Answer:

Step-by-step explanation:
C = Allowable concentration = 1.1 mg/L
= Flow rate of river =

= Discharge from plant =

= Background concentration = 0.69 mg/L
= Maximum concentration that of the pollutant
The concentration of the mixture will be

The maximum concentration that of the pollutant (in mg/L) that can be safely discharged from the wastewater treatment plant is
.