Page 368 - Chemical Process Equipment - Selection and Design

11.7. APPLICATIONS AND PERFORMANCE OF EQUIPMENT

TABLE 11.16. Examples of Filter Press Performance for Dewatering of Wastes in Municipal, Potable Water
arid Industrial Effluents

Filtration Solids Cake U p
Type of Material Natura and level of conditioning cycle time feed Wtmt thidcnass Remarks
(Hrl WtnNt (%I (mm)
(%I
Fine waste slurry Polyelectrolytes 0.05-0.3 lblton 0.5-2 15-35 75-82 25-40 More than 80% below
Fro'thed tailings Polyelectrolytes 0.05-0.3 Iblton 1-2.5 15-35 73-80 25-40 240% mesh
Primary sewage sludge 5-25% lime with 5-15% copperas, 5-25% 3-7 4-7 40-55 25-32
lime and 34% ferric chloride 1.5-2 3-6 35-50 25-32
Digested sewage sludge or 1.2% ACH(A1203) 2-3
West treated slud~ge 1-2 12-15 50-70 32

Mixed sewage sludge Up to 3% aluminium chlorohydrata 3-6 up to 4 30-45 32 Proportion of surplus
including surplus (A9203 basic) actiw. sludge is 40%
activated or 30% lime with 30% copperas 2-4 up to 4 30-40 25 bsq weight
Or 34% FECI,
Paper Mill Humus sludge 1% ACH 8 0.5-1.5 30-45 25
Paper Mill pool effluent 10% lime, 10% copperas of 1% FECI 3 1-3 1-1.5 40-55 25
sludge
Pickling and plating sludge Up to 10% lime if required 1.5-3 2-3 30-45 25-32

Potable water treatment In some instances no conditioning is 3-8 Q.5-3 25-35 19-25
sludge required 0.2-1 5% polyelectrotyte (Fre-
quently it is possible to decant large
quantities of clarified water after
mnditioning and before filtration).
%sin8 sludge 1.5-3 10-25 60-70 20-25
Hydroxide sludge 1 mgll polyelectrolyte or 10% lime 1.5-3 0.5-1.5 35-45 25-32
Lead hydroxide sludge 0.5 45 80 32

(Edwards and Jones Ltd.).