| In this paper,combined with the results of previous research,two light media of PVC plastic sheet and PE plastic ball are used to compare with the traditional quartz sand medium.The research focus is on the water head loss and sediment removal effect of the filter,and the experimental results of the three kinds of filters are compared and analyzed.The main results of the paper are as follows:The new light medium filter can effectively reduce the head loss of the filter.From the estimated mean value of the water head loss of the three filters,it can be seen that the quartz sand filter(1.335m)>the PVC plastic sheet filter(0.817m)> the PE pellet filter(0.739m).Moreover,the filter has a longer time to reach the clogging cycle,and the PVC medium filter has a clogging period point in about 30-45 minutes,while the quartz sand filter has a clogging period point in about 10-30 minutes.The operation period of the filtration system will be greatly prolonged by using light medium filter media,and the times of backwashing will be reduced obviously in the same operation time.In terms of sediment treatment capacity of filter,filtration flow rate is the main factor,and filter media type has the least influence.The difference of sediment treatment capacity of the three kinds of filters is not large.From the estimated mean value of sediment removal efficiency,the order of sediment treatment capacity is: quartz sand filter > PVC plastic sheet filter > PE ball filter.Generally speaking,the variability of the sediment removal rate of the filter is large,which needs further study.When backwashing,the time used for the light medium filter is less than the traditional quartz sand filter.The time of backwashing of PVC plastic sheet filter should not be less than 10 minutes.It is best to wash 20 minutes or so;the time of backwashing of quartz sand filter should not be less than 15 minutes,and the best effect is about 20 minutes washing.The cost of filter material for PVC slice and PE pellet is 3.54 times and 4.43 times that of quartz sand filter material respectively.When running an irrigation season,compared with the traditional quartz sand filter,the plastic media filter can save the backwash water fee of RMB 2016,and the total input and output ratio of the light media filter can reach 1.49 times.In summary,the PVC plastic media filter has good comprehensive benefits in many aspects,which can effectively reduce the water head loss of the filter system.The effect of sediment removal is similar to that of the traditional quartz sand filter.At the same time,the light filter media can be used to adapt to the low pressure working conditions and save the human and material needed in the backwashing process.It can reduce maintenance cost,save energy and economy,and meet the requirements of drip irrigation technology to low pressure and low energy consumption. |
