Study On A New Type Of Continuous Filtration Device Properties With Particle-moving Bed

As an important natural resources on the earth,Water resources is an important and indispensable material basis for human survival and development.The growing water scarcities at the global scale and the volume of wastewater effluents from industrial sites as well as from urban agglomerations are becoming of increasing environmental,economic and societal concern.Continuous filtration technology is generally used in advanced wastewater treatment,and it played as the gatekeeper for the sewage treatment process effluent.But the traditional continuous filtration device had a series of problem,such as high investment,high energy consumption and poor water quality after filtration.The research group developed a new type of continuous filtration device to meet the national conditions,which was provided with particle moving bed,gas stripping and gas-solid-liquid phase separation.And the equipment has many advantages,such as high space utilization,high degree of integration,anti-particle media distribution,stripping stable,a small proportion of the backwash water,no filter layer expansion and low power consumption.The settling properties of muddy water were investigated.Seven different groups graded filter got by screening experiments,the particle size ranges were 0.15mm～0.60mm,0.15mm～0.80mm,0.15mm～1.0mm,0.15 mm～1.25mm,0.355mm～1.0mm,0.5mm～1.25mm,0.8mm～2.0mm respectively.It was used to evaluate the influences of filter material gradation,working parameters of sand backwashing system,inlet flow rate and different filtering methods on the filtration characteristic.The anti-particle size distribution of filter bed and outlet water quality were investigated as well.The results show that different filter material gradation values had great effects on outlet water quality and the filtered water quality was best by 0.15mm-0.8mm and d10=0.27mm、k80=2.4quartz sand among them.Anti-particle size distribution could enhance the particle interception capacity of filter bed.When the renewing rate of filter layer reached 6.25 mm/min,the outlet water quality was improved.The filtered water quality of fixed bed was better than moving bed in short time,but the filter bed of moving bed could keep continually clean while the contamination of the fixed bed was more and more.The combination of continuous filtration and intermittent backwashing filtration can be optimized,and it can make use of the respective advantages of the fixed bed and moving bed.After an intermittent backwashing cycle,the filter bed was clean and consumption rate of backwashing water decreased to 5%.