To find the quantity of wastewater treated, we need to calculate the volume of the primary settling chamber and then use the detention time.

Calculating Chamber Volume

The primary settling chamber is cylindrical.

• Diameter = 50 m
• Radius ($r$) = Diameter / 2 = 50 m / 2 = 25 m
• Depth ($h$) = 2.5 m
• The area of the base ($A$) is given by the formula: $A = \pi r^2$
• $A = \pi \times (25 \text{ m})^2 = 625\pi \text{ m}^2$
• The Volume ($V$) of the chamber is: $V = A \times h$
• $V = (625\pi \text{ m}^2) \times (2.5 \text{ m}) = 1562.5\pi \text{ m}^3$
• $V \approx 1562.5 \times 3.14159 \approx 4908.7 \text{ m}^3$

Calculating Wastewater Quantity

The quantity of wastewater treated is the flow rate ($Q$).

• Detention Time ($T_d$) = 2 hours
• Convert detention time to days: $T_d = 2 \text{ hours} \times \frac{1 \text{ day}}{24 \text{ hours}} = \frac{1}{12} \text{ day}$
• The quantity treated per day is calculated as: $Q = \frac{\text{Volume}}{\text{Detention Time}}$
• $Q = \frac{4908.7 \text{ m}^3}{1/12 \text{ day}} = 4908.7 \text{ m}^3 \times 12 \text{ day}^{-1}$
• $Q \approx 58904.4 \text{ m}^3/\text{day} $

Comparing this value to the options, the closest quantity is approximately 58928 m$^3$/day.