Combination Mechanical Plus Chemical Pretreatment—Lime Softening

3 Combination Mechanical Plus Chemical Pretreatment—Lime Softening 

Lime softening is used to remove the following species from water  

Species Raw Water Cold Lime Cold Lime- Soda Warm Lime Hot Lime Hot Lime- Soda 

Lime softening can be conducted cold (ambient), at warmer temperatures, or hot, where steam is used to heat the process. The differences among the three options are in the removal of hardness, alkalinity, and silica. Table 8.10 lists approximate effluent from cold, warm, and hot lime softeners.16 

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