A municipal wastewater treatment plant processes an average flow of 15,000 m3/d with 200 mg/L of BOD5 and 320 mg/L of suspended solids. The peak flow is 1.5 times the average flow. Determine the mass of BOD5 and solids (kg/day) that are removed as sludge from 282 Fundamentals of wastewater treatment and engineering the primary clarifier for average and peak flow conditions. Assume a reasonable efficiency for the primary clarifier and the same peak flow factor for BOD5 and suspended solids.

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w