Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is

• A. Precoated on the filter medium prior to filtration
• B. Separated from the cake by dissolving solids or by burning it off
• C. Added to the feed slurry
• D. All of these

Answer: (D)