Which of the following causes thickening of the biofilm?

The liquid tends to move up through the interstices of contacting particles because of ___

While designing a clariflocculator what is the maximum detention time assumed for the flocculation zone?

What is the surface wash rate?

While designing a clarifier what is the maximum limit velocity that is assumed?

For rock type low filtration rate trickling filters what would be the recycling ratio assumed?

While designing a sand filter what is the velocity that is assumed?

In which type of trickling filter is nitrogen oxidized?