PRACTICE PROBLEMS 3.2: Loading Calculations-BOD, COD, and SS 1. The suspended solids concentration of the wastewater entering the primary system is 425 mg/L. If the plant flow is 1,620,000 gpd, how many lbs/day suspended solids enter the primary system? ANS _ 2. Calculate the BOD loading (lbs/day) on a stream if the secondary effluent flow is 2.98 MGD and the BOD of the secondary effluent is 26 mg/L. ANS _ PRACTICE PROBLEMS 3.3: BOD and SS Removal, lbs/day 1. If 148 mg/L suspended solids are removed by a primary clarifier, how many lbs/day suspended solids are removed when the flow is 5.2 MGD? ANS _ 2. The flow to a primary clarifier is 1.89 MOD. If the influent to the clarifier has a suspended solids concentration of 315 mg/Land the primary effluent has 126 mg/L SS, how many lbs/day suspended solids are removed by the clarifier? ANS _ 4. A primary clarifier receives a flow of 2.37 MOD with a suspended solids concentration of 387 mg/L. If the clarifier effluent has a suspended solids concentration of 166 mg!L, how many pounds of suspended solids are removed daily? ANS _