| The flocculation has a very important role in water treatment. The perfect degree in flocculation processes directly affect the treatment effect in the following treatment , such as sedimentation and filtration and so on. The theoretical basic about the flocculation was researched rather more in foreign countries. But in the forepassed research, the people all abstracted the colloid in the water as the sphericity and explained it by the known theory of the colloid chemistry. Moreover some people modified the result by the grain coefficient in the derivation of theory. But this assume had more difference on the observed phenomena in the experiment, so it was not perfect in theoretical speaking. Along with the science technology developing continuously and especially the computer technology getting perfect and popular, the request for the research and the application in flocculation processes improves. The flocculation morphology is an advanced subject that researchs flocculation processes from the reality shape and size of the colloid and the flocculating agent in the water, according to the reality structure of flocks.The fractal is a disciplinarian subject that describes many anomalous things in the mature. Generally the fractal is regarded as the aggregate state of the big and small fragments and the fractal is a general name to those without characteristic length, including the graphics , structure and phenomena .It is said that the fractal is a figure whose composed parts look like their whole by a certain mode. Two important characteristics of the fractal are self-similarity and dilation symmetry. The fractal dimension is a basic parameter thatdescribes the fractal quantificationally. The pullulation of floes is a random process and it has nonlinear character. If the fragmentation of floes is not considered , the routine flocculation process is to form the small group from initial particle and the big group from small groups. Finally the biggest group is formed from those big groups. In this way thick and big floes are formed. This process decides that floes have self-similarity and dilation symmetry in a certain extent, and they are two important characteristics of the fractal. So many scholars research the flocculation morphology based on the fractal theory.With the fractal theory and some sorts of kinetic growing model of fractal floes put forward by Written, Menkin and so on, this paper designs many static flocculation experiments to research the modal characteristic of the floc. And using the function relation between the projected area of floes and the maximum length to calculate fractal dimensions of floes formed in some different flocculation condition. Furthermore, with the model of flocculation kinetics put forward by Smoluchowski and basing on the assumed method of Coalesced Sphere (CS) founded anciently and using fractal theory, this paper puts forward the assumed method of Coalesced Fractal Sphere (CFS). Also this paper derives some basic formula describing characteristics of floes and some calculation formula with collision frequency function among fractal floes.At first, The water is put up by using the clay whose grain size is less than 76 um . By designing some static flocculation experiments duringdifferent flocculating agent and different flocculating condition, the modal characteristic of floes are observed in experimented process and microscope photo of floes are shot. Afterwards fractal dimensions of floes are calculated according to microscope photo of floes. The experimental result suggested that fractal dimensions of flocs are 1.31-2.38 during different flocculating condition when the flocculating agent is aluminum sulfate. While fractal dimensions of floes are 1.34-2.31 during different flocculating condition when the flocculating agents is polyaluminum chloride (PAC). Moreover, under the best added quantity condition (when the raw water is 170mg/L, the best added quantity of aluminum sulfate is 3.0mg/L and the best added quantity of PAC is 2.0mg/L),no matter...
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