In this paper

fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration (MF) process presented. Hermia's models for cross flow filtration were used to investigate the fouling mechanisms of membranes with various coagulating chemicals concentrations. Four coagulating chemicals (FeCl

2

·4H

2

O

FeSO

4

·7H

2

O

AlCl

3

·6H

2

O and Al

2

(SO

4

)

3

·18H

2

O) plus Ca(OH)

2

of the same concentration were evaluated in the coagulation-MF hybrid process with different concentrations (0

50 mg·L

-1

100 mg·L

-1

and 200 mg·L

-1

). To determine whether the data agree with models under consideration

the coefficients of determination (R

2

) of all models were compared with one another. In addition

average prediction errors of models were calculated. The results showed that cake filtration model can be applied for prediction of permeation flux decline for MF and coagulation-(MF) hybrid process with the best average error equal to 0.09%. Results indicated that pore blocking behavior changes as time of filtration increases

a

nd one model cannot predict pore blocking behavior in all filtration time with very good precision.