Determine the volume of three identical activated-sludge tanks following primary clarification to aerate 36,000 nv3/d witha bod concentration of 180 mg/l at a bod loading of 560 g/m3 0 d. what is the aeration time? for an fl m of 035. whatmlss concentration should be maintained in the aeration tanks? estimate the operating sludge age, assuming an effluentsuspended solids of 30 mg/l and the daily amount of waste-activated sludge solids from figure 13.1. if the waste sludgehas a concentration of 10.000 mg/l, what is the calculated volume of sludge to be wasted each day? determine thedimensions of three identical rectangular clarifiers (length. width, and side-water depth) with a 21 length-to-width ratio.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?