1. Page  1 Reverse Osmosis Electro-dialysis Sources of brine Water pollution by industrial brines Background BRINE TREATMENT USING FREEZE DESALINATION TECHNOLOGY (HybridICE™ Technology) T Mtombeni J P Maree, W J Louw, J K O Asante, F Oosthuizen, C M Zvinowanda Live your life. Create your destiny.

2. Page  2 A new approach to Brine treatment Current Treatment Methods Evaporation ponds Distillation Deep Well injection

3. Page  3 A new approach to Brine treatment Advantages Drawbacks Very low operational costs Free energy (solar driven) Minimal maintenance costs Very low operational costs Free energy (solar driven) Minimal maintenance costs Leaching Expensive lining material High cost of land Slow process Depends on climatic conditions Susceptible to natural disasters Leaching Expensive lining material High cost of land Slow process Depends on climatic conditions Susceptible to natural disasters Evaporation ponds

4. Page  4 A new approach to Brine treatment Advantages Drawbacks High water recovery (99%) Zero Liquid Discharge Potential mineral recovery High water recovery (99%) Zero Liquid Discharge Potential mineral recovery Energy intensive Costly process Scaling and Corrosion Energy intensive Costly process Scaling and Corrosion Distillation

5. Page  5 Comparison of Freeze and Evaporation methods Evaporate Freeze Parameter Temperature change dT25.075.0 Energy required to reduce tempt to 0°C (MJ/m 3 )104.5313.5 Energy required to freeze/evaporate 1 m 3 of water (MJ/m 3 )3332,257.0 Energy required to freeze/evaporate 1 m 3 water (GJ/m 3 ) 0.442.57 Energy required to freeze/evaporate 1 m 3 water (kWh/m 3 ) 121.53714.03 Price (R/kWh)0.30 Cost to freeze/desalinate 1 m 3 (R/m 3 )36.46214.21 Cost ratio 1 6 A new approach to Brine treatment

6. Page  6 A new approach to Brine treatment Freeze desalination History Old technology but generally not accepted due to: Process complexity Solid-Liquid phase separation High capital costs

7. Page  7 A new approach to Brine treatment Advantages Drawbacks Low energy costs Zero Liquid Discharge Potential mineral recovery Low operating temperature Minimal corrosion and scaling Energy recovery Low cost materials Pre-treatment not necessary Low ecological impact Low energy costs Zero Liquid Discharge Potential mineral recovery Low operating temperature Minimal corrosion and scaling Energy recovery Low cost materials Pre-treatment not necessary Low ecological impact High capital costs Process complexity Impurity entrapment Freeze-up High capital costs Process complexity Impurity entrapment Freeze-up Freeze desalination

8. Page  8 Brine The HybridICE™ Slurry Concentrate Ice The HybridICE™ Technology … a new approach to Freeze Desalination

9. Page  9 The HybridICE™ Technology … a new approach to Freeze Desalination PI M1 M2 M3 PI A WI 101 102 103 104 101 R-101 V-101 V-102 V-103 HX1 HX2 C1 P1 U-101 B HX3F1 VFD 2 VFD 1 A – Ice outlet (ice sampling point) B – Concentrate outlet (feed sampling point) C1 – Compressor HX1 & 2 – Scrapped Surface heat exchangers HX3 – Refrigerant condenser (forced air) M1,M2,M3 – Electric motors P1 – Centrifugal pump PI-101, PI-102, PI-103, PI-104 – Pressure indicators R-101 – Brine storage tank U-101 – Ice filter V-101 – Brine valve V-102, V-103 – Evaporation temperature control valves VFD1, VFD2 – Variable frequency drives WI-101 – Weight indicator (Mass lost = Mass of ice) HybridICE™ P&ID

10. The HybridICE™ Technology … a new approach to Freeze Desalination HybridICE™ Filter operation ……………… Ice out Concentrate out Slurry in

11. Page  11 The HybridICE™ Technology … a new approach to Freeze Desalination Ice from the HybridICE™ plant

12. Page  12 The HybridICE™ Technology … a new approach to Freeze Desalination HybridICE™ Key Attributes Production of ice without washing Compact and simple technology Low energy consumption and energy recovery Free cooling energy (Case of AngloGold, Mponeng Mine) Retrofitting of existing systems

13. Page  13 The HybridICE™ Technology … a new approach to Freeze Desalination HybridICE™ Key Attributes High impurity removal No use of chemicals Cheap materials used in plant design Minimal scaling and corrosion

14. Page  14 Case of Anglo Gold Ashanti Mponeng mine Depth : 3.5 km Virgin rock temp. : 54.5°C Cooling water temp.:3°C Service water :10°C Installed capacity:4,200t/day Water circulated:49ML/day (-5*) Electricity generation:32GWh/month Savings by load shifting:2.3% (ice dams) Mine cooling using ice The HybridICE™ Technology … a new approach to Freeze Desalination

15. Page  15 The HybridICE™ Technology … a new approach to Freeze Desalination HybridICE™ Applications HybridICE™ Space cooling Heat pump Pre-heating stage Impurity concentration for chemical recovery Brine treatment

16. Page  16 The HybridICE™ Technology … a new approach to Freeze Desalination Conclusion Evaporation pond disposal Attractive but environmentally unfriendly Slow process Distillation Energy intensive High operational & capital costs

17. Page  17 The HybridICE™ Technology … a new approach to Freeze Desalination Conclusion cont’d Freeze desalination (HybridICE™ Technology) Low energy consumption High impurity removal Simple and compact Environmentally benign

18. Page  18 The HybridICE™ Technology … a new approach to Freeze Desalination THANK YOU Email: mtombenit@tut.ac.za Cell: 0027788745617