1) A settling column analysis is run on a type-2 suspension with the following results. The entries are suspended solid concentrations at stated times. Depth, m Time, min. 0 40 80 120 160 200 240 280 0.5 820 369 238 164 107 66 41 33 1.0 820 442 369 279 213 164 115 90 1.5 820 631 476 361 287 230 180 148 2.0 820 672 558 426 353 287 238 187 2.5 820 713 590 492 402 344 262 230 3.0 820 722 615 533 460 394 320 262 3.5 820 738 656 574 492 418 360 303 2) Determine the theoretical efficiency (%) of a settling basin with a depth of 2.5 m, a volume of 2200 m, and an inflow of 13,200 m/day. A settling column with a total depth of 240 cm (7.87 ft) and sampling ports spaced at 60-cm (1.97ft) intervals is used to design a sedimentation basin. The following data have been obtained: Concentration (mg/L) Time (min) 60 cm (1.97 ft) 120 cm (3.94 ft) 180 cm (5.91 ft) 5 357 387 396 10 310 346 366 20 252 299 316 30 198 254 288 40 163 230 252 50 144 196 232 60 116 179 204 75 108 143 181 What is the theoretical efficiency (%) if a depth of 180 cm (5.91 ft) and a detention time of 60 minutes is chosen? The initial Suspended Solids (SS) concentration is 430 mg/L.