Experimental Research On The Properties Of Flocs Sedimentation

Flocculation is a very important process in the drinking water treatment, of which the effect will put directly impact on the following processes.The effect of the floccu- lation lies on the sedimentation of the flocculation body.To realize the sedimentation performance, many parameters that are hardly known in usual must be mastered, such as the rate of interspace, the mass, the sedimentation rate and so on.In recently, the research of Flocculation get rapid program in the field of nonlinearity science. The research and development of the theory of fractal uncover order with out-of-order, and the unite of abcertain and randomicity, which makes it possible to explore the ruel of these compicated nonlinearity phenomenans. The sedimentation performance of the flocculation body could be exhibited intuitivily applied by the theory of fractal. The application of the theory of fractal in the research of Flocculation creat a new research point, which has become an hotspot.Used Kaolin solution as the treated water, poly aluminum ferric chloride (PAFC) and Polyalumin Chloude (PAC) as the flocculant, The thesis acquired the best dosage of PAFCC and PAC and the best arrange of pH value, made certain the remarkabe rela- -tivity between the fractal dimension of the flocculation and the turbidity of the water after deposition through the jar test with the different dosage and the different pH value.Take the flocculation body produced in the jar test , in which the dosage of the flocculant or the pH value of the liquid is the only changing parameter, as the researc- hed object, the fractal dimension is analyzed and the turbidity of the water after dep- osition is mensurated. The relation between the fractal dimension of the flocculation body/ the turbidity of the water after deposition and the dosage of the flocculant is pr- esentation. From the result of the test, a conclusion could be drawn that the best dosa- ge of PAFC is 7mg/l while PAC is 10mg/l. Whichever, the fractal dimension of the fl- occulation body keeps good linear relation with he turbidity of the water after deposi- tion, that is along with the dosage's increasing, the trend of the fractal dimension is increase first then decrease, the trend of the turbidity of the water after deposition in opposition to it.To find the order of coagulation factors significant in the effects of the floccula- tion, a orthogonal test was done in which 13 factors including the best pH value and the best dosage that is received in the above test is considered. The results showed that:â‘ the type of coagulant and the dosage of coagulant are the most important fac- tor that put impact of the rusult of the flocculation,â‘¡the best combination of the factors is : pH value is 5.8, the dosage of PAFC is 7mg / l, n₁ = 400 (r / min), t₁ = 60s, n₂ = 300 (r / min), t₂ = 10s, n₃ = 180 (r / min), t₃ = 200s, n₄ = 100 (r / min), t₄ = 180s, n₅ = 40 (r / min), t₅ = 240s.In the last of the thesis, the research of morphology of flocculation body with the theory of fractal was introduced. The character of the flocculation body were express- ed by the mathod of fractal, such as the mass, the cubage, the density, the porosity, the size, the strength and sedimentation rate. The formula deduced by theory method ap- proveds that the conclusion drew by the test was right. The mathematical model between the sedimentation rate and the fractal dimsion of the flocculation body accord ing to the best condition received from the test is: u = 0 .068×(3×10^-7×1300^df-1.56×10^-3×1.59^df)^1/3。...