G 2000 m3/d flow from a dairy industry is treated in an activated sludge plant. The BOD5 is 300 mg/L, and most of it is in soluble form. Calculate (a) the volume of aeration basin, (b) aeration period, (c) return sludge, (d) volume of waste activated sludge at sp. gr. of 1.025, food-to-MO ratio, and oxygen requirement. Use the following data:

Acarnot refrigerator operates in a room in which the temperature is 21°c and of power when operating. if the food compartment of the refrigerator is consumes 3 kw to be maintained at 2°c, determine (a) the coefficient of performance of the cycle and (b) the rate of heat removal from the food compartment. refrigerator cycle that has a higher coefficient of performance than that of the discussed (e) is it possible to develop a carn ot refrigerator, operating between the same temperature limits? explain