The correct answer is A. 1 minute.
A grit chamber is a type of sedimentation tank that removes coarse solids from wastewater. The detention time in a grit chamber is the amount of time that the wastewater stays in the tank. The detention time is important because it determines how much time the solids have to settle out of the water.
The detention time for a grit chamber is typically 1 minute. This is because most grit particles settle out of the water within 1 minute. If the detention time is too short, the grit particles will not have time to settle out and will be discharged with the wastewater. If the detention time is too long, the wastewater will be held up in the tank for too long, which can lead to problems with odors and bacteria growth.
The other options are incorrect because they are not the typical detention time for a grit chamber. Option B, 5 minutes, is a common detention time for primary clarifiers. Option C, 24 hours, is a common detention time for secondary clarifiers. Option D, 12 hours, is a common detention time for aerated lagoons.