Study Of Biodegradability And Biological Degradation Of Simulated Dye Wasterwater From Dye Production Process

Dye wastewater from textile and dye production process is one of the most difficult to treat among industrial wastewater . This is because dyes usually have a synthetic origin and complex aromatic molecular structures which makes them more stable and more difficult to be biodegraded. Dye wastewater often has high COD concentration and color and many dyes are toxic to some organisms. If the wastewater wasn't treated well and discharged into the water body, it will severely contaminate the water body and may cause direct destruction of aquatic communities, so some form of treatment is necessary.Dye wastewater often contains complex components which are different with production technology. It is difficult to define a universal method that could be used for the elimination of organic substances from wastewater. Common physical and chemical methods are difficult to treat the wastewater, expensive, easily cause new pollution. Biological methods with lower expense attract more eyes. But low biogegradability of dyes is an important factor that affects biological process. So some pretreatment technique is necessary. In the experiment, electrolysis, Fenton oxidation, ozone oxidation and micro-electrolysis were used to pretreat the reactive yellow K-4G or K-6G dye. Warburg respiration apparatus was used to test the biodegradability of dyes treated with different technique. The relationships ofbiodegradability and structure of dyes treated with different ways were analyzed in terms of UV-VIS spectrums. Domesticated organism, which was attached on plastic fibers fixed in a aerobic tank BCOT ( biological contact oxidation tank) was used to treat the high salinity dye wastewater pretreated by Fenton reaction. COD degradation process and important factors that affect treatment process were also analyzed.The results indicate: (1) Electrolysis ^ ozone oxidation, Fenton oxidation and micro-electrolysis could destroy dye structure to different degree and improve its biodegradability. (2) When pretreated by ozone, pH of solution and treatment time also affect the biodegradability of dyes remarkably. (3) When K-6G dye wastewater with high salinity, pretreated by Fenton oxidation process, was treated in the BCOT, COD could be degraded effectively and removal efficiency arrived at 60% until 4h. (4) When K-6G dye wastewater with high salinity, pretreated by Fenton oxidation process, was treated in the BCOT, dye biodegradation kinetics conformed with one-order equation and the average rate constant was 0.0037mm"1.Innovative aspects of the paper are: (1) some pretreatment techniques, electrolysis ^ Fenton oxidation > ozone oxidation and micro-electrolysis, were used to pretreat the reactive yellow K-4G or K-6G dye. Biodegradability of dyes treated with different ways and effect of the reaction condition on biodegradability were tested and analyzed. (2) Appropriate organism that could effectively degrade aimed wastewater were domesticated. BCOX is used to treat high salinity dye wastewater pretreated by Fenton oxidation. The paper also analyzed COD degradation process of the solution and brought forward dye biodegradation kinetics. The main tasks of the paper haven't been reported in the literature presently.