In most cases the results gained obey the experimental theory.
However in the very few cases when the replicates were inevitable,
the experiments were repeated.
3.2.1. Determination of optimum operating parameters
Generally, it can be concluded that when the amount of activated
carbon was increased the dye removal also increased. For
example, when there was no activated carbon, the % removal of dye
was 14.5% but after adding 0.5 g/L activated carbon, the % removal
of dye increased to 23.5%. At the higher loading values, the effect
of activated carbon was negligible. Fig. 4 shows the results gained.
When the activated carbon loading increased from 0.5 g/L to 2 g/L,
Table 1
Results of the Experiments in the Microbial Process.
Experiments Changing parameters Results (%
dye
removal)
Continuous system I Synthetic dye solution 78.8
New wastewater
composition
29.5
Increasing the residence
time
78.6
Increasing the amount of
yeast extract in wastewater
89.2
Increasing the wastewater
flowrate
82.7
Continuous system II Washing the system with
forest residues solution
85.4
Increasing the wastewater
flowrate
82.8
Fig. 4. The effect of the activated carbon loading on dye removal.
the removal of dye increased from 23% to 28%. Therefore when the
results were evaluated, 0.5 g/L of activated carbon loading seemed
to be an optimum value