Best filter for tiny precipitate from very large water volumes:\nWhich filter type is most suitable for removing a very small amount of precipitate from very large volumes of water?

Introduction / Context:
Water-treatment operations often must polish huge flow rates containing very low solids concentrations. The correct choice of filtration technology balances hydraulic capacity, solids loading, maintenance, and cost. Rapid/slow sand filters are designed precisely for this service, unlike industrial cake filters which excel at higher solids slurries.

Given Data / Assumptions:

• Very large volumes of water with a very small amount of precipitate (low turbidity).
• Continuous operation and low operating cost desired.

Concept / Approach:
Sand filters (rapid or slow) pass water through a deep granular bed, capturing fine particulates throughout the depth (not only on the surface). They accommodate very high throughputs with periodic backwashing and modest pressure drop, making them ideal for polishing large volumes. Plate-and-frame, rotary, or vacuum filters are cake filters suited to higher solids slurries; they are inefficient and expensive per cubic metre treated when solids are trace. Candle filters are niche for clarity-critical, lower flow industrial services.

Step-by-Step Solution:

Verification / Alternative check:
Municipal and industrial water plants universally employ sand (and dual-media) filters for this duty.

Why Other Options Are Wrong:

• Vacuum/rotary/plate-and-frame: better for slurries with significant cake formation.
• Candle filter: not economical for very large water volumes.

Common Pitfalls:
Confusing clarity requirements with solids load; ultraclean but low-load streams still favour deep-bed filters over cake filters.

Final Answer:
Sand filter