6) (25 points) Suppose you are writing a permit for a wastewater treatment plant discharging into a river. Given the following data, what does the limit on the plant's maximum

BOD need to be for the river DO to remain greater than 5 mg/L at the point 1 km downstream? (Hint: you will need to use Table A-3 in the textbook to find DOsat. You may round the temperature to the nearest whole number when selecting this value.)

Fig: 1

Fig: 2