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.

In some variations, OCC is screened, cleaned, deinked, and mechanically refined to generate cellulose nanofibrils. The OCC may be subjected to further chemical, physical, or thermal processing, prior to mechanical refining. For example, the OCC may be subjected to hot-water extraction, or fractionation with an acid catalyst, a solvent for lignin, and water. In certain embodiments to produce cellulose nanocrystals, OCC is exposed to AVAP® digestor conditions. The resulting pulp is optionally bleached and is mechanically refined to generate cellulose nanocrystals. In certain embodiments to produce cellulose nanofibrils, OCC is exposed to GreenBox+® digestor conditions. The resulting pulp is mechanically refined to generate cellulose nanofibrils. The site of a system to convert OCC to nanocellulose may be co-located with an existing OCC processing site. The nanocellulose line may be a bolt-on retrofit system to existing infrastructure. In other embodiments, a dedicated plant for converting OCC to nanocellulose is used.

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 for controlling the deposition of stickies in pulping and papermaking processes comprises adding to fibre pulp or stock an additive comprising an organo-modified siloxane comprising units of the formula: [R.sup.1.sub.aZ.sub.bSiO.sub.(4-a-b)/2].sub.n in which each R.sup.1 is independently selected from a hydrogen atom, an alkyl, aryl, alkenyl, aralkyl, alkaryl, alkoxy, alkanoyloxy, hydroxyl, ester or ether group, and each Z is independently selected from an alkyl group substituted with an amine, amide, carboxyl, ester, or epoxy group, or preferably at least one or more groups —R.sup.2—(OC.sub.pH.sub.2p).sub.q(OC.sub.rH.sub.2r).sub.S—R.sup.3; wherein n is an integer greater than 1; a and b are independently 0, 1, 2 or 3; R.sup.2 is an alkylene group or a direct bond; R.sup.3 is a group as defined for R.sup.1 or Z above; p and r are independently an integer from 1 to 6; q and s are independently 0 or an integer such that 1≦q+s≦400; and wherein each molecule of the organo-modified siloxane contains at least one group Z. The organo-modified siloxane is preferably a hydroxyl- or alkyl-endcapped linear polydimethylsiloxane, in which 5 to 18 mole percent of silicon atoms are substituted by Z groups of the formula —R.sup.2—(OC.sub.pH.sub.2p).sub.q(OC.sub.rH.sub.2r).sub.s—R.sup.3, in which p is 2, r is 3 and q and s are independently 10 to 20, R.sup.2 is an alkylene group having from 1 to 6 carbon atoms or a direct bond, and R.sup.3 is a hydrogen atom or a hydroxyl, alkoxy, ester or ether group.

The present invention discloses a method for detackifying organic contaminants in the process of pulping and papermaking and a composition used for the same. Specifically, the invention discloses that the water circulation system of pulping and papermaking process can be provided with non-ionic cellulose ether and cationic coagulant in lower amount, through which, the deposition of organic contaminants can be inhibited under the synergistic action of pre-coagulation and detackification.

The present invention discloses a method for detackifying organic contaminants in the process of pulping and papermaking and a composition used for the same. Specifically, the invention discloses that the water circulation system of pulping and papermaking process can be provided with non-ionic cellulose ether and cationic coagulant in lower amount, through which, the deposition of organic contaminants can be inhibited under the synergistic action of pre-coagulation and detackification.

Methods of fractionating lignocellulosic biomass using maleic acids are provided. Also provided are methods of forming lignin particles, furans, sugars, and/or lignocellulosic micro- and nanofibrils from the liquid and solid fractions produced by fractionation process. The fractionation can be carried out at low temperatures with short reaction times to carboxylate and dissolve lignin with a low degree of condensation.

Methods of fractionating lignocellulosic biomass using maleic acids are provided. Also provided are methods of forming lignin particles, furans, sugars, and/or lignocellulosic micro- and nanofibrils from the liquid and solid fractions produced by fractionation process. The fractionation can be carried out at low temperatures with short reaction times to carboxylate and dissolve lignin with a low degree of condensation.

The present disclosure provides compositions and methods for treating volatile fatty acids and bacteria capable of producing volatile fatty acids. The compositions can convert acid-producing bacteria environments to nitrate-reducing bacteria environments. The compositions and methods can lower the amount of acid-producing bacteria present in the environment and thereby reduce the amount of volatile fatty acids present in the environment. The control agent may also inhibit the growth of acid-producing bacteria and volatile fatty acid concentrations. The compositions and methods can be used with any aqueous industrial system.

A feedstock includes feedstock paper and non-paper material. The feedstock paper includes lignin and cellulose. A method includes cooking the feedstock in cooking liquor to dissolve at least a portion of the lignin from the feedstock paper and to at least partially dissolve the non-paper material in the cooking liquor, thereby yielding a cooked pulp. The method further includes washing the cooked pulp to yield washed pulp and spent cooking liquor, regenerating the spent cooking liquor to yield regenerated cooking liquor, and bleaching the washed pulp.