In a clarifier, the function of baffles is to prevent short-circuiting of flow.

• A. They filter solids from water
• B. They prevent short-circuiting of flow
• C. They measure flow rate
• D. They aerate the water

Answer: (B)

Baffles in a clarifier are used to shape the flow so water doesn’t travel straight from the inlet to the outlet. By forcing the incoming water to follow a longer, more cross-tank path, they increase the time solids have to settle and prevent rapid, short-flowing jets from bypassing the settling zone. When flow shortcuts aren’t interrupted, unsettled solids can ride straight to the effluent, reducing clarification efficiency; baffles disrupt that direct path and promote better separation.

They aren’t filters, so they don’t remove solids themselves. They don’t measure flow rate, which is done by flow meters. They don’t aerate the water, a job for diffusers or air injectors.