seiner A batch settling test was performed in a laboratory settling column. The suspension was thoroughly mixed and placed in the column to a desired depth. Samples were withdrawn at 10 minute intervals from different ports. The suspended solids concentration was determined for each sample. A test duration of 90 minutes yielded sufficient data for design. A grid was plotted showing percent TSS removal for each port at different time intervals. These results are given in the table below Time, minutes Port No. Depth, m 10 20 30 40 50 60 70 80 90 1 0.5 33 62 74 90 2 1.0 21 41 65 71 80 89 90 16 36 59 67 78 81 86 91 22 56 64 71 78 86 88 91 5 2.5 14 32 54 64 66 76 82 85 88 6 3.0 30 52 63 62 75 81 83 85 7 3.5 Lines of equal percent removal i.e. isoremoval were drawn. These lines are drawn similar to contour lines and are shown in the figure below. Determine the theoretical overflow rate and detention time for 80 percent removal. Using the factors of safety 0.7 and 1.6, determine the design overflow rate and hydraulic retention time. 3 1.5 4 2.0 17 14 seiner A batch settling test was performed in a laboratory settling column. The suspension was thoroughly mixed and placed in the column to a desired depth. Samples were withdrawn at 10 minute intervals from different ports. The suspended solids concentration was determined for each sample. A test duration of 90 minutes yielded sufficient data for design. A grid was plotted showing percent TSS removal for each port at different time intervals. These results are given in the table below Time, minutes Port No. Depth, m 10 20 30 40 50 60 70 80 90 1 0.5 33 62 74 90 2 1.0 21 41 65 71 80 89 90 16 36 59 67 78 81 86 91 22 56 64 71 78 86 88 91 5 2.5 14 32 54 64 66 76 82 85 88 6 3.0 30 52 63 62 75 81 83 85 7 3.5 Lines of equal percent removal i.e. isoremoval were drawn. These lines are drawn similar to contour lines and are shown in the figure below. Determine the theoretical overflow rate and detention time for 80 percent removal. Using the factors of safety 0.7 and 1.6, determine the design overflow rate and hydraulic retention time. 3 1.5 4 2.0 17 14