1. Water Conditioning Process
Dr.Lek Wantha

2. Contents Water usage in industries Water sources
Water quality related to end-use
Water treatment for industrial supply
Water softening
Ion exchange process
Lime-soda process
Demineralization
Desalting or Desalinization
Electrodialysis (ED)
Reverse osmosis (RO)

3. Water Usage in Industries
Component in products
Energy carrying media (heat media), i.e. steam
Cooling media
Cleaning
Separating & Purification
Transportation of raw material & products
Mixing
Complete reaction

4. Water Sources (exclude tap water)
Sea water
Salt >>>2.6% by mass NaCl, MgCl2, sulfate
Gases>>> N2, O2,CO2
Surface water
Flowing in river, cannel
Contain of inorganic
and organic compounds
depend on climatic
Underground water
Artesian well
Water table well
Spring
Geysers (hot spring)

5. Water Sources

6. Water Quality Related to End-use
Inorganic salts
Ca2+
Mg2+
Na+ K+
Sulfate carbonate
Chloride ion
Organic compounds & dissolved gasses
CO2 O2
H2S
Organisms
Aquatic animals
Aquatic insects
Microorganisms

7. Water Quality Related to End- use
Water quality parameter
Measurement parameter pH
Suspended solid SS
Turbidity
Ca2+ and Mg2+
Hardness
Dissolved ion
Conductivity

8. Water quality Requirement for Agriculture
Fish, aquatic life, wide life requirements
Low toxic concentration
pH near neutral ( )
Low BOD (1-2 mg/L)
High DO
Cold: 6-7 mg/L (15 ºC)
Warm: 4-5 mg/L (20 ºC)
Low temperature, turbidity
Livestock
Low bacteria, <40/100 mL
Low toxic concentration
Irrigation
Low dissolved solids, <500 mg/L
Total bacteria, 100,000/100 mL
Low heavy metal
BOD= Biochemical oxygen demand
OD = Dissolved oxygen

9. Water quality Requirement for Industries
Cooling
Low hardness, 50 ppm of (Mg2+ + Ca2+)
Low corrosivity
Food processing, brewing & soft drinking
As public drinking water, but F- <1 ppm
Thermal power
Total Dissolved Solid (TDS) < 0.1 ppm
Public recreational requirements
Free of color, odor, taste and turbidity
Total bacteria, <1000/100 mL
Coliform bacteria <100/100 mL
Low nutrients

10. Water quality Requirement for Industries
Public drinking water (treated)
No bacteria
Low nitrate, nitrite (< 10 ppm)
Very low pesticide (none or < 0.05 ppm)
Fluoride allowable to 2.4 ppm
Toxic substances (below criteria level)
TDS < 500 ppm

11. Water Treatment for Industrial Supply
Clarification
Disinfection
Hardness removal (softening)
Physical methods
Thermal
Distillation
Freezing-out
Chemical methods
Lime soda process
Phosphate process
Physico-chemical methods
Cation exchange process
Deaeration
Chemical
Physical

12. Water treatment Water softening Demineralization Ion exchange process
Sodium Cation Exchange
Hydrogen Cation Exchange
Lime-soda process
Demineralization
Desalinization
Electrodialysis (ED)
Reverse osmosis (RO)
Hydrated lime (Ca(OH)2) 
Quicklime (CaO)
Soda ash (Na2CO3) 
Caustic soda (NaOH)
Ion exchange process
Reverse osmosis (RO)
Electrodialysis (ED)

13. Water Softening Reduce/remove hardness Hardness
Dissolved salts: Calcium and magnesium
Problems
Calcium bicarbonate → Calcium carbonate + Water + Carbon dioxide
Ca(HCO3)2 → CaCO3 + H2O + CO2
deposition of calcium carbonate scale in pipes and equipment
causes corrosion of iron or steel equipment
culprit in forming soap scum

14. Calcium & magnesium bicarbonate
Hardness of Water
Carbonate Hardness (Temporary hardness)
Calcium & magnesium bicarbonate
Non-Carbonate Hardness
(Permanent hardness)
Calcium & magnesium sulfate
Calcium & magnesium nitrate
Calcium & magnesium chloride
Softening
Boiling
Adding lime
Adding sodium carbonate
Exchange process
Softening
Adding sodium carbonate
Exchange process

15. Water Softening Adding lime Boiling
Adding sodium carbonate
Exchange process
Ca(HCO3)2 + heat  CaCO3 +CO2+H2O
Mg(HCO3)2 + heat  MgCO3 +CO2+H2O
Ca(HCO3)2 + Ca(OH)2  2CaCO3 +2H2O
MgCl2 + Ca(OH)2  Mg(OH)2  + CaCl2
CaCl2+Na2CO3  CaCo3  + 2NaCl
MgSO4+Na2CO3+ Ca(OH)2  Mg(OH)2  +CaCo3  + Na2SO4
Sodium Cation Exchange
Ion Exchange Process
Hydrogen Cation Exchange
Anion Exchanger

16. Ion Exchange Process
Zeolite softening

17. Ion Exchange Process Advantages Limitations
Ion exchange can be used with fluctuating flow rates.
Makes effluent contamination impossible.
Resins are available in large varieties from suppliers and each resin is effective in removing specific contaminants.
Limitations 
Pretreatment is required for most surface waters.
Waste is highly concentrated and requires careful disposal.
Unacceptable high levels of contamination in effluent.
Units are sensitive to the other ions present.

18. Sodium Cation Exchange

19. Hydrogen Cation Exchange

20. Anion Exchanger

21. Lime-soda Process Lime = CaO + Soda = soda ash (Na2CO3)
Carbonate hardness (temporary)
Ca(HCO3)2 + Ca(OH)2  2CaCO3 +2H2O
Mg(HCO3)2 + Ca(OH)2  MgCO3+CaCO3 +2H2O
MgCO3+ Ca(OH)2  Mg(OH)2 +CaCO3
Non-carbonate hardness (Permanent)
MgCl2 + Ca(OH)2  Mg(OH)2  + CaCl2
CaCl2+Na2CO3  CaCo3  + 2NaCl
CaSO4+Na2CO3  CaCo3  + Na2SO4
MgSO4+Na2CO3+ Ca(OH)2  Mg(OH)2  +CaCo3  + Na2SO4

22. Types of Lime
Hydrated lime (Ca(OH)2) 
quicklime (CaO)
Soda ash (Na2CO3) 
Caustic soda (NaOH)

23. Demineralization Process
Removal of minerals and nitrate from the water
Ion exchange:
removal of hardness ions (magnesium and calcium)
water demineralization
90% of barium, arsenic, cadmium, chromium, silver, radium, nitrites, selenium and nitrates can be effectively removed from water
Reverse osmosis
Electrodialysis
membrane processes, remove dissolved solids from water using membranes

24. Desalting or Desalinization Process
Treatment of highly saline water:
sea water
3,500 ppm of dissolved salt
Lowing saline contents
< 500 ppm
Two methods
Electrodialysis (ED)
Reverse Osmosis (RO)

25. Electrodialysis (ED)
2H2O + 2e- 2OH- +H2(g)
2Cl-  2e- +Cl2 (g)

26. Osmosis vs. Reverse Osmosis (RO)
Direction of water flow
Contaminants
Reverse Osmosis
Direction of water flow
Contaminants

27. Sources
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