What is the effective size of sand used in rapid sand filters?

Hindered zone settling refers to the suspensions of intermediate concentration.

For rock type of packing in intermediate filtration trickling filters what is the hydraulic rate considered?

What would happen if the tube settler is inclined at an angle lesser than 45 degrees?

While designing a pump for backwash for a filter what will be the velocity assumed?

In which type of trickling filter is nitrogen oxidized?

What is the porosity range during expansion of the filter bed?

Which of these don’t require a flash mixer and a flocculator prior to it?