Optimization of hydrodynamic treatment regime in the processes of sorption-flocculation water purification from organic contaminants

The impact of the hydrodynamic treatment on the flocculation process of various fine dispersed sorbents (modified clay minerals, aluminum hydroxide), utilized in the treatment procedures for water purification from dissolved and colloidal organic contaminants has been studied. It has been found that the optimum regime (mode) of hydrodynamic treatment is dependant on the type and disperse composition of contaminants and sorbent, as well as on the method of introducing the latter into the processed mixture. Measurements have been performed to determine the relation of flocculation efficiency versus the level of energy dissipation epsilon, and its corresponding average liquid velocity gradient G and their optimal values have been identified. It has been found that for studied sorbents the optimal regime of hydrodynamic treatment corresponds to conditions of generating developed turbulence, characterized by the values of epsilon = 5-18 J kg(-1).s(-1) (G = 2000-4000 s(-1)). It is shown that the increase in hydrodynamic treatment intensity results in decrease in the ratio liquid:solid in flocs. (C) 2000 Elsevier Science B.V. All rights reserved.