If 65,000 gallons/day of sludge from a primary clarifier with a solids content of 4% is pumped to a gravity thickener with a surface area of 850 sq ft, what is the solids loading rate of the thickener?

To determine the solids loading rate of the thickener, we first need to calculate the total amount of solids being transferred to it from the primary clarifier. The solids content is given as 4% for the sludge that is being pumped, which means that 4% of the total volume is solid material.

First, we convert the flow of sludge from gallons per day to pounds per day. The density of water is approximately 8.34 lbs/gallon, and since the sludge has a solids content of 4%, we can determine the total weight of solids in the flow as follows:

1. Calculate the total weight of the sludge:

[

\text{Total weight} = 65,000 \text{ gallons/day} \times 8.34 \text{ lbs/gallon} = 542,100 \text{ lbs/day}

]

2. Calculate the total weight of solids (4% of the total weight):

[

\text{Weight of solids} = 542,100 \text{ lbs/day} \times 0.04 = 21,684 \text{ lbs/day}

]

Now that we have the total weight of solids being pumped to the gravity thick