Which bioreactor is designed for fermentation?

Out of the below given methods which of these have the highest cake solids concentration?

What is the first step in the sewage treatment process?

What is the detention time considered while designing a Grit chamber?

Which of these is used to remove odour?

Which type of reactor is not used for oxidation?

What is the percentage of aerobically digested sludge?

Which type of mixer is used when the flow needs to be changed often?