A method for producing an aqueous copolymer solution, which comprises dissolving a copolymer of (meth)acrylamide and at least 1 mol-% cationic monomers, calculated from total amount of monomers in the dissolving water having calcium hardness of at least mg/l, expressed as Ca.sup.2+, and adding acid comprising monoprotic organic acid and/or mineral acid to the dissolving water and/or the aqueous solution of the copolymer in an amount sufficient to provide the aqueous solution of the copolymer with a pH of equal to or less than 4.5. The invention also relates to uses of the obtained polymer solutions in manufacturing of paper, board or the like or in treatment of sludge or water.

Provided is a filtration system and process that enhances mineral removal from sludge through a novel recirculation and mixing apparatus. In one example, the system may include a filter configured to remove minerals from sludge, a pump configured to move the sludge towards the filter, a pre-filtering system configured to add an agent into the sludge prior to the sludge making contact with the filter, a drainage collection system including one ore more reservoirs configured to collect water drained during and/or after the filtering and feedback the drained water to the pump, and valving configured configured to mix the drained water with the sludge to generate a mixture which is moved by the pump towards the filter.

Provided is a filtration system and process that enhances mineral removal from sludge through a novel recirculation and mixing apparatus. In one example, the system may include a filter configured to remove minerals from sludge, a pump configured to move the sludge towards the filter, a pre-filtering system configured to add an agent into the sludge prior to the sludge making contact with the filter, a drainage collection system including one ore more reservoirs configured to collect water drained during and/or after the filtering and feedback the drained water to the pump, and valving configured configured to mix the drained water with the sludge to generate a mixture which is moved by the pump towards the filter.

Provided are: a sludge dehydrating agent which can exert a steady dehydrating effect on various types of sludge and has excellent dehydration performance; and a sludge dehydration method using the sludge dehydrating agent. The sludge dehydrating agent of the present invention with a polymer which has a constituent unit derived from a cationic monomer, wherein a value k determined from an intrinsic viscosity [η] 1 [dL/g] of a 1-mol/L aqueous sodium nitrate solution of the polymer at 30° C. and an intrinsic viscosity [η] 0.01 [dL/g] of a 0.01-mol/L aqueous sodium nitrate solution of the polymer at 30° C. in accordance with formula (I) is 0.8 to 2.2 exclusive.

k=([η]0.01−[η]1)/9   (I)

Provided are: a sludge dehydrating agent which can exert a steady dehydrating effect on various types of sludge and has excellent dehydration performance; and a sludge dehydration method using the sludge dehydrating agent. The sludge dehydrating agent of the present invention with a polymer which has a constituent unit derived from a cationic monomer, wherein a value k determined from an intrinsic viscosity [η] 1 [dL/g] of a 1-mol/L aqueous sodium nitrate solution of the polymer at 30° C. and an intrinsic viscosity [η] 0.01 [dL/g] of a 0.01-mol/L aqueous sodium nitrate solution of the polymer at 30° C. in accordance with formula (I) is 0.8 to 2.2 exclusive.

k=([η]0.01−[η]1)/9   (I)

In described embodiments, a method of processing sludge of a poultry plant into solids includes storing sludge in a tank where the sludge is a dissolved air floatation (DAF) float treated with Polymer Chemistry. A polymer is added to the sludge to produce a slurry that is separated into at least one liquid phase and solids in a horizontal decanter centrifuge having a weir ring. In conjunction with operating the centrifuge with a laminar flow, adjusted feed rate and polymer dosing, the system allows for production of low moisture solids (<50%) from the poultry plant DAF float and discharge of a clear liquid phase.

A process of dewatering oil sands/coal tailings includes generating nanobubble water, mixing a chemical dispersant into the nanobubble water to form a nanobubble-dispersant mixture, adding tailings to the nanobubble-dispersant mixture to form a nanobubble-dispersant-tailings mixture, and agitating the nanobubble-dispersant-tailings mixture to form an agitated nanobubble-dispersant-tailings mixture having a solid portion and a liquid portion. The solid portion is thereafter separated from the liquid portion. The agitation may be a centrifugal motion or shaking motion to agitate the nanobubble-dispersant-tailings mixture The chemical dispersant may be sodium hydroxide dispersant for asphaltenes and the volume of the tailings added may be substantially equal to the volume of the nanobubble water generated. An oil layer may further be skimmed off the liquid portion a polymer clarifier may also be added to the liquid portion. The process may be applied to achieve accelerated tailings processing for rapid and economic environmental remediation.

A porous biological polymerizing agent for sediment dewatering in environmental dredging of rivers and lakes is disclosed, which is obtained by thoroughly mixing 50 wt % to 70 wt % of an agent A and 30 wt % to 50 wt % of an agent B into irregular spheres of 1 mm to 3 mm, and crushing the irregular spheres into solid particles with a particle size of ≤20 mesh, and the solid particles have a pH of 5.0 to 6.0. The agent A is obtained by thoroughly mixing 10 wt % to 30 wt % of cellulose, 20 wt % to 50 wt % of starch, and 20 wt % to 40 wt % of amino acid; and the agent B is obtained by thoroughly mixing 40 wt % to 70 wt % of saccharifying enzyme (SE) and 30 wt % to 60 wt % of citric acid.

A porous biological polymerizing agent for sediment dewatering in environmental dredging of rivers and lakes is disclosed, which is obtained by thoroughly mixing 50 wt % to 70 wt % of an agent A and 30 wt % to 50 wt % of an agent B into irregular spheres of 1 mm to 3 mm, and crushing the irregular spheres into solid particles with a particle size of ≤20 mesh, and the solid particles have a pH of 5.0 to 6.0. The agent A is obtained by thoroughly mixing 10 wt % to 30 wt % of cellulose, 20 wt % to 50 wt % of starch, and 20 wt % to 40 wt % of amino acid; and the agent B is obtained by thoroughly mixing 40 wt % to 70 wt % of saccharifying enzyme (SE) and 30 wt % to 60 wt % of citric acid.

A drilling mud treatment unit (100) comprises a primary duct (10) for feeding coagulated drilling mud, an in-line flocculation system (20) for flocculating the coagulated drilling mud flowing in the primary duct (10), and at least one hydrocyclone (30) fed by the primary duct (10) and arranged downstream from the flocculation system (20). The hydrocyclone (30) has an overflow orifice (32) for receiving a liquid product resulting from treatment of the drilling mud and an underflow orifice (34) for receiving a solid product resulting from treatment of the drilling mud. The overflow orifice (32) presents an overflow diameter (Do) and the underflow orifice presents an underflow diameter (Du), and the underflow diameter (Du) is greater than 1.1 times the overflow diameter (Do).