Research On Improvement Of Dissolved Air Flotation Process

The flotation process is a widely used and efficient processing in water treatment industry. The dissolved air flotation process is the most widely used and has best effect in the flotation process. The air saturator is an important equipment in pressurized dissolved air flotation process. The air saturator directly affects the dissolved gas efficiency and final solution air volume. At present the traditional air saturator is improved in many ways. Although these methods can improve the efficiency of dissolved air, they also have some limitations. These improved ways are not suitable for the full flow of dissolved air flotation process. In this paper, we design and research the new air saturator to improve the efficiency of the traditional air saturator. And to ensure that the new air saturator can be suitable for the full flow of pressurized dissolved air process.This paper can be divided into three parts. The first part of the paper is used to design and analysis the new air saturator. This part includes:the design concept of the new air saturator and the working principle of new air saturator; the detailed structure design of new air saturator; analysis of the new air saturator characteristic. The second part is to research and analysis of dynamic experiment of the new air saturator. This part includes:the research and analysis of the best structure of the new air saturator; the research and analysis of the contrary experiment between the new air saturator and other air saturator; the research and analysis of the best dosage of the new air saturator in turbidity removal experiment. For turbidity removal efficiency is different between low turbidity and high turbidity conditions in flotation process, the third part is the research and analysis of the flocs structure and flocs formation mechanism of the flotation process in different turbidity conditions.The experimental results show: the new air saturator improve the efficiency of dissolved air by increasing the contact area, prolonging the residence time, and reducing the thickness of Liquid film. The flotation process which use of the new air saturator has the better results than the flotation process which use of air saturator. Full-flow dissolved air flotation has better result than the reflux dissolved air flotation. In different turbidity conditions, flotation process has the differences in flocs structure and mechanism of the flocs formation. In the low turbidity the large/medium flocs have large volume and compact structure. And the medium/small flocs have small volume and loose structure. In the high turbidity the large/medium and medium/small flocs have large volume and compact structure. Therefore in high turbidity conditions it has better Treatment effect than in the low turbidity conditions.