1. Home Work
Each day 3780 m3 of wastewater is treated at a municipal wastewater treatment plant. The influent contains 220 mg/L of suspended solids. The clarified water has a suspended solids concentration of 5mg/L. Determine the mass of sludge produced daily from the clarifier and write down the mass balance of the clarifier.

2. Home Work
2. A wastewater treatment plant with an output of 38400m3/day discharges the liquid effluent with a BOD of 20mg/L into a river. If the BOD of the river upstream of the discharge point is 0.2mg/l, at a minimum flow of 20m3/s, compare the BOD of the river downstream of the discharge, assuming complete mixing.
Answer = 0.63mg/L

3. Home Work
3. A slurry containing 20 percent by weight of limestone (CaCO3) is processes to separate pure dry limestone from water. If feed rate is 2000kg/h, how much CaCO3 is produced per hour?