Purificn. of esp. oil polluted water - by upflow through bed of elastically deformable particles regenerated with raw water

Process comprises adding a flocculant to the water which is then pumped through a filter bed to trap the flakes etc. Periodic compressed air turbulence and rinsing are used to regenerate the filter bed. The filter bed is composed of elastically-deformable particles through which rising water is filtered. The degree of filtration is adjusted by regulationg the speed of flow of water into the filter bed. This alters the compression exerted upon the elastically deformable particles and hence the pore size of the bed. The pollution of the prefiltrate and/or the purity of the filtrate are pref. monitored intermittently or continuously by automatic equipment. Regeneration of the filter bed comprises using unfiltered water from the filter chamber assisted by agitation of the bed particles with compressed air. Used for filtration of polluted water, esp. oil-polluted water, to give a standard of purity suitable for drinking.