The present invention pertains to the field of pulp or paper making. More specifically the present invention relates to a method of preventing a build-up of slime or removing slime from a surface contacted with water from a pulp or paper making process. The present invention can control slime in an efficient and environmentally friendly way.

The present invention pertains to the field of pulp or paper making. More specifically the present invention relates to a method of preventing a build-up of slime or removing slime from a surface contacted with water from a pulp or paper making process. The present invention can control slime in an efficient and environmentally friendly way.

A method includes forming an aqueous fibre suspension including cellulosic fibres from one or more raw material flows, and applying at least one chemical and/or physical control measure to the aqueous fibre suspension or at least one of its raw material flows for control of microbial activity in the aqueous fibre suspension or the raw material flow before an inlet of an intermediate residence entity. In this manner a starting ORP value for the aqueous fibre suspension is obtained. The aqueous fibre suspension is in the intermediate residence entity at least a minimum delay time. A final ORP value is measured for the aqueous fibre suspension after an outlet of the intermediate residence entity before the formation of the fibrous web. An ORP difference value between the starting ORP and final ORP values is calculated. Finally, the aqueous fibre suspension is formed into a fibrous web and dried.

A method includes forming an aqueous fibre suspension including cellulosic fibres from one or more raw material flows, and applying at least one chemical and/or physical control measure to the aqueous fibre suspension or at least one of its raw material flows for control of microbial activity in the aqueous fibre suspension or the raw material flow before an inlet of an intermediate residence entity. In this manner a starting ORP value for the aqueous fibre suspension is obtained. The aqueous fibre suspension is in the intermediate residence entity at least a minimum delay time. A final ORP value is measured for the aqueous fibre suspension after an outlet of the intermediate residence entity before the formation of the fibrous web. An ORP difference value between the starting ORP and final ORP values is calculated. Finally, the aqueous fibre suspension is formed into a fibrous web and dried.

A method for suppressing sedimentation of suspended substances ef the present invention is a method for suppressing sedimentation of suspended substances in water at the bottom of a tank disposed in a water system in papermaking equipment, comprising a step of blowing an oxygen-containing gas into the water, for stirring and aeration; a step of detecting a change with time in existence states of the suspended substances in the tank by the stirring and the aeration; and a control step of feeding at least one of an oxygen-containing gas and a slime control agent to the tank based on the detection result to suppress the sedimentation of the suspended substances in the tank.

A method for suppressing sedimentation of suspended substances ef the present invention is a method for suppressing sedimentation of suspended substances in water at the bottom of a tank disposed in a water system in papermaking equipment, comprising a step of blowing an oxygen-containing gas into the water, for stirring and aeration; a step of detecting a change with time in existence states of the suspended substances in the tank by the stirring and the aeration; and a control step of feeding at least one of an oxygen-containing gas and a slime control agent to the tank based on the detection result to suppress the sedimentation of the suspended substances in the tank.

Disclosed is a method for controlling a biofilm removing a formed biofilm and/or controlling a growth of microorganisms, preferably bacteria, in an aqueous environment of an industrial manufacturing process including a cellulosic fibre material. A compound according to Formula I is administered to the aqueous environment, in which Formula I R1, R2 and R3 independently represent a hydrogen atom; halogen atom; hydroxy group; amino group; alkylamino group, alkyl group, hydroxyalkyl group, haloalkyl group or alkoxy group having 1 to 4 carbon atoms; or an acylamido group having 1 to 10 carbon atoms; and A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; alkyl ester or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or —CHCHCONR5R6 group, where R5 and R6 represent independently hydrogen atom, alkyl or hydroxyalkyl having 1 to 4 carbon atoms, with the proviso that the compound according to Formula I is not 3-[(4-methylphenyl)sulphonyl]-2-propenenitrile or 4-amino-N-2-thiazolyl-benzenesulphonamide.

Disclosed is a method for controlling a biofilm removing a formed biofilm and/or controlling a growth of microorganisms, preferably bacteria, in an aqueous environment of an industrial manufacturing process including a cellulosic fibre material. A compound according to Formula I is administered to the aqueous environment, in which Formula I R1, R2 and R3 independently represent a hydrogen atom; halogen atom; hydroxy group; amino group; alkylamino group, alkyl group, hydroxyalkyl group, haloalkyl group or alkoxy group having 1 to 4 carbon atoms; or an acylamido group having 1 to 10 carbon atoms; and A represents 2-thiazolamine; 2-propenenitrile; 2-propenoic acid; alkyl ester or hydroxyalkyl ester of 2-propenoic acid having 1 to 4 carbon atoms; or —CHCHCONR5R6 group, where R5 and R6 represent independently hydrogen atom, alkyl or hydroxyalkyl having 1 to 4 carbon atoms, with the proviso that the compound according to Formula I is not 3-[(4-methylphenyl)sulphonyl]-2-propenenitrile or 4-amino-N-2-thiazolyl-benzenesulphonamide.

A method of controlling volatile fatty acid (VFA) content in a pulp, paper, and/or board making processes is disclosed. The method may be used to provide process improvements in the form of reduced microbial contamination and odor, reduced starch degradation, optimized retention, and improved runability. The method includes treating a process flow comprising a cellulosic material comprising a starch with a VFA control agent. The VFA control agent is non-biocidal, comprises a surfactant or dispersant, a chelator or sequestrant, or a combination thereof, is capable of inhibiting amylase activity in the process flow, and is utilized in an amount sufficient to inhibit microbiological production of one or more VFA. The method optionally includes treating the process flow with a biocidal agent in combination with the VFA control agent.

The present invention relates to microorganism control field in process for treatment of pulp and/or water in paper-making process. More specifically, the present invention provides a microorganism control system, which comprises a first component and a second component which are separately provided, the first component comprises a stabilized halogen-containing bactericidal agent (e.g., a stabilized hypochlorite), and the second component comprises an aminosulfonic acid reagent (e.g., aminosulfonic acid). The present invention further provides a method for controlling microorganism in process for treatment of pulp and/or water in papermaking process, which comprises using the microorganism control system of the present invention.