Concentrate and permeate treatment processes for improving the sustainability

of inland brackish water desalinationW. Shane Walker, Ph.D.Anthony Tarquin, Ph.D.

Center for Inland Desalination SystemsThe University of Texas at El Paso

Multi-State Salinity Coalition SummitLas Vegas, NevadaJanuary 26, 2012

Objectives

• Review indicators of sustainability• Highlight several CIDS investigations

demonstrating improved sustainability

Sustainability

Environmental

EconomicSocio-Political

Environmental

EconomicSocio-Political

Select Sustainability Indicators

• Higher water recovery (product/feed)• Lower specific energy consumption (kWh/kgal)• Less chemical consumption, waste production• Lower economic cost ($/kgal; $/MGD)• Technical/operational complexity

Inland Membrane Desalination

Brackish Water Source

pretreatment membrane process

concentrate treatment

permeate treatment

Distribution

Reuse/Disposal

Permeate Treatment

Brackish Water Source

pretreatment membrane process

concentrate treatment

permeate treatment

Distribution

Disposal

Permeate Stabilization by Calcite

Three-step process1. Lower pH with CO2

– Relatively abundant and inexpensive gas

2. CO2 reacts with calcite– CO2 + CaCO3 → Ca2+ + 2 HCO3-

3. Add small dose of base for LSI > 0

Carollo Engineers, Inc. and Shane Walker, UTEPTexas Water Development Board (1004831105)

Permeate Stabilization by Calcite

• Feed: KBH permeate• TOMCO2: pH 5.6-5.7• Upflow calcite contactor

– Media: 0.5-2 mm particles– EBCT: 1-10 min– Overflow: 2-17 gal/ft2/min

• Product Quality:– pH: 7.5-8.5– Ca2+: 20-30 mg/L– ALK: 50-75 mg/L (as CaCO3)– LSI: -0.5-0.0

• Energy: < 0.1 kWh/kgal

Carollo Engineers, Inc. and Shane Walker, UTEP CIDSTexas Water Development Board (1004831105)

Concentrate Treatment

Brackish Water Source

pretreatment membrane process

concentrate treatment

permeate treatment

Distribution

Disposal

CERROAnthony Tarquin, UTEP

US Bureau of Reclamation, DWPR R10AP81217

concentrate Seawater RO Distribution

• Concentrate Enhanced Recovery RO (CERRO)• Batch-continuous seawater RO process

exploiting induction time of precipitation

CERRO

• Demonstrated at KBH (El Paso) and BGNDRF (Alamogordo)

• Feed: KBH- >10,000 mg/L BGNDRF- 6000 mg/L

• Product Flow: 1 gpm• Recovery: KBH- 97%

BGNDRF (ongoing)

• Energy: 6-7 kWh/kgal (w/ energy

recovery)

Anthony Tarquin, UTEPUS Bureau of Reclamation, DWPR R10AP81217

Zero Discharge Desalination (ZDD)

• Demonstrated at KBH (El Paso) and BGNDRF (Alamogordo)

• BGNDRF Feed: 2500 mg/L• NF/RO and Electrodialysis

Metathesis (EDM)• Product Flow: 20 gpm• Recovery: 97-98%• Energy: 6.6 kWh/kgal

Tom Davis & Malynda Cappelle, UTEPUS Bureau of Reclamation, DWPR R10AP81212

Conclusions

Sustainability of inland brackish water desalination can be improved by:– increasing system recovery– reducing specific energy consumption– reducing chemical consumption and production– reducing economic cost– designing appropriate technical complexity

Acknowledgements

• Permeate Stabilization by Calcite– Texas Water Development Board– El Paso Water Utilities, KBH Desalination Plant– Carollo Engineers: Winnie Shih, Bradley Sessions, Justin Sutherland– UTEP CIDS: Luis Maldonado, Cora Martinez, Sami Al-Haddad

• CERRO (High Recovery)– US Bureau of Reclamation, BGNDRF (Alamogordo, NM)– UTEP CIDS: Anthony Tarquin, Guillermo Delgado

• ZDD (High Recovery)– US Bureau of Reclamation, BGNDRF (Alamogordo, NM)– UTEP CIDS: Tom Davis, Malynda Cappelle, Lucy Camacho,

Noe Ortega, Jesse Valles

Questions or Comments

W. Shane Walker, Ph.D.Assistant ProfessorThe University of Texas at El Paso500 W. University Ave., Civil EngineeringEl Paso, TX 79968(915) 747-8729wswalker2@utep.edu