Study On Treatment Of Hardness Water Of Deep Well Through Ceramic Microfiltration

Alumina ceramic membrane is characteristic of thermal stability and highresistance to chemical attack. It is composed of single or multichannel tubular ceramicmembranes. It contains 1.5 to 6.5 millimeter(mm) diameter flow channels. Incomparison with organic membranes, Alumina ceramic membrane has excellentchemical and mechanical stability . Acid , caustic and active enzyme can be used asmembrane cleaning chemicals; backflushing is effective in cleaning off scalingagents. Deep well water from Sichuan province is characteristic of high hardness.Boiler piping and other system for recycling water can be scaled. Once it happens,energy consumtion increases and equipment service life shortens. In order to resolve this problem, this investigation provides a new way to utilizeAlumina ceramic membranes for water softening. Sodium carbonate and oxalic acid are selected to pretreat Sichuan deep wellwater. Through-flow filtration process is used to separate the hard water afterpretreatment. It is shown that it is effective to soften the deep well water by using thetwo chemical agents for pretreatment. The appropriate operating parameters wereexperimentally determined. The flux of pretreated water can be greatly improved byselection of pore size , pressure difference and temperature. The permeating flux isenhanced with increasing pressure difference and temperature. The optimumoperation conditions for deep well water microfiltration are determined to be: poresize 1 μm, pressure difference 0.08MPa, temperature 50℃ ~ 65℃. The cleaning conditions for the membrane used in microfiltration of deep wellwater are also experimentally investigated. The flux can be recovered by usingultrasonic for several minutes or 0.5% hydrochloric acid. The results also show that pretreatment to ceramic membrane can improve thestability of permeat flux; the permeating flux can remain high in the condition ofultrasonic treatment. The mode of filtration process for microfiltration was established. Theobstruction and infiltration of filter which were counted by Darcy based filtrationequation were in contradiction with practice. Hence , the Darcy filtration equation isreplenished and revised in the present work. It is shown that the filtration obstructionconsists of obstruction of filtering material and obstruction of mud cake.