| In addition to high salinity, aniline dyeing wastewater contains large amount of dissolved and toxic material such as aromatic compounds. This kind of wastewater will pollute water and soil seriously if it is discharged directly without treatment. This paper used the aerobic biological treatment and fenton oxidation treatment to confine the influenced level of various factors on the degradation of organic pollutants. Variation of microbial communities and microbial diversity was studied by high-throughput sequencing method. It can provide theoretical and technical support for treatment of anilines dyeing wastewater.Through the study on the change of COD and community diversity analysis in the cultivable process of activated sludge, it could conclude that the change of COD spends less time reaching stability in the period, which was from 72 h to 32 h. In the fifth period from start-up, the effluent concentration of COD reached about 1450 mg/L and the removal rate of COD was 50%, which showed that the activated sludge can fit the condition of original water quality gradually. High-throughput sequencing technology was employed to identify the microbial communities in different stages. The results showed that the addition of salinity induced a clear shift in the microbial communities and diversity. The bacterial diversity decreased significantly with the increased salinity. The Proteobacteria is the dominant Phylum in terms of quantity and species, while most of the strains belong to the class of α-proteobacteria and β-proteobacteria. A large number of Halophile was tested, which showed that salinity influenced the microbial communities. Sphingopyxis genus was detected in the third period, which could degrate aromatic compounds and Anthraquinone Dye and its intermediate. The results showed that the activated sludge system was operated for a certain extant, and it can be used for the study of aerobic biological treatment.Study on the influence of MLSS, initial pH value, salinity and other environmental factors of the aerobic biological treatment, it concluedd that the degradation rate of COD was the positive linear correlation with the MLSS. When the MLSS is 1 g/L, the degradation rate of COD is 6.24 mg/L·COD·h-1·(mg/L·MLSS)-1, and correlation coefficient R2=0.98704. The initial pH value has a positive correlativity with the degradation rate of COD when the initial pH value is below 7.0±0.2. The former has a nagative correlativity with the latter when the initial pH value is above 7.0±0.2. Then using the single-factor test to determine the optimal process conditions: MLSS is 4 g/L, the initial pH value is about 7.0, the optimum salinity is 1.7% for the reactor. When the COD of the activated sludge reactor system was decreased from 3000 mg/L to 1500 mg/L, the removal rate of COD was 50%, and pH decreased from 7.5 to 4.5. UV-VIS scanning is used to analyse the effluent of aerobic biological treatment, and the results showed significant effect in removing organic substances. The Ultraviolet-visible absorbance curves of the raw wastewater and the effluent from aerobic biological treatment are similar in shape, and absorption peaks in 250 nm still existed. The results qualitatively showed that part of organic pollutants can be degraded completely.Then Fenton oxidation experiment is used to degrade refractory organic matters further, and the degradation of pollutants is reflected by UV-VIS scanning. We first use the orthogonal test to detemine the scope and parameters of main factors in the test: the dosage of H2O2> the dosage of FeSO4·7H2O> initial pH value> reaction time. Then using the single-factor test to determine the optimal process conditions: in the Fenton oxidized experiment, the pH value is 3.0, H2O2 throws the increment is 12 g/L, FeSO4·7H2O throws the increment is 4.95 g/L, the reaction time is 20 min. Running the best parameters, wastewater COD was decreased from 1500 mg/L to 292.5 mg/L, the elimination rate of COD and color achieves about 80.5% and 50%. UV-VIS scanning is adopted to analyse the oxides in fenton system, and absorption peaks in 250 nm shift to zero. The results qualitatively showed that most organic pollutants can be degraded to non-polluting small molecule. |
PDF Full Text Request