摘要:
A coagulation monitoring device monitoring a treatment state of water to be treated undergoing a coagulation treatment includes a laser light irradiating part irradiating laser light on a measurement region of the water to be treated, the laser light being emitted at at least predetermined time intervals and subjected to an amplitude modulation at a predetermined frequency; a scattered light receiving part receiving scattered light from particles of the water to be treated residing in the measurement region; a signal processing part extracting a measurement value indicative of an intensity of the scattered light, from light-reception signal obtained at the scattered light receiving part; and a measurement value arithmetic part continuously or discontinuously capturing m (m=2 or more) sets of plural measurement values, each set consisting of n (n=2 or more) measurement values, the measurement value arithmetic part extracting a plurality of measurement values in ascending order from a lower value for each set, the measurement value arithmetic part figuring out an average measurement value from a plurality of measurement values with a lowest value removed therefrom. This enables avoidance of influence of flocs generated in water to be treated during coagulation and ensures stable measurement of SS turbidity of water to be treated.