Simulation of Coagulation, Flocculation, and Sedimentation

Abstract

The computer program ZB2 was used to study simulated coagulation, flocculation, and sedimentation. The effect of the initial velocity of soil particles on the values of reaction‐rate constants was investigated. In this respect, the results obtained with the program ZB2 corresponded to the theory and realities of coagulation carried out under practical conditions. The effect of coagulant excess/deficiency on the formation of the first floc and on the rate of coagulation of 50% of a soil was also estimated. An increase in simulated coagulant excess caused a decrease in the simulated rate of soil coagulation. In this respect, the results obtained with the program ZB2 did not correspond to the realities of coagulation carried out under practical conditions. An attempt was made to explain this inconsistency referring to the coagulation‐flocculation theory. The simulation program ZB2 may provide a basis for developing “local” programs simulating coagulation‐flocculation, which can be successfully applied at wastewater treatment plants.

Computer simulation of the polydispersive sol coagulation process

“…The applied simulation method is a stochastic and dynamic model (Smoczynski et al, 2009a) based on random variables, and its state changes over simulation time. The simulation program features a module solving the equation of motion of a given number of points (particles) in a closed vessel.…”

“…Coagulation, aggregation, flocculation and sedimentation processes are usually investigated in natural systems, such as wastewater (Smoczynski and Wardzynska, 1996) model systems including silica suspensions (Smoczynski, 2000; Lee et al, 2002; Hong et al, 2009) as well as computer‐simulated systems (Yang and Biswas, 1999; Evilevitch et al, 2002; Ratnaweera et al, 2002; Smoczynski et al, 2009a, b). Computer‐based simulations that account for short‐range attractive forces and long‐range repulsive forces (Romero‐Cano et al, 2000; Stradner et al, 2004; Richardi, 2009) in a pulsed system usually describe molecular collision models, the mechanism of latent, slow and rapid coagulation, the aggregation mechanism, as well as the conditions and the kinetic parameters of those processes (Elimelech et al, 1995; Ehrl et al, 2009; Kovalchuk et al, 2009; Siddique et al, 2009).…”

Study of Sludge Particles Formed during Coagulation of Synthetic and Municipal Wastewater for Increasing the Sludge Dewatering Efficiency

“…Filling the space with the mass of a sludge floc can be defined with the fractal dimension, D f , previously defined in Equation (2). There are more data available [19,29,[46][47][48] on the fractal dimension values of various types of flocs, including the values of D f in sludge of municipal wastewater. Depending on the measurement method applied, the type of a coagulant and other parameters of the process, the values of D f can be equal with the following values: 1.72 [19] [48].…”

“…Probably the most important effect of flocs on the structure of municipal wastewater sludge is through aggregation and agglomeration-flocculation (aaf ) processes [26][27][28][29]. Numerous papers have been published, including information about measurements, modeling and characterization of the structure of municipal wastewater sludge [30][31][32][33].…”

Destabilization Of Model Wastewater In The Chemical Coagulation Process

“…Coagulation, aggregation and flocculation lead to colloidal system destabilization [1]. Aluminum and iron(III) cations found in the most commonly applied inorganic coagulants [2][3][4][5][6], PAC (PACl) and PIX, are used for primary coagulation of negatively charged wastewater colloids.…”