QUESTION 3 The following data are from the Ohio River in the vicinity of Cincinnati (mile 470) during low flow, September 1967. Distance miles) 460 465 470 472 475 480 490 500 510 520 540 560 580 L BOD, mg/l 4 4 4 12 11 9.3 7.5 6 5.3 4.5 D.O., mgl 7.5 7.8 8 8 6.7 5.3 3.8 3.2 2.8 2.8 3.1 4.1 5.3 3 2.5 (a) If the mean velocity of the river is 0.3 m s-1 calibrate the Streeter-Phelps model using the field data, and solve for the rate constant ka and kd. The saturation concentration for dissolved oxygen at the time of the survey was 8.3 mg/l, and the main wastewater discharge was at mile point 472. What are k and kd? O ka = 0.3/day; kd = 0.1/day ka = 0.3/day; kd = 0.26/day ka = 0.1/day; ka = 0.3/day ka = 0.26/day; kd = 0.3/day