细菌与真菌优化组合降解污水中氰化物研究

On the ways to degrade cyanide in the sewage by using optimum mixed-strain of bacteria and fungi

研究降氰细菌与真菌组合对工业废水中氰化物的降解性能。将从电镀厂水样和活性污泥中分离出的8株降氰细菌与降氰真菌的悬浮液进行等体积混合,以降氰效果最佳的混菌组合为研究对象,研究其组成比例、废水温度、废水pH值、降解时间和摇床转速对降氰率的影响,并在试验得到的适宜降解条件下处理电镀厂实际含氰废水。结果表明,除2#细菌和真菌及9#细菌和真菌的组合外,其他混菌组合的降氰率均优于已筛选获得的单菌株,其中8#细菌与真菌组合的降氰率最高。该组合的适宜降氰条件为8#细菌悬浮液∶真菌悬浮液=3∶2(体积比)3、4℃、pH=6.0、降解20 h、114 r/min转速。适宜降氰条件下,菌液∶废水∶细菌生长培养基=1∶1∶1(体积比)时,8#细菌与真菌组合对氰化物质量浓度为202 mg/L、42.9 mg/L、9.07 mg/L、1.57mg/L和1.09 mg/L的5种实际废水的降氰率分别为84.85%8、2.77%、80.37%8、0.25%和79.82%。其中,氰化物初始质量浓度为1.57 mg/L和1.09 mg/L时,废水经混菌降解处理后的氰化物质量浓度低于0.5mg/L,符合国家一级排放标准(GB 8978—88)(≤0.5 mg/L)。研究表明,8#细菌与真菌混合菌的降氰率较高,在实际含氰废水处理中具有良好的应用前景。

The present paper is inclined to introduce the authors＇ experiments on the ways of how to degrade cyanide in industrial effluents by using mixed strains,especially,bacteria and fungi.In our research,we have used eight kinds of bacteria strains isolated from the industrial discharge of electroplating process,and made the bacteria combined with the fungi strain,respectively.Then,we have explored the mixed-strains combined with the highest degradation rate and investigated the optimum conditions,including the bulk ratio among the strains of bacteria and fungi,temperature,pH,degradation time and rotation rate.Furthermore,we have also treated biologically the actual cyanide-containing sewage from three different electroplating industries by optimizing the mixed-strain in proper conditions.The results of our experiments have shown that the degradation of cyanide with the mixed strains turns to be much better than that with the single strain when the mixed strains of bacteria 8# and fungi strain M1 combination are used.Our experiments also indicate that the optimum bulk ratio between the bacteria strain 8# and the fungi strain M1 was 3∶2,and the other appropriate conditions may include the temperature of 34 ℃,pH=6.0,the degradation time of 20 h,and the rotation rate of 114 r/min.To be exact,when bacteria ∶ sewage ∶ bacteria growth medium= 1∶1∶1（bulk ratio）,the degradation rate for the five kinds of cyanide-containing sewage with initial cyanide mass concentration 202 mg/L,42.9 mg/L,9.07 mg/L,1.57 mg/L,1.09 mg/L,under above optimum conditions may have reached 84.85%, 82.77%, 80.37%, 80.25%, 79.82%, respectively. Moreover,after the biotreatment by the mixed strain,the cyanide mass concentration of two kinds of sewage（with initial cyanide mass concentration 1.57 mg/L and 1.09 mg/L） turned to be below 0.5 mg/L,that is in full conformity with the first-grade state pollution emission standards.The above-said mixed strains have also proved relatively high cyanide-degrading potential and should therefore have a bright prospect for the actual cyanide-containing sewage bioprocessing degradation.