Application of Cationic Polyacrylamide PRAESTOL 851

Cationic polyacrylamide PRAESTOL 851 is a high-performance water-soluble polymer designed for efficient solid–liquid separation in municipal wastewater treatment, industrial effluent treatment, sludge thickening and dewatering, pulp and paper production, food processing, and other industrial processes involving negatively charged suspended solids. With its optimized cationic charge density and high molecular weight, cationic polyacrylamide PRAESTOL 851 delivers excellent floc formation, rapid settling, strong floc structure, and superior water release.

Flocculation Mechanism

The flocculation performance of cationic polyacrylamide PRAESTOL 851 is based on a combination of charge neutralization and polymer bridging. Most suspended solids in wastewater systems—such as organic matter, biomass, clay, fibers, and colloidal particles—carry a negative surface charge. The positively charged polymer chains of cationic polyacrylamide PRAESTOL 851 adsorb onto these particles, neutralizing surface charges and reducing electrostatic repulsion.

At the same time, the long molecular chains create bridges between multiple particles, forming large, dense, and shear-resistant flocs. This dual mechanism significantly improves sedimentation, clarification, thickening, and dewatering efficiency, even under challenging hydraulic or solids-loading conditions.

Municipal Wastewater Treatment Applications

In municipal wastewater treatment plants, cationic polyacrylamide PRAESTOL 851 is widely used in:

• Primary sludge thickening

• Waste activated sludge (WAS) conditioning

• Mixed sludge dewatering

• Tertiary clarification

PRAESTOL 851 enhances floc strength and settling speed, improving the performance of gravity thickeners and clarifiers. During dewatering with belt filter presses, centrifuges, or screw presses, cationic polyacrylamide PRAESTOL 851 increases cake solids content and reduces filtrate turbidity. This leads to lower sludge volume, reduced disposal costs, and more stable plant operation.

Industrial Wastewater Treatment Applications

Cationic polyacrylamide PRAESTOL 851 is extensively applied in industrial wastewater treatment systems that contain high concentrations of organic or mixed solids. Typical industries include:

• Food and beverage processing

• Meat and poultry plants

• Dairy and starch production

• Chemical and pharmaceutical manufacturing

• Textile and dyeing operations

In these applications, PRAESTOL 851 effectively flocculates organic solids, biological sludge, and colloidal matter, enabling efficient separation by sedimentation or mechanical dewatering. It is frequently used in combination with inorganic coagulants such as ferric chloride, aluminum sulfate, or polyaluminum chloride to optimize overall clarification performance.

Sludge Thickening and Dewatering

One of the most important applications of cationic polyacrylamide PRAESTOL 851 is sludge thickening and dewatering. It is suitable for use with:

• Gravity belt thickeners

• Rotary drum thickeners

• Belt filter presses

• Decanter centrifuges

• Screw presses and filter presses

PRAESTOL 851 promotes rapid water release from sludge, producing firm, well-structured flocs that withstand shear forces during mechanical processing. Higher cake solids, clearer centrate or filtrate, and reduced polymer consumption are commonly achieved when dosing and mixing are properly optimized.

Pulp and Paper Industry Applications

In the pulp and paper industry, cationic polyacrylamide PRAESTOL 851 is used for:

• Biological sludge dewatering

• Fiber and fines recovery

• Clarification of paper machine whitewater

• Effluent treatment

The cationic nature of PRAESTOL 851 allows it to bind effectively with negatively charged cellulose fibers, fillers, and organic residues. This improves fiber retention, reduces solids loss, enhances water reuse, and lowers the environmental load of discharged effluent.

Food Processing and Organic Sludge Treatment

Cationic polyacrylamide PRAESTOL 851 is particularly effective for sludges with high organic content, such as those generated in food processing and fermentation industries. Organic sludges tend to retain water and are difficult to dewater. PRAESTOL 851 improves floc cohesion and drainage characteristics, resulting in better dewatering performance and reduced sludge handling costs.

Mining and Industrial Process Water

Although primarily used in organic-rich systems, cationic polyacrylamide PRAESTOL 851 can also be applied in certain mining and industrial process water circuits where suspended solids have a negative surface charge. It is sometimes used in clarification steps or as a co-flocculant with anionic polymers to improve floc structure and settling behavior.

Construction and Slurry Treatment

In construction and civil engineering projects, cationic polyacrylamide PRAESTOL 851 may be used for the treatment of tunneling, foundation, or drilling slurries that contain fine negatively charged particles. The polymer facilitates rapid solids separation, allowing treated water to be reused and reducing environmental discharge.

Compatibility and Process Integration

Cationic polyacrylamide PRAESTOL 851 is compatible with most commonly used coagulants, pH adjustment chemicals, and other flocculants. It can be applied as a standalone product or as part of a dual-polymer system. Optimal performance depends on correct dosing point, mixing intensity, and residence time. Over-mixing or excessive shear should be avoided to prevent floc breakage.

Dosage and Preparation

Typical dosage levels of cationic polyacrylamide PRAESTOL 851 range from 0.5 to 8 g/m³, depending on sludge type, solids concentration, and equipment used. The polymer is usually prepared as a 0.05–0.3% aqueous solution using clean water. Adequate hydration time and gentle agitation are essential to fully activate the polymer and ensure consistent performance.