Abstract
The paper presents a study on the possibility of using the laser diffraction method for measuring the size of the activated sludge particles. Susceptibility of the particles to mechanical disintegration, dependent on the programmed value of stirring intensity, was observed (stirring was caused by required dynamic flow of analysed suspension through the measurement unit). According to the conclusions presented in this paper, it may be assumed that the laser diffraction method can be applied for measurement of activated sludge particle diameters under the following conditions: 1) the size of activated sludge particles measured by the laser diffraction method is not a real value, but after standardisation of measurement conditions can be treated as a parameter describing the sludge; 2) the particle diameters of activated sludge should be stabilised before the measurement, eg by mixing in the measurement unit or by ultrasound waves application.