Decolorization Of Azo Dye By Halomonas Sp. Gyw And The Accelerating Effect Of Functional Bio-Carrier

Dye wastewater with high color and high salinity is difficult to be treated by traditional biotreatment technology. High salinity of the dye wastewater usually causes plasmolysis and/or loss of activity of cells in some traditional aerobic- and anaerobic-biological treatments. Therefore, there is clearly a need for a salt-tolerant and efficient bio-treatment system for the removal of dye wastewater with high salt concentration.Taking azo dye as the model pollutant, the purpose of this dissertation is to isolate and acclimate the salt-tolerant bacterium. And the experiments are conducted to investigate the physio-biochmical characteristics, the degradation characteristics of high-salt wastewater and the growth characteristics of the selected strain. Meanwhile, the experiments are also conducted to explore the new incorporation biotreatment technology of salt-tolerant bacteria, redox mediator and carrier, study the accelerating to degrade azo dyes by salt-tolerant bacterium.The salt-tolerant bacterium isolated from drain of printworks, is identified as Halomonas sp. GYW based on the 16S rDNA sequence analysis and the morphological characteristics. The 16S rDNA sequence is also submitted to GenBank with the number EF188281. Strain GYW could tolerate the concentration of 0～20% NaCl and grow well under the concentration of 10% NaCl; The optimal pH and temperature for growth are 7.2～7.5 and 30℃respectively. Lycine can increase the growth rate of strain GYW under high salt.The NaCl has little effect on decolorization of acid scarlet red GR when NaCl concentration is no more than 10%, but the NaCl concentration beyond 10%, the decolorization of acid scarlet red GR is restrained significantly. The effect of Na₂SO₄ on decolorization is less than NaCl when the total-salt concentration is constant. Strain GYW can take low weight hydrocarbons as the cometabolism carbon source, and the decolorization can reach 70% by the strain GYW in 48 hours, and the selected strain was observed to decolorize many azo dyes in this dissertation.The functional bio-carrier, which is the terylene fabric modified by disperse turquoise blue S-GL in light of the optimization experiments, could increase 1.5～2 fold of the azo dye decolorization rate. The accelerating mechanism of functional bio-carrier is explored from the electrochemistry and biology aspects. The results of the experiments suggest that the oxidation-reduction potential (ORP) can decrease about 80 mV during the decolorization process and the role of disperse turquoise blue S-GL is similar to the role of coenzyme NADH. At the same time, the accelerate effect was observed during the decolorization process of many azo dyes.Therefore, the new incorporation bio-treatment technology of salt-tolerant bacterium with functional bio-carrier could increase the azo dye decolorization rate and has the practical application and knowledge values.