In set II, the biofilter was operated from 69 to 155 days (87 days) in five distinct phases. Fig. 6(a–e) shows the removal profiles of BTEX at slightly higher concentrations than that of set I.
Fig. 6(a–e), also shows that the model is in good agreement with the experimental values with lower sum of square errors (SSEs) for BTEX of 0.0227, 0.0188, 0.0378 and 0.0075, respectively.