DIMENSIONS FOR SETTLING TANKS ══════════════════════════════════════╤══════════╤══════════╤══════════ Persons Served by Sewer. │ Mean │ Mean │ Depth │ Inside │ Inside │(Feet).[1] │ Width │ Length │ │ (Feet). │ (Feet). │ ──────────────────────────────────────┼──────────┼──────────┼────────── 4 │3 │ 4 │ 5 8 │3 │ 7 │ 5 12 │4 │ 7.5 │ 5 15 │4 │ 8 │ 5 25 │4 │10 │ 5 35 │4.5 │12 │ 5 50 │6 │12 │ 5 75 │6 │15 │ 6 100 │7 │17 │ 6 125 │8 │17.5 │ 6 150 │8 │18 │ 6 175 │8 │20 │ 6 200 │8 │22 │ 6 250 –-2 compartments in tank, each │5.5 │18 │ 6 300 –-2 compartments in tank, each │5.5 │18.5 │ 7 350 –-2 compartments in tank, each │6 │19 │ 7 400 –-2 compartments in tank, each │6 │19 │ 8 450 –-2 compartments in tank, each │6 │22 │ 8 500 –-2 compartments in tank, each │6 │24 │ 8 ──────────────────────────────────────┴──────────┴──────────┴────────── Footnote 1: 12 inches greater than depth of sewage. [Illustration: FIG. 3.—Sketch of Settling Tank with Longitudinal Partition Wall.]