Study On Removal Cr³⁺ And OPnEO In The Tannery Wastewater By Free And Immobilized Mixed Bacteria At The Same Time

There are a large number of harmful substances Cr³⁺ and OPnEO in tannery wastewater,also the organic substance OPnEO makes Cr³⁺ behavior in the environment become more complex, even has increased the difficulty of the pollution treatment of waste water. In the past, when the single environmental behaviors of pollutants in a single medium governance research results applied to the actual pollution treatment, usually because of the existence of other pollutants in the medium beyond the reach of the expected effect. So study on Removal Cr³⁺and OPnEO in the Tannery Wastewater by bacteria is very meaningful. This topic taking the micro purple Penicillium B5 and calcium acetate Acinetobacter H1 as the research object, study on Removal Cr³⁺ and OPnEO in the Tannery Wastewater by free and immobilized mixed bacteria has the main reseach results as follows:（1）Taking the micro purple Penicillium B5 and calcium acetate Acinetobacter H1 filtered from Jinjin Tannery Wastewater Factory as the research object and using diphenyl hydrazine spectrophotometry and high performance liquid phase chromatography （HPLC） to do the research which focus on the removal effect of Cr³⁺ and OPnEO by B5 and H1 mixture. The results show that the removal effect of Cr³⁺ and OPnEO by the mixed culture of the micro-purple Penicillium B5 and calcium acetate Acinetobacter HI is better than a single strain. It has a certain synergy between the two strains.（2） By investigating the influence factors of mixed bacteria on Cr³⁺ and OPnEO removal, we found that the suitable temperature range is 20-35℃, pH is 5-9, and slightly alkaline environment tend to be beneficial for removing the Cr³⁺ and OPnEO; Furthermore, when the total amount of inoculation is 2%, pH=7,28℃ cultured 7d, the removal rate of Cr³⁺ and OPnEO by mixed bacteria reached the highest, the Cr³⁺ removal rate reached 55%, the removal rate of OPnEO reached 56.8%.（3）The mixed bacteria Z1, which was configured by Penicillium janthinellum B5 and Acinetobacter calcoaceticus H1 with the proportion of 1:1, was imbedded with Polyethylene glycols, modified straw and alginate to explore its synchronous removal on Cr³⁺ and OPnEO respectively. The removal rate of OPnEO resulted 53.92%,46.99%,55.14% and the removal rate of Cr³⁺ was 58.41%、54.24%、60.95%, that alginate was confirmed as the optimum embedding material.（4）Removal rate of Cr³⁺ used as the response value, Cr³⁺ initial concentration, pH, temperature, through the Plackett-Burman experiment, were ascertained three major factors effecting the mixed bacteria Z1 removal of Cr³⁺. The steepest ascent experimental design, Box-Behnken experimental design and response surface method analysis have confirmed that under the condition of initial pH 7.64, Cr³⁺initial concentration 856.34 mg·L-1, temperature 30.39℃, OPnEO initial concentration 950 mg·L-1, plusr 2ml tryptone, training 7d, removal rate of Cr³⁺ reached 77.69%, significantly increased 7% than in the experimental conditions of single factor.