Page 138 - Membranes for Industrial Wastewater Recovery and Re-Use

112 Membranesfor Industrial Wastewater Recoverg and Re-use

Table 3.14 Characteristics of mechanical pulp (thermomechanical pulp, TMP, (Thornton,
1993)) and mechanical puIp mill water fractions: groundwood mill circulation water (Huu-
hilo et aJ., 2002) and plug screw feeder pressate from semi-chemical mechanical palp mill
(SCMP) (Dal-Cin et aJ., 1995)
Parameter Unit Groundwood mill SCMP mill Thermomechanical
circulation watera pressated pulpb
Average Range Plug screw DCSC DCSC
feeder pressate unbleached bleached
Temperature 63 50-70 60 60
PH 5.3 4.8-6.1 5.7
Conductivity 905 5100 700 5800
Cationic demand 100 3 60
Colour 364 222-5 5 5
Suspended solids 460 250-1300 1700
Dissolved solids 12 600
Soluble COD 1400 1100-1750
Total organic carbon 500 5670 214 288
Dissolved organic 510 300-750
carbon
Extracted UV280 nm 2.6 1.7-3.7
Lignin-like COD 220 150-320
Lignin + other 420 300-550
aromatics COD
Lignin soluble 2400
Lignin insoluble 1900
Sugar COD 300 190-540
Carbohydrates 2680 209 136
Lipophilic extractives 16 11-26 50 45
Resin and fatty acids 432
Neutral hydrophobics 37 20
Acidic hydrophobics 67 90
Lignans 63 42-80 23 6
Volatile acids 920
Acetic acid 10 200
Formic acid 1 35
CaZ+ 19 11-28
Cl- 6 4-9
SO2+ 246 153-395
a Analysed from mill samples
Analysed from supernatant resulting from pulp agitated in clean water (60'C) and centrifuged in
laboratory
DCS, dissolved and colloidal substances.

supplied by waste paper merchants (British Recovered Paper Association,
2002). For comparison, out of the 14.4 million tonnes of paper and board
manufactured in Finland in 2001,0.7 Mt of recovered fibre used as raw material
equates to 5%. However, 90% of the paper produced in Finland is exported and,
within Finland, around two-thirds of the paper and board used is recovered, i.e.
14 kg per capita per annum. The global average for paper and board recovery and
reuse is around 40% (Finnish Forest Industries Federation, 2002).