The function of skimming tank in sewage treatment is to remove A. Oil and fatty substances B. Suspended solids C. Gritty substances D. Inorganic substances

The correct answer is A. Oil and fatty substances.

A skimming tank is a type of primary clarifier used in sewage treatment to remove oil and grease from the wastewater. The tank is typically rectangular in shape and has a sloped bottom. The

wastewater enters the tank at the top and flows down the sloped bottom. As the wastewater flows, the oil and grease float to the surface and are skimmed off. The skimmed oil and grease are then disposed of or recycled.

Suspended solids are removed in a secondary clarifier. Gritty substances are removed in a grit chamber. Inorganic substances are removed in a variety of ways, including chemical precipitation, filtration, and ion exchange.

Here is a brief explanation of each

option:

• Option A: Oil and fatty substances are removed in a skimming tank by skimming off the surface of the wastewater.
• Option B: Suspended solids are removed in a secondary clarifier by settling out of the wastewater.
• Option C: Gritty substances are removed in a grit chamber by settling out of the wastewater.
• Option D: Inorganic substances are removed in a variety of ways, including chemical precipitation, filtration, and ion exchange.