Prediction of filter cake resistance

Some Anomalies in Precoat Filter Operation and Their Effect on Filtration Performance Prediction

“…filtration for producing potable water (1) precoating the septum, (2) the filtration cycle, and (3) backwashing the septum. 12 Essentially, the BSM consisted of a 1-L capacity raw water tank, a 1-L precoat pot, and an acrylic filter assembly containing, a flat, 5-cm (2-in.) septum filter with an area of 20.2 cm2 (3.14 sq in.).…”

Constant‐Rate and Constant‐Pressure Filtration Look Similar—But Are They?

“…Other considerations that led to this particular design of the BSCPA are discussed else where. 10 i The data were plotted (t/V vs Vj and the specific resistance of the filter cake calculated as previously described.…”

“…Complete working drawings and description of the apparatus are included in Ref. 10. Essen tially the apparatus consists of 1-1 capacity raw-water tank, a precoat pot (also 1-1 capacity), a flat septum filter about 5 cm in diameter with arrangement to regulate and observe the flow rate using a rotameter* and to measure the head loss across the filter cake with a 64cm.…”

“…This has been discussed in great detail elsewhere. 10 It should be noted that Eq (1-3) are valid only for filtration through flat septa, where the filter-cake area remains constant during the run. For cylindrical septa, where the cake area enlarges, these equations have to be modified.…”

Comparison of Commercial Filter Aids

“…9 By and large, filter aids of both the diatomite and perlite families contain about 70-90 per cent silica and several other compounds in small proportions. 8 The purpose of this study was to compare the performance of some of the more commonly used filter aids, both diatomite and perlite, while filtering .laboratory-prepared, iron-bearing water under identical filtering conditions. These were Temperature = 16 C (60F) Precoat = 0.07 kg/m-(0.15 Ib/sq ft) of septa area Suspended solids concentration (Cs) = 8( ) mg/1 as Fe + * + Flow rate = 0.7 X 10-1 m/s (1 gpm/sq ft) of septa area…”