Wastewater is being treated in two well-mixed ponds in series. The flow rate of the wastewater is 4000 m3/d, and the ponds each have volumes of 20,000 m3 and 12,000 m3, respectively. The influent to the first pond has an ultimate BOD (i. e., L0) of 200 mg/L, and the system has been operating long enough to reach steady-state. If kd is 0.35 d-1 in each pond, how much BOD remains in the effluent as the water exits the second pond?

A-mn has a cubic structure with a0 0.8931 nm and a density of 7.47 g/cm3. b-mn has a different cubic structure, with a0 0.6326 nm and a density of 7.26 g/cm3. the atomic weight of manganese is 54.938 g/mol and the atomic radius is 0.112 nm. determine the percent volume change that would occur if a-mn transforms to b-mn.

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa.s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)

For a process taking place in a closed system containing gas, the volume and pressure relationship is pvi-constant. -1.5 bar, the process starts with initial conditions, pi = =0.03 m3 and ends with final volume, v2-0.05 m3 determine the work done by the gas.