Calculate the detention time of wastewater flowing at 20 gpm through a 1600 gallon clarifier.

To find the detention time of wastewater in a clarifier, you can use the formula:

[

\text{Detention Time} = \frac{\text{Volume of Clarifier}}{\text{Flow Rate}}

]

In this case, the volume of the clarifier is 1600 gallons, and the flow rate of the wastewater is 20 gallons per minute (gpm).

1. First, calculate the detention time in minutes:

[

\text{Detention Time (minutes)} = \frac{1600 \text{ gallons}}{20 \text{ gpm}} = 80 \text{ minutes}

]

2. To convert the detention time from minutes to hours, divide by the number of minutes in an hour (60 minutes):

[

\text{Detention Time (hours)} = \frac{80 \text{ minutes}}{60} \approx 1.33 \text{ hours}

]

This value can be rounded to 1.3 hours, confirming that this is the correct choice.

This calculation demonstrates that the clarifier allows wastewater to remain for approximately 1.3 hours, providing adequate time for solid particles to settle out of the wastewater before it is treated further or