METHOD FOR PURIFYING PROCESS WATER FROM PULP MANUFACTURE

摘要

Process water from pulp manufacture (2) is purified in a separator device (7) by mechanical or a combination of mechanical and chemical methods and is thereafter evaporated (3), at least palt of the concentrate resulting from the evaporation being recycled (4) and mixed with the process water fed into the separator device (7). In a preferred embodiment, a precipitant (5) is added to the mixed water comprising the process water and the concentrate. The part of the concentrate not recycled and mixed with the process water (11) is supplied, optionally after further evaporation, with an acid (13) to a pH of 1-5, whereupon resulting flocs and precipitates are removed in a separator device (12).