Filtered operation method

Depending on the filter equipment used , the nature of the filter media and the nature of the material being processed , and the requirements for product collection , the filtering operation can be divided into two major types : intermittent and continuous . According to the way of providing filtration driving to force , there are gravity filtration , pressure filtration , vacuum filtration and centrifugal filtration , the purpose of which is to overcome the filtration resistance . Filtration is a water purification process that removes suspended solids , microorganisms , etc . from the water as it passes through the filter media . The filter tank is usually located after the sedimentation tank or clarifier . The purpose is to make the turbidity of the filtered water meet the requirements of the water quality standard . After the water is filtered , the residual bacteria and viruses lose the protective effect of suspended substances , thus creating conditions for disinfection after filtration . Therefore , in the purification of drinking water using surface water as a source of water , sedimentation or clarification can sometimes be omitted , but filtration is indispensable .
 (1 ) The principle of filtering water purification . 1 Screening action : When water passes through the filter media , particles larger than the pores of the Cartridge filter housing layer are trapped ; subsequently , the pores of the filter layer become smaller and smaller particles are also trapped . 2 Contact condensation : Fine flocs or desaturated particles that are not precipitated and removed are adsorbed due to contact with the filter media ; after adsorption of the filter by the filter material , its adsorption is further enhanced .
 (2 ) Water purification efficiency of filtration . Depending on the quality of incoming water , the size of the filter material , the thickness of the filter layer , the structure of the filter , the filtration rate and the management , etc . The filtration rate is the amount of water passing through the unit filter area per hour . The greater the filtration rate , the deeper the impurities penetrate through the filter . However , the excessive filtration rate affects the filtered water quality .
(3 ) Requirements for filter media . With sufficient mechanical strength , no deterioration of water quality , a certain degree of particle grading , and economical availability .
 (4 ) Common filter types . 1 Ordinary fast filter tank , the plane is square or round . When filtering , the influent water are drained by the drainage canal , then evenly distributed among / over the surfaceof the filter tank , then through the filter layer and the support layer ; finally by the filter tube system Collected and discharged through the clear water pipe . During sand washing , the clean water are flushed up and down through the filter tube system to make the sand layer expand and float , the sand numbers rub against each other , and the sludge is washed off ; the sewage flows from the water distribution and drainage channels to the distribution channel , and finally from the wash tank sewer . The fast filter tank is reliable in operation and can improve the quality of the effluent water by lowering the filtration rate ; 2 Double and triple filter media is to add a layer of smokeless media with larger particle size and smaller specific gravity on the quartz sand layer . Material , due to the anthracite porosity of the pores , so the mud faster filter capacity higher ; 3 siphon filter , valveless filter and mobile rinsing hood filter : The filter waters / watered purification principle of the same with the ordinary fast filter . Their common advantage is the reduction of valves and ease of operation and management ; however , the construction is complicated .