| The waste water from paper-making tobacco sheet producing was characteristic of high concentration of suspended solids, organic pollutants and dark color to be perishable, the properties with high pollution loads of the secondary effluents after air flotation and biological treatments can’t meet the demands of relevant national standards. In this study the union techniques of Catalytic oxidation-BAF was applied and researched systematically to develop a feasible and effective way for advanced treatment of secondary effluents for paper-making tobacco sheet productions(as secondary effluents).Firstly, the properties of the secondary effluents were analyzed systematically. The reason of dark color was explained by UV-VIS spectrum, organic pollutants were analyzed by FTIR and GC-MS spectrum. The results showed that lignin and its derivatives were the main contaminations in the secondary effluents which provided foundation for the application of advanced treatments for the secondary effluents.According to advanced treatment for pulping industry effluents, the secondary effluents were treated with ozone oxidation alone. Through the analysis’ s of single factor and response surface methodology, the optimal conditions of ozone oxidation were determinate as p H8, 30 ℃ and C(O3) of 14.76 mg·l-1, the removal ratio of CODCr and color were about 30% and more than 95% respectively with about 500 mg·l-1 of original COD of secondary effluents, and BOD5/CODCr increased from 0.46 to 0.53. The degradation of CODCr in this process can be related to the pseudo-first-order kinetics. The results revealed that ozone oxidation alone can degrade the organics partly to increase the biodegradability of secondary effluents.Homogeneous catalytic ozonation treatments with transition metal ions were established to improve the biodegradability of secondary effluents further. The influences of type’s metal ions, temperature, p H, dosage of metal ion and ozone dosage on the catalytic performance were researched. The results showed that transition metal ions could improve the degradation efficiency significantly. The total removal ratio of CODCr can be increased to 80% and color removal ratio was above 95%. Among the Ti(Ⅳ) ions, Fe(Ⅱ) ions, Mn(Ⅱ) ions, and Zr(Ⅳ) ions, the catalytic activity of Mn(Ⅱ) was best, and the catalytic efficiency of Zr(Ⅳ) and Fe(Ⅱ) were much better than others. With optimal conditions, it is consistent in the energy ozone dosage, consumption, and p H. With the difference of mental ions dosage:the maximum C(Fe) was 0.6 m M; the minimum C(Zr) was 0.1 m M; the CODCr removal ratio with Fe(Ⅱ) ions or Zr(Ⅳ) ions were all 82.29%, with Mn(Ⅱ) ions lowest was at 71.03%. The decreased of CODCr was beneficial to BAF treatment.The biodegradability of the secondary effluents has been improved with ozone oxidation or homogeneous catalytic ozonation treatments, BAF technology was united for advanced biological treatment. Bio-films were acclimated with nutrients cultivation and effluent. The removal ratio of CODCr, color, SS and ammonia nitrogen of secondary effluents were 19.45%, about 80%, about 24% and above 98%, respectively for the secondary effluents with BAF treatment only, and the removal ratio of refractory compounds as alkanets and benzenes were low with inconspicuous decrease of total organic pollution load. In the process of ozonation/BAF union, the average CODCr value of effluent was 186.15 mg·L-1, the CODCr average removal ratio was 64.67% which was 45 percentages higher than that in BAF. The removal ratio of ammonia nitrogen in BAF stage was up to 99.33%, which was only 20% in ozonation stage alone, and the final concentration of ammonia nitrogen was decreased to 0.23 mg·l-1. In the process of catalytic ozonation-BAF union, the average CODCr removal ratio was 79.52%, and CODCr value was 103.69 mg·l-1. The total average nitrogen removal ratio reached to 99.53%, and the concentration of ammonia nitrogen was 0.23 mg·l-1. After catalytic ozonation-BAF union treatment, the average concentration of CODCr and ammonia meet the demands of pulp and paper industry waste water discharge standard(GB3544-2008).The bio-films were analyzed by PCR-DGGE molecular biology technique. The results showed that there were abundant bacterial species in bio-films with carious bands and positions according to cultural time and acclimation conditions. The mainly bands in the gel were analyzed by statistical methods and excited from the gel for sequencing, and the sequences were used for homo logy analysis and then phylogenetic tree was constructed, the analysis indicated that the enrichment of some bacterium related to bio degradation of CODCr and removal of ammonia resulted in the advanced bio degradation CODCr. This methods and technology was feasible from molecular and microbial angle. |
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