Experimental Study And Mechanism Analysis On The Water Purification Efficiency Of Co-Coagulation-DAF

After the diversion of water from the south to North Water Diversion, the water supply of the drinking water source is mixed with the local reservoir water. Blending water for the study, copolymerized Co-Coagulation-DAF technology, tested the effectiveness of the purification on dissolved organic matter, turbidity, algae and other pollutants, provide the basis for blending water purification technology. The main contents and findings in the following areas.(1) A test device for Co-Coagulation-DAF was designed. Co-Coagulation-DAF process consists of enhanced flocculation system, flotation systems, and dissolved air system. The treatment scale is 0.5m3/h. In the process soluble gas back flow is passed into the secondary flocculation pool, the bubble directly involved in the flocculation process, the micro bubbles with micro flocs formed at the same time, grow together, and become bubble-flocs, continue to react with the coagulant, and further growth.(2) The process parameters were determined by static test, and with the response surface method (RSM) on the operation parameters were analyzed and optimized, results in dosage 6mg/L, flocculation time of 6min, run a reflux ratio of 15% of the best running condition.(3) Co-Coagulation-DAF process was designed to treat the mixing water (1:1). Investigation for turbidity, particulate matter, organic matter removal efficiency and removal along the way, and compared with the conventional flotation process. Compared with the conventional flotation process, the Co-Coagulation-DAF process is superior to the conventional air floatation process, the test results show that the Co-Coagulation-DAF process of turbidity, particle, CODMn and UV254 removal rate respectively:93.92%,84.73%, 38.88%, and 44.29%. The removal rate of these four kinds of pollutants increased along the path. The removal rate of turbidity was 6.03% higher than that of conventional flotation process, the removal rate of CODMn was 2.61% higher than that of conventional flotation process, the removal rate of UV254 was 1.82% higher than that of conventional flotation process.(4) Tests showed that the process on the algae count removal rate was 93.43%; chlorophyll a removal rate was 73.87%, the MIB removal rate was 74.51%. Co-Coagulation-DAF process has better removal efficiency.(5) In this study, the adhesion mechanism of bubbles and particles, the shape of bubble-flocs, the fractal dimension of the bubble-flocs, and the fractal model of the aggregates are summarized. And using the Matlab software to simulate the DLA model of the fractal dimension. It is found that the release of particles through the diffusion to reach the flocculation group, in addition to the growth rate of the other groups are not the same. The probability of the growth of the tip of the flocculation Group is large and the growth rate is fast, the probability of the growth of the Group smooth part is small.