| Besides promoting mixing of the bacterial population with the fecal waste material, what is the purpose of aeration system as used in a biological sewage treatment plant? |
| A) The air provides an oxygen source for the aerobic bacteria required for metabolism, and it helps promote settling in the aeration chamber. |
| B) The air provides an oxygen source for the anaerobic bacteria required for metabolism, and it helps promote settling in the aeration chamber. |
| C) The air provides an oxygen source for the anaerobic bacteria required for metabolism, and it helps prevent settling in the aeration chamber. |
| D) The air provides an oxygen source for the aerobic bacteria required for metabolism, and it helps prevent settling in the aeration chamber. |
