2 To determine the BOD in an industrial wastewater sample a

2. To determine the BOD in an industrial wastewater sample, a seeded BOD analysis was conducted; data are summarized in the table below. Ten mL of wastewater was added per 300 mL bottle to determine the dissolved oxygen demand of the aged, settled wastewater seed (test A). The seeded test bottles (test B) contained 2.5 mL of industrial wastewater and 1.2 mL of seed wastewater a). What is the five-day BOD in this industrial wastewater? What is the k-value using the graphical procedure (k- 2.61*B/A)? (6 pts) b). If the BOD oxidation rate can be described based on ABOD (ultimate BOD - BOD(t)) versus time, and the ultimate BOD is about 740 mg O2/L. For the industrial wastewater, does a zero, 1st, or 2nd order reaction rate model provide the best fit? What is the value of the rate constant? (5 pts) DO measurement in bottles Time (days) 0 Test A (seed) (mg/L) 8.2 Test B (seeded wastewater) (mg/L) 8.0 5.3 2.2 3.0 4.3 6.7 6.4 5.8 5.6 5.4 5.5 3.4 2.7 2.3 2.0 6.0 7.3

Solution

a)

                    1. Carbonaceous BOD (initial) ,

                    2. Nitrogenous BOD (final).