| 摘要 |
<p>PURPOSE:To achieve an expression in a numeral value by a method wherein a membership value is defined preliminarily as indicating possibility of appearance per microorganism in each BOD concentration band and the membership values in respective BOD concentration bands are picked up in water to be measured to estimate a concentration. CONSTITUTION:The maximum number of indicative microorganisms appearing in each oxygen demand band is determined previously in terms of the indicative microorganisms while a membership value indicating possibility of appearance is determined previously at least with the maximum number thereof as factor. The number of the indicative microorganisms per unit water quantity is measured in water to be measured to determine a belonging rank from among multiple appearance ranks. Membership values for the indicative microorganisms appearing are picked up in the respective oxygen demand quantity bands and totalized in terms of the oxygen demand quantity bands by being weighted. With the oxygen demand quantity taken on an axis of abscissa and the membership values totalized on an axis of ordinate, the center of gravity of the membership value in the axis of abscissa is determined to estimate an oxygen demand quantity at the position of the center of gravity as that of the water to be measured, thereby enabling expression of a water quality in a specific numeral value.</p> |
