A plant serving a population of 50,000 has an influent settleable solids of 10 mL/L. What is the sludge production in cubic feet/day if the per capita contribution to the flow is 100 gallons/day?

To determine the correct sludge production in cubic feet per day for a plant serving a population of 50,000 with an influent settleable solids concentration of 10 mL/L, it's essential to follow the calculation systematically.

First, we need to calculate the total influent flow for the entire population. The per capita contribution is given as 100 gallons per day. To find the total flow, you multiply the per capita flow by the population:

Total flow = 50,000 people * 100 gallons/person/day = 5,000,000 gallons/day.

Next, convert gallons to liters since the settleable solids concentration is given in mL/L. The conversion factor is:

1 gallon = 3.78541 liters.

Therefore, to convert total flow:

Total flow in liters = 5,000,000 gallons/day * 3.78541 liters/gallon ≈ 18,927,059 liters/day.

Now, we know the influent settleable solids concentration is 10 mL/L. To find the total settleable solids in liters, we can use the formula:

Total settleable solids (mL) = total flow (L/day) * settleable solids concentration (mL/L).

Total settleable