engineering recuitment GATE CE 2023-24 Test Series Environmental Engineering Disposing of Sewage Effluents
A wastewater plant disposes 1500 l/s of sewage into a river flowing whose rate of flow is 6000 l/s. The saturation D.O of the river is 9 mg/l. The initial oxygen deficit is found to be 0.31 mg/l. Also, it is important to maintain dissolved oxygen content of 4 mg/l in the stream to support aquatic life. The deoxygenation coefficient (KD) is 0.1. (Take coefficient of purification of river = 3). If the initial B0D of the sewage is 200 mg/l. What is the Degree of treatment required ______% before disposal into the river?
1
45%
2
50%
3
56%
4
60%