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.

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.

There is provided a defoaming agent having excellent defoaming persistence. The defoaming agent includes; hydrophobic silica having a hydrophobicity (M.sub.X) of 50 to 85, and a rate of change (M.sub.Y/M.sub.X) of a hydrophobicity (M.sub.Y) after immersion for 1 hour in a methanol/ion-exchange aqueous solution (volume ratio of 80/20) of sodium hydroxide with a pH of 13 at 25° C. to the hydrophobicity (M.sub.X) of 0.8 to 1.0; and at least one kind of liquid selected from the group consisting of a hydrocarbon oil, a non-reactive silicone oil and a polyoxyalkylene compound.

There is provided a defoaming agent having excellent defoaming persistence. The defoaming agent includes; hydrophobic silica having a hydrophobicity (M.sub.X) of 50 to 85, and a rate of change (M.sub.Y/M.sub.X) of a hydrophobicity (M.sub.Y) after immersion for 1 hour in a methanol/ion-exchange aqueous solution (volume ratio of 80/20) of sodium hydroxide with a pH of 13 at 25° C. to the hydrophobicity (M.sub.X) of 0.8 to 1.0; and at least one kind of liquid selected from the group consisting of a hydrocarbon oil, a non-reactive silicone oil and a polyoxyalkylene compound.

Rapid and long lasting defoaming is accomplished by use of a defoamer formulation employing an organopolysiloxane having siloxy groups linked by an alkylene group, a filler, a silicone resin, a silanol-terminated organopolysiloxane, and an inorganic or organic acid.

Rapid and long lasting defoaming is accomplished by use of a defoamer formulation employing an organopolysiloxane having siloxy groups linked by an alkylene group, a filler, a silicone resin, a silanol-terminated organopolysiloxane, and an inorganic or organic acid.

Defoamer compositions which act rapidly and over an extended period of time employ organopolysiloxanes having alkylene linking groups bridging siloxy groups, a filler, a silicone resin, and phosphoric acid.

Defoamer compositions which act rapidly and over an extended period of time employ organopolysiloxanes having alkylene linking groups bridging siloxy groups, a filler, a silicone resin, and phosphoric acid.

Defoamer formulations with rapid knockdown and extended performance contain specific polyorganosiloxanes having alkylene linkages between siloxy groups, silicone resins, fillers, a polyoxyethylene surfactant, and an organic or inorganic acid.

Defoamer formulations with rapid knockdown and extended performance contain specific polyorganosiloxanes having alkylene linkages between siloxy groups, silicone resins, fillers, a polyoxyethylene surfactant, and an organic or inorganic acid.