING
*From primary RO and MAX-RO
Regen (to
Reactor)
Brine concentration
Purifics Ceramic Ultrafiltration (Cuf™) System



Tubular, silicon carbide membrane module
Extremely high permeability (~4000 LMH-bar @ 25oC)
High solids loading when operated in x-flow with patented ‘shock
wave’ backpulse
Graphics courtesy of Purifics
Reverse Osmosis

Coupled conventional and ultra-high pressure technologies
Stage
Technology
Max Feed
Pressure (psig)
Recovery*
(%)
Brine TDS
(g/L)
1
Conventional spiral
wound (seawater)
1,200
72
90
2
Brine concentrator spiral
wound (seawater)
1,400
76
105
3
Disc-tube/flat plate
(seawater)
1,800
84
160
*Based on 25,000 mg/L feed
Silica Saturation and RO Recovery (SiO2 reduction)
2500
Brine silica concentration vs recovery ratio
2000
RO Recovery
limited by brine
pressure
Silica mg/L
1500
No silica removal
Feedwater subject
to silica limitation
at reject pH of 9.2
1000
Maximum feasible
silica at brine pH = 10.5
500
0
0%
10%
20%
30%
40%
50%
60%
RO recovery ratio
70%
80%
90%
100%
Silica Saturation and RO Recovery (SiO2 reduction)
2500
Brine silica concentration vs recovery ratio
2000
RO Recovery
limited by brine
pressure
Silica mg/L
1500
No silica removal
Feedwater subject
to silica limitation
at reject pH of 9.2
1000
With silica removal
Maximum feasible
silica at brine pH = 10.5
500
1
Operating Points
1 - Toray BCM - 75%
2 - DT-RO - 80%
2
0
0%
10%
20%
30%
40%
50%
60%
RO recovery ratio
70%
80%
90%
100%
MAX-RO Treatability Study

Objectives
– Phase 1: Demonstrate, at bench-scale, that reactive silica in a high
osmotic strength RO concentrate can be reduced from ~200 mg/L to
<50 mg/L using magnesium-augmented lime precipitation
• Identify optimum precipitation (reaction) conditions
– Phase 2: Conduct short-term pilot-scale filterability testing of ROC
containing ppt’d solids using Cuf® to confirm process suitability (target
filtrate quality, flux and recovery)
– Phase 3: Evaluate ability to elute minerals from precipitated solids to
allow for beneficial use (land application)


Empirically determining ppt chemistry was deemed critical given
the lack of experience with such chemistry in treatment high ionic
strength solutions
RO treatability not considered necessary given application of each
stage/technology has been well demonstrated
Bench-Scale Precipitation Study


~200 liters of concentrate from
RO treatment of CSG
produced water was air
freighted from Queensland to
CH2M HILL Applied Sciences
Laboratory in Corvallis, OR
To achieve target 200 mg/L
SiO2 concentration,
concentrate was further
processed using table top
SWRO unit.
Graphic courtesy of Applied Membranes, Inc.
Parameter
ROC
Conc. ROC
(CROC)
Turbidity
0.94
<0.1
81
200
Alkalinity
2,740
6,810
Ca
32.6
66
Mg
16.0
35.9
13,600
26,335
Na
446
8,940
Cl
5170
12,200
SO4
225
535
pH
8.10
8.5
Reactive SiO2
TDS
Phase 1: Precipitation (Jar) Tests with CROC

Phase 1a
–
–
–
–
–
Determine Mg dose, reaction pH to achieve SiO2 goal
10 g/L CaCO3 seed (to promote ppt)
MgCl2 dosed at 780 and 1,400 mg/L (1:1 and 2:1 Mg:SiO2 ratios)
Lime dosed to achieve initial pH of 10.0
Additional step-wise lime addition to achieve pH of 10.3, 10.6 and 10.9 at 30,
60 and 90 minutes reaction time
– Tests conducted at room temperature (23 deg C)
– Reacted samples collected, filtered and analyzed for SiO2, hardness and
alkalinity at 30/60/90 minutes
Phase 1a Precipitation (Jar) Test Results
Jar 5a
(MgCl2 = 780 mg/L, 22°C)
Alkalinity - M
400
12,000
350
10,500
300
9,000
250
7,500
200
6,000
150
4,500
100
3,000
50
1,500
0
0
pH
Silica
Calcium
Magnesium
Alkalinity - M
400
12,000
350
10,500
300
9,000
250
7,500
200
6,000
150
4,500
100
3,000
50
1,500
0
0
pH
Alkalinity (mg/L as CaCO 3)
Magnesium
Silica, Ca, Mg Concentration (mg/L)
Calcium
Alkalinity (mg/L as CaCO3)
Silica, Ca, Mg Concentration (mg/L)
Silica
Jar 5b
(MgCl2 = 1,404 mg/L, 22°C)
Precipitation (Jar) Tests with Conc. ROC

Phase 1b
–
–
–
–
–
–
Determine impact of reaction time and temp (using MgCl2)
10 g/L CaCO3 seed (to promote ppt)
MgCl2 dosed at 780 and 1,170 mg/L
Lime dosed to achieve pH of 10.9
Tests conducted at 22 and 36 deg C
Reacted samples collected, filtered and analyzed for SiO2, hardness and
alkalinity at 30/60/90 minutes
Phase 1b Precipitation (Jar) Test Results
Jar 9c
(pH = 10.9; MgCl2 = 780 mg/L, 22°C)
8,000
350
7,000
300
6,000
250
5,000
200
4,000
150
3,000
100
2,000
50
1,000
0
Silica
0,000
0
30
60
90
Time Elapsed (min.)
7,000
300
6,000
250
5,000
200
4,000
150
3,000
100
2,000
50
1,000
0
Alkalinity - M
8,000
350
7,000
300
6,000
250
5,000
200
4,000
150
3,000
100
2,000
50
1,000
0
0
30
60
90
Time Elapsed (min.)
30
60
90
Time Elapsed (min.)
120
Jar 10b
(pH = 10.6; MgCl2 = 1,170 mg/L, 35°C)
400
0
22 deg C
0,000
0
120
Silica
Silica, Ca, Mg Concentration (mg/L)
Magnesium
Alkalinity - M
350
120
Alkalinity (mg/L as CaCO 3)
Silica, Ca, Mg Concentration (mg/L)
Calcium
Magnesium
8,000
Jar 10a
(pH = 10.6; MgCl2 = 780 mg/L, 35°C)
Silica
Calcium
400
Alkalinity (mg/L as CaCO 3)
Alkalinity - M
Calcium
Magnesium
Alkalinity - M
400
8,000
350
7,000
300
6,000
250
5,000
200
4,000
150
3,000
100
2,000
50
1,000
0
0
0
30
60
90
Time Elapsed (min.)
120
Alkalinity (mg/L as CaCO3)
Magnesium
Silica, Ca, Mg Concentration (mg/L)
Calcium
400
Alkalinity (mg/L as CaCO 3)
Silica, Ca, Mg Concentration (mg/L)
Silica
Jar 9d
(pH = 10.9; MgCl2 = 1,170 mg/L, 22°C)
35 deg C
Mg:SiO2 Dose Ratio Envelope
Phase 2: Ceramic Ultrafiltration (Cuf®) Factory
Testing

Objectives
– Using optimized precipitation chemistry, conduct short-term, pilot-scale testing
of the combined precipitation-Cuf® process of CSG RO concentrate (ROC).
– Monitor transmembrane pressure (TMP), flux and permeability as measures
of Cuf® performance.
– ID a preliminary Cuf® flux (range) for two operating modes:
• direct filtration and dewatering of the reacted (precipitated) ROC to a target
solids concentration
• Filtration of reacted ROC following precipitation and short-duration settling
– Characterize the quality of Cuf® filtrate and solids

Tests
– Test 1: Operate Cuf® on CSG RO concentrate (no treatment)
– Tests 2 and 3: Operate Cuf® on reacted ROC with filtrate recycle and with
volume concentration (to 50% of initial)
– Test 4: Operate Cuf® on reacted and settled ROC
Cuf® Batch Operational Modes
Filtrate Recycle Mode
Filtrate
Reject
Volume Reduction Mode
Filtrate
Reject
Cuf® Testing – Baseline and Direct Filtration
Baseline Flux - Test 1
Average Flux
Flux (LMH)
TMP (bar)
0.80
0.60
0.40
0.20
y = 5E-10x2.5998
R² = 0.9224
0.00
Flux (LMH)
0
500
1,000
1,500
2,000
Flux (LMH)
2,500
3,000
Test 2 - Perm Recycle
Test 2 - Vol. Reduction
Test 3 - Perm Recycle
Test 3 - Vol. Reduction
3,500
450
400
350
300
250
200
150
100
50
0
0
10
20
30
40
Time (min)
50
60
70
500
450
400
350
300
250
200
150
100
50
0
5.0
4.0
3.0
2.0
1.0
0.0
Test 2 - Perm
Recycle
(60 min)
Test 2 - Vol.
Reduction
(20 min)
Test 3 - Perm
Recycle
(60 min)
Test 3 - Vol.
Reduction
(15 min)
TMP (bar)
1.00
Average TMP
Cuf® Testing – Settled Water
Stable flux at 3,000
LMH over a 60-min
period at 1 bar TMP
Permeability
10000
Permeability (LMH/bar)
3000
1000
280
225
160
150
100
10
1
Test 2 - DF
Test 2 - DF (Vol.
Test 3 - DF
Test 3 - DF (Vol.
Test 4 - SW
(Perm Recycle) Reduction) (20 (Perm Recycle) Reduction) (20 (Perm Recycle)
(60 min)
min)
(60 min)
min)
(60 min)
Cuf® Testing – Filtrate Water Quality

Chemical dosing
–
–
MgCl2 – 1,170 mg/L
Ca(OH)2 – 4,000 – 5,000 mg/L
RO Recovery Progression and Brine Volume
Reduction
100
DT-RO
BCM
BWRO/SWRO
145
10
Volume
10
Brine pressure
151
Relative Brine Volume
Pressure
Brine
Pressure (Bar)
Brine (psig)
(ML/d),
Flow
1450
100
1
1.5
0.1
0.1
Recovery (%)
(assuming a 2,500 mg/L produced water TDS)
Phase 3: Dewatered Solids Elution

MAX-RO process produces a significant amount of solids
– CaCO3
– Mg(OH)2
– SiO2




~5,000 mg per L of ROC treated
Solids will also contain water-associated (soluble) salts, primarily NaCl
and NaHCO3/Na2CO3
To make beneficial use of solids for land application, soluble salts must
be eluted
Bench-scale elution tests were conducted to determine how much RO
permeate is needed to elute soluble salts from dewatered solids
250 mL sample of reacted ROC from Cuf® testing was dewatered and
eluted
Dewatered Solids Elution Test
~25 mL of RO permeate was required to elute salts from
dewatered solids derived from 250 mL of reacted RO
concentrate  12% of RO permeate production*
Elutriability Test
Sample 1
Conductivity (µS/cm)

Sample 2
2,200
2,000
1,800
1,600
1,400
1,200
1,000
800
600
400
200
0
0
5
*at 80% RO recovery
10
15
20
Total Permeate Rinse Volume (mL)
25
30
Conclusions


The MAX-RO process represents a viable alternative to MVR-type
brine concentrators to achieve a sufficiently high degree of RO
brine reduction to enable deep well brine injection
MAX-RO brine is more suitable for direct (DW) injection
– Solids free (assuming effective scale control)
– Ambient temperature (no cooling and stabilization required)
– SiO2 supersaturation controllable by antiscalant use



Energy consumption is significantly less than MVR (6 versus ~24
kWh/m3)
Chemical consumption and solids production is significant;
process viability will hinge on salt elution effectiveness to allow for
agricultural land application
Planned pilot-scale study will better define design criteria, Cuf®
operability and overall process cost
Acknowledgements

CH2M HILL Applied Sciences Laboratory
– Tim Maloney – ROC concentration
– Brad Suedbeck – jar tests and bench analysis

Mike Hwang – CH2M HILL PHX office
– Test protocol preparation and testing management

Andrew Hodgkinson – CH2M HILL Melbourne (AUS) office
– Client interface and ROC shipment logistics

Jesus Garcia Aleman/TOR office
– Purifics Cuf® testing oversight

Purifics
– Tony Powell
Questions?

jlozier@ch2m.com