602
J. Bebin, P. Boulenger and J.C. Bourdelot
The respective estimated total costs of colour removal by either of these processes are
given for a modern factory with a 300 tons/day production of bleached Kraft pulp.
These calculations are based on a discharge of 13 m
3 per ton of pulp, for a sodation
effluent with the following characteristics:
pH = 10.2
colour = 3700 mg/Pt/1
COD = 2300 mg/1
Colour removal:
Aluminium sulphate 93%, Lime 88%
Reduction in COD:
Aluminium sulphate 77%, Lime 69.5%
From these figures it appears that the cost including depreciation of the alumina
process is very competitive with lime treatment and, moreover, it gives better
purification.
The breakdown of running and capital costs differs greatly. Chemicals, in one case,
account for 50% of the total cost, and nothing in the other. The cost of the lime process
is mainly due to energy consumption and equipment depreciation.
CONCLUSION
Colour removal of paper-pulp effluents with aluminium sulphate is competitive with
lime treatment. It gives efficient decoloration of the water. The pH of the effluent is then
low enough to allow direct polishing treatment on granular activated carbon to be carried
out and for further re-usal as make up water.
Most of the colour and the non-biodegradable COD can be removed by this treatment
applied separately to waste water from the bleaching section of a Kraft pulp factory; the
other wastes are amenable to efficient biological treatment and can be treated separately.
REFERENCES
1 LESZCZYNSKI, C.Z., "Usuwanie barwy sciekow posiarczanowych" - Przegl. Papiern
26, No. 7,221-227(1970).
2 National Council of the Paper Industry for Air and Stream Improvement - Tech. Bull.
No. 199 - N e w York (1967).
3 National Council of the Paper Industry for Air and Stream Improvement - Tech. Bull.
No. 203 - New York (1967).
4 National Council of the Paper Industry for Air and Stream Improvement - Tech. Bull.
No. 239 - N e w York (1970).
5 O'DONNELL, A.F. and KING, P.W., "The lime kiln in the Kraft recovery cycle" -
Appita 23, No. 6, 434-436 (1970).
6 THIRUMURTHI, D., McKENNA, G. and BOWN, H.G., "BOD and colour removal
from Kraft mill wastes" - Water & Sewage Works 116, No. 12, 491-494 (1969).
7 US Patent Nr. 3, 120,464(1964).
J. Bebin, P. Boulenger and J.C. Bourdelot
The respective estimated total costs of colour removal by either of these processes are
given for a modern factory with a 300 tons/day production of bleached Kraft pulp.
These calculations are based on a discharge of 13 m
3 per ton of pulp, for a sodation
effluent with the following characteristics:
pH = 10.2
colour = 3700 mg/Pt/1
COD = 2300 mg/1
Colour removal:
Aluminium sulphate 93%, Lime 88%
Reduction in COD:
Aluminium sulphate 77%, Lime 69.5%
From these figures it appears that the cost including depreciation of the alumina
process is very competitive with lime treatment and, moreover, it gives better
purification.
The breakdown of running and capital costs differs greatly. Chemicals, in one case,
account for 50% of the total cost, and nothing in the other. The cost of the lime process
is mainly due to energy consumption and equipment depreciation.
CONCLUSION
Colour removal of paper-pulp effluents with aluminium sulphate is competitive with
lime treatment. It gives efficient decoloration of the water. The pH of the effluent is then
low enough to allow direct polishing treatment on granular activated carbon to be carried
out and for further re-usal as make up water.
Most of the colour and the non-biodegradable COD can be removed by this treatment
applied separately to waste water from the bleaching section of a Kraft pulp factory; the
other wastes are amenable to efficient biological treatment and can be treated separately.
REFERENCES
1 LESZCZYNSKI, C.Z., "Usuwanie barwy sciekow posiarczanowych" - Przegl. Papiern
26, No. 7,221-227(1970).
2 National Council of the Paper Industry for Air and Stream Improvement - Tech. Bull.
No. 199 - N e w York (1967).
3 National Council of the Paper Industry for Air and Stream Improvement - Tech. Bull.
No. 203 - New York (1967).
4 National Council of the Paper Industry for Air and Stream Improvement - Tech. Bull.
No. 239 - N e w York (1970).
5 O'DONNELL, A.F. and KING, P.W., "The lime kiln in the Kraft recovery cycle" -
Appita 23, No. 6, 434-436 (1970).
6 THIRUMURTHI, D., McKENNA, G. and BOWN, H.G., "BOD and colour removal
from Kraft mill wastes" - Water & Sewage Works 116, No. 12, 491-494 (1969).
7 US Patent Nr. 3, 120,464(1964).