During removal of suspension in course of water and wastewater treatment processes the crucial role is played by properties and features of individual parti-cles. Such parameters as specific surface area, shape, size and compaction of sus-pension particles may decide on their settling and sorptive properties. The results of grain size analysis, obtained by means of laser granulometer, give information about structure and size of particles that form suspension.
In this paper the original results of suspension's grain size analysis con-ducted on municipal wastes originating from mechanical-biological wastewater treatment plants and on filter backwash water taken from iron and manganese re-moval filters on groundwater treatment plants are presented.
The modified form of Avrami equation was used in order to describe grain size results and to identify the process of suspension's formation.