Fluid Dynamics and Grit Chamber
Tutorial 5&6:
1. A trickling filter has a diameter of 20 m and a depth of 2.5 m. It is operated with a direct recirculation ratio of 1.0, and the influent sewage flow rate is 3 ML/d. Influent BOD to the primary tank is 200 mg/L, and the BOD removal efficiency in that tank is 35 percent. Compute the organic load on the trickling filter.
2. A grit of specific gravity 2.8 flows into a grit chamber, 1.5-m wide, 10.5-m long and 2.5-m deep. The flow-rate of wastewater into the chamber is 2 m3/s. What is the minimum radius of the grit (in mm) if it was to be captured by the grit chamber? Assume the flow is laminar and Stoke’s Law is applicable. first, I need to find the value of horizontal velocity
3. A primary settling tank sized can handle a maximum hourly flow of 0.570 m3/s at an overflow rate of 60 m/d. If the effective tank depth is 3.0 m, what is the effective theoretical retention time (in hours)?
4. For a wastewater pre-treatment grit chamber (10m wide x 3m deep x 30m long):
(a) The terminal settling velocity of a particle with a specific gravity of 1.4 and a diameter of 0.010mm is x 10-5 m/s.
(b) The time for the particle to settle in the grit chamber is x 105 s.
(c) If the wastewater is treated at a flow rate of 7500m3/day, the horizontal velocity of the particle is x 10-3 m/s.
(d) Does the particle settle in the grit chamber? (select 'yes' or 'no')
Since the time needed for the particle to settle is more than the time that the particle will remain in the chamber, the particle will not settle.
1. A trickling filter has a diameter of 20 m and a depth of 2.5 m. It is operated with a direct recirculation ratio of 1.0, and the influent sewage flow rate is 3 ML/d. Influent BOD to the primary tank is 200 mg/L, and the BOD removal efficiency in that tank is 35 percent. Compute the organic load on the trickling filter.
2. A grit of specific gravity 2.8 flows into a grit chamber, 1.5-m wide, 10.5-m long and 2.5-m deep. The flow-rate of wastewater into the chamber is 2 m3/s. What is the minimum radius of the grit (in mm) if it was to be captured by the grit chamber? Assume the flow is laminar and Stoke’s Law is applicable. first, I need to find the value of horizontal velocity
3. A primary settling tank sized can handle a maximum hourly flow of 0.570 m3/s at an overflow rate of 60 m/d. If the effective tank depth is 3.0 m, what is the effective theoretical retention time (in hours)?
4. For a wastewater pre-treatment grit chamber (10m wide x 3m deep x 30m long):
(a) The terminal settling velocity of a particle with a specific gravity of 1.4 and a diameter of 0.010mm is x 10-5 m/s.
(b) The time for the particle to settle in the grit chamber is x 105 s.
(c) If the wastewater is treated at a flow rate of 7500m3/day, the horizontal velocity of the particle is x 10-3 m/s.
(d) Does the particle settle in the grit chamber? (select 'yes' or 'no')
Since the time needed for the particle to settle is more than the time that the particle will remain in the chamber, the particle will not settle.