The desired solids loading rate for a 80 ft. diameter clarifier is 40 lbs/day/sq ft. If the flow to the clarifier is 6.5 MGD, what is the required MLSS concentration?

To determine the required Mixed Liquor Suspended Solids (MLSS) concentration for the clarifier, you first need to understand how to calculate the surface area of the clarifier and then how to apply the desired solids loading rate.

The surface area of the clarifier can be calculated using the formula for the area of a circle, which is:

[

\text{Area} = \pi \times r^2

]

Given that the diameter of the clarifier is 80 feet, the radius will be half of that:

[

\text{Radius} = \frac{80}{2} = 40 \text{ ft}

]

Now, substituting the radius into the area formula:

[

\text{Area} = \pi \times (40)^2 \approx 5026.55 \text{ sq ft}

]

Next, we know the desired solids loading rate, which is 40 lbs/day/sq ft. To find the total solids loading rate for the clarifier, multiply the surface area by the solids loading rate:

[

\text{Total Solids Loading} = 5026.55 \text{ sq ft} \times 40 \text{ lbs/day/s