WATER QUALITY ESTIMATING APPARATUS AND WATER QUALITY ESTIMATING METHOD

PROBLEM TO BE SOLVED: To grasp a more accurate BOD of water without measuring the BOD of evaluation object water. SOLUTION: A water quality estimating apparatus includes at least an arithmetic device 2 accepting turbidity of water, electrical conductivity (EC), concentration of dissolved oxygen (DO), and the biochemical oxygen demand (BOD). The arithmetic device 2 comprises: a ratio calculating section 24; a time period selecting section 25; a measurement value acquiring section 26 acquiring each measurement value of the BOD, the turbidity, and the concentration of the DO; a first power regression creating section 27 creating a first power regression which takes each acquired measurement value of the BOD and the turbidity as each coordinate; a BOD calculating section 28 calculating an estimation value of the BOD by the first power regression formula; a second power regression formula creating section 29 creating a second power regression formula which takes a ratio of the measurement value of the BOD to the estimation value of the BOD and the measurement value of the concentration of the DO as each coordinate; and an estimation formula creating section 30 creating a BOD estimation formula for calculating the estimation value of the BOD by both the formulas. COPYRIGHT: (C)2010,JPO&INPIT