ANS:A - open sand

Filtration of water in a paper mill is typically done by a vacuum leaf filter.

Explanation:

• Vacuum Leaf Filter: This type of filter is commonly used in industries like paper mills for filtering liquids with high solids content or where a high degree of clarity is required. It consists of a series of vertical leaves or discs mounted on a central manifold.
• Operation:
  • The filter operates under vacuum, where suction is applied to the inside of the leaves or discs.
  • The liquid (in this case, water in a paper mill) with suspended solids is pumped into the filter.
  • Solids are captured on the surface of the filter leaves/discs, forming a cake, while the clarified liquid passes through and is collected.
• Applications:
  • Paper Mills: Used for filtering process water to remove suspended solids and impurities before reuse or discharge.
  • Chemical Processing: Often used in chemical industries for similar purposes due to its effective filtration capabilities.
• Other Options:
  • Open Sand Filter: Typically used for larger-scale water treatment systems or in municipal water treatment, less common in paper mills.
  • Plate and Frame Filter: Commonly used for filtering liquids with lower solids content or for applications where a high degree of filtration is required.
• Sparkler Filter: Typically used for smaller-scale batch filtration of liquids in pharmaceutical or food processing industries, less commonly used in large-scale industrial water filtration like in paper mills.