1.A drinking water treatment plant will be designed to process a flow of 15,000 m3/d. The sedimentation tank will have a residence (detention) time of 4 hours and the overflow rate (Q/A) of 16 m3/m2-day. Estimate the required surface area (A), and the diameter and the depth of the tank.
2.Determine the depth of a French drain (saturated depth) if the width is 3.0 feet, the effective permeability of the aggregate is 2000 ft/day, and the rate of discharge for 100 feet of trench is 1000 feet^3/day. The trench slope along the flow line is 0.001. Discuss.