Experimental Study On Filtration Performance Parameters Of Glass Media In Micro Irrigation System

As a new type of environmental protection filter material,glass microsphere filter material has the characteristics of stable physical and chemical properties,wear resistance and smaller filtration head loss.It has been applied in water treatment industry abroad.Filter glass filter in micro irrigation equipment and the backwash principle like sand filter,with the interception ability,filter cleaning convenient,can remove the filter water effectively caused by organic impurities and inorganic impurities blocking of filter head,ensure the efficient operation of micro filtration equipment.Before the working principle of domestic and foreign scholars on the gravel filter made a lot of theoretical and experimental studies,compared with the traditional filter according to the glass sand filtration and backwashing filter performance,carry out performance filtration under different conditions of the glass microsphere filter with different particle size of the pilot study,provide a reference for setting reasonable filtration time the use of glass microsphere filter and filter in micro irrigation design in micro irrigation equipment and filter backwash frequency.First of all,a comparative experiment of filtration and backwash was carried out for three kinds of filter media:quartz sand,glass microsphere and crushed recycled glass.The change rule of three kinds of filter material's cleaning pressure drop with filtration rate was analyzed.The following research results are mainly obtained through the experiment:1.The glass filter and quartz sand filtration and backwashing performance comparison test are carried out,filter of quartz sand filter play a role interception height about filter column height of filter layer below 1/3,while the glass filter is 60% of the thickness of the filter layer play the interception effect,compared with quartz sand filter,with smaller head loss the thorough backwashing characteristics of long period running backwashing water more than quartz sand.2.The following conclusions are obtained by carrying out the comparison test of the filtration performance of three kinds of glass microsphere filter material.(1)For the glass microsphere filter particle diameter of 0.7 mm and 0.9 mm,when the mass fraction of muddy water filtration is 0.01%,initial filtration velocity has little effect on the filter effluent turbidity;when the mass fraction of muddy water filtration increases and the initial filtration speed is small,there are fluctuations in the filtered water turbidity tends to be stable,when the initial the filtration rate increases,the turbidity of filtered water decreases rapidly with time and tends to be stable,the effluent turbidity is small.For the glass microsphere filter media with a particle size of 1.13 mm,the average turbidity of filtered water depends on the initial filtration rate,and the average turbidity of filtered effluent is greater than that of the first two kinds of filter materials in a filtration period.(2)For the same particle size filter,the instantaneous flow rate decreases with the increase of the filtration time.For the same filter material,under the same initial filtration speed,the greater the mass fraction of filtered muddy water,the greater the reduction of filtration instantaneous flow in a filtration period.When the mass fraction of filtered muddy water is the same,under the same filtration speed,the instantaneous flow rate of filter particle with smaller particle size in the whole filtration period is the largest,and the instantaneous flow rate of filter particle with larger particle size in the whole filtration period is the smallest.In the same kind of filtration muddy water mass fraction under the same filtration velocity,particle filter instantaneous flow diameter of 0.7 mm and 0.9 mm filter in a filter cycle reduction increases with the increase of initial filtration velocity,and the particle size reduction of 1.13 mm glass microspheres filter instantaneous flow within a filtration cycle decreases with the increase of initial filtration rate.(3)For the glass microsphere filter with particle size of 0.7 mm and 0.9 mm,under the same initial filtration rate,the pressure difference between the inlet and outlet of filter material increases with the increase of filtration and muddy water mass fraction.Under the condition of different filtration and muddy water mass fraction,when the initial filtration rate is small,the increase of pressure difference between the inlet and outlet of the glass microsphere filter material with particle size of 0.7 mm,0.9 mm and 1.13 mm decreases in sequence.For the glass microsphere filter with a particle size of 1.13 mm,the increase of the pressure difference between the inlet and outlet of the filter layer increases with the increase of initial filtration rate under the condition of the same filtration of muddy water mass fraction.