The theoretical aerobic oxidation of biomass (C5H7O2N) is given below:
C5H7O2N + 5O2 โ 5CO2 + NH3 + 2H2O
The biochemical oxidation of biomass is assumed as a first-order reaction with a rate constant of 0.23/d at 20ยบC (logarithm to base e). Neglecting the second-stage oxygen demand from its biochemical oxidation, the ratio of BOD5 at 20ยบC to total organic carbon (TOC) of biomass is _______ (round off to two decimal places).
[Consider the atomic weights of C, H, O and N as 12 g/mol, 1 g/mol, 16 g/mol and 14 g/mol, respectively
A system of seven river segments is shown in the schematic diagram. The Riโs, Qiโs, and Ciโs (i = 1 to 7) are the river segments, their corresponding flow rates, and concentrations of a conservative pollutant, respectively. Assume complete mixing at the intersections, no additional water loss or gain in the system, and steady state condition. Given: Q1 = 5 m3/s ; Q2 = 15 m3/s ; Q4 = 3 m3/s ; Q6 = 8 m3/s ; C1 = 8 kg/m3; C2 = 12 kg/m3; C6 = 10 kg/m3. What is the steady state concentration (in kg/m3, rounded off to two decimal place) of the pollutant in the river segment 7 ? ______