Modelling the kinetics of sewage sludge dewatering using the dimensional analysis method

With the growth of the population, the development of industrial construction, and the acceleration of urbanization, the generation of wastewater increases annually. Accordingly, the amount of sewage sludge is also rising, including sewage sludge containing significant concentrations of heavy metals, pathogens, and bacteria. The high moisture content of municipal sewage sludge creates serious challenges for its safe disposal and further utilization. In the countries of the European Union, landfilling of sewage sludge is prohibited. Therefore, sewage sludge is no longer accumulated in sewage sludge drying beds, sewage sludge storage lagoons, or dumps, as is still practiced in our country. Consequently, there is a need to revise the existing sewage sludge management approach. Mathematical modeling of the kinetics of sewage sludge dewatering using the dimensional analysis method made it possible to obtain a functional relationship expressed in terms of dimensionless similarity numbers. These similarity numbers have a clear physical meaning as ratios of forces or as analogues of classical similarity criteria. The analogy with filtration theory was confirmed in the study of the compression–filtration properties of sewage sludge mixture from the Lviv municipal wastewater treatment plants.