You are assessing the performance of a CSTR that is 60 m long, 5 m wide, and 2 m deep. It receives 250 m3/d of wastewater with a BOD5 of 325 mg-BOD5/L. The following microbial kinetic constants were determined in the lab: Ks = 76 mg-BOD5/L kd = 0.08 d-1 μm = 1.1 d-1 Y = 0.80 mg-VSS/mg-BOD5 (a) What is the efficiency of the CSTR in terms of BOD5 removal?

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2