| With the increase of oily wastewater emissions in industries as petrochemical, ferrous metallurgy, mechanical recent years, plus with developments and applications of emulsifiers, components of oily wastewater became complex, and its treatment process increased. DAF(Pressurized dissolved-air flotation) possesses advantages as high efficiency and rate of recovery, large capacity of disposal, short HRT(hydraulic retention time). In the current China that supporting Clean production and energy saving background, the study on enhance DAF technology will bring reality significant influence in both theory and practice.0 # diesel was used to simulated oily wastewater in this paper. Several tipieal coagulants was examined. The process parameters of coagulation and DAF was optimized and flocs cocoagulation and flotation behavior of bubble and oil droplet was researched. With surfactants dispersion, different oil droplets and bubble size, effects of flotation oil removal was researched. The behavor of collision and adherence on oil droplet and bubble was characterized by high-speed camera, and its efficiency was discussed in order to increase flotation oil removal and provide oil-water separation regular pattern, which impetus the development of molecular separate science.Optimal technical parameters were obtained, and oily wastewater effluent turbidity removal the highest was 98.23%,98.76%of oil removal. And oil removal was 56.42% under DAF without coagulantion process.The research results indicates that 10mg/L SDBS emulsified oil droplets size was 22.33μm,59.90μm without SDBS. Oil droplets influence on DAF upon different size was showed that size could bring more variant on the removal of oil upon turbidity. And lOmg/L SDBS on dispersing bubble size was 115.6μm,176.51μm without SDBS, 107.95/180.6μm of sodium oleate. and that indicated sodium performed better than SDBS in dispersion. Compared with laser particle size analyzer, oil droplet characterization results(57.10/59.94μm) by high speed camera was verified and ensured in this paper.Characterization on oil droplet and bubble, with Dynamic track Analysis were studied, including velocity, acceleration, displacement. Bubble size with dynamic characteristics and flotation oil removal influences were investigated in this paper. According to the research, bubble size decreased properly could sharply increase the collision and adherence efficiency, and flotation oil removal could be enhanced by appropriate combination of oil droplet and bubble, and thus foster turbidity removal. Oil removal efficiency increased by the decrease size of bubble. |
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