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研究论文

摘要：在水的卫生学检验中,四管发酵法是一种经常使用的方法,但在实际应用中,经常只能得到MPN表中为数很少的几个结果,因而用四管MPN表来考察污水处理中工艺条件的变比对于大肠菌灭活效果则往往很困难.本文用概率理论和计算机的蒙特卡罗(概率计算)模拟阐述了这个问题。在MPN检数表中,如果出现表中所列的阳性管和阴性管发酵结果,按照概率理论,大肠菌浓度必以最大概率等于表中相应MPN值.但如果以表中所列出的MPN值的大肠菌数作发酵试验,最可能出现的发酵结果并非为表中所列的相应数值.本文提出了六管发酵法,作为四管法的改进.对于某种特定的目的应该寻求不同稀释浓度的最优组合.

Abstract：The four-tube fermentation method is the routine one to measure the concentration of coliform groups in tests for water. However, in practice, a few results could only be obtained by using MPN tables. It is because of difficulty to study the effects of variousprocessing conditions on coliform in sewage treatment with MPN tables.This problem has been interpreted in this paper with probability theory and Moute-Carlo simulation on computer. It is noted that if a combination of the positive tube and the negative tube appeared in MPN tables is obtained,then concentration of coliform groups must probably be equal to the value in MPN tables. However, if the fermentation process is carried out according to concentration of coliform groups listed in the corresponding table, then the most probable results of such an experiment would not coincide with the value listed in MPN tables. A six-tube method has thus been proposed in this paper as an improvement of the four-tube method. It is concluded that optimum combination of different dilution levels should be sought for in order to meet the given specific purpose.