Question

The old plant grit removal process, that is used to treat the average flow of 15 MGD consists of horizontal flow grit chamber that have a volume of 15,000 gallons. To reduce the footprint of the process, the new plant will use a Vortex type grit chamber that is capable of achieving the same grit removal performance in a fraction of the reactor volume. Remember that the flow to the new plant is 10 MGD

. 11. What is the old plant average grit removal process detention time at the average 15 MGD flow? (answer will be given in the unit of (sec))

12. How long is the old plant grit chamber if it has a flow depth of 5 ft and a total width of 5 ft? (answer will be given in the unit of (ft))

13. What is the surface area of the old plant grit chamber? (answer will be given in the unit of (ft^2)))

14. What is the water velocity in the grit chambers? (answer will be given in the unit of ft/sec)

15. When considering particle settling theory and the forces that apply to a particle, how does a Vortex type grit chamber allow reducing footprint compare to a horizontal flow grit chamber?

16. What should be the volume of the vortex type grit chamber if the targeted process detention time is 30 sec? (answer will be given in the unit of (gal)) Remember that the flow to the new plant is 10 MGD.

17. Assuming that the vortex type grit chamber is a cylinder (same width throughout), what will be the surface area of the chamber if it has a liquid depth of 10 ft? (answer will be given in the unit of (ft^2)))

Answer 1