:: Journal of International Environmental Application & Science ::

Year 2006, Volume I (Issue I-II)

Journal of International Environmental Application and Science , Vol. 1, No. 1 (2006), 1-26


The fate and inhibition effect of Direct Red 28 in an anaerobic mixed culture

Mustafa Işık1, Delia Teresa Sponza2

1Aksaray University, Eng. Faculty, Environmental Engineering Dept, Aksaray/Turkey
2 Dokuz Eylul University, Eng. Faculty, Environmental Engineering Dept. Buca Kaynaklar Campus, Izmir/Turkey


Abstract: The fate of an azo dye namely Direct Red 28 (DR 28) was investigated with partially granulated anaerobic mixed culture using glucose (3000 mg l-1 COD) as carbon source and electron donor during batch incubation. The course of the decolorization process approximates to zero order kinetic with respect to dye concentration. The decolorization kinetic constant (K1) values increased from 3.6 to 11.8 mg l-1h-1 as increases in dye concentrations from 200 to 3200 mg l-1 in DR 28. Monod, 0., 1., and 2. order reaction kinetics were tested in order to determine the most suitable substrate removal kinetic. Since the increasing dye concentrations significantly inhibited substrate degradation, different kinetics was tested in order to detect the type and the level of inhibition. Aromatic amine and volatile fatty acid accumulation was observed proportionally at a higher DR 28 concentration. A competitive kinetic model that describes the anaerobic co-metabolism of increasing DR 28 dye concentrations with glucose as co-substrate has been developed based on the experimental data.

 

Keywords: Azo dye; Direct Red 28; decolorization; competitive inhibition.