Releasing of textile dye effluents into general water bodies is a major environmental and health problem. Color removal, in particular, has recently become of major scientific interest, as indicated by the multitude of related research reports. During the past two decades, several physico-chemical decolorization techniques have been reported, few, however, have been accepted by the textile industries. Their lack of implementation has been largely due to high cost, low efficiency and inapplicability to a wide variety of dyes. The ability of microorganisms to carry out dye decolorization has received much attention. Cyanobacteria are considered as an important source for decolorizing dye and textile effluent. In the current study four local cyanobacteria strains viz. Anabaena fertilissima, Nostoc muscorum, Phormidium fragile and Wollea sp., were used in the preliminary screening for their ability to grow on and the removal of the red color and the heavy metals, i.e., iron, manganese, boron, lead and arsenic from the crude effluent discharged by EL-Shafie textile factory at EL- Mahalla EL- Kobra East Delta, Gharbia Governorate, Egypt. Results revealed that all tested cyanobacteria strains were able to gradually remove the color of the crude textile effluent in parallel with increasing the incubation periods. Also, N. muscorum recorded the highest percentage of color removal percentage followed by Wollea sp., Ph. fragile and finally A. fertilissima after 28 days of incubation. All the tested cyanobacteria strains were able to remove any of Fe, Mn, B, Pb, and As in different degrees. N. muscorum was superior in removing all discharged heavy metals compared to the other tested cyanobacteria strains. On the other respect, all tested cyanobacteria strains had slightly raised pH of the discharged textile crude effluent, while they reduced any of EC, COD and BOD compared to the initial values of the discharged textile crude effluent. However, the research of cyanobacteria to remove color in dye wastewaters is still in the early stage, but is a promising alternative of biological treatment. |
