Figure 1 Schematic diagram of the novel pilot-scale OD system
1—influent; 2—influent pump; 3—pre-anoxic zone; 4—anaerobic zone I; 5—anaerobic zone II; 6—OD; 7—disc aerator; 8—liquid
propeller; 9—secondary clarifier; 10—effluent; 11—RAS; 12—RAS pump; 13—pre-concentration tank; 14—supernatant fluid;
15—pre-concentrated RAS pump; 16—pre-concentrated RAS; 17—pH probe; 18—ORP probe; 19, 20—DO probe; 21—MLSS
probe; A—influent; B—pre-concentrated return activated sludge; C—pre-anoxic zone; D—anaerobic zone I; E—anaerobic zone II;
F—anoxic zone in OD; G—aerobic zone in OD; H—effluent; I—supernatant of pre-concentration tank