Final answer:
The filtration process that uses precoat and body fed operation is Diatomaceous earth filtration. This method is particularly effective for fluids with varying qualities, and it uses precoat for initial quality improvement and ongoing body feed to maintain filtration rates.
Step-by-step explanation:
The filtration process that uses the precoat and body fed operation is C) Diatomaceous earth filtration. This method of filtration is specifically designed to handle varying qualities of water or fluid. Diatomaceous earth, a fine powder made from the fossilized remains of diatoms, acts as the precoat. This substance is added to the water before it starts to filter through the medium. During the filtration process, more diatomaceous earth, known as body feed, is continuously added to maintain the effectiveness of the filter. The precoat serves to improve filtrate quality and protect the filter septum, while the body feed helps to maintain filter flow rates. These operational features distinguish diatomaceous earth filtration from other filtration systems like slow sand filtration, dual media filtration, and activated carbon filtration.