Interdependence of hydraulic and physico-chemical phenomena in water and sewage treatment systems

Interdependence between hydraulic and technological phenomena is observed in every flow-through sewage treatment system, as well as tanks and other units in water treatment systems. Flow conditions in sewage treatment plants settling tanks come down to keep velocity and turbulence parameters adequate as a type of suspended matter. Uniformity of flow distribution affects sedimentation effectiveness which results in the capacity of a unit, hence the ability to determine and shape flow distribution constitutes a basic skill for any practical operation. In biological units, particularly in activated sludge chambers, the relationship between hydraulic phenomena and technological effectiveness is much more complex than in settling tanks. In these chambers it is necessary to ensure:full intermixing of sewage and activated sludge, an adequate range of velocities, homogeneity of oxygen and biomass concentrations, proper reaction time. Uniform velocity distribution in rectangular chambers of units (biological chamber in sewage treatment plant; sedimentation and flocculation facilities; fresh, sour and bath water tanks; accelerators), as well as equal turbulence, could eliminate sludge banks, hydraulic clasps and penetrations. This ensures taking technological advantage of chamber capacity completely. Hydraulic resistance is minimized, which reduces energy consumption during the operating process. Velocity distribution, homogeneity of mixture in a reactor as well as its hydraulic effectiveness characterize the level of taking advantage of project capacity for a given water or sewage treatment technology. These parameters are interdependent and very closely related, hence, searching for the most efficient solutions for chambers and channels, as well as mixing systems should be supported by detailed knowledge as to hydraulic behaviour of the investigated plants and facilities