Media Movement During Simultaneous Air-water Backwashing

Filter mainly included two processes of filtration and backwashing.Efficient backwash is not only the key to ensure treatment's effect,but also one of the core contents to save energy and reduct consumption by water purification plants. The Research elaborated systematicly about the development and theory of filter backwash. At the same time according to the relevant operating parameters and design-rules, the current problems of the widely used air-water backwashing was studied by research and actual production process,mainly considered about media loss.Based on the data from model filter backwashing experiment, the effecters from water and air-scour rates and media diameter to bubbles diameter were discussed. The results revealed that media rised when the bubbles diameter larger than 10mm. Bubbles size affect the heighte media can reach.Bubbles size also affect medias rising.Based on the data from the strain vector,get equation of relationship between water and air-scour rates and vertical height and media loss. The parameters can provide references to research in the future and the solution of media loss.