Reliable additives for boiler water, cooling circuits, membrane systems and waste water treatment in the pulp & paper industry

In modern paper machines, fillers such as calcium carbonate, kaolin or talc are used to improve whiteness, bulk and printability. These additives can account for up to 35% of the paper weight - which makes their retention economically crucial. Without suitable process additives, large quantities are lost with the white water, end up in the waste water or pollute circulation systems.

• Retention agents (e.g. cationic polymers or aluminum compounds) ensure that fillers and fibers are bound in the sheet formation process and retained in the screen.

• Flocculants support the formation of larger aggregates (macroflocs) that are stable enough not to be rinsed out again.

• This combination of additives works in a similar way to industrial wastewater treatment, where precipitants and flocculants are used to separate fine particles and dissolved substances.

Practical relevance:

• Increased retention reduces raw material consumption and saves costs.

• At the same time, process stability is improved as fewer fines enter the cycle.

• Wastewater treatment also benefits because lower solids loads are produced and the treatment stage is relieved.

Conclusion: Retention and flocculation agents are a key tool for achieving efficient stock utilization in the paper machine - with direct parallels to wastewater technology.

The paper industry works with large quantities of process and circulation water that are rich in organic substances (fibers, starch, lignin residues). These substances provide ideal conditions for bacteria, yeasts and algae. At the same time, air ingress and surfactants promote strong foaming. Both can massively disrupt production: Foam causes measurement errors and overflows, biofilms lead to deposits, odor, hole formation or stains in the paper.

• Defoamers break up stable foam immediately and prevent foam formation. They have a physical effect without impairing the paper quality.

• Biocides (oxidative and non-oxidative) control microbiological growth. A rotating biocide strategy is important here to prevent the development of resistance.

• In combination, both types of additive ensure that circuits remain free of slime, biofilms and unwanted foam.

Parallel to wastewater treatment:
Foam and biofilms are also typical problems in biological wastewater treatment plants or return sludge, which are solved with targeted additives. The experience gained from these applications flows directly into the process additives for the paper industry.

Practical benefits:

• Fewer unplanned shutdowns and cleanings

• Stable paper quality without stains and holes

• Lower microbiological load in the circuits, which also improves the wastewater values

Conclusion: With the right additive package, biofouling and foaming can be permanently controlled - for trouble-free production and consistent paper quality.

In addition to fibers, filler losses and starch, wastewater streams in the paper industry also contain organic residues (e.g. lignin, resins, pulping chemicals). Depending on the additives used, heavy metals such as aluminum, iron or traces of dye components may also occur. Without targeted treatment, it is not possible to comply with the strict limit values.

• Precipitants (e.g. iron or aluminum salts) react with dissolved ions and organic substances and convert them into insoluble, separable compounds.

• Flocculants (polymers) enlarge the resulting particles and facilitate their separation in sedimentation or flotation systems.

• pH regulation ensures that the additives work in the optimum effective range - similar to electroplating or the metal industry, where metals are specifically precipitated in the hydroxide range.

• For residues that are particularly difficult to break down, oxidative additives can also be used to break down dyes and lignin fragments.

Practical benefits for the paper industry:

• Reliable compliance with legal limits even during peak loads

• Reduced sludge volumes thanks to optimized precipitation and flocculation combinations

• Relief of biological stages and improved effluent quality

Conclusion: Wastewater treatment in the paper industry uses very similar process additives to industrial wastewater treatment - with the difference that the high organic load and fiber residues pose a particular challenge here.

Background
In pulp production, bleaching is a key step in removing lignin residues and brightening the pulp. Typical oxidizing agents are chlorine dioxide, hydrogen peroxide, oxygen or peroxyacetic acid. This process is one of the biggest cost factors in a paper mill and has a direct impact on product quality and wastewater pollution.

Solution with process additives

• Chemical stabilizers prevent hydrogen peroxide or chlorine dioxide from decomposing prematurely. This prolongs the effectiveness and stabilizes the bleaching effect.

• pH regulators maintain the optimum environment: peroxide develops its maximum effect in the slightly alkaline range, chlorine dioxide in the slightly acidic environment. Additives help to reliably maintain these narrow windows.

• Oxidation enhancers (e.g. metal catalysts or Fenton-like systems) can increase efficiency so that fewer primary chemicals are required.

• Foam and slime control in the bleaching stages using defoamers and biocides avoids side problems that are often underestimated but lead to malfunctions.

Benefits for the paper industry

• Reduce chemical costs: Less consumption with the same or better effect.

• Constant degrees of whiteness even with changing wood quality.

• Relief for wastewater treatment, as fewer residual chemicals are introduced.

Background
Paper mills are among the largest industrial users of energy and water. They work with large quantities of cooling water and operate powerful steam boilers for process heat and drying. Problems caused by limescale deposits, corrosion and biofouling lead directly to energy losses, increased operating costs and production stoppages.

Solution with process additives

• Hardness stabilizers and dispersants bind calcium and magnesium ions and prevent the formation of limescale and salt deposits in cooling water and boiler systems.

• Corrosion inhibitors protect metallic surfaces (steel, copper, aluminum) in pipelines, heat exchangers and pressure systems.

• Defoamers prevent foam cushions in the boiler water, which can lead to turbulent steam formation and mechanical problems.

• Biocides in cooling circuits reduce microbial growth (bacteria, algae, fungi) and prevent biofilms that block heat exchangers and accelerate corrosion processes.

Benefits for the paper industry

• Energy savings thanks to clean heat exchanger surfaces without insulation layers.

• Longer service life of boilers, cooling systems and paper machines thanks to protection against corrosion.

• Less downtime and predictable maintenance intervals.

• Reliable compliance with OEM specifications for water quality and additive compatibility.

Background
Paper mills consume enormous amounts of process heat and cooling capacity. Steam boilers generate the energy required for the drying process, while large cooling water systems keep paper machines and ancillary equipment stable. Deposits, corrosion and biofouling not only lead to high energy costs, but also to unplanned downtimes.

Solution with process additives

• Boiler water: Oxygen binders prevent corrosion processes, alkalizing agents stabilize the pH value in the steam space and condensate, hardness stabilizers reduce scale formation, and defoamers ensure trouble-free steam formation.

• Cooling water: Hardness stabilizers and dispersants prevent limescale and salt deposits, corrosion inhibitors protect pipes and heat exchangers, biocides inhibit microbial growth and prevent biofouling.

• Combination with monitoring: The effectiveness of the additives is continuously checked by online measurements (pH, conductivity, oxygen, corrosion rates) so that dosages can be precisely adjusted.

Benefits for the paper industry

• Energy efficiency: Clean heat exchanger surfaces and boiler-side linings save up to double-digit percentages of energy.

• System protection: Extended service life of boilers, pipes and cooling circuits.

• Operational safety: fewer unplanned shutdowns due to corrosion, scaling or biofouling.

• Legal compliance: Additives are OEM-compatible and matched to the water quality of the paper industry.