Study On The Re-flocculation Of Broken Flocs

Flocculation plays a very important role in the supply water treatment process. Generally speaking,coagulation process is consisted of two parts:rapid mixing and slow flocculation.In the actual water treatment process, the formation of floe breakage often occurred, which has many reasons, such as:water blocking effect of internal space structures, the asymmetry of liquid field, excessive flow shear stress,and so on.The properties of flocs will change after broken, directly affecting the solid-liquid separation, thereby affecting subsequent processing unit, resulting in deterioration of the water treatment. Generally speaking, floc breakage and floc growth happen in the same time to obtain a dynamic balance. Therefore, it becomes a new research area to investigate the process and mechanism of floc growth, breakage and re-growth.This paper describes the coagulation system and the coagulation mechanism on the basis of morphology, the PAC (PAC) as a flocculant, suspended particles of clay in water to remove the object, through high-pixel digital camera for the constant motion of the floc body particles shooting, study the different turbidity raw water, different dosage, flocculation growth under different hydraulic conditions-broken-and then flocculation process, the average particle size and fractal dimension of variation. Comparative analysis of floc break before and after water turbidity and floc own characteristics, from the perspective of macro-and micro coagulation process, to explore the reasons for floc break to find the broken floc maximum recovery measures, designed to study floc growth, fragmentation and re-flocculation mechanism, the actual optimization of flocculation in water treatment to provide a valid reference.The results show that, at low dosage, the electrical and mechanism plays a major role in, broken floc can fully recover the higher dosage, the network rolls sweep mechanism plays a major role, broken floc can not be completely recovery; Broken flocs exert some slow mixing, flocculation experience a certain degree of recovery; PAM can increase the dosage again broken floc flocculation ability, high turbidity water is especially effective; Dosing clay, can effectively improve the low turbidity raw water and then broken floc flocculation ability; effect of pH on the flocculation process is significantly,, the best results occur at pH=7and8.