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采用砂柱装置,在实验室研究了自养微生物和异养微生物2种生物反硝化方法对地下水中硝酸盐的去除效果。自养反硝化反应在以硫作为电子供体的硫/石灰石/细沙反应柱中进行,异养反硝化反应在石灰石/细沙反应柱中进行,进水增加乙醇作为外加碳源。实验结果用以比较2种反硝化方法在硝酸盐去除率、微生物反应动力学和反应产物三者的异同。结果表明,自养反硝化反应中NO3--N去除率达95.4%,异养反硝化反应去除率可达99.3%;分别与Monod微生物0级、1/2级和1级反应动力学方程进行拟合,2种反硝化反应均符合1/2级微生物反应动力学,适合用1/2级微生物反应方程描述;在反应结束阶段,自养反硝化主要反应产物SO42-出水浓度低于250mg/L,异养反硝化副产物CH3OO-易成为二次污染源,异养反硝化的反硝化速率明显高于自养反硝化反应。
Using sand column device, two kinds of biological denitrification methods of autotrophic microorganisms and heterotrophic microorganisms were studied in laboratory to remove nitrate in groundwater. Autotrophic denitrification is carried out in a sulfur / limestone / fine sand reaction column with sulfur as the electron donor. Heterotrophic denitrification is carried out in a limestone / fine sand reaction column and the water is fed with ethanol as the additional carbon source. The experimental results are used to compare the similarities and differences between nitrate removal rate, microbial reaction kinetics and reaction products of two denitrification methods. The results showed that the removal rate of NO3 - N in autotrophic denitrification was 95.4%, and the removal rate of heterotrophic denitrification was 99.3%. The kinetic equations of 0, 1/2 and 1 Fitting, two kinds of denitrification reaction are consistent with 1/2 of the microbial reaction kinetics, suitable for use 1/2 of the microbial response equation described; at the end of the reaction, the main reaction product of autotrophic denitrification SO42- effluent concentration is less than 250mg / L, heterotrophic denitrification byproducts CH3OO- easily become a secondary source of pollution, heterotrophic denitrification denitrification rate was significantly higher than autotrophic denitrification.