In the sorting activity,
special wastes were discarded and the remaining material was
sorted proportionally to obtain the required 9.4 kg of solid waste in
the bioreactors, for each reactor. In order to assess leachate
recirculation as in-situ treatment of ammonia which is a greater
problem of bioreactor landfill than conventional landfills, oxygen
was introduced to the overall set up mentioned above for
nitrification denitrification process using an oxygen cylinder.
Moreover, varied amounts of oxygen were introduced throughout
the experiment based on the concentration of ammonia nitrogen
concentration during each consecutive week, based on the
following equations.
Nitrification equations
logram of ammonia oxidized to nitrate, the following occurs:
4.18 Kg of oxygen are consumed
Oxygen requirement (kg/L) = Y kg/L of NH4
+ 4.18 kg of O2 / 1 kg
of NH4
+
7.14 kg of alkalinity as calcium carbonate (as CaCO3) is consumed
Alkalinity as CaCO3 (kg/L) = Y kg/L of NH4
+ 7.14 kg alkalinity as
CaCO3 / 1 kg of NH4
+
Y = concentration of NH4
+ in the leachate
At standard temperature and pressure, density of oxygen is
equal to 1.43 g/L (1430 mg/L). Since the rotameter measures the
volumetric flow rate of a material the density serves as a
conversion factor to change the mass flow rate to volumetric flow
rate as follows:
Density = mass flow rate/volumetric flow rate
Mass flow rate of oxygen = [O2] required in kg/L flow rate of
leachate
Therefore, volumetric flow rate of oxygen from each
cylinder = mass flow rate of oxygen / density of oxygen.