EP 0784721 A1 19970723 - A METHOD FOR TREATING ACID AND ALKALINE WASTE STREAMS FROM A BLEACH PLANT SEPARATELY
Title (en)
A METHOD FOR TREATING ACID AND ALKALINE WASTE STREAMS FROM A BLEACH PLANT SEPARATELY
Title (de)
VERFAHREN ZUR GETRENNTEN BEHANDLUNG VON SÄUREN UND ALKALISCHEN ABFALLWASSER EINER BLEICHANLAGE
Title (fr)
PROCEDE DE TRAITEMENT SEPARE DES EAUX RESIDUAIRES ACIDES ET ALCALINES PROVENANT D'UNE INSTALLATION DE BLANCHIMENT
Publication
Application
Priority
- SE 9501121 W 19951003
- SE 9403372 A 19941005
- SE 9502169 A 19950614
- US 13995 P 19950612
- US 191495 P 19950620
Abstract (en)
[origin: WO9611299A1] Acid and alkaline waste water from a bleach plant comprise different amounts of inorganic and organic materials and have varying salts contents. If the acid and the alkaline waste water are mixed, it becomes more difficult to separate the different substances from the process flow in a subsequent treatment and it also results in larger amounts of waste water, which is disadvantageous in methods where aiming at closing up the bleach plant. Also, problems arise due to the formation of incrustations on heat-transfer surfaces. This invention relates to an improved method for treating the process waste water from a bleach plant, where the acid and the alkaline process flow being separately concentrated in evaporators, whereupon the salt content of the acid process flow is reduced by electrodialysis and the alkaline process flow is combusted. This method enables the recirculated amount of water to be reduced and the problems regarding the processing equipment to be avoided, and also contributes to a higher degree of closing, even if the bleaching involves clorine dioxide (ECF).
IPC 1-7
IPC 8 full level
D21C 11/00 (2006.01); B01D 5/00 (2006.01); C02F 1/04 (2006.01); D21C 9/10 (2006.01)
IPC 8 main group level
D21C (2006.01)
CPC (source: EP)
B01D 5/009 (2013.01); C02F 1/048 (2013.01); D21C 9/1026 (2013.01); D21C 11/0028 (2013.01); D21C 11/0042 (2013.01)
Citation (search report)
See references of WO 9611299A1
Designated contracting state (EPC)
AT DE ES FR PT SE
DOCDB simple family (publication)
WO 9611299 A1 19960418; AU 3712195 A 19960502; BR 9509188 A 19971230; CA 2201117 A1 19960418; EP 0784721 A1 19970723; FI 971605 A0 19970416; FI 971605 A 19970416; JP H10506964 A 19980707; NO 971504 D0 19970403; NO 971504 L 19970403
DOCDB simple family (application)
SE 9501121 W 19951003; AU 3712195 A 19951003; BR 9509188 A 19951003; CA 2201117 A 19951003; EP 95934908 A 19951003; FI 971605 A 19970416; JP 51251596 A 19951003; NO 971504 A 19970403