The Effects Of V-filter During Simultaneous Air-water Backwashing In Bed Filtration

The V-filter for drinking water treatment, which mainly contains filtration andair-water backwashing two operation processes, has been widely used in our country.Air-water backwashing is the most important section to improve filtration performanceand water quality.Aiming at verify currently widely used air-water backwashing technology’s effecton filter layer after long-running and prove the basis for efficient filter backwashingtechnology’s application and development. The research systematic elaboratedair-water backwashing theory and its developing, analyzed changes in filterlayer structure and influence of air-water backwashing control parameters to actualwashing effect.Three aspects were discussed in research. Firstly, evaluated efficiency of air-waterbackwashing by measuring the clay content and the interception capacity of quartzsand particles. Secondly, analyzed the variation through measuring the ball diameterequal volume and the Wadell sphericity factor of particles. Thirdly, found the existenceof microorganisms in bed filtration through column experiments and measured thesurface microbiological of particles. Results of above three aspects comprehensivelyreflected the influence of air-water backwashing to filter layer configuration features inrunning filter. Actual detection discovered a phenomenon, that the most unfavorablefilter cleaning point of V-filter is located at a position below the surface of10cm~40cm, has significant importance for improving the current production of filterbackwashing efficiency. The recommendations that exchange the upper and lower parts of silica particlesafter air-water backwashing is proposed based on above conclusion. According to thisfiltration performance and water quality improved, the cycle life of quartz sandparticles extended, costs of whole filtration process decreased.