This document summarizes a water recycling project at the Cache Creek Casino Resort in California. The resort was using groundwater for its water supply but needed to soften the water. The ion exchange softening process increased the salinity of the wastewater effluent. To address this, a water desalination treatment facility was built to desalinate the recycled water using electrodialysis reversal and vibratory shear enhanced process technologies. This reduced the salinity of the recycled water effluent by 66-75%, allowing it to be used for irrigation while meeting regulatory discharge limits. The facility has an average daily production capacity of 650,000 gallons per day and recovers 97% of the water treated.

1. Your Water – Locally Produced!
Jason M. Brabec, P.E.
Innovative Recycled Water Desalination for the
Cache Creek Casino Resort
HYDROSCIENCE ENGINEERS INC.
WateReuse California Annual Section Conference 2010

2. Background

3. PROJECT LOCATION
Cache Creek Casino Resort
Brooks, California

4. WASTEWATER EFFLUENT QUALITY
Recycled water meets Title 22 Criteria (Unrestricted Use)
PARAMETER EFFLUENT AVERAGE
Flow 230,000 gpd
Peak Treatment Capacity 475,000 gpd
Chlorine Residual 1-5 mg/L
Turbidity 0.10 NTU

5. RECYCLED WATER DISTRIBUTION
• Toilet flushing within the Resort
• Decorative water features
• Landscape site irrigation
• Yocha Dehe Golf Course irrigation

6. SITE WATER CYCLE
1.1 MG
WELLS
RW
RESORT / FACILITIES
WWTP
18
GOLF
COURSE
WATER FEATURES
CACHE CREEK
LANDSCAPE
IRRIGATION

7. Water Quality Impacts

8. SOURCE GROUNDWATER
• Elevated levels of TDS
• High hardness

9. ION EXCHANGE SOFTENER
1.1 MG
WELLS
RW
RESORT / FACILITIES
WWTP
18
GOLF
COURSE
WATER FEATURES
CACHE CREEK
LANDSCAPE
IRRIGATION
WATER
SOFTENERS
NaCl

10. RECYCLED WATER QUALITY IMPACTS
Significantly Impacted Recycled Water Effluent Quality
WATER SOURCES
TDS
mg/L
Sodium
mg/L
Chloride
mg/L
Hardness
grains
Groundwater (source water) 539 81 113 17.5
Potable water supply after ion-exchange 717 183 107 0-1
Recycled water effluent 1,582 491 630 NA

11. IMPACTS OF HIGH SALTS
• Reduced irrigation suitability
• Significant dilution required to comply with WDR
discharge limits
• Increased maintenance of toilet flushing valves
• Aesthetic issues

12. Development of
Solutions

13. GOALS & OBJECTIVES
• Provide soft water
• Suitable recycled water quality for irrigation
purposes
• Comply with WDR
• Minimize distribution system maintenance
• Maximize water reuse
• Maintain environmental stewardship

14. BRINE DISPOSAL
• Ocean discharge
• Deep well injection
• Discharge to other municipality
• Crystalizer
• Off-haul for disposal

15. ALTERNATIVES
A) Off haul ion-exchange regeneration brine
B) Desalinate recycled water
C) Desalinate potable water

16. ALTERNATIVE A
1.1 MG
WELLS
RW
RESORT / FACILITIES
WWTP
18
GOLF
COURSE
WATER FEATURES
CACHE CREEK
LANDSCAPE
IRRIGATION
WATER
SOFTENERS
NaCl
OFF-HAUL
BRINE DISPOSAL

17. ALTERNATIVE B
1.1 MG
WELLS
RW
RESORT / FACILITIES
WWTP
18
GOLF
COURSE
WATER FEATURES
CACHE CREEK
LANDSCAPE
IRRIGATION
WATER
SOFTENERS
NaCl
DESALINATION
BRINE
DISPOSAL

18. ALTERNATIVE C
1.1 MG
WELLS
RW
RESORT / FACILITIES
WWTP
18
GOLF
COURSE
WATER FEATURES
CACHE CREEK
LANDSCAPE
IRRIGATION
OFF-HAUL
BRINE DISPOSAL
POTABLE
WATER
DESALINATION
WATER
SOFTENERS
NaCl
THE WINNER!

19. OTHER DESIGN CONSIDERATIONS
• Site constraints –
topography
• Out of sight from
patrons
• Two-step brine
concentration
process
(due to brine off-haul)

20. Water Desalination
Treatment Facility

21. FIRST STEP: DESAL AND SOFTENING
• Elevated silica levels in source ground water
• High recovery rates
Electrodialysis
Reversal (EDR)
Selected

22. EDR TECHNOLOGY
Cl
_
Na
+
Na
+
Cl
_
Cl
_
Cl
_
Na+
ANODE (+)FEED PRODUCT
BLOWDOWN
(WASTE)
CATHODE (-)
Cl
_
Cl
_
Na
+
Na+
CONCENTRATE
MAKEUP
CONCENTRATE
RECYCLE
RECYCLE PUMP
C
A
C
A
C
A
C
SOURCE:GE

23. SECOND STEP: BRINE CONCENTRATION
• Clarifier and pH conditioning
• Elevated silica levels in EDR reject
• Piloted Vibratory Shear Enhanced
Process (VSEP) system
VSEP selected for
2nd stage

24. VSEP TECHNOLOGY
SOURCE:NEWLOGICRESEARCH

25. EDR TREATMENT PROCESS
EDR PUMPS BLEND TANK AND TREATMENT TRAINS

26. VSEP FEED TANK VSEP FILTER PACKS
VSEP TREATMENT PROCESS
BRINE
CONCENTRATION

27. CHEMICAL HANDLING FACILITY
CHEMICAL LOADING AREACHEMICALS

28. WDTF DESIGN CAPACITY
Parameter Capacity Description
Avg. Daily Softening
Production Capacity
650,000 GPD
Finished Water
(< 3 grain hardness)
Reject Concentration 125,000 GPD Reject Treatment
Brine Generation 20,000 GPD Brine Concentrate
Building 8,500 sq-ft
Process area, lab,
chemical room, MCC

29. RECYCLED WATER QUALITY IMPACTS
Water Source TDS
(mg/L)
Sodium
(mg/L)
Chloride
(mg/L)
Groundwater (Source Water) 539 81 113
Potable Water (EDR Finish Water) 195 39 53
Recycled Water Effluent 545 (1,582) 146 (491) 159 (630)
Percent Reduction (2007 vs 2009) 66% 70% 75%

30. WDTF RECOVERY RATE
System
Percent
Recovery
Electrodialysis Reversal System 85%
VSEP System 85%
Water Desalination Treatment Facility 97%

31. POTENTIAL IMPROVEMENTS
• Increase recovery of EDR
• Evaluate waste streams
• Conditioning of VSEP feed

32. Conclusion

33. GOALS & OBJECTIVES - Revisited
Provide soft water
Suitable recycled water for irrigation
Comply with WDR
Minimize distribution system maintenance
Maximize water reuse
Environmental stewardship

34. Jason M. Brabec, P.E.
10569 Old Placerville Road
Sacramento, CA 95827
916-364-1490
jbrabec@hydroscience.com
HydroScience Engineers