1. ©AMTA July 13-16, 2009 1
Pilot Testing of Zero Liquid
Discharge (ZLD)
Technologies Using
Brackish Ground Water for
Inland Desert Communities
Renee Morquecho, Ph.D., Tom Mulvihill – Indian Wells Valley
Water District
Andrew Wiesner , Adam Zacheis, Ph.D., P.E., and Graham
Juby, Ph.D., P.E. – Carollo Engineers

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Presentation Outline
Project Background
Pretreatment
Reverse OsmosisElectrodialysis Reversal
Project Costs

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The Indian Wells Valley Water District
is Located in the Mojave Desert
Ridgecrest, CA

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Influent Water Characteristics Present
Challenges to Desalting
Well Water Quality
•pH = 7.1
•TDS = 1500 mg/L
•Hardness = 500 mg/L as CaCO3
•Calcium = 140 mg/L
•Sulfate = 500 mg/L
•Silica = 50 mg/L
•Silt Density Index = 1.0
Contaminants of Concern
•Iron = 40 μg/L
•Manganese = 46 μg/L
•Arsenic = 6 μg/L
•Selenium = 40 μg/L

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Despite the Many Challenges, Potable
Water Can Be Obtained by a Zero Liquid
Discharge Treatment Train
Pre-Treatment Reverse
Osmosis
Stabilization/
Disinfection
Electrodialysis
Reversal
Brine
Concentrator
Coagulation
Pond
Pilot Scale
Full-Scale Plant

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Pilot Project Objectives
Demonstrate feasibility of selected
treatment train.
1.
2. Demonstrate primary RO and
secondary EDR can achieve
predicted recovery with minimal
fouling.
3.
RO
Evaluate the effectiveness of a
reversible RO configuration.

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Pretreatment
Project Background
Pretreatment
Reverse OsmosisElectrodialysis Reversal
Project Costs

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Pretreatment Can Effectively Remove
RO Constituents of Concern
•Fe/Mn Removal
•Granular Media Filtration
•Filtronics FV-03 Electromedia I

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Pretreatment Can Effectively Remove
RO Constituents of Concern
0
5
10
15
20
25
30
35
40
45
50
Total Iron Manganese
Concentration(μg/L)
Well
RO Feed

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Reverse Osmosis
Project Background
Pretreatment
Reverse OsmosisElectrodialysis Reversal
Project Costs

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The RO Unit was Operated for
Over 4,000 Hours

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The RO Process Can Operate at
High Recoveries
0
10
20
30
40
50
60
70
80
90
100
0 25 50 75 100 125 150 175 200
Run Time (Days)
Recovery(%)
Recovery (%)

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The RO Process Produces a Low Total
Dissolved Solids (TDS) Product
0
1000
2000
3000
4000
5000
6000
Well RO Feed RO Permeate RO Concentrate at
70% recovery
Concentration(mg/L)

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The RO Process Can Operate with
Minimal Fouling
0
2
4
6
8
10
12
14
16
18
20
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Operation (Days)
Flow(gpm)
Stage 1 flow
Stage 2 flow
Total system flow
Restart Clean #1 Clean #2
Start of Reversible
operation

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Reversible RO Configuration Has the
Potential to Increase Recovery and
Decrease Membrane Fouling

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Reversible RO Configuration Has the
Potential to Increase Recovery and
Decrease Membrane Fouling

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System Normalized Permeate Flow - Reversible
Operation vs. Conventional Operation
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
Throughput (gal x 100,000)
NPF/NPFinitial
Reversible
Conventional

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1st Stage Normalized Permeate Flow -
Reversible Operation vs. Conventional Operation
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
Throughput (gal x 100,000)
NPF/NPFinitial
Reversible
Conventional

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2nd Stage Normalized Permeate Flow -
Reversible Operation vs. Conventional Operation
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
Throughput (gal x 100,000)
NPF/NPFinitial
Reversible
Conventional

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RO Concentrate Silt Density Index (SDI)
Indicates Particle Removal After Flow Reversal
0
0.5
1
1.5
2
2.5
3
3.5
Before Flow Reversal After Flow Reversal
SDI

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Electrodialysis Reversal
Project Background
Pretreatment
Reverse OsmosisElectrodialysis Reversal
Project Costs

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The EDR was Operated Continuously for
Over 1,600 hours
Na
+
Cl
-
Cl
-
Na
+
Concentrate
Compartment
Product
Compartment
Na
+
Na
+
Cl
-
Cationic
Membrane
Anionic
Membrane
Cationic
Membrane
Cl
-
Cathode
-ve Anode
+ve

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Reduced RO Recovery to Meet EDR
Feed Requirements
Pre-Treatment Reverse
Osmosis
Electrodialysis
Reversal
RO Recovery = 60%
RO Bypass
EDR Influent Silica Limit = 115 mg/L

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EDR can Effectively Remove TDS from
the RO Concentrate
0
2000
4000
6000
8000
10000
12000
14000
16000
EDR Feed EDR Product EDR Concentrate
TDS(mg/L)

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EDR can Achieve High Recoveries
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 200 400 600 800 1,000 1,200 1,400 1,600 1,800
Run Time (hr)
Recovery(%)
(-)ve Polarity
(+)ve Polarity

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EDR Performance has been Stable
0
5
10
15
20
25
30
35
0 200 400 600 800 1000 1200 1400 1600 1800
Run Time (hr)
Pressure(psi)
Feed Pressure
Stack Inlet Pressure (+)
Stack Inlet Pressure (-)

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EDR Performance has been Stable
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
0 200 400 600 800 1000 1200 1400 1600 1800
Run Time (hr)
Resistance(Ohms)
Stage 1 (+) Resistance
Stage 1 ( - ) Resistance
Stage 2 (+) Resistance
Stage 2 ( - ) Resistance

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RO Primary Desalting and EDR
Secondary Desalting can Achieve High
Overall Recovery
Pre-Treatment Reverse
Osmosis
Electrodialysis
Reversal
31 gpm 28 gpm
3 gpm
System Recovery = 90%

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RO Primary Desalting and EDR Secondary
Desalting can Produce a Low TDS Product
0
2000
4000
6000
8000
10000
12000
14000
16000
Well Product Concentrate
TDS(mg/L)

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Project Costs
Project Background
Pretreatment
Reverse OsmosisElectrodialysis Reversal
Project Costs

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Limiting the Volume of Brine for Final
Treatment Reduces Cost
Reverse
Osmosis
Capital – 1 mgd $2 million $22 million
Power (kWh/1000 gal) 2.2 90
Brine
Concentration

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Impact of Overall Recovery is
Significant – Example: 1-mgd Plant
0
50
100
150
200
250
70% 75% 80% 85% 90% 95%
Overall Recovery
Brine
Flowrate
(gpm)
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
Brine
Concentration
(mg/L)
Primary RO Brine
Secondary
EDR Brine
174 gpm
70 gpm

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Limiting the Volume of Brine for Final
Treatment Reduces Cost – Full-Scale
Facility at 2.7 mgd
Capital
Cost
(MM$/yr)
O&M
Cost
(MM$/yr)
Total
Cost
(MM$/yr)
RO + BC 2.8 3.7 6.5
RO + EDR + BC 2.4 2.6 5.0

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Summary and Conclusions
Selected treatment train is feasible.1.
2. Primary RO and secondary EDR
can achieve predicted
recoveries.
3.
RO
The reversible function has potential to improve RO
performance, but additional testing is needed.

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Acknowledgements
California Department of Water Resources
(Chapter 6(a) of Proposition 50)
Staff Indian Wells Valley Water District

36. Questions?
Questions?
awiesner@carollo.com

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Comparing Water Costs Indicates that
Costs are Reasonable Given Water
Quality and Inland Location
Typical Brackish Desalting
Ocean Disposal for Brine
This Project
Primary Desalting Step
Zero-Liquid Discharge/
Brine Treatment
Bottled Water
AWWA – June 2005
Crystal Geyser
500 1000 1500
~ 450 - 550
~ 500
~ 620
~ 1,160
~ 974,000
~ 6,500,000
$/AF
Total ~ 1,000
Total ~ 1,780