Question

A municipal wastewater treatment plant discharges secondary effluent to a river. The worst condition occurs in the summer when the treated wastewater in summer is found to have a maximum flow rate of 10000 m /day, a BODs of 30 mg/L, dissolved oxygen concentration of 1.5 mg/L and temperature of 25°C. At upstream of the disposal point the minimum flow in the stream is 0.65 m/sec with BODs of 3.0 mg/L, dissolved oxygen concentration of 7.0 mg/L and temperature of 22°C. The mixing of wastewater and stream is almost instantaneous at the point of disposal and velocity of the mixture is 0.2 m/sec. The reaeration constant is estimated to be 0.4 per day at 20°C temperature. Determine the critical DO deficit and distance at which it will occur. Also draw the dissolve oxygen profile for 100 km downstream of the river from the point of discharge.

Answer 1

Answer:

hi please follow me please