Suspension formation and separation

The formation of suspension – aggregation – via coagulation and flocculation is a crucial process for the separation of colloidal particles during drinking water treatment. The properties of aggregates (size, shape, density, etc.) depend on physico-chemical parameters (e.g., the type and dose of a coagulant, pH, temperature) as well as on hydrodynamic conditions in a flocculation tank, namely the velocity gradient magnitude and distribution; the latter depend primarily on the tank shape and the stirrer type and speed. The properties of the aggregates (flocs) significantly affect their subsequent separation, hence are directly linked to the pollutant removal efficiency. Therefore, we focus our research on the chemical and mechanical aspects of aggregate formation, on their separability, and on the optimisation of agitation in the water treatment process in general. Special attention is paid to the identification of the pollutant properties having a strong influence on the aggregates characteristics and separability. To support our research, the development of new methods for aggregate characterisation is an integral part of our work.

Research Activities

  • Research on the effects of physico-chemical parameters (the type and dose of a coagulant, character and concentration of pollutants, pH, ACN5, temperature) on coagulation-flocculation
  • Characterisation of aggregates (in terms of their size, structure, porosity, shape, etc.) formed during the water treatment process
  • Research on the influence of hydrodynamic conditions (velocity gradient magnitude and distribution, and duration of its application) on the properties of aggregates formed in agitation tanks of various geometry
  • Research on the effects of aggregate properties on their separability via sand filtration and/or sedimentation
  • Modelling of aggregation kinetics
  • Optimisation of aggregation at lab-scale, at pilot-scale, and in practice
  • Design of equipment for the formation and separation of suspension in water treatment facilities