ANS:C - sand

For the removal of very small amounts of precipitate from a large volume of water, the most suitable filter is the sand filter. Here’s why:

1. Plate & Frame Filter:
   • Effective for filtering slurries and thicker suspensions but not typically used for large volumes of water with very small amounts of precipitate.
2. Shell & Leaf Filter:
   • Suitable for fine filtration and can handle relatively smaller volumes compared to the requirements stated.
3. Sand Filter:
   • Commonly used for filtering water, especially when dealing with very small amounts of precipitate. Sand filters are effective for large volumes of water and can efficiently remove fine particulates.
4. Rotary Vacuum Filter:
   • More suited for continuous removal of larger quantities of solids from slurries rather than small amounts of precipitate from large volumes of water.