Question

Environmental Engineering

biological processes,

A wastewater with a COD concentration of 970 mg / L 8,000 m3 / day flow, fully mixed back It will be treated in a cyclic activated sludge system.Treatment system mud age will be 5 days will be designed in a way. Kinetic and stoichiometric coefficients were determined as follows.

Volumetric organic loading speed: 0,5 kg COD/m3.day

uH : 3,7 day-1,

bH: 0,04 day-1,

KS: 45 mg

COD/L, YH: 0,5 g VSS/g COD

VSS/TSS: 0,8 mg VSS/mg TSS

iN: 0,12 mg N/mg VSS

a) Calculate the substrate concentration in the outlet stream.

b) Calculate the reactor volume.

c) Calculate the hydraulic holding time.

d) Calculate the amount of sludge discarded daily.

e) Calculate the daily need for oxygen.

f) Calculate the biomass concentration held in the reactor.

g) If biomass concentration is 12.000 mg / l   TSS in back flow, back flow Calculate the flow rate and return rate of the sludge to be thrown from the stream.

h) Amount of nitrogen removed per unit wastewater flow rate treated

i) Calculate the amount of nitrogen required per unit of BOD5 removed.

Answer 1