Analysis of pollutants removal
The determinations of pollution parameters including colour and COD were accomplished at the beginning and at the end of each run, in agreement with the methodology described by APHA (2000).
The percent reductions of these parameters were calculated by the equation:
Parameter reduction ð%Þ ¼ xi xf=xf 100 being :
xi =Parameter before the biomass growth and xf= Parameter after the biomass growth.
The results of colour and COD removal of the CCD runs were analyzed statistically through the analysis of variance (ANOVAs) at 95% confidence interval and response surface methodology.