DISPERSED COMPOSITION OF INSOLUBLE CONTAMINANTS OF MUNICIPAL WASTEWATER

Abstract

The properties and characteristics of individual particles play an important role in wastewater treatment processes. The specificsurface area, density, shape, size and degree of agglomeration of particles determine the sedimentation properties of the suspension. Today, there are many methods for determining particle sizes: methods of group analysis of particles, methods of individual particle counting and methods of particle size separation. All of them allow us to estimate their size based on one of the properties of the particles, for example, the ability to scatter or block a laser beam, change the electrical resistance of the hole when passing through it, settle under the action of gravity or centrifugal forces, scatter an acoustic signal, etc. Group analysis methods include small-angle laser light scattering methods, correlation photon spectroscopy, backscatter spectroscopy, and others. The following devices are used to count particles: an electric field counter, a light counter, a particle transit time counter, a microscope (optical or electronic). Separation methods include filtration through porous membranes, gravitational  sedimentation, disk centrifuges, capillary hydrodynamic fractionation, field sedimentation from the flow, and others. To determine the dispersed composition in this work, it was decided to combine a digital USB microscope with subsequent processing of the obtained images on a computer. This method is quite simple to perform, allows you to determine not only the size of the particles, but also to estimate their shape and has a fairly large measurement range. In this work, the dispersed composition of the suspension of untreated urban wastewater at the entrance to urban treatment plants and at the entrance and exit from primary sedimentation tanks was determined. The relationship between the concentration of suspended solids and the median diameter of wastewater particles and the  logarithm of their standard deviation was studied.