A water treatment plan is processing a total flow rate of 42,000 md. The flocculation system consists of three identical parallel units of paddle flocculators. A side view of one of the units is shown in Figure 1 EN 571 (MATLAB Grader on Canvas) Homework 8 Baffle 0.8 m 18.8 m Figure 1: Paddle flocculator. The dimensions of each flocculation unit are 4.5 m wide by 4.5 m deep by 18.8 m long. The inlet battle is located 0.3 m from the front wall. Each unit has three sets of paddles mounted on a horizontal shaft. There are three sets of paddles attached to the shaft. The first set of paddles has four paddles on each arm (total of eight paddles) with centers located at 1.9. 1.7. 1.5. and 1.3 m from the shaft. The second set has three paddles on each arm with centers located at 1.9, 1.7, and 1.5 mm from the shaft, and the third set has two paddles per arm with centers located at 1.9 and 1.5 m from the shaft. Each paddle is 0.1 m wide and 4.5 m long. The first paddle set is 0.8 m from the inlet baffle and the paddle sets are separated by a distance of 0.8 m. Calculate the detention time of a unit. At temperature of 25 C. what is the rotational speed of the shaft to achieve a meau velocity gradient of 20 1/s in a unit? What is the local velocity gradient for each paddle set? Consider Cp = 1.8 and k = 0.25. a Problem 2 [40] A carbonic acid solution has an ionic strength of 10-3 M, a total alkalinity of 7 mmol/L, a carbonate alkalinity of 2 mmol/L, and its temperature is 50C. Calculate the pH, and the concentrations of carbonate (HCO3-] and bicarbonate [CO32-] species at equilibrium in the solution. Thermodynamic Data at 25C: Species H2CO3* HCO3 0032 OH H -167.22 -165.39 -161.84 -68.31 -54.97 , Kcal/mole