Introduction
Textile waste waters are rated among the most polluting of all industrial sectors,
both in terms of discharged volumes and composition,
but their most important environmental problems arise
from the high organic loads and the presence of color.
Azo dyes are the most common synthetic colorants released
in textile waste waters due to their ease of synthesis, stability and variety of colors.
Due to the electron-withdrawing nature
of azo bonds,
azo dyes are easily reduced by bacteria under anaerobic conditions,resulting in color removal
with the formation of aromatic amines[3].
Key data on the health hazard associated with the majority ofthese aromatic amines are limited [4], but some of these azo dyebreakdown products have been considered of higher concern thanthe original dye with respect to their possible (eco) toxicity and/ormutagenicity/carcinogenicity [5,6].