Study On The Multistage High-speed Fine Filtration Performance Of Ceramics Media

Filtration is one of the key techniques for water treatment. The main goal of continuously research and improvement to the filtration technique is to achieve the ideal filter bed, which in order to overcome most of the problems of the traditional quick filter tank single-stage downstream filtration. This paper, on the base of analysis of reviewing systematically the development of filtration and media filter, has proposed a new concept of filtration-multistage high-speed fine filtration.In "multistage high-speed fine filtration", the filter is divided into several independent but connectivity grills. Different sizes of uniform ceramics filters are separately set into every grill. Each grill has individual backwash system. The size of filter material in every grill should be homogeneous, but the average size of the whole filter should be decrease gradually. This filter has integral interception-capacity, and enormous filter deposits, little hydraulic pressure loss, high filter velocity. Every stage filters act as fine filtration. The application of ceramics filter, with higher porosity, bigger specific area and better adsorptive capacity, in multistage high-speed fine filtration make the filter more advantages. This paper, with emphasis, makes a preliminary experiment research and theory analysis for the feasibility and performance of the two-stage high-speed fine filtration of ceramics media (two-stage filtration for short).Some post model experiments on ceramics media(finer: 1.2～1.4mm, K₈₀= 1.17; coarser: d=0.8～1.2mm, K₈₀=1.30) have been done in lab and confirm the optimal operational factors, then the filter was tested under the different influencing factors in order to study its performance.The test experiments of removing suspended matters from raw water and the law of filter deposits have been done firstly. The conclusion is that the two-stage filtration has better performance, higher deposits and filter velocity. The effluent turbidity is below 0.5NTU. The conclusion also indicated that the filter's L/d has powerful effect to the performance. Every stage filter's L/d should greater than 300 to meet the effluent turbidity standard. The higher filter velocity is, the deeper breakthrough depth is. So the effluent quality goes worse. The velocity is between 15～20m/h under...