The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 30, 2002
Filed:
Nov. 08, 1999
Patrick Bryant, Roswell, GA (US);
Jiri Basta, Partille, SE;
Akzo Nobel N.V., Arnhem, NL;
Abstract
The process according to the present invention relates to the treatment of wastewater discharged from a bleach plant and more particularly treatment of bleach plant alkaline wash filtrate from treatment-steps and/or delignification/bleaching-steps of pulp. Further improvements of known processes are needed for solving the problems associated with the recovery of alkaline filtrates into the chemical recovery system. According to the process of the present invention, alkaline wash filtrate from treatment-steps and/or delignification/bleaching-steps of pulp is treated in a process by the following steps: i) treating at least a part of the alkaline filtrate in order to produce an alkaline concentrate enriched in high molecular weight dissolved organic compounds and a stream depleted in organic compounds, where the share of the alkaline concentrate to the total amount of the alkaline filtrate corresponds to a volume reduction factor (VRP) in the range of from about 2.0 up to about 7.5; ii) withdrawing the depleted stream; iii) collecting at least a part of the alkaline concentrate from step i) and using the concentrate as wash or dilution water in brownstock washing fiberline with a dilution factor of up to about 4.0, where at least a part of the washing filtrate is brought to the chemical recovery system.