Abstract: Fibres which have an increased specific surface area and improved absorption properties, preferably intended for use in the form of fluff pulp in absorption articles such as diapers, incontinence guards, etc., in which the fibres present a porous layer of hydrophilic chemicals anchored on the fibre surface; a method of producing such fibres, their use in absorption articles and an absorption material which includes the fibres.

Abstract: The invention relates to a method of treating wastewater from the manufacture of peroxide bleached mechanical or chemi-mechanical pulp. The method comprises a hydrolysis step, a methane fermentation steps and an aerobic step. After the hydrolysis and methane fermentation steps, sludge is separated from the wastewater and partially recycled to the hydrolysis step. The redox potential of the outgoing water from the hydrolysis step is continuously measured and controlled to a value between -400 and -260 mV by regulating the amount of sludge recycled or by passing ingoing wastewater directly to the aerobic treating step.

Abstract: The invention relates to a method of treating wastewater from closed manufacture of mechanical or chemi-mechanical cellulose pulp, which treatment is carried out in a hydrolysis and acid fermentation step and a methane fermentation step with subsequent sludge separation and recycling of separated sludge.

Abstract: A method is disclosed for delignification of ligno-cellulose containing fiber material comprising mixing an oxygen-containing gas with the cellulose fiber material so as to atomize the gas and form a foam of the gas and the cellulose fiber material, and without an intervening oxidation step, subjecting the foam to upwardly flowing, substantially non-pressurized, alkali extraction. The alkali extraction step is conducted at a temperature of from about 40.degree. to about 80.degree. C. and at a pH, ligno cellulose containing fiber concentration and oxygen containing gas concentration sufficient to provide a bleached, delignified cellulose fiber without bleaching the lignin substance extracted from the material and to suppress lignin condensation reaction during the extraction.