Development of Alternative Water Supplies Water Reuse and - - PowerPoint PPT Presentation

Development of Alternative Water Supplies – Water Reuse and Desalination

Pei Xu, PhD Associate Professor, Civil Engineering

NMSU College of Engineering Dean’s Advisory Council February 23, 2018

Development of Alternative Water Supplies is Crucial for Water Security

Water Scarcity Elevated Salinity High sodium adsorption ratio Contaminants of emerging concerns Desalination Water Conservation Water Reuse

Concentrate

Challenges of Alternative Water Supplies

• Water quality concerns
• Intensive energy use
• Concentrate and waste management

Need Innovative Approaches

Short-term solutions: Modify and optimize current technologies Long-term solutions: Develop next generation

• f technologies

Research Areas

NSF DOE BoR NMED

NMWRRI Industry /Water Utilities

Sustainable Water and Wastewater Systems for

• Wastewater treatment and reuse
• Membrane processes & desalination
• Water and energy
• Resources recovery

Funding and Research Group

• $3M funding since 2013, averaging $0.5M per year
• Current research group
• 2 full-time postdocs
• 1 senior researcher
• 4 PhD students
• 3 Master graduate students
• Undergraduate students
• Peer-reviewed journal publications: 5 to 8 per year

From Fundamental Laboratory Study to Field Demonstration Testing

Highlights of Research Projects

• Selective electrodialysis for non-potable water use, e.g.,

irrigation and thermal power plant cooling water

• Hybrid algal-membrane system for potable water reuse
• Produced water treatment and beneficial reuse

High Sodium to Hardness Ratio Resulted in Reuse Challenges

 SAR = Sodium Adsorption Ratio

SAR = [Na+] / {([Ca2+] + [Mg2+]) / 2}1/2

≤3 6 to 9 > 9

(use meql units)

Cathode (-) Anode (+) Anion Exchange Membrane Cation Exchange Membrane Cation Exchange Membrane

• - - - - - - - - - - -

Feed

+ + + + + + + + + + +

Electrodialysis Consists of Electrodes and A Stack of Membrane Cell Pairs

• - - - - - - - - - - -
• - - - - - - - - - - -

+ + + + + + + + + + +

Spacer Spacer Repeating Cell Pairs

Cathode (-) Anode (+)

Cl-

Na+ Na+

Anion Exchange Membrane Cation Exchange Membrane Cation Exchange Membrane

• - - - - - - - - - - -

Feed

+ + + + + + + + + + +

Na+ Na+ Na+

Cl- Cl- Cl- Cl-

Na+ Na+ Na+

Desalted water ED concentrate

• - - - - - - - - - - -
• - - - - - - - - - - -

+ + + + + + + + + + +

Saline water Saline water

Electrodialysis with Normal Grade IX Membranes Remove All Cations and Anions

SO4

2-

Ca2+ Ca2+

Cathode (-) Anode (+)

Cl-

Na+ Na+

Anion Exchange Membrane Cation Exchange Membrane Cation Exchange Membrane

• - - - - - - - - - - -

Feed

+ + + + + + + + + + +

Na+ Na+ Na+

Cl- Cl- Cl- Cl-

Na+ Na+ Na+

Desalted water ED concentrate

• - - - - - - - - - - -
• - - - - - - - - - - -

+ + + + + + + + + + +

Saline water Saline water

Electrodialysis with Selective IX Membranes Remove Preferentially Monovalent Ions

SO4

2-

Ca2+ Ca2+

Selective Electrodialysis for ZLD of Reclaimed Water

CaSO4 MgCl2 CaCl2

Ca2+ Mg2+ Ca 2+ Mg2+ SO4

2-

Cl- Na + Cl- Na + SO4

2-

Ca 2+

Irrigation Cooling Water Wetland

Salty Reclaimed Water

Na + Na + Na + Na +

Na2SO4 NaCl Ion Switcher Reclaimed water with low hardness, higher salinity Reclaimed water with low sodium, lower salinity

Selective Membrane Coating

Pilot Site Development

Modeling and Full Scale Design

Bench Testing Pilot Testing Full Scale Design Data Fitting and Mathematical Modeling Water and Salt Balance, Process Modeling Cost Analysis WATSYS: Specialty EDR Projection Model by GE (Normal Grade Membrane Only)

Scottsdale Blending Analysis and Cost Comparison – 1 MGD Reclaimed Water

Baseline Alternative Alternative 1A Alternative 1 Alternative 2 UF + RO Normal EDR - WATSYS Normal EDR - Testing Selective EDR Feed Water Flow (mgd) 1 Feed Water Sodium (mg/L) 235 % Flow Treated 60.5% 69.0% 78.0% 57.5% Overall Recovery 88% 93% 92% 94% Unit Recovery 85% 90% 90% 90% Blended Water Flow (mgd) 0.88 0.93 0.92 0.94 Product Water Sodium (mg/L) 110 Product TDS (mg/L) 530 522 433 634 Concentrate Flow (gpm) 60 48 54 40 Concentrate TDS (mg/L) 7530 9662 9662 9662 Concentrate Sodium (mg/L) 1524 1927 1715 2287 Number of Product Line

• 7

6 6 Number of Stages

• 4

4 4 Capital ($/gpd product flow) $6.1 $6.5 $7.6 $6.5

O&M ($/kgal) $1.09 $0.88 $0.83 $0.81 26% cost reduction using selective electrodialysis

Development of Antifouling Ion-exchange Membranes

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0% 5% 10% 15% 20% 25% 30%

Energy Consumption (kWh/kgal) Conductivity Cut

AR204 AR204 + PDA AR204 + PDA + 10% GO AR204 + PDA +7.5%GO AR204 + PDA + 5%GO AR204 + PDA + 2.5% GO

1 2 3 1 2 3 4 5 6 7 8 9 10 Transport Number SO4/Cl Current Density (mA/cm2) AR204 AR204 + PDA AR204 + PDA + 10%TiO2 AR204 + PDA + 3%TiO2 AR204+ PDA+ 5% TiO2 AR204 + PDA + 7.5% TiO2

Highlights of Research Projects

• Selective electrodialysis for non-potable water use, e.g.,

irrigation and thermal power plant cooling water

• Hybrid algal-membrane system for potable water reuse
• Produced water treatment and beneficial reuse

Primary&Secondary treatment Tertiary filtration Disinfection Degas/Lime Reverse Osmosis Injection Microfiltration

Treatment Technologies Leading to Potable Water Reuse

Advanced Oxidation

Energy Savings in ‘Engineered Osmosis’

Forward Osmosis (FO)

“engineered osmosis”

Brine Reconcentration

Osmosis

∆P=∆π

Brine Feed Draw Solution Feed

Integrated FO-RO System for Algae Separation and Potable Water Recovery

Integrated FO-RO System for Algae Separation and Potable Water Recovery

Potable Water Recovery

Parameters Primary effluent Product water Primary and Secondary Maximum Contaminant Level pH 7.64 6.65 6.5-8.5 TDS (mg L-1) 765 311 500 TOC (mg L-1) 30.7 2.0 Na+ (mg L-1) 142 103 250 Cl- (mg L-1) 187 174 250 NO3

• (mg L-1)

2.5 2.4 10 F- (mg L-1) 0.02 BDL (<0.008) 2 SO4

2- (mg L-1)

131 1.1 250 Cr (µg L-1) 14.7 6.41 100 Fe (µg L-1) 1145.8 23.89 300 As (µg L-1) 2.7 0.06 10 Se (µg L-1) 6.3 BDL (<0.01) 50 Cd (µg L-1) 0.2 0.05 5 Ba (µg L-1) 19.6 3.15 2000 Pb (µg L-1) 3.9 0.97 15 √ √ √ √ √ √ √ √ √ √ √ √ √ √

Fate and Transport of Organic matter

Product water Algal treatment Fulvic Humic Primary effluent Protein Draw solution

Fluorescence excitation emission matrix

2017 International Environmental Design Contest Awards

Highlights of Research Projects

• Selective electrodialysis for non-potable water use, e.g.,

irrigation and thermal power plant cooling water

• Hybrid algal-membrane system for potable water reuse
• Produced water treatment and beneficial reuse

Produced Water Treatment and Beneficial Uses

Stream augmentation Produced Water Treatment Plant Potable Water Treatment Plant Domestic Home Use Livestock & Crop Irrigation

• Other beneficial reuse options
• Hydraulic fracturing
• Industrial processes, power plants
• Municipal- Dust and fire control

Shale gas

• Target water quality

requirements are defined for each beneficial use category based on existing standards

• Disposal via deep well

injection

28

Produced Water Treatment Tool Box Developed in Xu’s Research Group

Produced Water Characterization, Treatment, Reuse

Membrane processes: MF, NF, RO, ED Membrane fouling and characterization Novel desalination processes: CDI, EDI, FO Decision Support Tool Selective removal of contaminants (e.g., SO4

2-, I2)

Coagulation and adsorption Innovative biological and bioelectrochemical processes Photocatalysis & oxidation Water quality analysis (inorganic,

• rganic, toxicity)

Challenges – Limited Lab Space

Pei Xu: pxu@nmsu.edu