A method is disclosed for treating aqueous feed by dissolved gas flotation. The aqueous feed originates from industrial processing of fibrous material, where the aqueous feed includes an aqueous phase and solid particulate material suspended in the aqueous phase. The method includes bringing a flocculant in contact with the aqueous feed, flocculating suspended solid particulate material into flocs and contacting formed flocs with gas bubbles and inducing their flotation in a flotation basin. The flocculant includes a polymer composition having a charge density of at the most 1.7 meq/g dry and the polymer composition includes a cationic synthetic first polymer having a charge density at least 1.0 meq/g dry at pH 2.8, and at least one second polymer obtained by polymerization of (meth)acrylamide, the second polymer being polymerized in presence of the cationic first polymer, where the first polymer has a higher charge density than the second polymer.

An apparatus for dispersing or refining organic material includes a rotor shaft extending along a rotation axis, a rotor to be driven to rotate by the rotation axis, and a housing arranged around the rotor shaft and the rotor, the housing having an inlet for receiving the organic material and an outer wall. The housing has a stator disc, and the rotor has a rotor disc, each disc having teeth on a surface that is turned toward the other disc. After organic material has been dispersed by the teeth, the organic material is fed into a dilution zone where the organic material is mixed with dilution liquid introduced through a number of dilution inlets before the mix is fed out of the apparatus via an outlet arranged in the outer wall. The dilution inlets are angled in relation to the radial of the rotation axis, in a plane perpendicular to the rotation axis. By angling the dilution inlets in such a way, a better mix is achieved between dilution liquid and dispersed or refined organic material, which results in increased energy efficiency of the apparatus.

An apparatus for dispersing or refining organic material includes a rotor shaft extending along a rotation axis, a rotor to be driven to rotate by the rotation axis, and a housing arranged around the rotor shaft and the rotor, the housing having an inlet for receiving the organic material and an outer wall. The housing has a stator disc, and the rotor has a rotor disc, each disc having teeth on a surface that is turned toward the other disc. After organic material has been dispersed by the teeth, the organic material is fed into a dilution zone where the organic material is mixed with dilution liquid introduced through a number of dilution inlets before the mix is fed out of the apparatus via an outlet arranged in the outer wall. The dilution inlets are angled in relation to the radial of the rotation axis, in a plane perpendicular to the rotation axis. By angling the dilution inlets in such a way, a better mix is achieved between dilution liquid and dispersed or refined organic material, which results in increased energy efficiency of the apparatus.

This specification describes a system and process for treating waste, for example municipal solid waste (MSW) or post-recycling municipal solid waste. The system includes a press and a pulper. The press is adapted to provide a wet fraction of the waste suitable for anaerobic digestion and rejects. The pulper is adapted to receive the rejects and produce pulp. The pulper may be, for example, a drum pulper. In the process, waste is separated into a press into an organic fraction and rejects. The organic fraction is treated by way of anaerobic digestion. The rejects are separated, optionally in a drum pulper, to produce a fraction containing pulp. The pulp can be re-used to make paper or other products. In some case, 70% or more or 80% or more of MSW can be diverted from landfill.

This specification describes a system and process for treating waste, for example municipal solid waste (MSW) or post-recycling municipal solid waste. The system includes a press and a pulper. The press is adapted to provide a wet fraction of the waste suitable for anaerobic digestion and rejects. The pulper is adapted to receive the rejects and produce pulp. The pulper may be, for example, a drum pulper. In the process, waste is separated into a press into an organic fraction and rejects. The organic fraction is treated by way of anaerobic digestion. The rejects are separated, optionally in a drum pulper, to produce a fraction containing pulp. The pulp can be re-used to make paper or other products. In some case, 70% or more or 80% or more of MSW can be diverted from landfill.

A device and method for cleaning contaminated solid-liquid mixtures by removing impurities and contaminants from an aqueous paper fiber suspension by flotation. Apparatus includes a first conduit (2) for a liquid, a second conduit (3) for a solid-liquid mixture, a third conduit (4) connecting first and second conduit (2, 3), a Venturi mixing element (5) with cones (7, 11), having small through-opening into chamber (9) which forms a cavity with small through-opening (12, 13) of the cones; the through-opening of first cone (7) connected with first conduit (2) and the rough-opening connected to second conduit (2), the small through-opening (12) of first cone (7) and the non-conical conduit sections arranged in longitudinal axial alignment, a fourth conduit (6) for conveying gas, wherein the fourth conduit (6) opens to the Venturi mixing element (5), and a fractionator arranged downstream of the second conduit (3) for removing the foam produced by flotation.

The purpose of the present invention is to provide a recycled pulp fiber manufacturing method with which it is possible to easily obtain recycled pulp fibers containing less of a high water-absorption polymer without requiring any mechanical equipment such as an ozone generation apparatus. This method is for manufacturing recycled pulp fibers from used sanitary goods including pulp fibers and a high water-absorption polymer, and is characterized by comprising: an inactivation step (S1) for immersing a sanitary goods constituent material in an acid-containing aqueous solution so as to inactivate the high water-absorption polymer; a high water-absorption polymer degradation step (S3) for generating chlorine dioxide by adding a chlorine dioxide generating material, which is capable of generating chlorine dioxide through reaction with an acid, to the acid-containing aqueous solution that has undergone the inactivation step (S1), and then degrading the inactivated high water-absorption polymer using said chlorine dioxide; and a recycled pulp fiber recovery step (S4) for recovering the recycled pulp fibers from the acid-containing aqueous solution that has undergone the high water-absorption polymer degradation step (S3).

The purpose of the present invention is to provide a recycled pulp fiber manufacturing method with which it is possible to easily obtain recycled pulp fibers containing less of a high water-absorption polymer without requiring any mechanical equipment such as an ozone generation apparatus. This method is for manufacturing recycled pulp fibers from used sanitary goods including pulp fibers and a high water-absorption polymer, and is characterized by comprising: an inactivation step (S1) for immersing a sanitary goods constituent material in an acid-containing aqueous solution so as to inactivate the high water-absorption polymer; a high water-absorption polymer degradation step (S3) for generating chlorine dioxide by adding a chlorine dioxide generating material, which is capable of generating chlorine dioxide through reaction with an acid, to the acid-containing aqueous solution that has undergone the inactivation step (S1), and then degrading the inactivated high water-absorption polymer using said chlorine dioxide; and a recycled pulp fiber recovery step (S4) for recovering the recycled pulp fibers from the acid-containing aqueous solution that has undergone the high water-absorption polymer degradation step (S3).

A material supply device includes a supply section that supplies a small piece made of a material containing a fiber, a weight measurement section that detects a weight of the small piece supplied from the supply section to a receiving portion, and a supply amount adjustment section that adjusts a supply amount per unit time of the small piece supplied by the supply section, based on a detection result detected by the weight measurement section. The supply section has a storage portion that stores the small piece, an outlet that discharges the small piece from the storage portion, and a shutter that opens and closes the outlet.

A method is disclosed for predicting the microbial status of a paper or board making process and/or quality of the dry board or paper obtained from the process for controlling microbial status of a paper or board making process or quality of the dry board or paper obtained from the process. Surface level and duration of time in at least one storage tower or pulper are monitored and correlated with respective predetermined values for the tower or pulper in order to predict the risk of microbial activity.