To provide a continuous method for delignifying and/or bleaching a raw or a recycled chemical paper pulp by which the amount of a discharged effulent is reduced and, on the other hand, good performances related to the delignifying and bleaching are maintained and further reduce the accumulation of an organic compound in a paper pulp suspension to be treated with a peroxide.

This continuous method is to delignify and/or bleach a raw or a recycled chemical paper pulp. The method comprises (a) preparing a paper pulp suspension, (b) carrying out the pretreatment of the prepared suspension with an enzyme and subsequently conducting a treatment with a peroxide, (c) collecting the treated paper pulp suspension, (d) separating at least a part of a liquid from the collected suspension and (e) recycling at least a part of the separated liquid and introducing the liquid into the stage (a) for preparing the paper pulp suspension.