1. LIME SOFTENING & STABILIZATION

2. Murder Parties Ralph Rottingrape Marilyn Merlot George W. Taliban

3. Queen Illicibeth; Gridlock, the Merchant of Tennis Pen Ta Gon Advisor to the Emperor

5. Classifying Water Hardness Description of waterHardness expressed as mg/L of CaCO 3 Soft less than 50 Moderately soft 50–75 Slightly hard 75–150 Hard 150–300 Very hard greater than 300

6. What is “lime”? Limestone, mainly calcium carbonate, CaCO 3 Quicklime, calcium oxide, CaO Slaked lime, calcium hydroxide, Ca(OH) 2

7. Limestone mining, preparation and use

8. Limestone Mining, cont’d

10. Limestone Handling and Shipping

11. Lime Conversions Limestone can be converted to quick lime: CaCO 3  CaO + CO 2 (1800F) Quick lime is slaked with water: CaO + H 2 O  Ca(OH) 2 Slaked lime slowly reacts with CO 2 in air: …Ca(OH) 2 + CO 2  CaCO 3 + H 2 O Dissolved lime (hardness) can precipitate: Ca(HCO 3 ) 2  CaCO 3 + H 2 O + CO 2

12. Lime Kilns

13. Calcination of Limestone CaCO 3  CaO + CO 2

14. Hydration: slaking with water Water reacts with the quicklime to form hydrated lime: CaO + H 2 O  Ca(OH) 2

15. The removal of divalent metal ions Precipitation/settling or IX resins

16. Typical lime softening process… Lime sludge Ca(OH) 2 Lime    …presented as a complete drinking water treatment process

17. LIME SLAKING …and DOSING

18. Precipitation occurs in a settling tank

19. LAGOON DEWATERING

20. Why are we concerned about corrosion?

21. Stability Relationship The basic Relationship in Stabilization Has been simplified by Powell, Bacon and Lill to pHs =p(Ca 2+ ) + p(Alk) + C

22. Powell, Bacon and Lill Diagram mg/L Langelier index

23. Modified Caldwell Lawrence Diagram