الفهرس | Only 14 pages are availabe for public view |
Abstract Bio-treatment has been demonstrated to be the most efficient, environmentally friendly, and cost-effective technique in order to treat of wastewater contaminated with textile dyes. Synthetic dyes widely used in the commercial textile industry constitute, When released into an aqueous environment, it becomes hazardous and recalcitrant.. In the present study, water quality assessment studies for wastewater contaminated with textile dyes have been studied by evaluating the physical-chemical and microbiological profile for 10 water samples collected from 10 different sites. Different microbial consortia collected from the different 10 sites were screened for their abilities of decolorization of five dyes used extensively in the textile industry. Factors affecting bio-decolorization such as; inoculum size, dye concentration, solution pH, incubation temperature, and incubation time were studied. Isolation, purification, and identification of bacterial strains showed the high capability to decolorize dyes were performed. Ten bacterial consortia were collected from the different water sites using an enrichment technique by methylene blue dye. The optimum conditions under which they could show the high capability of bio-decolorization were 107, 200 mg-1, 7, and 30oC for inoculum size, dye concentration, solution pH, and incubation temperature, respectively. Twelve potential bacterial strains were isolated from the best 4 consortia capable of degrading different dyes through the study. Made mixed groups of twelve strains and then choose the best mix in decolorization activity Using 16S rRNA sequence analysis on the best mix in Biodegradation, the bacterial strains were identified as Bacillus subtilis, Bacillus megaterium, Bacillus cereus. Further biodegradation studies were carried out using Direct red 81 dye at a concentration of 200 mg L-1 and B. cereus at an incubation temperature of 30oC for 24h. The by-products of biodegradation were followed up by Liquid chromatography- mass spectrometry LC-MS. A textile wastewater sample contaminated with red color was obtained from 10th of Ramadan city treatment plant station, of it, 2 L have been inoculated with Bacillus cereus for 10 days at room temperature 25oC. The fate of the original dye (Direct red 81) after treatment with B. cereus was followed up by LC-MS, which confirmed the degradation of Direct red 81 dye by B. cereus to small aliphatic compounds and then CO2. The use of B. cereus in decolorizing textile wastewater contaminated with red color was achieved after 10 days of incubation with color removing of 98% at ambient conditions. The chemical oxygen demand COD and Total organic carbon TOC of the wastewater sample were reduced by 78.6 % and 69.3 %, respectively. Yeast may be less expensive and better than other microorganisms. This experiment attempted to investigate the decolorization of blue coloring in methylene blue by Saccharomyces cerevisiae. The study was conducted to determine the best conditions in which the maximum decolorization occurred. The highest decolorization was monitored at 30oC and a concentration of 100 ppm (0,01g/100ml), during which a maximum decolorization of 95,95% occurred after the 20 h incubation period. In the next assay at concentrations of 100 ppm (0.01g/100 ml) and pH 7 for 20 h, accumulative decolorization of 98.90% has been obtained at dosages of 0.1 gram/l with 30oC, which is considered as the best conditions. Saccharomyces cerevisiae was able to handle the textile wastewater in optimal conditions. |