An industrial wastewater is discharged into a municipal wastewater sewer. The characteristics of the two wastes are given below. Determine the characteristics of the mixture. Parameter Industrial Municipal Flow, m 3 /day 3000 18000 BOD 5 , mg/L 1500 250 PO 4 3- , mg/L 150 2.3 Solution Qi = 3000 m 3 /day = 3000*10 3 L /day Qm= 18000 m 3 / day = 18000*10 3 L /day BOD5 of Mixture =(Ci * Qi +Cm* Qm) / Qi + Qm) = (1500*3000* 10 3 + 250*18000* 10 3 ) /( 3000 * 10 3 + 18000* 10 3 ) BOD5 of Mixture = 428.57 mg/L. PO43- of mixture= (Ci * Qi +Cm* Qm) / Qi + Qm) = (150*3000* 10 3 + 2.3*18000* 10 3 ) /( 3000 * 10 3 + 18000* 10 3 ) PO43- of mixture= 23.4 mg/L .